[PATCH v2 0/4] eventfd: simplify signal helpers

[PATCH v2 0/4] eventfd: simplify signal helpers

[Christian Brauner]

Hey everyone,

This simplifies the eventfd_signal() and eventfd_signal_mask() helpers
significantly. They can be made void and not take any unnecessary
arguments.

I've added a few more simplifications based on Sean's suggestion.

Signed-off-by: Christian Brauner <brauner@kernel.org>

Changes in v2:
- further simplify helpers
- Link to v1: https://lore.kernel.org/r/20230713-vfs-eventfd-signal-v1-0-7fda6c5d212b@kernel.org

---



---
base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86
change-id: 20230713-vfs-eventfd-signal-0b0d167ad6ec

[PATCH v2 1/4] i915: make inject_virtual_interrupt() void

[Christian Brauner]

The single caller of inject_virtual_interrupt() ignores the return value
anyway. This allows us to simplify eventfd_signal() in follow-up
patches.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 drivers/gpu/drm/i915/gvt/interrupt.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/interrupt.c b/drivers/gpu/drm/i915/gvt/interrupt.c
index de3f5903d1a7..9665876b4b13 100644
--- a/drivers/gpu/drm/i915/gvt/interrupt.c
+++ b/drivers/gpu/drm/i915/gvt/interrupt.c
@@ -422,7 +422,7 @@ static void init_irq_map(struct intel_gvt_irq *irq)
 #define MSI_CAP_DATA(offset) (offset + 8)
 #define MSI_CAP_EN 0x1
 
-static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
+static void inject_virtual_interrupt(struct intel_vgpu *vgpu)
 {
 	unsigned long offset = vgpu->gvt->device_info.msi_cap_offset;
 	u16 control, data;
@@ -434,10 +434,10 @@ static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
 
 	/* Do not generate MSI if MSIEN is disabled */
 	if (!(control & MSI_CAP_EN))
-		return 0;
+		return;
 
 	if (WARN(control & GENMASK(15, 1), "only support one MSI format\n"))
-		return -EINVAL;
+		return;
 
 	trace_inject_msi(vgpu->id, addr, data);
 
@@ -451,10 +451,10 @@ static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
 	 * returned and don't inject interrupt into guest.
 	 */
 	if (!test_bit(INTEL_VGPU_STATUS_ATTACHED, vgpu->status))
-		return -ESRCH;
-	if (vgpu->msi_trigger && eventfd_signal(vgpu->msi_trigger, 1) != 1)
-		return -EFAULT;
-	return 0;
+		return;
+	if (!vgpu->msi_trigger)
+		return;
+	eventfd_signal(vgpu->msi_trigger, 1);
 }
 
 static void propagate_event(struct intel_gvt_irq *irq,

-- 
2.42.0

[PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Christian Brauner]

Ever since the evenfd type was introduced back in 2007 in commit
e1ad7468c77d ("signal/timer/event: eventfd core") the eventfd_signal()
function only ever passed 1 as a value for @n. There's no point in
keeping that additional argument.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 arch/x86/kvm/hyperv.c                     |  2 +-
 arch/x86/kvm/xen.c                        |  2 +-
 drivers/accel/habanalabs/common/device.c  |  2 +-
 drivers/fpga/dfl.c                        |  2 +-
 drivers/gpu/drm/drm_syncobj.c             |  6 +++---
 drivers/gpu/drm/i915/gvt/interrupt.c      |  2 +-
 drivers/infiniband/hw/mlx5/devx.c         |  2 +-
 drivers/misc/ocxl/file.c                  |  2 +-
 drivers/s390/cio/vfio_ccw_chp.c           |  2 +-
 drivers/s390/cio/vfio_ccw_drv.c           |  4 ++--
 drivers/s390/cio/vfio_ccw_ops.c           |  6 +++---
 drivers/s390/crypto/vfio_ap_ops.c         |  2 +-
 drivers/usb/gadget/function/f_fs.c        |  4 ++--
 drivers/vdpa/vdpa_user/vduse_dev.c        |  6 +++---
 drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c    |  2 +-
 drivers/vfio/pci/vfio_pci_core.c          |  6 +++---
 drivers/vfio/pci/vfio_pci_intrs.c         | 12 ++++++------
 drivers/vfio/platform/vfio_platform_irq.c |  4 ++--
 drivers/vhost/vdpa.c                      |  4 ++--
 drivers/vhost/vhost.c                     | 10 +++++-----
 drivers/vhost/vhost.h                     |  2 +-
 drivers/virt/acrn/ioeventfd.c             |  2 +-
 drivers/xen/privcmd.c                     |  2 +-
 fs/aio.c                                  |  2 +-
 fs/eventfd.c                              |  9 +++------
 include/linux/eventfd.h                   |  4 ++--
 mm/memcontrol.c                           | 10 +++++-----
 mm/vmpressure.c                           |  2 +-
 samples/vfio-mdev/mtty.c                  |  4 ++--
 virt/kvm/eventfd.c                        |  4 ++--
 30 files changed, 60 insertions(+), 63 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 238afd7335e4..4943f6b2bbee 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2388,7 +2388,7 @@ static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *h
 	if (!eventfd)
 		return HV_STATUS_INVALID_PORT_ID;
 
-	eventfd_signal(eventfd, 1);
+	eventfd_signal(eventfd);
 	return HV_STATUS_SUCCESS;
 }
 
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index e53fad915a62..523bb6df5ac9 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -2088,7 +2088,7 @@ static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
 		if (ret < 0 && ret != -ENOTCONN)
 			return false;
 	} else {
-		eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1);
+		eventfd_signal(evtchnfd->deliver.eventfd.ctx);
 	}
 
 	*r = 0;
diff --git a/drivers/accel/habanalabs/common/device.c b/drivers/accel/habanalabs/common/device.c
index 9711e8fc979d..3a89644f087c 100644
--- a/drivers/accel/habanalabs/common/device.c
+++ b/drivers/accel/habanalabs/common/device.c
@@ -2044,7 +2044,7 @@ static void hl_notifier_event_send(struct hl_notifier_event *notifier_event, u64
 	notifier_event->events_mask |= event_mask;
 
 	if (notifier_event->eventfd)
-		eventfd_signal(notifier_event->eventfd, 1);
+		eventfd_signal(notifier_event->eventfd);
 
 	mutex_unlock(&notifier_event->lock);
 }
diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index dd7a783d53b5..e73f88050f08 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -1872,7 +1872,7 @@ static irqreturn_t dfl_irq_handler(int irq, void *arg)
 {
 	struct eventfd_ctx *trigger = arg;
 
-	eventfd_signal(trigger, 1);
+	eventfd_signal(trigger);
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 01da6789d044..b9cc62982196 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -1365,7 +1365,7 @@ static void syncobj_eventfd_entry_fence_func(struct dma_fence *fence,
 	struct syncobj_eventfd_entry *entry =
 		container_of(cb, struct syncobj_eventfd_entry, fence_cb);
 
-	eventfd_signal(entry->ev_fd_ctx, 1);
+	eventfd_signal(entry->ev_fd_ctx);
 	syncobj_eventfd_entry_free(entry);
 }
 
@@ -1388,13 +1388,13 @@ syncobj_eventfd_entry_func(struct drm_syncobj *syncobj,
 	entry->fence = fence;
 
 	if (entry->flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE) {
-		eventfd_signal(entry->ev_fd_ctx, 1);
+		eventfd_signal(entry->ev_fd_ctx);
 		syncobj_eventfd_entry_free(entry);
 	} else {
 		ret = dma_fence_add_callback(fence, &entry->fence_cb,
 					     syncobj_eventfd_entry_fence_func);
 		if (ret == -ENOENT) {
-			eventfd_signal(entry->ev_fd_ctx, 1);
+			eventfd_signal(entry->ev_fd_ctx);
 			syncobj_eventfd_entry_free(entry);
 		}
 	}
diff --git a/drivers/gpu/drm/i915/gvt/interrupt.c b/drivers/gpu/drm/i915/gvt/interrupt.c
index 9665876b4b13..7f4db438e400 100644
--- a/drivers/gpu/drm/i915/gvt/interrupt.c
+++ b/drivers/gpu/drm/i915/gvt/interrupt.c
@@ -454,7 +454,7 @@ static void inject_virtual_interrupt(struct intel_vgpu *vgpu)
 		return;
 	if (!vgpu->msi_trigger)
 		return;
-	eventfd_signal(vgpu->msi_trigger, 1);
+	eventfd_signal(vgpu->msi_trigger);
 }
 
 static void propagate_event(struct intel_gvt_irq *irq,
diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
index 8ba53edf2311..869369cb5b5f 100644
--- a/drivers/infiniband/hw/mlx5/devx.c
+++ b/drivers/infiniband/hw/mlx5/devx.c
@@ -2498,7 +2498,7 @@ static void dispatch_event_fd(struct list_head *fd_list,
 
 	list_for_each_entry_rcu(item, fd_list, xa_list) {
 		if (item->eventfd)
-			eventfd_signal(item->eventfd, 1);
+			eventfd_signal(item->eventfd);
 		else
 			deliver_event(item, data);
 	}
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index ac69b7f361f5..7eb74711ac96 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -184,7 +184,7 @@ static irqreturn_t irq_handler(void *private)
 {
 	struct eventfd_ctx *ev_ctx = private;
 
-	eventfd_signal(ev_ctx, 1);
+	eventfd_signal(ev_ctx);
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/s390/cio/vfio_ccw_chp.c b/drivers/s390/cio/vfio_ccw_chp.c
index d3f3a611f95b..38c176cf6295 100644
--- a/drivers/s390/cio/vfio_ccw_chp.c
+++ b/drivers/s390/cio/vfio_ccw_chp.c
@@ -115,7 +115,7 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_ccw_private *private,
 
 	/* Notify the guest if more CRWs are on our queue */
 	if (!list_empty(&private->crw) && private->crw_trigger)
-		eventfd_signal(private->crw_trigger, 1);
+		eventfd_signal(private->crw_trigger);
 
 	return ret;
 }
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 43601816ea4e..bfb35cfce1ef 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -112,7 +112,7 @@ void vfio_ccw_sch_io_todo(struct work_struct *work)
 		private->state = VFIO_CCW_STATE_IDLE;
 
 	if (private->io_trigger)
-		eventfd_signal(private->io_trigger, 1);
+		eventfd_signal(private->io_trigger);
 }
 
 void vfio_ccw_crw_todo(struct work_struct *work)
@@ -122,7 +122,7 @@ void vfio_ccw_crw_todo(struct work_struct *work)
 	private = container_of(work, struct vfio_ccw_private, crw_work);
 
 	if (!list_empty(&private->crw) && private->crw_trigger)
-		eventfd_signal(private->crw_trigger, 1);
+		eventfd_signal(private->crw_trigger);
 }
 
 /*
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index cba4971618ff..ea532a8a4a0c 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -421,7 +421,7 @@ static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
 	case VFIO_IRQ_SET_DATA_NONE:
 	{
 		if (*ctx)
-			eventfd_signal(*ctx, 1);
+			eventfd_signal(*ctx);
 		return 0;
 	}
 	case VFIO_IRQ_SET_DATA_BOOL:
@@ -432,7 +432,7 @@ static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
 			return -EFAULT;
 
 		if (trigger && *ctx)
-			eventfd_signal(*ctx, 1);
+			eventfd_signal(*ctx);
 		return 0;
 	}
 	case VFIO_IRQ_SET_DATA_EVENTFD:
@@ -612,7 +612,7 @@ static void vfio_ccw_mdev_request(struct vfio_device *vdev, unsigned int count)
 					       "Relaying device request to user (#%u)\n",
 					       count);
 
-		eventfd_signal(private->req_trigger, 1);
+		eventfd_signal(private->req_trigger);
 	} else if (count == 0) {
 		dev_notice(dev,
 			   "No device request channel registered, blocked until released by user\n");
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 4db538a55192..542b5be73a6a 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1794,7 +1794,7 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
 					       "Relaying device request to user (#%u)\n",
 					       count);
 
-		eventfd_signal(matrix_mdev->req_trigger, 1);
+		eventfd_signal(matrix_mdev->req_trigger);
 	} else if (count == 0) {
 		dev_notice(dev,
 			   "No device request registered, blocked until released by user\n");
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index efe3e3b85769..fdd0fc7b8f25 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -831,7 +831,7 @@ static void ffs_user_copy_worker(struct work_struct *work)
 	io_data->kiocb->ki_complete(io_data->kiocb, ret);
 
 	if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
-		eventfd_signal(io_data->ffs->ffs_eventfd, 1);
+		eventfd_signal(io_data->ffs->ffs_eventfd);
 
 	if (io_data->read)
 		kfree(io_data->to_free);
@@ -2738,7 +2738,7 @@ static void __ffs_event_add(struct ffs_data *ffs,
 	ffs->ev.types[ffs->ev.count++] = type;
 	wake_up_locked(&ffs->ev.waitq);
 	if (ffs->ffs_eventfd)
-		eventfd_signal(ffs->ffs_eventfd, 1);
+		eventfd_signal(ffs->ffs_eventfd);
 }
 
 static void ffs_event_add(struct ffs_data *ffs,
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 0ddd4b8abecb..6cb5ce4a8b9a 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -493,7 +493,7 @@ static void vduse_vq_kick(struct vduse_virtqueue *vq)
 		goto unlock;
 
 	if (vq->kickfd)
-		eventfd_signal(vq->kickfd, 1);
+		eventfd_signal(vq->kickfd);
 	else
 		vq->kicked = true;
 unlock:
@@ -911,7 +911,7 @@ static int vduse_kickfd_setup(struct vduse_dev *dev,
 		eventfd_ctx_put(vq->kickfd);
 	vq->kickfd = ctx;
 	if (vq->ready && vq->kicked && vq->kickfd) {
-		eventfd_signal(vq->kickfd, 1);
+		eventfd_signal(vq->kickfd);
 		vq->kicked = false;
 	}
 	spin_unlock(&vq->kick_lock);
@@ -960,7 +960,7 @@ static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)
 
 	spin_lock_irq(&vq->irq_lock);
 	if (vq->ready && vq->cb.trigger) {
-		eventfd_signal(vq->cb.trigger, 1);
+		eventfd_signal(vq->cb.trigger);
 		signal = true;
 	}
 	spin_unlock_irq(&vq->irq_lock);
diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
index c51229fccbd6..d62fbfff20b8 100644
--- a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
+++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
@@ -54,7 +54,7 @@ static irqreturn_t vfio_fsl_mc_irq_handler(int irq_num, void *arg)
 {
 	struct vfio_fsl_mc_irq *mc_irq = (struct vfio_fsl_mc_irq *)arg;
 
-	eventfd_signal(mc_irq->trigger, 1);
+	eventfd_signal(mc_irq->trigger);
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 1929103ee59a..1cbc990d42e0 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -443,7 +443,7 @@ static int vfio_pci_core_runtime_resume(struct device *dev)
 	 */
 	down_write(&vdev->memory_lock);
 	if (vdev->pm_wake_eventfd_ctx) {
-		eventfd_signal(vdev->pm_wake_eventfd_ctx, 1);
+		eventfd_signal(vdev->pm_wake_eventfd_ctx);
 		__vfio_pci_runtime_pm_exit(vdev);
 	}
 	up_write(&vdev->memory_lock);
@@ -1883,7 +1883,7 @@ void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count)
 			pci_notice_ratelimited(pdev,
 				"Relaying device request to user (#%u)\n",
 				count);
-		eventfd_signal(vdev->req_trigger, 1);
+		eventfd_signal(vdev->req_trigger);
 	} else if (count == 0) {
 		pci_warn(pdev,
 			"No device request channel registered, blocked until released by user\n");
@@ -2302,7 +2302,7 @@ pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
 	mutex_lock(&vdev->igate);
 
 	if (vdev->err_trigger)
-		eventfd_signal(vdev->err_trigger, 1);
+		eventfd_signal(vdev->err_trigger);
 
 	mutex_unlock(&vdev->igate);
 
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index cbb4bcbfbf83..237beac83809 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -94,7 +94,7 @@ static void vfio_send_intx_eventfd(void *opaque, void *unused)
 		ctx = vfio_irq_ctx_get(vdev, 0);
 		if (WARN_ON_ONCE(!ctx))
 			return;
-		eventfd_signal(ctx->trigger, 1);
+		eventfd_signal(ctx->trigger);
 	}
 }
 
@@ -342,7 +342,7 @@ static irqreturn_t vfio_msihandler(int irq, void *arg)
 {
 	struct eventfd_ctx *trigger = arg;
 
-	eventfd_signal(trigger, 1);
+	eventfd_signal(trigger);
 	return IRQ_HANDLED;
 }
 
@@ -689,11 +689,11 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_core_device *vdev,
 		if (!ctx)
 			continue;
 		if (flags & VFIO_IRQ_SET_DATA_NONE) {
-			eventfd_signal(ctx->trigger, 1);
+			eventfd_signal(ctx->trigger);
 		} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 			uint8_t *bools = data;
 			if (bools[i - start])
-				eventfd_signal(ctx->trigger, 1);
+				eventfd_signal(ctx->trigger);
 		}
 	}
 	return 0;
@@ -707,7 +707,7 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
 	if (flags & VFIO_IRQ_SET_DATA_NONE) {
 		if (*ctx) {
 			if (count) {
-				eventfd_signal(*ctx, 1);
+				eventfd_signal(*ctx);
 			} else {
 				eventfd_ctx_put(*ctx);
 				*ctx = NULL;
@@ -722,7 +722,7 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
 
 		trigger = *(uint8_t *)data;
 		if (trigger && *ctx)
-			eventfd_signal(*ctx, 1);
+			eventfd_signal(*ctx);
 
 		return 0;
 	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index 665197caed89..61a1bfb68ac7 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -155,7 +155,7 @@ static irqreturn_t vfio_automasked_irq_handler(int irq, void *dev_id)
 	spin_unlock_irqrestore(&irq_ctx->lock, flags);
 
 	if (ret == IRQ_HANDLED)
-		eventfd_signal(irq_ctx->trigger, 1);
+		eventfd_signal(irq_ctx->trigger);
 
 	return ret;
 }
@@ -164,7 +164,7 @@ static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
 {
 	struct vfio_platform_irq *irq_ctx = dev_id;
 
-	eventfd_signal(irq_ctx->trigger, 1);
+	eventfd_signal(irq_ctx->trigger);
 
 	return IRQ_HANDLED;
 }
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 30df5c58db73..8d9f958946d6 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -178,7 +178,7 @@ static irqreturn_t vhost_vdpa_virtqueue_cb(void *private)
 	struct eventfd_ctx *call_ctx = vq->call_ctx.ctx;
 
 	if (call_ctx)
-		eventfd_signal(call_ctx, 1);
+		eventfd_signal(call_ctx);
 
 	return IRQ_HANDLED;
 }
@@ -189,7 +189,7 @@ static irqreturn_t vhost_vdpa_config_cb(void *private)
 	struct eventfd_ctx *config_ctx = v->config_ctx;
 
 	if (config_ctx)
-		eventfd_signal(config_ctx, 1);
+		eventfd_signal(config_ctx);
 
 	return IRQ_HANDLED;
 }
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e0c181ad17e3..045f666b4f12 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2248,7 +2248,7 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 		len -= l;
 		if (!len) {
 			if (vq->log_ctx)
-				eventfd_signal(vq->log_ctx, 1);
+				eventfd_signal(vq->log_ctx);
 			return 0;
 		}
 	}
@@ -2271,7 +2271,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
 		log_used(vq, (used - (void __user *)vq->used),
 			 sizeof vq->used->flags);
 		if (vq->log_ctx)
-			eventfd_signal(vq->log_ctx, 1);
+			eventfd_signal(vq->log_ctx);
 	}
 	return 0;
 }
@@ -2289,7 +2289,7 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq)
 		log_used(vq, (used - (void __user *)vq->used),
 			 sizeof *vhost_avail_event(vq));
 		if (vq->log_ctx)
-			eventfd_signal(vq->log_ctx, 1);
+			eventfd_signal(vq->log_ctx);
 	}
 	return 0;
 }
@@ -2715,7 +2715,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
 		log_used(vq, offsetof(struct vring_used, idx),
 			 sizeof vq->used->idx);
 		if (vq->log_ctx)
-			eventfd_signal(vq->log_ctx, 1);
+			eventfd_signal(vq->log_ctx);
 	}
 	return r;
 }
@@ -2763,7 +2763,7 @@ void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 {
 	/* Signal the Guest tell them we used something up. */
 	if (vq->call_ctx.ctx && vhost_notify(dev, vq))
-		eventfd_signal(vq->call_ctx.ctx, 1);
+		eventfd_signal(vq->call_ctx.ctx);
 }
 EXPORT_SYMBOL_GPL(vhost_signal);
 
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index f60d5f7bef94..9e942fcda5c3 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -249,7 +249,7 @@ void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
 #define vq_err(vq, fmt, ...) do {                                  \
 		pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 		if ((vq)->error_ctx)                               \
-				eventfd_signal((vq)->error_ctx, 1);\
+				eventfd_signal((vq)->error_ctx);\
 	} while (0)
 
 enum {
diff --git a/drivers/virt/acrn/ioeventfd.c b/drivers/virt/acrn/ioeventfd.c
index ac4037e9f947..4e845c6ca0b5 100644
--- a/drivers/virt/acrn/ioeventfd.c
+++ b/drivers/virt/acrn/ioeventfd.c
@@ -223,7 +223,7 @@ static int acrn_ioeventfd_handler(struct acrn_ioreq_client *client,
 	mutex_lock(&client->vm->ioeventfds_lock);
 	p = hsm_ioeventfd_match(client->vm, addr, val, size, req->type);
 	if (p)
-		eventfd_signal(p->eventfd, 1);
+		eventfd_signal(p->eventfd);
 	mutex_unlock(&client->vm->ioeventfds_lock);
 
 	return 0;
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 1ce7f3c7a950..7efc0c62e984 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -1147,7 +1147,7 @@ static irqreturn_t ioeventfd_interrupt(int irq, void *dev_id)
 		if (ioreq->addr == kioeventfd->addr + VIRTIO_MMIO_QUEUE_NOTIFY &&
 		    ioreq->size == kioeventfd->addr_len &&
 		    (ioreq->data & QUEUE_NOTIFY_VQ_MASK) == kioeventfd->vq) {
-			eventfd_signal(kioeventfd->eventfd, 1);
+			eventfd_signal(kioeventfd->eventfd);
 			state = STATE_IORESP_READY;
 			break;
 		}
diff --git a/fs/aio.c b/fs/aio.c
index f8589caef9c1..5c5b09e52d75 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1166,7 +1166,7 @@ static void aio_complete(struct aio_kiocb *iocb)
 	 * from IRQ context.
 	 */
 	if (iocb->ki_eventfd)
-		eventfd_signal(iocb->ki_eventfd, 1);
+		eventfd_signal(iocb->ki_eventfd);
 
 	/*
 	 * We have to order our ring_info tail store above and test
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 33a918f9566c..dc9e01053235 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -74,20 +74,17 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
 /**
  * eventfd_signal - Adds @n to the eventfd counter.
  * @ctx: [in] Pointer to the eventfd context.
- * @n: [in] Value of the counter to be added to the eventfd internal counter.
- *          The value cannot be negative.
  *
  * This function is supposed to be called by the kernel in paths that do not
  * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
  * value, and we signal this as overflow condition by returning a EPOLLERR
  * to poll(2).
  *
- * Returns the amount by which the counter was incremented.  This will be less
- * than @n if the counter has overflowed.
+ * Returns the amount by which the counter was incremented.
  */
-__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
+__u64 eventfd_signal(struct eventfd_ctx *ctx)
 {
-	return eventfd_signal_mask(ctx, n, 0);
+	return eventfd_signal_mask(ctx, 1, 0);
 }
 EXPORT_SYMBOL_GPL(eventfd_signal);
 
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
index b9d83652c097..562089431551 100644
--- a/include/linux/eventfd.h
+++ b/include/linux/eventfd.h
@@ -35,7 +35,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
 struct file *eventfd_fget(int fd);
 struct eventfd_ctx *eventfd_ctx_fdget(int fd);
 struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
-__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
+__u64 eventfd_signal(struct eventfd_ctx *ctx);
 __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask);
 int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
 				  __u64 *cnt);
@@ -58,7 +58,7 @@ static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
 	return ERR_PTR(-ENOSYS);
 }
 
-static inline int eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
+static inline int eventfd_signal(struct eventfd_ctx *ctx)
 {
 	return -ENOSYS;
 }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 774bd6e21e27..dfbb1d3b77b7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4378,7 +4378,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
 	 * only one element of the array here.
 	 */
 	for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
-		eventfd_signal(t->entries[i].eventfd, 1);
+		eventfd_signal(t->entries[i].eventfd);
 
 	/* i = current_threshold + 1 */
 	i++;
@@ -4390,7 +4390,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
 	 * only one element of the array here.
 	 */
 	for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
-		eventfd_signal(t->entries[i].eventfd, 1);
+		eventfd_signal(t->entries[i].eventfd);
 
 	/* Update current_threshold */
 	t->current_threshold = i - 1;
@@ -4430,7 +4430,7 @@ static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
 	spin_lock(&memcg_oom_lock);
 
 	list_for_each_entry(ev, &memcg->oom_notify, list)
-		eventfd_signal(ev->eventfd, 1);
+		eventfd_signal(ev->eventfd);
 
 	spin_unlock(&memcg_oom_lock);
 	return 0;
@@ -4649,7 +4649,7 @@ static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
 
 	/* already in OOM ? */
 	if (memcg->under_oom)
-		eventfd_signal(eventfd, 1);
+		eventfd_signal(eventfd);
 	spin_unlock(&memcg_oom_lock);
 
 	return 0;
@@ -4941,7 +4941,7 @@ static void memcg_event_remove(struct work_struct *work)
 	event->unregister_event(memcg, event->eventfd);
 
 	/* Notify userspace the event is going away. */
-	eventfd_signal(event->eventfd, 1);
+	eventfd_signal(event->eventfd);
 
 	eventfd_ctx_put(event->eventfd);
 	kfree(event);
diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index 22c6689d9302..bd5183dfd879 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -169,7 +169,7 @@ static bool vmpressure_event(struct vmpressure *vmpr,
 			continue;
 		if (level < ev->level)
 			continue;
-		eventfd_signal(ev->efd, 1);
+		eventfd_signal(ev->efd);
 		ret = true;
 	}
 	mutex_unlock(&vmpr->events_lock);
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 69ba0281f9e0..2284b3751240 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -234,10 +234,10 @@ static void mtty_trigger_interrupt(struct mdev_state *mdev_state)
 
 	if (is_msi(mdev_state)) {
 		if (mdev_state->msi_evtfd)
-			eventfd_signal(mdev_state->msi_evtfd, 1);
+			eventfd_signal(mdev_state->msi_evtfd);
 	} else if (is_intx(mdev_state)) {
 		if (mdev_state->intx_evtfd && !mdev_state->intx_mask) {
-			eventfd_signal(mdev_state->intx_evtfd, 1);
+			eventfd_signal(mdev_state->intx_evtfd);
 			mdev_state->intx_mask = true;
 		}
 	}
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 89912a17f5d5..c0e230f4c3e9 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -61,7 +61,7 @@ static void irqfd_resampler_notify(struct kvm_kernel_irqfd_resampler *resampler)
 
 	list_for_each_entry_srcu(irqfd, &resampler->list, resampler_link,
 				 srcu_read_lock_held(&resampler->kvm->irq_srcu))
-		eventfd_signal(irqfd->resamplefd, 1);
+		eventfd_signal(irqfd->resamplefd);
 }
 
 /*
@@ -786,7 +786,7 @@ ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,
 	if (!ioeventfd_in_range(p, addr, len, val))
 		return -EOPNOTSUPP;
 
-	eventfd_signal(p->eventfd, 1);
+	eventfd_signal(p->eventfd);
 	return 0;
 }
 

-- 
2.42.0

[PATCH v2 3/4] eventfd: simplify eventfd_signal_mask()

[Christian Brauner]

The eventfd_signal_mask() helper was introduced for io_uring and similar
to eventfd_signal() it always passed 1 for @n. So don't bother with that
argument at all.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 fs/eventfd.c            | 7 ++++---
 include/linux/eventfd.h | 5 ++---
 io_uring/io_uring.c     | 4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/eventfd.c b/fs/eventfd.c
index dc9e01053235..a9a6de920fb4 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -43,9 +43,10 @@ struct eventfd_ctx {
 	int id;
 };
 
-__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
+__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
 {
 	unsigned long flags;
+	__u64 n = 1;
 
 	/*
 	 * Deadlock or stack overflow issues can happen if we recurse here
@@ -68,7 +69,7 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
 	current->in_eventfd = 0;
 	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
 
-	return n;
+	return n == 1;
 }
 
 /**
@@ -84,7 +85,7 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
  */
 __u64 eventfd_signal(struct eventfd_ctx *ctx)
 {
-	return eventfd_signal_mask(ctx, 1, 0);
+	return eventfd_signal_mask(ctx, 0);
 }
 EXPORT_SYMBOL_GPL(eventfd_signal);
 
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
index 562089431551..4f8aac7eb62a 100644
--- a/include/linux/eventfd.h
+++ b/include/linux/eventfd.h
@@ -36,7 +36,7 @@ struct file *eventfd_fget(int fd);
 struct eventfd_ctx *eventfd_ctx_fdget(int fd);
 struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
 __u64 eventfd_signal(struct eventfd_ctx *ctx);
-__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask);
+__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
 int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
 				  __u64 *cnt);
 void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
@@ -63,8 +63,7 @@ static inline int eventfd_signal(struct eventfd_ctx *ctx)
 	return -ENOSYS;
 }
 
-static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n,
-				      unsigned mask)
+static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
 {
 	return -ENOSYS;
 }
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index ed254076c723..70170a41eac4 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -558,7 +558,7 @@ static void io_eventfd_ops(struct rcu_head *rcu)
 	int ops = atomic_xchg(&ev_fd->ops, 0);
 
 	if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT))
-		eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
+		eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
 
 	/* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
 	 * ordering in a race but if references are 0 we know we have to free
@@ -594,7 +594,7 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx)
 		goto out;
 
 	if (likely(eventfd_signal_allowed())) {
-		eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
+		eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
 	} else {
 		atomic_inc(&ev_fd->refs);
 		if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))

-- 
2.42.0

[PATCH v2 4/4] eventfd: make eventfd_signal{_mask}() void

[Christian Brauner]

No caller care about the return value.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 fs/eventfd.c            | 40 +++++++++++++++-------------------------
 include/linux/eventfd.h | 16 +++++++---------
 2 files changed, 22 insertions(+), 34 deletions(-)

diff --git a/fs/eventfd.c b/fs/eventfd.c
index a9a6de920fb4..13be2fb7fc96 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -43,10 +43,19 @@ struct eventfd_ctx {
 	int id;
 };
 
-__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
+/**
+ * eventfd_signal - Adds @n to the eventfd counter.
+ * @ctx: [in] Pointer to the eventfd context.
+ * @mask: [in] poll mask
+ *
+ * This function is supposed to be called by the kernel in paths that do not
+ * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
+ * value, and we signal this as overflow condition by returning a EPOLLERR
+ * to poll(2).
+ */
+void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
 {
 	unsigned long flags;
-	__u64 n = 1;
 
 	/*
 	 * Deadlock or stack overflow issues can happen if we recurse here
@@ -57,37 +66,18 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
 	 * safe context.
 	 */
 	if (WARN_ON_ONCE(current->in_eventfd))
-		return 0;
+		return;
 
 	spin_lock_irqsave(&ctx->wqh.lock, flags);
 	current->in_eventfd = 1;
-	if (ULLONG_MAX - ctx->count < n)
-		n = ULLONG_MAX - ctx->count;
-	ctx->count += n;
+	if (ctx->count < ULLONG_MAX)
+		ctx->count++;
 	if (waitqueue_active(&ctx->wqh))
 		wake_up_locked_poll(&ctx->wqh, EPOLLIN | mask);
 	current->in_eventfd = 0;
 	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
-
-	return n == 1;
-}
-
-/**
- * eventfd_signal - Adds @n to the eventfd counter.
- * @ctx: [in] Pointer to the eventfd context.
- *
- * This function is supposed to be called by the kernel in paths that do not
- * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
- * value, and we signal this as overflow condition by returning a EPOLLERR
- * to poll(2).
- *
- * Returns the amount by which the counter was incremented.
- */
-__u64 eventfd_signal(struct eventfd_ctx *ctx)
-{
-	return eventfd_signal_mask(ctx, 0);
 }
-EXPORT_SYMBOL_GPL(eventfd_signal);
+EXPORT_SYMBOL_GPL(eventfd_signal_mask);
 
 static void eventfd_free_ctx(struct eventfd_ctx *ctx)
 {
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
index 4f8aac7eb62a..fea7c4eb01d6 100644
--- a/include/linux/eventfd.h
+++ b/include/linux/eventfd.h
@@ -35,8 +35,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
 struct file *eventfd_fget(int fd);
 struct eventfd_ctx *eventfd_ctx_fdget(int fd);
 struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
-__u64 eventfd_signal(struct eventfd_ctx *ctx);
-__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
+void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
 int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
 				  __u64 *cnt);
 void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
@@ -58,14 +57,8 @@ static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
 	return ERR_PTR(-ENOSYS);
 }
 
-static inline int eventfd_signal(struct eventfd_ctx *ctx)
+static inline void eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
 {
-	return -ENOSYS;
-}
-
-static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
-{
-	return -ENOSYS;
 }
 
 static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
@@ -91,5 +84,10 @@ static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
 
 #endif
 
+static inline void eventfd_signal(struct eventfd_ctx *ctx)
+{
+	eventfd_signal_mask(ctx, 0);
+}
+
 #endif /* _LINUX_EVENTFD_H */
 

-- 
2.42.0

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Xu Yilun]

On Wed, Nov 22, 2023 at 01:48:23PM +0100, Christian Brauner wrote:
> Ever since the evenfd type was introduced back in 2007 in commit
> e1ad7468c77d ("signal/timer/event: eventfd core") the eventfd_signal()
> function only ever passed 1 as a value for @n. There's no point in
> keeping that additional argument.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> ---
>  arch/x86/kvm/hyperv.c                     |  2 +-
>  arch/x86/kvm/xen.c                        |  2 +-
>  drivers/accel/habanalabs/common/device.c  |  2 +-
>  drivers/fpga/dfl.c                        |  2 +-
>  drivers/gpu/drm/drm_syncobj.c             |  6 +++---
>  drivers/gpu/drm/i915/gvt/interrupt.c      |  2 +-
>  drivers/infiniband/hw/mlx5/devx.c         |  2 +-
>  drivers/misc/ocxl/file.c                  |  2 +-
>  drivers/s390/cio/vfio_ccw_chp.c           |  2 +-
>  drivers/s390/cio/vfio_ccw_drv.c           |  4 ++--
>  drivers/s390/cio/vfio_ccw_ops.c           |  6 +++---
>  drivers/s390/crypto/vfio_ap_ops.c         |  2 +-
>  drivers/usb/gadget/function/f_fs.c        |  4 ++--
>  drivers/vdpa/vdpa_user/vduse_dev.c        |  6 +++---
>  drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c    |  2 +-
>  drivers/vfio/pci/vfio_pci_core.c          |  6 +++---
>  drivers/vfio/pci/vfio_pci_intrs.c         | 12 ++++++------
>  drivers/vfio/platform/vfio_platform_irq.c |  4 ++--
>  drivers/vhost/vdpa.c                      |  4 ++--
>  drivers/vhost/vhost.c                     | 10 +++++-----
>  drivers/vhost/vhost.h                     |  2 +-
>  drivers/virt/acrn/ioeventfd.c             |  2 +-
>  drivers/xen/privcmd.c                     |  2 +-
>  fs/aio.c                                  |  2 +-
>  fs/eventfd.c                              |  9 +++------
>  include/linux/eventfd.h                   |  4 ++--
>  mm/memcontrol.c                           | 10 +++++-----
>  mm/vmpressure.c                           |  2 +-
>  samples/vfio-mdev/mtty.c                  |  4 ++--
>  virt/kvm/eventfd.c                        |  4 ++--
>  30 files changed, 60 insertions(+), 63 deletions(-)
> 
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index dd7a783d53b5..e73f88050f08 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -1872,7 +1872,7 @@ static irqreturn_t dfl_irq_handler(int irq, void *arg)
>  {
>  	struct eventfd_ctx *trigger = arg;
>  
> -	eventfd_signal(trigger, 1);
> +	eventfd_signal(trigger);

For FPGA part,

Acked-by: Xu Yilun <yilun.xu@intel.com>

>  	return IRQ_HANDLED;
>  }

Re: [PATCH v2 1/4] i915: make inject_virtual_interrupt() void

[Jan Kara]

On Wed 22-11-23 13:48:22, Christian Brauner wrote:
> The single caller of inject_virtual_interrupt() ignores the return value
> anyway. This allows us to simplify eventfd_signal() in follow-up
> patches.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  drivers/gpu/drm/i915/gvt/interrupt.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/interrupt.c b/drivers/gpu/drm/i915/gvt/interrupt.c
> index de3f5903d1a7..9665876b4b13 100644
> --- a/drivers/gpu/drm/i915/gvt/interrupt.c
> +++ b/drivers/gpu/drm/i915/gvt/interrupt.c
> @@ -422,7 +422,7 @@ static void init_irq_map(struct intel_gvt_irq *irq)
>  #define MSI_CAP_DATA(offset) (offset + 8)
>  #define MSI_CAP_EN 0x1
>  
> -static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
> +static void inject_virtual_interrupt(struct intel_vgpu *vgpu)
>  {
>  	unsigned long offset = vgpu->gvt->device_info.msi_cap_offset;
>  	u16 control, data;
> @@ -434,10 +434,10 @@ static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
>  
>  	/* Do not generate MSI if MSIEN is disabled */
>  	if (!(control & MSI_CAP_EN))
> -		return 0;
> +		return;
>  
>  	if (WARN(control & GENMASK(15, 1), "only support one MSI format\n"))
> -		return -EINVAL;
> +		return;
>  
>  	trace_inject_msi(vgpu->id, addr, data);
>  
> @@ -451,10 +451,10 @@ static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
>  	 * returned and don't inject interrupt into guest.
>  	 */
>  	if (!test_bit(INTEL_VGPU_STATUS_ATTACHED, vgpu->status))
> -		return -ESRCH;
> -	if (vgpu->msi_trigger && eventfd_signal(vgpu->msi_trigger, 1) != 1)
> -		return -EFAULT;
> -	return 0;
> +		return;
> +	if (!vgpu->msi_trigger)
> +		return;
> +	eventfd_signal(vgpu->msi_trigger, 1);
>  }
>  
>  static void propagate_event(struct intel_gvt_irq *irq,
> 
> -- 
> 2.42.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Jan Kara]

On Wed 22-11-23 13:48:23, Christian Brauner wrote:
> Ever since the evenfd type was introduced back in 2007 in commit
> e1ad7468c77d ("signal/timer/event: eventfd core") the eventfd_signal()
> function only ever passed 1 as a value for @n. There's no point in
> keeping that additional argument.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>
								Honza

> ---
>  arch/x86/kvm/hyperv.c                     |  2 +-
>  arch/x86/kvm/xen.c                        |  2 +-
>  drivers/accel/habanalabs/common/device.c  |  2 +-
>  drivers/fpga/dfl.c                        |  2 +-
>  drivers/gpu/drm/drm_syncobj.c             |  6 +++---
>  drivers/gpu/drm/i915/gvt/interrupt.c      |  2 +-
>  drivers/infiniband/hw/mlx5/devx.c         |  2 +-
>  drivers/misc/ocxl/file.c                  |  2 +-
>  drivers/s390/cio/vfio_ccw_chp.c           |  2 +-
>  drivers/s390/cio/vfio_ccw_drv.c           |  4 ++--
>  drivers/s390/cio/vfio_ccw_ops.c           |  6 +++---
>  drivers/s390/crypto/vfio_ap_ops.c         |  2 +-
>  drivers/usb/gadget/function/f_fs.c        |  4 ++--
>  drivers/vdpa/vdpa_user/vduse_dev.c        |  6 +++---
>  drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c    |  2 +-
>  drivers/vfio/pci/vfio_pci_core.c          |  6 +++---
>  drivers/vfio/pci/vfio_pci_intrs.c         | 12 ++++++------
>  drivers/vfio/platform/vfio_platform_irq.c |  4 ++--
>  drivers/vhost/vdpa.c                      |  4 ++--
>  drivers/vhost/vhost.c                     | 10 +++++-----
>  drivers/vhost/vhost.h                     |  2 +-
>  drivers/virt/acrn/ioeventfd.c             |  2 +-
>  drivers/xen/privcmd.c                     |  2 +-
>  fs/aio.c                                  |  2 +-
>  fs/eventfd.c                              |  9 +++------
>  include/linux/eventfd.h                   |  4 ++--
>  mm/memcontrol.c                           | 10 +++++-----
>  mm/vmpressure.c                           |  2 +-
>  samples/vfio-mdev/mtty.c                  |  4 ++--
>  virt/kvm/eventfd.c                        |  4 ++--
>  30 files changed, 60 insertions(+), 63 deletions(-)
> 
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index 238afd7335e4..4943f6b2bbee 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -2388,7 +2388,7 @@ static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *h
>  	if (!eventfd)
>  		return HV_STATUS_INVALID_PORT_ID;
>  
> -	eventfd_signal(eventfd, 1);
> +	eventfd_signal(eventfd);
>  	return HV_STATUS_SUCCESS;
>  }
>  
> diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
> index e53fad915a62..523bb6df5ac9 100644
> --- a/arch/x86/kvm/xen.c
> +++ b/arch/x86/kvm/xen.c
> @@ -2088,7 +2088,7 @@ static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
>  		if (ret < 0 && ret != -ENOTCONN)
>  			return false;
>  	} else {
> -		eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1);
> +		eventfd_signal(evtchnfd->deliver.eventfd.ctx);
>  	}
>  
>  	*r = 0;
> diff --git a/drivers/accel/habanalabs/common/device.c b/drivers/accel/habanalabs/common/device.c
> index 9711e8fc979d..3a89644f087c 100644
> --- a/drivers/accel/habanalabs/common/device.c
> +++ b/drivers/accel/habanalabs/common/device.c
> @@ -2044,7 +2044,7 @@ static void hl_notifier_event_send(struct hl_notifier_event *notifier_event, u64
>  	notifier_event->events_mask |= event_mask;
>  
>  	if (notifier_event->eventfd)
> -		eventfd_signal(notifier_event->eventfd, 1);
> +		eventfd_signal(notifier_event->eventfd);
>  
>  	mutex_unlock(&notifier_event->lock);
>  }
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index dd7a783d53b5..e73f88050f08 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -1872,7 +1872,7 @@ static irqreturn_t dfl_irq_handler(int irq, void *arg)
>  {
>  	struct eventfd_ctx *trigger = arg;
>  
> -	eventfd_signal(trigger, 1);
> +	eventfd_signal(trigger);
>  	return IRQ_HANDLED;
>  }
>  
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index 01da6789d044..b9cc62982196 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -1365,7 +1365,7 @@ static void syncobj_eventfd_entry_fence_func(struct dma_fence *fence,
>  	struct syncobj_eventfd_entry *entry =
>  		container_of(cb, struct syncobj_eventfd_entry, fence_cb);
>  
> -	eventfd_signal(entry->ev_fd_ctx, 1);
> +	eventfd_signal(entry->ev_fd_ctx);
>  	syncobj_eventfd_entry_free(entry);
>  }
>  
> @@ -1388,13 +1388,13 @@ syncobj_eventfd_entry_func(struct drm_syncobj *syncobj,
>  	entry->fence = fence;
>  
>  	if (entry->flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE) {
> -		eventfd_signal(entry->ev_fd_ctx, 1);
> +		eventfd_signal(entry->ev_fd_ctx);
>  		syncobj_eventfd_entry_free(entry);
>  	} else {
>  		ret = dma_fence_add_callback(fence, &entry->fence_cb,
>  					     syncobj_eventfd_entry_fence_func);
>  		if (ret == -ENOENT) {
> -			eventfd_signal(entry->ev_fd_ctx, 1);
> +			eventfd_signal(entry->ev_fd_ctx);
>  			syncobj_eventfd_entry_free(entry);
>  		}
>  	}
> diff --git a/drivers/gpu/drm/i915/gvt/interrupt.c b/drivers/gpu/drm/i915/gvt/interrupt.c
> index 9665876b4b13..7f4db438e400 100644
> --- a/drivers/gpu/drm/i915/gvt/interrupt.c
> +++ b/drivers/gpu/drm/i915/gvt/interrupt.c
> @@ -454,7 +454,7 @@ static void inject_virtual_interrupt(struct intel_vgpu *vgpu)
>  		return;
>  	if (!vgpu->msi_trigger)
>  		return;
> -	eventfd_signal(vgpu->msi_trigger, 1);
> +	eventfd_signal(vgpu->msi_trigger);
>  }
>  
>  static void propagate_event(struct intel_gvt_irq *irq,
> diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
> index 8ba53edf2311..869369cb5b5f 100644
> --- a/drivers/infiniband/hw/mlx5/devx.c
> +++ b/drivers/infiniband/hw/mlx5/devx.c
> @@ -2498,7 +2498,7 @@ static void dispatch_event_fd(struct list_head *fd_list,
>  
>  	list_for_each_entry_rcu(item, fd_list, xa_list) {
>  		if (item->eventfd)
> -			eventfd_signal(item->eventfd, 1);
> +			eventfd_signal(item->eventfd);
>  		else
>  			deliver_event(item, data);
>  	}
> diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
> index ac69b7f361f5..7eb74711ac96 100644
> --- a/drivers/misc/ocxl/file.c
> +++ b/drivers/misc/ocxl/file.c
> @@ -184,7 +184,7 @@ static irqreturn_t irq_handler(void *private)
>  {
>  	struct eventfd_ctx *ev_ctx = private;
>  
> -	eventfd_signal(ev_ctx, 1);
> +	eventfd_signal(ev_ctx);
>  	return IRQ_HANDLED;
>  }
>  
> diff --git a/drivers/s390/cio/vfio_ccw_chp.c b/drivers/s390/cio/vfio_ccw_chp.c
> index d3f3a611f95b..38c176cf6295 100644
> --- a/drivers/s390/cio/vfio_ccw_chp.c
> +++ b/drivers/s390/cio/vfio_ccw_chp.c
> @@ -115,7 +115,7 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_ccw_private *private,
>  
>  	/* Notify the guest if more CRWs are on our queue */
>  	if (!list_empty(&private->crw) && private->crw_trigger)
> -		eventfd_signal(private->crw_trigger, 1);
> +		eventfd_signal(private->crw_trigger);
>  
>  	return ret;
>  }
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
> index 43601816ea4e..bfb35cfce1ef 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -112,7 +112,7 @@ void vfio_ccw_sch_io_todo(struct work_struct *work)
>  		private->state = VFIO_CCW_STATE_IDLE;
>  
>  	if (private->io_trigger)
> -		eventfd_signal(private->io_trigger, 1);
> +		eventfd_signal(private->io_trigger);
>  }
>  
>  void vfio_ccw_crw_todo(struct work_struct *work)
> @@ -122,7 +122,7 @@ void vfio_ccw_crw_todo(struct work_struct *work)
>  	private = container_of(work, struct vfio_ccw_private, crw_work);
>  
>  	if (!list_empty(&private->crw) && private->crw_trigger)
> -		eventfd_signal(private->crw_trigger, 1);
> +		eventfd_signal(private->crw_trigger);
>  }
>  
>  /*
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index cba4971618ff..ea532a8a4a0c 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -421,7 +421,7 @@ static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
>  	case VFIO_IRQ_SET_DATA_NONE:
>  	{
>  		if (*ctx)
> -			eventfd_signal(*ctx, 1);
> +			eventfd_signal(*ctx);
>  		return 0;
>  	}
>  	case VFIO_IRQ_SET_DATA_BOOL:
> @@ -432,7 +432,7 @@ static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
>  			return -EFAULT;
>  
>  		if (trigger && *ctx)
> -			eventfd_signal(*ctx, 1);
> +			eventfd_signal(*ctx);
>  		return 0;
>  	}
>  	case VFIO_IRQ_SET_DATA_EVENTFD:
> @@ -612,7 +612,7 @@ static void vfio_ccw_mdev_request(struct vfio_device *vdev, unsigned int count)
>  					       "Relaying device request to user (#%u)\n",
>  					       count);
>  
> -		eventfd_signal(private->req_trigger, 1);
> +		eventfd_signal(private->req_trigger);
>  	} else if (count == 0) {
>  		dev_notice(dev,
>  			   "No device request channel registered, blocked until released by user\n");
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 4db538a55192..542b5be73a6a 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -1794,7 +1794,7 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
>  					       "Relaying device request to user (#%u)\n",
>  					       count);
>  
> -		eventfd_signal(matrix_mdev->req_trigger, 1);
> +		eventfd_signal(matrix_mdev->req_trigger);
>  	} else if (count == 0) {
>  		dev_notice(dev,
>  			   "No device request registered, blocked until released by user\n");
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index efe3e3b85769..fdd0fc7b8f25 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -831,7 +831,7 @@ static void ffs_user_copy_worker(struct work_struct *work)
>  	io_data->kiocb->ki_complete(io_data->kiocb, ret);
>  
>  	if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
> -		eventfd_signal(io_data->ffs->ffs_eventfd, 1);
> +		eventfd_signal(io_data->ffs->ffs_eventfd);
>  
>  	if (io_data->read)
>  		kfree(io_data->to_free);
> @@ -2738,7 +2738,7 @@ static void __ffs_event_add(struct ffs_data *ffs,
>  	ffs->ev.types[ffs->ev.count++] = type;
>  	wake_up_locked(&ffs->ev.waitq);
>  	if (ffs->ffs_eventfd)
> -		eventfd_signal(ffs->ffs_eventfd, 1);
> +		eventfd_signal(ffs->ffs_eventfd);
>  }
>  
>  static void ffs_event_add(struct ffs_data *ffs,
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index 0ddd4b8abecb..6cb5ce4a8b9a 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -493,7 +493,7 @@ static void vduse_vq_kick(struct vduse_virtqueue *vq)
>  		goto unlock;
>  
>  	if (vq->kickfd)
> -		eventfd_signal(vq->kickfd, 1);
> +		eventfd_signal(vq->kickfd);
>  	else
>  		vq->kicked = true;
>  unlock:
> @@ -911,7 +911,7 @@ static int vduse_kickfd_setup(struct vduse_dev *dev,
>  		eventfd_ctx_put(vq->kickfd);
>  	vq->kickfd = ctx;
>  	if (vq->ready && vq->kicked && vq->kickfd) {
> -		eventfd_signal(vq->kickfd, 1);
> +		eventfd_signal(vq->kickfd);
>  		vq->kicked = false;
>  	}
>  	spin_unlock(&vq->kick_lock);
> @@ -960,7 +960,7 @@ static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)
>  
>  	spin_lock_irq(&vq->irq_lock);
>  	if (vq->ready && vq->cb.trigger) {
> -		eventfd_signal(vq->cb.trigger, 1);
> +		eventfd_signal(vq->cb.trigger);
>  		signal = true;
>  	}
>  	spin_unlock_irq(&vq->irq_lock);
> diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
> index c51229fccbd6..d62fbfff20b8 100644
> --- a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
> +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
> @@ -54,7 +54,7 @@ static irqreturn_t vfio_fsl_mc_irq_handler(int irq_num, void *arg)
>  {
>  	struct vfio_fsl_mc_irq *mc_irq = (struct vfio_fsl_mc_irq *)arg;
>  
> -	eventfd_signal(mc_irq->trigger, 1);
> +	eventfd_signal(mc_irq->trigger);
>  	return IRQ_HANDLED;
>  }
>  
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 1929103ee59a..1cbc990d42e0 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -443,7 +443,7 @@ static int vfio_pci_core_runtime_resume(struct device *dev)
>  	 */
>  	down_write(&vdev->memory_lock);
>  	if (vdev->pm_wake_eventfd_ctx) {
> -		eventfd_signal(vdev->pm_wake_eventfd_ctx, 1);
> +		eventfd_signal(vdev->pm_wake_eventfd_ctx);
>  		__vfio_pci_runtime_pm_exit(vdev);
>  	}
>  	up_write(&vdev->memory_lock);
> @@ -1883,7 +1883,7 @@ void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count)
>  			pci_notice_ratelimited(pdev,
>  				"Relaying device request to user (#%u)\n",
>  				count);
> -		eventfd_signal(vdev->req_trigger, 1);
> +		eventfd_signal(vdev->req_trigger);
>  	} else if (count == 0) {
>  		pci_warn(pdev,
>  			"No device request channel registered, blocked until released by user\n");
> @@ -2302,7 +2302,7 @@ pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
>  	mutex_lock(&vdev->igate);
>  
>  	if (vdev->err_trigger)
> -		eventfd_signal(vdev->err_trigger, 1);
> +		eventfd_signal(vdev->err_trigger);
>  
>  	mutex_unlock(&vdev->igate);
>  
> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
> index cbb4bcbfbf83..237beac83809 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -94,7 +94,7 @@ static void vfio_send_intx_eventfd(void *opaque, void *unused)
>  		ctx = vfio_irq_ctx_get(vdev, 0);
>  		if (WARN_ON_ONCE(!ctx))
>  			return;
> -		eventfd_signal(ctx->trigger, 1);
> +		eventfd_signal(ctx->trigger);
>  	}
>  }
>  
> @@ -342,7 +342,7 @@ static irqreturn_t vfio_msihandler(int irq, void *arg)
>  {
>  	struct eventfd_ctx *trigger = arg;
>  
> -	eventfd_signal(trigger, 1);
> +	eventfd_signal(trigger);
>  	return IRQ_HANDLED;
>  }
>  
> @@ -689,11 +689,11 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_core_device *vdev,
>  		if (!ctx)
>  			continue;
>  		if (flags & VFIO_IRQ_SET_DATA_NONE) {
> -			eventfd_signal(ctx->trigger, 1);
> +			eventfd_signal(ctx->trigger);
>  		} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
>  			uint8_t *bools = data;
>  			if (bools[i - start])
> -				eventfd_signal(ctx->trigger, 1);
> +				eventfd_signal(ctx->trigger);
>  		}
>  	}
>  	return 0;
> @@ -707,7 +707,7 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
>  	if (flags & VFIO_IRQ_SET_DATA_NONE) {
>  		if (*ctx) {
>  			if (count) {
> -				eventfd_signal(*ctx, 1);
> +				eventfd_signal(*ctx);
>  			} else {
>  				eventfd_ctx_put(*ctx);
>  				*ctx = NULL;
> @@ -722,7 +722,7 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
>  
>  		trigger = *(uint8_t *)data;
>  		if (trigger && *ctx)
> -			eventfd_signal(*ctx, 1);
> +			eventfd_signal(*ctx);
>  
>  		return 0;
>  	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
> index 665197caed89..61a1bfb68ac7 100644
> --- a/drivers/vfio/platform/vfio_platform_irq.c
> +++ b/drivers/vfio/platform/vfio_platform_irq.c
> @@ -155,7 +155,7 @@ static irqreturn_t vfio_automasked_irq_handler(int irq, void *dev_id)
>  	spin_unlock_irqrestore(&irq_ctx->lock, flags);
>  
>  	if (ret == IRQ_HANDLED)
> -		eventfd_signal(irq_ctx->trigger, 1);
> +		eventfd_signal(irq_ctx->trigger);
>  
>  	return ret;
>  }
> @@ -164,7 +164,7 @@ static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
>  {
>  	struct vfio_platform_irq *irq_ctx = dev_id;
>  
> -	eventfd_signal(irq_ctx->trigger, 1);
> +	eventfd_signal(irq_ctx->trigger);
>  
>  	return IRQ_HANDLED;
>  }
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 30df5c58db73..8d9f958946d6 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -178,7 +178,7 @@ static irqreturn_t vhost_vdpa_virtqueue_cb(void *private)
>  	struct eventfd_ctx *call_ctx = vq->call_ctx.ctx;
>  
>  	if (call_ctx)
> -		eventfd_signal(call_ctx, 1);
> +		eventfd_signal(call_ctx);
>  
>  	return IRQ_HANDLED;
>  }
> @@ -189,7 +189,7 @@ static irqreturn_t vhost_vdpa_config_cb(void *private)
>  	struct eventfd_ctx *config_ctx = v->config_ctx;
>  
>  	if (config_ctx)
> -		eventfd_signal(config_ctx, 1);
> +		eventfd_signal(config_ctx);
>  
>  	return IRQ_HANDLED;
>  }
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index e0c181ad17e3..045f666b4f12 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -2248,7 +2248,7 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
>  		len -= l;
>  		if (!len) {
>  			if (vq->log_ctx)
> -				eventfd_signal(vq->log_ctx, 1);
> +				eventfd_signal(vq->log_ctx);
>  			return 0;
>  		}
>  	}
> @@ -2271,7 +2271,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
>  		log_used(vq, (used - (void __user *)vq->used),
>  			 sizeof vq->used->flags);
>  		if (vq->log_ctx)
> -			eventfd_signal(vq->log_ctx, 1);
> +			eventfd_signal(vq->log_ctx);
>  	}
>  	return 0;
>  }
> @@ -2289,7 +2289,7 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq)
>  		log_used(vq, (used - (void __user *)vq->used),
>  			 sizeof *vhost_avail_event(vq));
>  		if (vq->log_ctx)
> -			eventfd_signal(vq->log_ctx, 1);
> +			eventfd_signal(vq->log_ctx);
>  	}
>  	return 0;
>  }
> @@ -2715,7 +2715,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
>  		log_used(vq, offsetof(struct vring_used, idx),
>  			 sizeof vq->used->idx);
>  		if (vq->log_ctx)
> -			eventfd_signal(vq->log_ctx, 1);
> +			eventfd_signal(vq->log_ctx);
>  	}
>  	return r;
>  }
> @@ -2763,7 +2763,7 @@ void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
>  {
>  	/* Signal the Guest tell them we used something up. */
>  	if (vq->call_ctx.ctx && vhost_notify(dev, vq))
> -		eventfd_signal(vq->call_ctx.ctx, 1);
> +		eventfd_signal(vq->call_ctx.ctx);
>  }
>  EXPORT_SYMBOL_GPL(vhost_signal);
>  
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index f60d5f7bef94..9e942fcda5c3 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -249,7 +249,7 @@ void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
>  #define vq_err(vq, fmt, ...) do {                                  \
>  		pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
>  		if ((vq)->error_ctx)                               \
> -				eventfd_signal((vq)->error_ctx, 1);\
> +				eventfd_signal((vq)->error_ctx);\
>  	} while (0)
>  
>  enum {
> diff --git a/drivers/virt/acrn/ioeventfd.c b/drivers/virt/acrn/ioeventfd.c
> index ac4037e9f947..4e845c6ca0b5 100644
> --- a/drivers/virt/acrn/ioeventfd.c
> +++ b/drivers/virt/acrn/ioeventfd.c
> @@ -223,7 +223,7 @@ static int acrn_ioeventfd_handler(struct acrn_ioreq_client *client,
>  	mutex_lock(&client->vm->ioeventfds_lock);
>  	p = hsm_ioeventfd_match(client->vm, addr, val, size, req->type);
>  	if (p)
> -		eventfd_signal(p->eventfd, 1);
> +		eventfd_signal(p->eventfd);
>  	mutex_unlock(&client->vm->ioeventfds_lock);
>  
>  	return 0;
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index 1ce7f3c7a950..7efc0c62e984 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -1147,7 +1147,7 @@ static irqreturn_t ioeventfd_interrupt(int irq, void *dev_id)
>  		if (ioreq->addr == kioeventfd->addr + VIRTIO_MMIO_QUEUE_NOTIFY &&
>  		    ioreq->size == kioeventfd->addr_len &&
>  		    (ioreq->data & QUEUE_NOTIFY_VQ_MASK) == kioeventfd->vq) {
> -			eventfd_signal(kioeventfd->eventfd, 1);
> +			eventfd_signal(kioeventfd->eventfd);
>  			state = STATE_IORESP_READY;
>  			break;
>  		}
> diff --git a/fs/aio.c b/fs/aio.c
> index f8589caef9c1..5c5b09e52d75 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1166,7 +1166,7 @@ static void aio_complete(struct aio_kiocb *iocb)
>  	 * from IRQ context.
>  	 */
>  	if (iocb->ki_eventfd)
> -		eventfd_signal(iocb->ki_eventfd, 1);
> +		eventfd_signal(iocb->ki_eventfd);
>  
>  	/*
>  	 * We have to order our ring_info tail store above and test
> diff --git a/fs/eventfd.c b/fs/eventfd.c
> index 33a918f9566c..dc9e01053235 100644
> --- a/fs/eventfd.c
> +++ b/fs/eventfd.c
> @@ -74,20 +74,17 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
>  /**
>   * eventfd_signal - Adds @n to the eventfd counter.
>   * @ctx: [in] Pointer to the eventfd context.
> - * @n: [in] Value of the counter to be added to the eventfd internal counter.
> - *          The value cannot be negative.
>   *
>   * This function is supposed to be called by the kernel in paths that do not
>   * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
>   * value, and we signal this as overflow condition by returning a EPOLLERR
>   * to poll(2).
>   *
> - * Returns the amount by which the counter was incremented.  This will be less
> - * than @n if the counter has overflowed.
> + * Returns the amount by which the counter was incremented.
>   */
> -__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
> +__u64 eventfd_signal(struct eventfd_ctx *ctx)
>  {
> -	return eventfd_signal_mask(ctx, n, 0);
> +	return eventfd_signal_mask(ctx, 1, 0);
>  }
>  EXPORT_SYMBOL_GPL(eventfd_signal);
>  
> diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
> index b9d83652c097..562089431551 100644
> --- a/include/linux/eventfd.h
> +++ b/include/linux/eventfd.h
> @@ -35,7 +35,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
>  struct file *eventfd_fget(int fd);
>  struct eventfd_ctx *eventfd_ctx_fdget(int fd);
>  struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
> -__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
> +__u64 eventfd_signal(struct eventfd_ctx *ctx);
>  __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask);
>  int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
>  				  __u64 *cnt);
> @@ -58,7 +58,7 @@ static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
>  	return ERR_PTR(-ENOSYS);
>  }
>  
> -static inline int eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
> +static inline int eventfd_signal(struct eventfd_ctx *ctx)
>  {
>  	return -ENOSYS;
>  }
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 774bd6e21e27..dfbb1d3b77b7 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4378,7 +4378,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
>  	 * only one element of the array here.
>  	 */
>  	for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
> -		eventfd_signal(t->entries[i].eventfd, 1);
> +		eventfd_signal(t->entries[i].eventfd);
>  
>  	/* i = current_threshold + 1 */
>  	i++;
> @@ -4390,7 +4390,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
>  	 * only one element of the array here.
>  	 */
>  	for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
> -		eventfd_signal(t->entries[i].eventfd, 1);
> +		eventfd_signal(t->entries[i].eventfd);
>  
>  	/* Update current_threshold */
>  	t->current_threshold = i - 1;
> @@ -4430,7 +4430,7 @@ static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
>  	spin_lock(&memcg_oom_lock);
>  
>  	list_for_each_entry(ev, &memcg->oom_notify, list)
> -		eventfd_signal(ev->eventfd, 1);
> +		eventfd_signal(ev->eventfd);
>  
>  	spin_unlock(&memcg_oom_lock);
>  	return 0;
> @@ -4649,7 +4649,7 @@ static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
>  
>  	/* already in OOM ? */
>  	if (memcg->under_oom)
> -		eventfd_signal(eventfd, 1);
> +		eventfd_signal(eventfd);
>  	spin_unlock(&memcg_oom_lock);
>  
>  	return 0;
> @@ -4941,7 +4941,7 @@ static void memcg_event_remove(struct work_struct *work)
>  	event->unregister_event(memcg, event->eventfd);
>  
>  	/* Notify userspace the event is going away. */
> -	eventfd_signal(event->eventfd, 1);
> +	eventfd_signal(event->eventfd);
>  
>  	eventfd_ctx_put(event->eventfd);
>  	kfree(event);
> diff --git a/mm/vmpressure.c b/mm/vmpressure.c
> index 22c6689d9302..bd5183dfd879 100644
> --- a/mm/vmpressure.c
> +++ b/mm/vmpressure.c
> @@ -169,7 +169,7 @@ static bool vmpressure_event(struct vmpressure *vmpr,
>  			continue;
>  		if (level < ev->level)
>  			continue;
> -		eventfd_signal(ev->efd, 1);
> +		eventfd_signal(ev->efd);
>  		ret = true;
>  	}
>  	mutex_unlock(&vmpr->events_lock);
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 69ba0281f9e0..2284b3751240 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -234,10 +234,10 @@ static void mtty_trigger_interrupt(struct mdev_state *mdev_state)
>  
>  	if (is_msi(mdev_state)) {
>  		if (mdev_state->msi_evtfd)
> -			eventfd_signal(mdev_state->msi_evtfd, 1);
> +			eventfd_signal(mdev_state->msi_evtfd);
>  	} else if (is_intx(mdev_state)) {
>  		if (mdev_state->intx_evtfd && !mdev_state->intx_mask) {
> -			eventfd_signal(mdev_state->intx_evtfd, 1);
> +			eventfd_signal(mdev_state->intx_evtfd);
>  			mdev_state->intx_mask = true;
>  		}
>  	}
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index 89912a17f5d5..c0e230f4c3e9 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -61,7 +61,7 @@ static void irqfd_resampler_notify(struct kvm_kernel_irqfd_resampler *resampler)
>  
>  	list_for_each_entry_srcu(irqfd, &resampler->list, resampler_link,
>  				 srcu_read_lock_held(&resampler->kvm->irq_srcu))
> -		eventfd_signal(irqfd->resamplefd, 1);
> +		eventfd_signal(irqfd->resamplefd);
>  }
>  
>  /*
> @@ -786,7 +786,7 @@ ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,
>  	if (!ioeventfd_in_range(p, addr, len, val))
>  		return -EOPNOTSUPP;
>  
> -	eventfd_signal(p->eventfd, 1);
> +	eventfd_signal(p->eventfd);
>  	return 0;
>  }
>  
> 
> -- 
> 2.42.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v2 3/4] eventfd: simplify eventfd_signal_mask()

[Jan Kara]

On Wed 22-11-23 13:48:24, Christian Brauner wrote:
> The eventfd_signal_mask() helper was introduced for io_uring and similar
> to eventfd_signal() it always passed 1 for @n. So don't bother with that
> argument at all.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Nice. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/eventfd.c            | 7 ++++---
>  include/linux/eventfd.h | 5 ++---
>  io_uring/io_uring.c     | 4 ++--
>  3 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/eventfd.c b/fs/eventfd.c
> index dc9e01053235..a9a6de920fb4 100644
> --- a/fs/eventfd.c
> +++ b/fs/eventfd.c
> @@ -43,9 +43,10 @@ struct eventfd_ctx {
>  	int id;
>  };
>  
> -__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
> +__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
>  {
>  	unsigned long flags;
> +	__u64 n = 1;
>  
>  	/*
>  	 * Deadlock or stack overflow issues can happen if we recurse here
> @@ -68,7 +69,7 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
>  	current->in_eventfd = 0;
>  	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
>  
> -	return n;
> +	return n == 1;
>  }
>  
>  /**
> @@ -84,7 +85,7 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
>   */
>  __u64 eventfd_signal(struct eventfd_ctx *ctx)
>  {
> -	return eventfd_signal_mask(ctx, 1, 0);
> +	return eventfd_signal_mask(ctx, 0);
>  }
>  EXPORT_SYMBOL_GPL(eventfd_signal);
>  
> diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
> index 562089431551..4f8aac7eb62a 100644
> --- a/include/linux/eventfd.h
> +++ b/include/linux/eventfd.h
> @@ -36,7 +36,7 @@ struct file *eventfd_fget(int fd);
>  struct eventfd_ctx *eventfd_ctx_fdget(int fd);
>  struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
>  __u64 eventfd_signal(struct eventfd_ctx *ctx);
> -__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask);
> +__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
>  int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
>  				  __u64 *cnt);
>  void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
> @@ -63,8 +63,7 @@ static inline int eventfd_signal(struct eventfd_ctx *ctx)
>  	return -ENOSYS;
>  }
>  
> -static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n,
> -				      unsigned mask)
> +static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
>  {
>  	return -ENOSYS;
>  }
> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
> index ed254076c723..70170a41eac4 100644
> --- a/io_uring/io_uring.c
> +++ b/io_uring/io_uring.c
> @@ -558,7 +558,7 @@ static void io_eventfd_ops(struct rcu_head *rcu)
>  	int ops = atomic_xchg(&ev_fd->ops, 0);
>  
>  	if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT))
> -		eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
> +		eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
>  
>  	/* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
>  	 * ordering in a race but if references are 0 we know we have to free
> @@ -594,7 +594,7 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx)
>  		goto out;
>  
>  	if (likely(eventfd_signal_allowed())) {
> -		eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
> +		eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
>  	} else {
>  		atomic_inc(&ev_fd->refs);
>  		if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))
> 
> -- 
> 2.42.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v2 4/4] eventfd: make eventfd_signal{_mask}() void

[Jan Kara]

On Wed 22-11-23 13:48:25, Christian Brauner wrote:
> No caller care about the return value.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Yup. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/eventfd.c            | 40 +++++++++++++++-------------------------
>  include/linux/eventfd.h | 16 +++++++---------
>  2 files changed, 22 insertions(+), 34 deletions(-)
> 
> diff --git a/fs/eventfd.c b/fs/eventfd.c
> index a9a6de920fb4..13be2fb7fc96 100644
> --- a/fs/eventfd.c
> +++ b/fs/eventfd.c
> @@ -43,10 +43,19 @@ struct eventfd_ctx {
>  	int id;
>  };
>  
> -__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
> +/**
> + * eventfd_signal - Adds @n to the eventfd counter.
> + * @ctx: [in] Pointer to the eventfd context.
> + * @mask: [in] poll mask
> + *
> + * This function is supposed to be called by the kernel in paths that do not
> + * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
> + * value, and we signal this as overflow condition by returning a EPOLLERR
> + * to poll(2).
> + */
> +void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
>  {
>  	unsigned long flags;
> -	__u64 n = 1;
>  
>  	/*
>  	 * Deadlock or stack overflow issues can happen if we recurse here
> @@ -57,37 +66,18 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
>  	 * safe context.
>  	 */
>  	if (WARN_ON_ONCE(current->in_eventfd))
> -		return 0;
> +		return;
>  
>  	spin_lock_irqsave(&ctx->wqh.lock, flags);
>  	current->in_eventfd = 1;
> -	if (ULLONG_MAX - ctx->count < n)
> -		n = ULLONG_MAX - ctx->count;
> -	ctx->count += n;
> +	if (ctx->count < ULLONG_MAX)
> +		ctx->count++;
>  	if (waitqueue_active(&ctx->wqh))
>  		wake_up_locked_poll(&ctx->wqh, EPOLLIN | mask);
>  	current->in_eventfd = 0;
>  	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
> -
> -	return n == 1;
> -}
> -
> -/**
> - * eventfd_signal - Adds @n to the eventfd counter.
> - * @ctx: [in] Pointer to the eventfd context.
> - *
> - * This function is supposed to be called by the kernel in paths that do not
> - * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
> - * value, and we signal this as overflow condition by returning a EPOLLERR
> - * to poll(2).
> - *
> - * Returns the amount by which the counter was incremented.
> - */
> -__u64 eventfd_signal(struct eventfd_ctx *ctx)
> -{
> -	return eventfd_signal_mask(ctx, 0);
>  }
> -EXPORT_SYMBOL_GPL(eventfd_signal);
> +EXPORT_SYMBOL_GPL(eventfd_signal_mask);
>  
>  static void eventfd_free_ctx(struct eventfd_ctx *ctx)
>  {
> diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
> index 4f8aac7eb62a..fea7c4eb01d6 100644
> --- a/include/linux/eventfd.h
> +++ b/include/linux/eventfd.h
> @@ -35,8 +35,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
>  struct file *eventfd_fget(int fd);
>  struct eventfd_ctx *eventfd_ctx_fdget(int fd);
>  struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
> -__u64 eventfd_signal(struct eventfd_ctx *ctx);
> -__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
> +void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
>  int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
>  				  __u64 *cnt);
>  void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
> @@ -58,14 +57,8 @@ static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
>  	return ERR_PTR(-ENOSYS);
>  }
>  
> -static inline int eventfd_signal(struct eventfd_ctx *ctx)
> +static inline void eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
>  {
> -	return -ENOSYS;
> -}
> -
> -static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
> -{
> -	return -ENOSYS;
>  }
>  
>  static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
> @@ -91,5 +84,10 @@ static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
>  
>  #endif
>  
> +static inline void eventfd_signal(struct eventfd_ctx *ctx)
> +{
> +	eventfd_signal_mask(ctx, 0);
> +}
> +
>  #endif /* _LINUX_EVENTFD_H */
>  
> 
> -- 
> 2.42.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Jani Nikula]

On Wed, 22 Nov 2023, Christian Brauner <brauner@kernel.org> wrote:
> diff --git a/fs/eventfd.c b/fs/eventfd.c
> index 33a918f9566c..dc9e01053235 100644
> --- a/fs/eventfd.c
> +++ b/fs/eventfd.c
> @@ -74,20 +74,17 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
>  /**
>   * eventfd_signal - Adds @n to the eventfd counter.

This still refers to @n here, and in patch 4.

BR,
Jani.

>   * @ctx: [in] Pointer to the eventfd context.
> - * @n: [in] Value of the counter to be added to the eventfd internal counter.
> - *          The value cannot be negative.
>   *
>   * This function is supposed to be called by the kernel in paths that do not
>   * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
>   * value, and we signal this as overflow condition by returning a EPOLLERR
>   * to poll(2).
>   *
> - * Returns the amount by which the counter was incremented.  This will be less
> - * than @n if the counter has overflowed.
> + * Returns the amount by which the counter was incremented.
>   */
> -__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
> +__u64 eventfd_signal(struct eventfd_ctx *ctx)
>  {
> -	return eventfd_signal_mask(ctx, n, 0);
> +	return eventfd_signal_mask(ctx, 1, 0);
>  }
>  EXPORT_SYMBOL_GPL(eventfd_signal);
>  

-- 
Jani Nikula, Intel

Re: [PATCH v2 1/4] i915: make inject_virtual_interrupt() void

[Zhenyu Wang]

[-- Attachment #1: Type: text/plain, Size: 2135 bytes --]

On 2023.11.22 13:48:22 +0100, Christian Brauner wrote:
> The single caller of inject_virtual_interrupt() ignores the return value
> anyway. This allows us to simplify eventfd_signal() in follow-up
> patches.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> ---
>  drivers/gpu/drm/i915/gvt/interrupt.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/interrupt.c b/drivers/gpu/drm/i915/gvt/interrupt.c
> index de3f5903d1a7..9665876b4b13 100644
> --- a/drivers/gpu/drm/i915/gvt/interrupt.c
> +++ b/drivers/gpu/drm/i915/gvt/interrupt.c
> @@ -422,7 +422,7 @@ static void init_irq_map(struct intel_gvt_irq *irq)
>  #define MSI_CAP_DATA(offset) (offset + 8)
>  #define MSI_CAP_EN 0x1
>  
> -static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
> +static void inject_virtual_interrupt(struct intel_vgpu *vgpu)
>  {
>  	unsigned long offset = vgpu->gvt->device_info.msi_cap_offset;
>  	u16 control, data;
> @@ -434,10 +434,10 @@ static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
>  
>  	/* Do not generate MSI if MSIEN is disabled */
>  	if (!(control & MSI_CAP_EN))
> -		return 0;
> +		return;
>  
>  	if (WARN(control & GENMASK(15, 1), "only support one MSI format\n"))
> -		return -EINVAL;
> +		return;
>  
>  	trace_inject_msi(vgpu->id, addr, data);
>  
> @@ -451,10 +451,10 @@ static int inject_virtual_interrupt(struct intel_vgpu *vgpu)
>  	 * returned and don't inject interrupt into guest.
>  	 */
>  	if (!test_bit(INTEL_VGPU_STATUS_ATTACHED, vgpu->status))
> -		return -ESRCH;
> -	if (vgpu->msi_trigger && eventfd_signal(vgpu->msi_trigger, 1) != 1)
> -		return -EFAULT;
> -	return 0;
> +		return;
> +	if (!vgpu->msi_trigger)
> +		return;
> +	eventfd_signal(vgpu->msi_trigger, 1);
>  }

I think it's a little simpler to write as
    if (vgpu->msi_trigger)
            eventfd_signal(vgpu->msi_trigger, 1);

Looks fine with me.

Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>

Thanks!

>  
>  static void propagate_event(struct intel_gvt_irq *irq,
> 
> -- 
> 2.42.0
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]

Re: [PATCH v2 1/4] i915: make inject_virtual_interrupt() void

[Christian Brauner]

> > +	if (!vgpu->msi_trigger)
> > +		return;
> > +	eventfd_signal(vgpu->msi_trigger, 1);
> >  }
> 
> I think it's a little simpler to write as
>     if (vgpu->msi_trigger)
>             eventfd_signal(vgpu->msi_trigger, 1);

Good point. I folded that suggestion into the patch.

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Christian Brauner]

> >   * eventfd_signal - Adds @n to the eventfd counter.
> 
> This still refers to @n here, and in patch 4.

Fixed and folded. Thanks!

Re: [PATCH v2 0/4] eventfd: simplify signal helpers

[Jens Axboe]

On 11/22/23 5:48 AM, Christian Brauner wrote:
> Hey everyone,
> 
> This simplifies the eventfd_signal() and eventfd_signal_mask() helpers
> significantly. They can be made void and not take any unnecessary
> arguments.
> 
> I've added a few more simplifications based on Sean's suggestion.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> 
> Changes in v2:
> - further simplify helpers
> - Link to v1: https://lore.kernel.org/r/20230713-vfs-eventfd-signal-v1-0-7fda6c5d212b@kernel.org

Only oddity I spotted was the kerneldoc, which someone else already
brought up.

Reviewed-by: Jens Axboe <axboe@kernel.dk>

-- 
Jens Axboe

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Andrew Donnellan]

On Wed, 2023-11-22 at 13:48 +0100, Christian Brauner wrote:
> Ever since the evenfd type was introduced back in 2007 in commit
> e1ad7468c77d ("signal/timer/event: eventfd core") the
> eventfd_signal()
> function only ever passed 1 as a value for @n. There's no point in
> keeping that additional argument.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Acked-by: Andrew Donnellan <ajd@linux.ibm.com> # ocxl

-- 
Andrew Donnellan    OzLabs, ADL Canberra
ajd@linux.ibm.com   IBM Australia Limited

Re: [PATCH v2 0/4] eventfd: simplify signal helpers

[Christian Brauner]

On Wed, 22 Nov 2023 13:48:21 +0100, Christian Brauner wrote:
> Hey everyone,
> 
> This simplifies the eventfd_signal() and eventfd_signal_mask() helpers
> significantly. They can be made void and not take any unnecessary
> arguments.
> 
> I've added a few more simplifications based on Sean's suggestion.
> 
> [...]

Applied to the vfs.misc branch of the vfs/vfs.git tree.
Patches in the vfs.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.misc

[1/4] i915: make inject_virtual_interrupt() void
      https://git.kernel.org/vfs/vfs/c/858848719210
[2/4] eventfd: simplify eventfd_signal()
      https://git.kernel.org/vfs/vfs/c/ded0f31f825f
[3/4] eventfd: simplify eventfd_signal_mask()
      https://git.kernel.org/vfs/vfs/c/45ee1c990e88
[4/4] eventfd: make eventfd_signal{_mask}() void
      https://git.kernel.org/vfs/vfs/c/37d5d473e749

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Eric Farman]

On Wed, 2023-11-22 at 13:48 +0100, Christian Brauner wrote:
> Ever since the evenfd type was introduced back in 2007 in commit

s/evenfd/eventfd/

> e1ad7468c77d ("signal/timer/event: eventfd core") the
> eventfd_signal()
> function only ever passed 1 as a value for @n. There's no point in
> keeping that additional argument.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> ---
>  arch/x86/kvm/hyperv.c                     |  2 +-
>  arch/x86/kvm/xen.c                        |  2 +-
>  drivers/accel/habanalabs/common/device.c  |  2 +-
>  drivers/fpga/dfl.c                        |  2 +-
>  drivers/gpu/drm/drm_syncobj.c             |  6 +++---
>  drivers/gpu/drm/i915/gvt/interrupt.c      |  2 +-
>  drivers/infiniband/hw/mlx5/devx.c         |  2 +-
>  drivers/misc/ocxl/file.c                  |  2 +-
>  drivers/s390/cio/vfio_ccw_chp.c           |  2 +-
>  drivers/s390/cio/vfio_ccw_drv.c           |  4 ++--
>  drivers/s390/cio/vfio_ccw_ops.c           |  6 +++---
>  drivers/s390/crypto/vfio_ap_ops.c         |  2 +-

Acked-by: Eric Farman <farman@linux.ibm.com>  # s390

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Stefan Hajnoczi]

vhost and VIRTIO-related parts:

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

On Wed, 22 Nov 2023 at 07:50, Christian Brauner <brauner@kernel.org> wrote:
>
> Ever since the evenfd type was introduced back in 2007 in commit
> e1ad7468c77d ("signal/timer/event: eventfd core") the eventfd_signal()
> function only ever passed 1 as a value for @n. There's no point in
> keeping that additional argument.
>
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> ---
>  arch/x86/kvm/hyperv.c                     |  2 +-
>  arch/x86/kvm/xen.c                        |  2 +-
>  drivers/accel/habanalabs/common/device.c  |  2 +-
>  drivers/fpga/dfl.c                        |  2 +-
>  drivers/gpu/drm/drm_syncobj.c             |  6 +++---
>  drivers/gpu/drm/i915/gvt/interrupt.c      |  2 +-
>  drivers/infiniband/hw/mlx5/devx.c         |  2 +-
>  drivers/misc/ocxl/file.c                  |  2 +-
>  drivers/s390/cio/vfio_ccw_chp.c           |  2 +-
>  drivers/s390/cio/vfio_ccw_drv.c           |  4 ++--
>  drivers/s390/cio/vfio_ccw_ops.c           |  6 +++---
>  drivers/s390/crypto/vfio_ap_ops.c         |  2 +-
>  drivers/usb/gadget/function/f_fs.c        |  4 ++--
>  drivers/vdpa/vdpa_user/vduse_dev.c        |  6 +++---
>  drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c    |  2 +-
>  drivers/vfio/pci/vfio_pci_core.c          |  6 +++---
>  drivers/vfio/pci/vfio_pci_intrs.c         | 12 ++++++------
>  drivers/vfio/platform/vfio_platform_irq.c |  4 ++--
>  drivers/vhost/vdpa.c                      |  4 ++--
>  drivers/vhost/vhost.c                     | 10 +++++-----
>  drivers/vhost/vhost.h                     |  2 +-
>  drivers/virt/acrn/ioeventfd.c             |  2 +-
>  drivers/xen/privcmd.c                     |  2 +-
>  fs/aio.c                                  |  2 +-
>  fs/eventfd.c                              |  9 +++------
>  include/linux/eventfd.h                   |  4 ++--
>  mm/memcontrol.c                           | 10 +++++-----
>  mm/vmpressure.c                           |  2 +-
>  samples/vfio-mdev/mtty.c                  |  4 ++--
>  virt/kvm/eventfd.c                        |  4 ++--
>  30 files changed, 60 insertions(+), 63 deletions(-)
>
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index 238afd7335e4..4943f6b2bbee 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -2388,7 +2388,7 @@ static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *h
>         if (!eventfd)
>                 return HV_STATUS_INVALID_PORT_ID;
>
> -       eventfd_signal(eventfd, 1);
> +       eventfd_signal(eventfd);
>         return HV_STATUS_SUCCESS;
>  }
>
> diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
> index e53fad915a62..523bb6df5ac9 100644
> --- a/arch/x86/kvm/xen.c
> +++ b/arch/x86/kvm/xen.c
> @@ -2088,7 +2088,7 @@ static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
>                 if (ret < 0 && ret != -ENOTCONN)
>                         return false;
>         } else {
> -               eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1);
> +               eventfd_signal(evtchnfd->deliver.eventfd.ctx);
>         }
>
>         *r = 0;
> diff --git a/drivers/accel/habanalabs/common/device.c b/drivers/accel/habanalabs/common/device.c
> index 9711e8fc979d..3a89644f087c 100644
> --- a/drivers/accel/habanalabs/common/device.c
> +++ b/drivers/accel/habanalabs/common/device.c
> @@ -2044,7 +2044,7 @@ static void hl_notifier_event_send(struct hl_notifier_event *notifier_event, u64
>         notifier_event->events_mask |= event_mask;
>
>         if (notifier_event->eventfd)
> -               eventfd_signal(notifier_event->eventfd, 1);
> +               eventfd_signal(notifier_event->eventfd);
>
>         mutex_unlock(&notifier_event->lock);
>  }
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index dd7a783d53b5..e73f88050f08 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -1872,7 +1872,7 @@ static irqreturn_t dfl_irq_handler(int irq, void *arg)
>  {
>         struct eventfd_ctx *trigger = arg;
>
> -       eventfd_signal(trigger, 1);
> +       eventfd_signal(trigger);
>         return IRQ_HANDLED;
>  }
>
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index 01da6789d044..b9cc62982196 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -1365,7 +1365,7 @@ static void syncobj_eventfd_entry_fence_func(struct dma_fence *fence,
>         struct syncobj_eventfd_entry *entry =
>                 container_of(cb, struct syncobj_eventfd_entry, fence_cb);
>
> -       eventfd_signal(entry->ev_fd_ctx, 1);
> +       eventfd_signal(entry->ev_fd_ctx);
>         syncobj_eventfd_entry_free(entry);
>  }
>
> @@ -1388,13 +1388,13 @@ syncobj_eventfd_entry_func(struct drm_syncobj *syncobj,
>         entry->fence = fence;
>
>         if (entry->flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE) {
> -               eventfd_signal(entry->ev_fd_ctx, 1);
> +               eventfd_signal(entry->ev_fd_ctx);
>                 syncobj_eventfd_entry_free(entry);
>         } else {
>                 ret = dma_fence_add_callback(fence, &entry->fence_cb,
>                                              syncobj_eventfd_entry_fence_func);
>                 if (ret == -ENOENT) {
> -                       eventfd_signal(entry->ev_fd_ctx, 1);
> +                       eventfd_signal(entry->ev_fd_ctx);
>                         syncobj_eventfd_entry_free(entry);
>                 }
>         }
> diff --git a/drivers/gpu/drm/i915/gvt/interrupt.c b/drivers/gpu/drm/i915/gvt/interrupt.c
> index 9665876b4b13..7f4db438e400 100644
> --- a/drivers/gpu/drm/i915/gvt/interrupt.c
> +++ b/drivers/gpu/drm/i915/gvt/interrupt.c
> @@ -454,7 +454,7 @@ static void inject_virtual_interrupt(struct intel_vgpu *vgpu)
>                 return;
>         if (!vgpu->msi_trigger)
>                 return;
> -       eventfd_signal(vgpu->msi_trigger, 1);
> +       eventfd_signal(vgpu->msi_trigger);
>  }
>
>  static void propagate_event(struct intel_gvt_irq *irq,
> diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
> index 8ba53edf2311..869369cb5b5f 100644
> --- a/drivers/infiniband/hw/mlx5/devx.c
> +++ b/drivers/infiniband/hw/mlx5/devx.c
> @@ -2498,7 +2498,7 @@ static void dispatch_event_fd(struct list_head *fd_list,
>
>         list_for_each_entry_rcu(item, fd_list, xa_list) {
>                 if (item->eventfd)
> -                       eventfd_signal(item->eventfd, 1);
> +                       eventfd_signal(item->eventfd);
>                 else
>                         deliver_event(item, data);
>         }
> diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
> index ac69b7f361f5..7eb74711ac96 100644
> --- a/drivers/misc/ocxl/file.c
> +++ b/drivers/misc/ocxl/file.c
> @@ -184,7 +184,7 @@ static irqreturn_t irq_handler(void *private)
>  {
>         struct eventfd_ctx *ev_ctx = private;
>
> -       eventfd_signal(ev_ctx, 1);
> +       eventfd_signal(ev_ctx);
>         return IRQ_HANDLED;
>  }
>
> diff --git a/drivers/s390/cio/vfio_ccw_chp.c b/drivers/s390/cio/vfio_ccw_chp.c
> index d3f3a611f95b..38c176cf6295 100644
> --- a/drivers/s390/cio/vfio_ccw_chp.c
> +++ b/drivers/s390/cio/vfio_ccw_chp.c
> @@ -115,7 +115,7 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_ccw_private *private,
>
>         /* Notify the guest if more CRWs are on our queue */
>         if (!list_empty(&private->crw) && private->crw_trigger)
> -               eventfd_signal(private->crw_trigger, 1);
> +               eventfd_signal(private->crw_trigger);
>
>         return ret;
>  }
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
> index 43601816ea4e..bfb35cfce1ef 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -112,7 +112,7 @@ void vfio_ccw_sch_io_todo(struct work_struct *work)
>                 private->state = VFIO_CCW_STATE_IDLE;
>
>         if (private->io_trigger)
> -               eventfd_signal(private->io_trigger, 1);
> +               eventfd_signal(private->io_trigger);
>  }
>
>  void vfio_ccw_crw_todo(struct work_struct *work)
> @@ -122,7 +122,7 @@ void vfio_ccw_crw_todo(struct work_struct *work)
>         private = container_of(work, struct vfio_ccw_private, crw_work);
>
>         if (!list_empty(&private->crw) && private->crw_trigger)
> -               eventfd_signal(private->crw_trigger, 1);
> +               eventfd_signal(private->crw_trigger);
>  }
>
>  /*
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index cba4971618ff..ea532a8a4a0c 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -421,7 +421,7 @@ static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
>         case VFIO_IRQ_SET_DATA_NONE:
>         {
>                 if (*ctx)
> -                       eventfd_signal(*ctx, 1);
> +                       eventfd_signal(*ctx);
>                 return 0;
>         }
>         case VFIO_IRQ_SET_DATA_BOOL:
> @@ -432,7 +432,7 @@ static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
>                         return -EFAULT;
>
>                 if (trigger && *ctx)
> -                       eventfd_signal(*ctx, 1);
> +                       eventfd_signal(*ctx);
>                 return 0;
>         }
>         case VFIO_IRQ_SET_DATA_EVENTFD:
> @@ -612,7 +612,7 @@ static void vfio_ccw_mdev_request(struct vfio_device *vdev, unsigned int count)
>                                                "Relaying device request to user (#%u)\n",
>                                                count);
>
> -               eventfd_signal(private->req_trigger, 1);
> +               eventfd_signal(private->req_trigger);
>         } else if (count == 0) {
>                 dev_notice(dev,
>                            "No device request channel registered, blocked until released by user\n");
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 4db538a55192..542b5be73a6a 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -1794,7 +1794,7 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
>                                                "Relaying device request to user (#%u)\n",
>                                                count);
>
> -               eventfd_signal(matrix_mdev->req_trigger, 1);
> +               eventfd_signal(matrix_mdev->req_trigger);
>         } else if (count == 0) {
>                 dev_notice(dev,
>                            "No device request registered, blocked until released by user\n");
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index efe3e3b85769..fdd0fc7b8f25 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -831,7 +831,7 @@ static void ffs_user_copy_worker(struct work_struct *work)
>         io_data->kiocb->ki_complete(io_data->kiocb, ret);
>
>         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
> -               eventfd_signal(io_data->ffs->ffs_eventfd, 1);
> +               eventfd_signal(io_data->ffs->ffs_eventfd);
>
>         if (io_data->read)
>                 kfree(io_data->to_free);
> @@ -2738,7 +2738,7 @@ static void __ffs_event_add(struct ffs_data *ffs,
>         ffs->ev.types[ffs->ev.count++] = type;
>         wake_up_locked(&ffs->ev.waitq);
>         if (ffs->ffs_eventfd)
> -               eventfd_signal(ffs->ffs_eventfd, 1);
> +               eventfd_signal(ffs->ffs_eventfd);
>  }
>
>  static void ffs_event_add(struct ffs_data *ffs,
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index 0ddd4b8abecb..6cb5ce4a8b9a 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -493,7 +493,7 @@ static void vduse_vq_kick(struct vduse_virtqueue *vq)
>                 goto unlock;
>
>         if (vq->kickfd)
> -               eventfd_signal(vq->kickfd, 1);
> +               eventfd_signal(vq->kickfd);
>         else
>                 vq->kicked = true;
>  unlock:
> @@ -911,7 +911,7 @@ static int vduse_kickfd_setup(struct vduse_dev *dev,
>                 eventfd_ctx_put(vq->kickfd);
>         vq->kickfd = ctx;
>         if (vq->ready && vq->kicked && vq->kickfd) {
> -               eventfd_signal(vq->kickfd, 1);
> +               eventfd_signal(vq->kickfd);
>                 vq->kicked = false;
>         }
>         spin_unlock(&vq->kick_lock);
> @@ -960,7 +960,7 @@ static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)
>
>         spin_lock_irq(&vq->irq_lock);
>         if (vq->ready && vq->cb.trigger) {
> -               eventfd_signal(vq->cb.trigger, 1);
> +               eventfd_signal(vq->cb.trigger);
>                 signal = true;
>         }
>         spin_unlock_irq(&vq->irq_lock);
> diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
> index c51229fccbd6..d62fbfff20b8 100644
> --- a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
> +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
> @@ -54,7 +54,7 @@ static irqreturn_t vfio_fsl_mc_irq_handler(int irq_num, void *arg)
>  {
>         struct vfio_fsl_mc_irq *mc_irq = (struct vfio_fsl_mc_irq *)arg;
>
> -       eventfd_signal(mc_irq->trigger, 1);
> +       eventfd_signal(mc_irq->trigger);
>         return IRQ_HANDLED;
>  }
>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 1929103ee59a..1cbc990d42e0 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -443,7 +443,7 @@ static int vfio_pci_core_runtime_resume(struct device *dev)
>          */
>         down_write(&vdev->memory_lock);
>         if (vdev->pm_wake_eventfd_ctx) {
> -               eventfd_signal(vdev->pm_wake_eventfd_ctx, 1);
> +               eventfd_signal(vdev->pm_wake_eventfd_ctx);
>                 __vfio_pci_runtime_pm_exit(vdev);
>         }
>         up_write(&vdev->memory_lock);
> @@ -1883,7 +1883,7 @@ void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count)
>                         pci_notice_ratelimited(pdev,
>                                 "Relaying device request to user (#%u)\n",
>                                 count);
> -               eventfd_signal(vdev->req_trigger, 1);
> +               eventfd_signal(vdev->req_trigger);
>         } else if (count == 0) {
>                 pci_warn(pdev,
>                         "No device request channel registered, blocked until released by user\n");
> @@ -2302,7 +2302,7 @@ pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
>         mutex_lock(&vdev->igate);
>
>         if (vdev->err_trigger)
> -               eventfd_signal(vdev->err_trigger, 1);
> +               eventfd_signal(vdev->err_trigger);
>
>         mutex_unlock(&vdev->igate);
>
> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
> index cbb4bcbfbf83..237beac83809 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -94,7 +94,7 @@ static void vfio_send_intx_eventfd(void *opaque, void *unused)
>                 ctx = vfio_irq_ctx_get(vdev, 0);
>                 if (WARN_ON_ONCE(!ctx))
>                         return;
> -               eventfd_signal(ctx->trigger, 1);
> +               eventfd_signal(ctx->trigger);
>         }
>  }
>
> @@ -342,7 +342,7 @@ static irqreturn_t vfio_msihandler(int irq, void *arg)
>  {
>         struct eventfd_ctx *trigger = arg;
>
> -       eventfd_signal(trigger, 1);
> +       eventfd_signal(trigger);
>         return IRQ_HANDLED;
>  }
>
> @@ -689,11 +689,11 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_core_device *vdev,
>                 if (!ctx)
>                         continue;
>                 if (flags & VFIO_IRQ_SET_DATA_NONE) {
> -                       eventfd_signal(ctx->trigger, 1);
> +                       eventfd_signal(ctx->trigger);
>                 } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
>                         uint8_t *bools = data;
>                         if (bools[i - start])
> -                               eventfd_signal(ctx->trigger, 1);
> +                               eventfd_signal(ctx->trigger);
>                 }
>         }
>         return 0;
> @@ -707,7 +707,7 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
>         if (flags & VFIO_IRQ_SET_DATA_NONE) {
>                 if (*ctx) {
>                         if (count) {
> -                               eventfd_signal(*ctx, 1);
> +                               eventfd_signal(*ctx);
>                         } else {
>                                 eventfd_ctx_put(*ctx);
>                                 *ctx = NULL;
> @@ -722,7 +722,7 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
>
>                 trigger = *(uint8_t *)data;
>                 if (trigger && *ctx)
> -                       eventfd_signal(*ctx, 1);
> +                       eventfd_signal(*ctx);
>
>                 return 0;
>         } else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
> index 665197caed89..61a1bfb68ac7 100644
> --- a/drivers/vfio/platform/vfio_platform_irq.c
> +++ b/drivers/vfio/platform/vfio_platform_irq.c
> @@ -155,7 +155,7 @@ static irqreturn_t vfio_automasked_irq_handler(int irq, void *dev_id)
>         spin_unlock_irqrestore(&irq_ctx->lock, flags);
>
>         if (ret == IRQ_HANDLED)
> -               eventfd_signal(irq_ctx->trigger, 1);
> +               eventfd_signal(irq_ctx->trigger);
>
>         return ret;
>  }
> @@ -164,7 +164,7 @@ static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
>  {
>         struct vfio_platform_irq *irq_ctx = dev_id;
>
> -       eventfd_signal(irq_ctx->trigger, 1);
> +       eventfd_signal(irq_ctx->trigger);
>
>         return IRQ_HANDLED;
>  }
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 30df5c58db73..8d9f958946d6 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -178,7 +178,7 @@ static irqreturn_t vhost_vdpa_virtqueue_cb(void *private)
>         struct eventfd_ctx *call_ctx = vq->call_ctx.ctx;
>
>         if (call_ctx)
> -               eventfd_signal(call_ctx, 1);
> +               eventfd_signal(call_ctx);
>
>         return IRQ_HANDLED;
>  }
> @@ -189,7 +189,7 @@ static irqreturn_t vhost_vdpa_config_cb(void *private)
>         struct eventfd_ctx *config_ctx = v->config_ctx;
>
>         if (config_ctx)
> -               eventfd_signal(config_ctx, 1);
> +               eventfd_signal(config_ctx);
>
>         return IRQ_HANDLED;
>  }
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index e0c181ad17e3..045f666b4f12 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -2248,7 +2248,7 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
>                 len -= l;
>                 if (!len) {
>                         if (vq->log_ctx)
> -                               eventfd_signal(vq->log_ctx, 1);
> +                               eventfd_signal(vq->log_ctx);
>                         return 0;
>                 }
>         }
> @@ -2271,7 +2271,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
>                 log_used(vq, (used - (void __user *)vq->used),
>                          sizeof vq->used->flags);
>                 if (vq->log_ctx)
> -                       eventfd_signal(vq->log_ctx, 1);
> +                       eventfd_signal(vq->log_ctx);
>         }
>         return 0;
>  }
> @@ -2289,7 +2289,7 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq)
>                 log_used(vq, (used - (void __user *)vq->used),
>                          sizeof *vhost_avail_event(vq));
>                 if (vq->log_ctx)
> -                       eventfd_signal(vq->log_ctx, 1);
> +                       eventfd_signal(vq->log_ctx);
>         }
>         return 0;
>  }
> @@ -2715,7 +2715,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
>                 log_used(vq, offsetof(struct vring_used, idx),
>                          sizeof vq->used->idx);
>                 if (vq->log_ctx)
> -                       eventfd_signal(vq->log_ctx, 1);
> +                       eventfd_signal(vq->log_ctx);
>         }
>         return r;
>  }
> @@ -2763,7 +2763,7 @@ void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
>  {
>         /* Signal the Guest tell them we used something up. */
>         if (vq->call_ctx.ctx && vhost_notify(dev, vq))
> -               eventfd_signal(vq->call_ctx.ctx, 1);
> +               eventfd_signal(vq->call_ctx.ctx);
>  }
>  EXPORT_SYMBOL_GPL(vhost_signal);
>
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index f60d5f7bef94..9e942fcda5c3 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -249,7 +249,7 @@ void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
>  #define vq_err(vq, fmt, ...) do {                                  \
>                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
>                 if ((vq)->error_ctx)                               \
> -                               eventfd_signal((vq)->error_ctx, 1);\
> +                               eventfd_signal((vq)->error_ctx);\
>         } while (0)
>
>  enum {
> diff --git a/drivers/virt/acrn/ioeventfd.c b/drivers/virt/acrn/ioeventfd.c
> index ac4037e9f947..4e845c6ca0b5 100644
> --- a/drivers/virt/acrn/ioeventfd.c
> +++ b/drivers/virt/acrn/ioeventfd.c
> @@ -223,7 +223,7 @@ static int acrn_ioeventfd_handler(struct acrn_ioreq_client *client,
>         mutex_lock(&client->vm->ioeventfds_lock);
>         p = hsm_ioeventfd_match(client->vm, addr, val, size, req->type);
>         if (p)
> -               eventfd_signal(p->eventfd, 1);
> +               eventfd_signal(p->eventfd);
>         mutex_unlock(&client->vm->ioeventfds_lock);
>
>         return 0;
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index 1ce7f3c7a950..7efc0c62e984 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -1147,7 +1147,7 @@ static irqreturn_t ioeventfd_interrupt(int irq, void *dev_id)
>                 if (ioreq->addr == kioeventfd->addr + VIRTIO_MMIO_QUEUE_NOTIFY &&
>                     ioreq->size == kioeventfd->addr_len &&
>                     (ioreq->data & QUEUE_NOTIFY_VQ_MASK) == kioeventfd->vq) {
> -                       eventfd_signal(kioeventfd->eventfd, 1);
> +                       eventfd_signal(kioeventfd->eventfd);
>                         state = STATE_IORESP_READY;
>                         break;
>                 }
> diff --git a/fs/aio.c b/fs/aio.c
> index f8589caef9c1..5c5b09e52d75 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1166,7 +1166,7 @@ static void aio_complete(struct aio_kiocb *iocb)
>          * from IRQ context.
>          */
>         if (iocb->ki_eventfd)
> -               eventfd_signal(iocb->ki_eventfd, 1);
> +               eventfd_signal(iocb->ki_eventfd);
>
>         /*
>          * We have to order our ring_info tail store above and test
> diff --git a/fs/eventfd.c b/fs/eventfd.c
> index 33a918f9566c..dc9e01053235 100644
> --- a/fs/eventfd.c
> +++ b/fs/eventfd.c
> @@ -74,20 +74,17 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
>  /**
>   * eventfd_signal - Adds @n to the eventfd counter.
>   * @ctx: [in] Pointer to the eventfd context.
> - * @n: [in] Value of the counter to be added to the eventfd internal counter.
> - *          The value cannot be negative.
>   *
>   * This function is supposed to be called by the kernel in paths that do not
>   * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
>   * value, and we signal this as overflow condition by returning a EPOLLERR
>   * to poll(2).
>   *
> - * Returns the amount by which the counter was incremented.  This will be less
> - * than @n if the counter has overflowed.
> + * Returns the amount by which the counter was incremented.
>   */
> -__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
> +__u64 eventfd_signal(struct eventfd_ctx *ctx)
>  {
> -       return eventfd_signal_mask(ctx, n, 0);
> +       return eventfd_signal_mask(ctx, 1, 0);
>  }
>  EXPORT_SYMBOL_GPL(eventfd_signal);
>
> diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
> index b9d83652c097..562089431551 100644
> --- a/include/linux/eventfd.h
> +++ b/include/linux/eventfd.h
> @@ -35,7 +35,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
>  struct file *eventfd_fget(int fd);
>  struct eventfd_ctx *eventfd_ctx_fdget(int fd);
>  struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
> -__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
> +__u64 eventfd_signal(struct eventfd_ctx *ctx);
>  __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask);
>  int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
>                                   __u64 *cnt);
> @@ -58,7 +58,7 @@ static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
>         return ERR_PTR(-ENOSYS);
>  }
>
> -static inline int eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
> +static inline int eventfd_signal(struct eventfd_ctx *ctx)
>  {
>         return -ENOSYS;
>  }
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 774bd6e21e27..dfbb1d3b77b7 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4378,7 +4378,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
>          * only one element of the array here.
>          */
>         for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
> -               eventfd_signal(t->entries[i].eventfd, 1);
> +               eventfd_signal(t->entries[i].eventfd);
>
>         /* i = current_threshold + 1 */
>         i++;
> @@ -4390,7 +4390,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
>          * only one element of the array here.
>          */
>         for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
> -               eventfd_signal(t->entries[i].eventfd, 1);
> +               eventfd_signal(t->entries[i].eventfd);
>
>         /* Update current_threshold */
>         t->current_threshold = i - 1;
> @@ -4430,7 +4430,7 @@ static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
>         spin_lock(&memcg_oom_lock);
>
>         list_for_each_entry(ev, &memcg->oom_notify, list)
> -               eventfd_signal(ev->eventfd, 1);
> +               eventfd_signal(ev->eventfd);
>
>         spin_unlock(&memcg_oom_lock);
>         return 0;
> @@ -4649,7 +4649,7 @@ static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
>
>         /* already in OOM ? */
>         if (memcg->under_oom)
> -               eventfd_signal(eventfd, 1);
> +               eventfd_signal(eventfd);
>         spin_unlock(&memcg_oom_lock);
>
>         return 0;
> @@ -4941,7 +4941,7 @@ static void memcg_event_remove(struct work_struct *work)
>         event->unregister_event(memcg, event->eventfd);
>
>         /* Notify userspace the event is going away. */
> -       eventfd_signal(event->eventfd, 1);
> +       eventfd_signal(event->eventfd);
>
>         eventfd_ctx_put(event->eventfd);
>         kfree(event);
> diff --git a/mm/vmpressure.c b/mm/vmpressure.c
> index 22c6689d9302..bd5183dfd879 100644
> --- a/mm/vmpressure.c
> +++ b/mm/vmpressure.c
> @@ -169,7 +169,7 @@ static bool vmpressure_event(struct vmpressure *vmpr,
>                         continue;
>                 if (level < ev->level)
>                         continue;
> -               eventfd_signal(ev->efd, 1);
> +               eventfd_signal(ev->efd);
>                 ret = true;
>         }
>         mutex_unlock(&vmpr->events_lock);
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 69ba0281f9e0..2284b3751240 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -234,10 +234,10 @@ static void mtty_trigger_interrupt(struct mdev_state *mdev_state)
>
>         if (is_msi(mdev_state)) {
>                 if (mdev_state->msi_evtfd)
> -                       eventfd_signal(mdev_state->msi_evtfd, 1);
> +                       eventfd_signal(mdev_state->msi_evtfd);
>         } else if (is_intx(mdev_state)) {
>                 if (mdev_state->intx_evtfd && !mdev_state->intx_mask) {
> -                       eventfd_signal(mdev_state->intx_evtfd, 1);
> +                       eventfd_signal(mdev_state->intx_evtfd);
>                         mdev_state->intx_mask = true;
>                 }
>         }
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index 89912a17f5d5..c0e230f4c3e9 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -61,7 +61,7 @@ static void irqfd_resampler_notify(struct kvm_kernel_irqfd_resampler *resampler)
>
>         list_for_each_entry_srcu(irqfd, &resampler->list, resampler_link,
>                                  srcu_read_lock_held(&resampler->kvm->irq_srcu))
> -               eventfd_signal(irqfd->resamplefd, 1);
> +               eventfd_signal(irqfd->resamplefd);
>  }
>
>  /*
> @@ -786,7 +786,7 @@ ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,
>         if (!ioeventfd_in_range(p, addr, len, val))
>                 return -EOPNOTSUPP;
>
> -       eventfd_signal(p->eventfd, 1);
> +       eventfd_signal(p->eventfd);
>         return 0;
>  }
>
>
> --
> 2.42.0
>
>

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Anthony Krowiak]

For vfio_ap_ops.c

Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>

On 2/6/24 2:44 PM, Stefan Hajnoczi wrote:
> vhost and VIRTIO-related parts:
>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
>
> On Wed, 22 Nov 2023 at 07:50, Christian Brauner <brauner@kernel.org> wrote:
>> Ever since the evenfd type was introduced back in 2007 in commit
>> e1ad7468c77d ("signal/timer/event: eventfd core") the eventfd_signal()
>> function only ever passed 1 as a value for @n. There's no point in
>> keeping that additional argument.
>>
>> Signed-off-by: Christian Brauner <brauner@kernel.org>
>> ---
>>   arch/x86/kvm/hyperv.c                     |  2 +-
>>   arch/x86/kvm/xen.c                        |  2 +-
>>   drivers/accel/habanalabs/common/device.c  |  2 +-
>>   drivers/fpga/dfl.c                        |  2 +-
>>   drivers/gpu/drm/drm_syncobj.c             |  6 +++---
>>   drivers/gpu/drm/i915/gvt/interrupt.c      |  2 +-
>>   drivers/infiniband/hw/mlx5/devx.c         |  2 +-
>>   drivers/misc/ocxl/file.c                  |  2 +-
>>   drivers/s390/cio/vfio_ccw_chp.c           |  2 +-
>>   drivers/s390/cio/vfio_ccw_drv.c           |  4 ++--
>>   drivers/s390/cio/vfio_ccw_ops.c           |  6 +++---
>>   drivers/s390/crypto/vfio_ap_ops.c         |  2 +-
>>   drivers/usb/gadget/function/f_fs.c        |  4 ++--
>>   drivers/vdpa/vdpa_user/vduse_dev.c        |  6 +++---
>>   drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c    |  2 +-
>>   drivers/vfio/pci/vfio_pci_core.c          |  6 +++---
>>   drivers/vfio/pci/vfio_pci_intrs.c         | 12 ++++++------
>>   drivers/vfio/platform/vfio_platform_irq.c |  4 ++--
>>   drivers/vhost/vdpa.c                      |  4 ++--
>>   drivers/vhost/vhost.c                     | 10 +++++-----
>>   drivers/vhost/vhost.h                     |  2 +-
>>   drivers/virt/acrn/ioeventfd.c             |  2 +-
>>   drivers/xen/privcmd.c                     |  2 +-
>>   fs/aio.c                                  |  2 +-
>>   fs/eventfd.c                              |  9 +++------
>>   include/linux/eventfd.h                   |  4 ++--
>>   mm/memcontrol.c                           | 10 +++++-----
>>   mm/vmpressure.c                           |  2 +-
>>   samples/vfio-mdev/mtty.c                  |  4 ++--
>>   virt/kvm/eventfd.c                        |  4 ++--
>>   30 files changed, 60 insertions(+), 63 deletions(-)
>>
>> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
>> index 238afd7335e4..4943f6b2bbee 100644
>> --- a/arch/x86/kvm/hyperv.c
>> +++ b/arch/x86/kvm/hyperv.c
>> @@ -2388,7 +2388,7 @@ static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *h
>>          if (!eventfd)
>>                  return HV_STATUS_INVALID_PORT_ID;
>>
>> -       eventfd_signal(eventfd, 1);
>> +       eventfd_signal(eventfd);
>>          return HV_STATUS_SUCCESS;
>>   }
>>
>> diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
>> index e53fad915a62..523bb6df5ac9 100644
>> --- a/arch/x86/kvm/xen.c
>> +++ b/arch/x86/kvm/xen.c
>> @@ -2088,7 +2088,7 @@ static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
>>                  if (ret < 0 && ret != -ENOTCONN)
>>                          return false;
>>          } else {
>> -               eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1);
>> +               eventfd_signal(evtchnfd->deliver.eventfd.ctx);
>>          }
>>
>>          *r = 0;
>> diff --git a/drivers/accel/habanalabs/common/device.c b/drivers/accel/habanalabs/common/device.c
>> index 9711e8fc979d..3a89644f087c 100644
>> --- a/drivers/accel/habanalabs/common/device.c
>> +++ b/drivers/accel/habanalabs/common/device.c
>> @@ -2044,7 +2044,7 @@ static void hl_notifier_event_send(struct hl_notifier_event *notifier_event, u64
>>          notifier_event->events_mask |= event_mask;
>>
>>          if (notifier_event->eventfd)
>> -               eventfd_signal(notifier_event->eventfd, 1);
>> +               eventfd_signal(notifier_event->eventfd);
>>
>>          mutex_unlock(&notifier_event->lock);
>>   }
>> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
>> index dd7a783d53b5..e73f88050f08 100644
>> --- a/drivers/fpga/dfl.c
>> +++ b/drivers/fpga/dfl.c
>> @@ -1872,7 +1872,7 @@ static irqreturn_t dfl_irq_handler(int irq, void *arg)
>>   {
>>          struct eventfd_ctx *trigger = arg;
>>
>> -       eventfd_signal(trigger, 1);
>> +       eventfd_signal(trigger);
>>          return IRQ_HANDLED;
>>   }
>>
>> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
>> index 01da6789d044..b9cc62982196 100644
>> --- a/drivers/gpu/drm/drm_syncobj.c
>> +++ b/drivers/gpu/drm/drm_syncobj.c
>> @@ -1365,7 +1365,7 @@ static void syncobj_eventfd_entry_fence_func(struct dma_fence *fence,
>>          struct syncobj_eventfd_entry *entry =
>>                  container_of(cb, struct syncobj_eventfd_entry, fence_cb);
>>
>> -       eventfd_signal(entry->ev_fd_ctx, 1);
>> +       eventfd_signal(entry->ev_fd_ctx);
>>          syncobj_eventfd_entry_free(entry);
>>   }
>>
>> @@ -1388,13 +1388,13 @@ syncobj_eventfd_entry_func(struct drm_syncobj *syncobj,
>>          entry->fence = fence;
>>
>>          if (entry->flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE) {
>> -               eventfd_signal(entry->ev_fd_ctx, 1);
>> +               eventfd_signal(entry->ev_fd_ctx);
>>                  syncobj_eventfd_entry_free(entry);
>>          } else {
>>                  ret = dma_fence_add_callback(fence, &entry->fence_cb,
>>                                               syncobj_eventfd_entry_fence_func);
>>                  if (ret == -ENOENT) {
>> -                       eventfd_signal(entry->ev_fd_ctx, 1);
>> +                       eventfd_signal(entry->ev_fd_ctx);
>>                          syncobj_eventfd_entry_free(entry);
>>                  }
>>          }
>> diff --git a/drivers/gpu/drm/i915/gvt/interrupt.c b/drivers/gpu/drm/i915/gvt/interrupt.c
>> index 9665876b4b13..7f4db438e400 100644
>> --- a/drivers/gpu/drm/i915/gvt/interrupt.c
>> +++ b/drivers/gpu/drm/i915/gvt/interrupt.c
>> @@ -454,7 +454,7 @@ static void inject_virtual_interrupt(struct intel_vgpu *vgpu)
>>                  return;
>>          if (!vgpu->msi_trigger)
>>                  return;
>> -       eventfd_signal(vgpu->msi_trigger, 1);
>> +       eventfd_signal(vgpu->msi_trigger);
>>   }
>>
>>   static void propagate_event(struct intel_gvt_irq *irq,
>> diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
>> index 8ba53edf2311..869369cb5b5f 100644
>> --- a/drivers/infiniband/hw/mlx5/devx.c
>> +++ b/drivers/infiniband/hw/mlx5/devx.c
>> @@ -2498,7 +2498,7 @@ static void dispatch_event_fd(struct list_head *fd_list,
>>
>>          list_for_each_entry_rcu(item, fd_list, xa_list) {
>>                  if (item->eventfd)
>> -                       eventfd_signal(item->eventfd, 1);
>> +                       eventfd_signal(item->eventfd);
>>                  else
>>                          deliver_event(item, data);
>>          }
>> diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
>> index ac69b7f361f5..7eb74711ac96 100644
>> --- a/drivers/misc/ocxl/file.c
>> +++ b/drivers/misc/ocxl/file.c
>> @@ -184,7 +184,7 @@ static irqreturn_t irq_handler(void *private)
>>   {
>>          struct eventfd_ctx *ev_ctx = private;
>>
>> -       eventfd_signal(ev_ctx, 1);
>> +       eventfd_signal(ev_ctx);
>>          return IRQ_HANDLED;
>>   }
>>
>> diff --git a/drivers/s390/cio/vfio_ccw_chp.c b/drivers/s390/cio/vfio_ccw_chp.c
>> index d3f3a611f95b..38c176cf6295 100644
>> --- a/drivers/s390/cio/vfio_ccw_chp.c
>> +++ b/drivers/s390/cio/vfio_ccw_chp.c
>> @@ -115,7 +115,7 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_ccw_private *private,
>>
>>          /* Notify the guest if more CRWs are on our queue */
>>          if (!list_empty(&private->crw) && private->crw_trigger)
>> -               eventfd_signal(private->crw_trigger, 1);
>> +               eventfd_signal(private->crw_trigger);
>>
>>          return ret;
>>   }
>> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
>> index 43601816ea4e..bfb35cfce1ef 100644
>> --- a/drivers/s390/cio/vfio_ccw_drv.c
>> +++ b/drivers/s390/cio/vfio_ccw_drv.c
>> @@ -112,7 +112,7 @@ void vfio_ccw_sch_io_todo(struct work_struct *work)
>>                  private->state = VFIO_CCW_STATE_IDLE;
>>
>>          if (private->io_trigger)
>> -               eventfd_signal(private->io_trigger, 1);
>> +               eventfd_signal(private->io_trigger);
>>   }
>>
>>   void vfio_ccw_crw_todo(struct work_struct *work)
>> @@ -122,7 +122,7 @@ void vfio_ccw_crw_todo(struct work_struct *work)
>>          private = container_of(work, struct vfio_ccw_private, crw_work);
>>
>>          if (!list_empty(&private->crw) && private->crw_trigger)
>> -               eventfd_signal(private->crw_trigger, 1);
>> +               eventfd_signal(private->crw_trigger);
>>   }
>>
>>   /*
>> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
>> index cba4971618ff..ea532a8a4a0c 100644
>> --- a/drivers/s390/cio/vfio_ccw_ops.c
>> +++ b/drivers/s390/cio/vfio_ccw_ops.c
>> @@ -421,7 +421,7 @@ static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
>>          case VFIO_IRQ_SET_DATA_NONE:
>>          {
>>                  if (*ctx)
>> -                       eventfd_signal(*ctx, 1);
>> +                       eventfd_signal(*ctx);
>>                  return 0;
>>          }
>>          case VFIO_IRQ_SET_DATA_BOOL:
>> @@ -432,7 +432,7 @@ static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
>>                          return -EFAULT;
>>
>>                  if (trigger && *ctx)
>> -                       eventfd_signal(*ctx, 1);
>> +                       eventfd_signal(*ctx);
>>                  return 0;
>>          }
>>          case VFIO_IRQ_SET_DATA_EVENTFD:
>> @@ -612,7 +612,7 @@ static void vfio_ccw_mdev_request(struct vfio_device *vdev, unsigned int count)
>>                                                 "Relaying device request to user (#%u)\n",
>>                                                 count);
>>
>> -               eventfd_signal(private->req_trigger, 1);
>> +               eventfd_signal(private->req_trigger);
>>          } else if (count == 0) {
>>                  dev_notice(dev,
>>                             "No device request channel registered, blocked until released by user\n");
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
>> index 4db538a55192..542b5be73a6a 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -1794,7 +1794,7 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
>>                                                 "Relaying device request to user (#%u)\n",
>>                                                 count);
>>
>> -               eventfd_signal(matrix_mdev->req_trigger, 1);
>> +               eventfd_signal(matrix_mdev->req_trigger);
>>          } else if (count == 0) {
>>                  dev_notice(dev,
>>                             "No device request registered, blocked until released by user\n");
>> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
>> index efe3e3b85769..fdd0fc7b8f25 100644
>> --- a/drivers/usb/gadget/function/f_fs.c
>> +++ b/drivers/usb/gadget/function/f_fs.c
>> @@ -831,7 +831,7 @@ static void ffs_user_copy_worker(struct work_struct *work)
>>          io_data->kiocb->ki_complete(io_data->kiocb, ret);
>>
>>          if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
>> -               eventfd_signal(io_data->ffs->ffs_eventfd, 1);
>> +               eventfd_signal(io_data->ffs->ffs_eventfd);
>>
>>          if (io_data->read)
>>                  kfree(io_data->to_free);
>> @@ -2738,7 +2738,7 @@ static void __ffs_event_add(struct ffs_data *ffs,
>>          ffs->ev.types[ffs->ev.count++] = type;
>>          wake_up_locked(&ffs->ev.waitq);
>>          if (ffs->ffs_eventfd)
>> -               eventfd_signal(ffs->ffs_eventfd, 1);
>> +               eventfd_signal(ffs->ffs_eventfd);
>>   }
>>
>>   static void ffs_event_add(struct ffs_data *ffs,
>> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
>> index 0ddd4b8abecb..6cb5ce4a8b9a 100644
>> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
>> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
>> @@ -493,7 +493,7 @@ static void vduse_vq_kick(struct vduse_virtqueue *vq)
>>                  goto unlock;
>>
>>          if (vq->kickfd)
>> -               eventfd_signal(vq->kickfd, 1);
>> +               eventfd_signal(vq->kickfd);
>>          else
>>                  vq->kicked = true;
>>   unlock:
>> @@ -911,7 +911,7 @@ static int vduse_kickfd_setup(struct vduse_dev *dev,
>>                  eventfd_ctx_put(vq->kickfd);
>>          vq->kickfd = ctx;
>>          if (vq->ready && vq->kicked && vq->kickfd) {
>> -               eventfd_signal(vq->kickfd, 1);
>> +               eventfd_signal(vq->kickfd);
>>                  vq->kicked = false;
>>          }
>>          spin_unlock(&vq->kick_lock);
>> @@ -960,7 +960,7 @@ static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)
>>
>>          spin_lock_irq(&vq->irq_lock);
>>          if (vq->ready && vq->cb.trigger) {
>> -               eventfd_signal(vq->cb.trigger, 1);
>> +               eventfd_signal(vq->cb.trigger);
>>                  signal = true;
>>          }
>>          spin_unlock_irq(&vq->irq_lock);
>> diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
>> index c51229fccbd6..d62fbfff20b8 100644
>> --- a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
>> +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
>> @@ -54,7 +54,7 @@ static irqreturn_t vfio_fsl_mc_irq_handler(int irq_num, void *arg)
>>   {
>>          struct vfio_fsl_mc_irq *mc_irq = (struct vfio_fsl_mc_irq *)arg;
>>
>> -       eventfd_signal(mc_irq->trigger, 1);
>> +       eventfd_signal(mc_irq->trigger);
>>          return IRQ_HANDLED;
>>   }
>>
>> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
>> index 1929103ee59a..1cbc990d42e0 100644
>> --- a/drivers/vfio/pci/vfio_pci_core.c
>> +++ b/drivers/vfio/pci/vfio_pci_core.c
>> @@ -443,7 +443,7 @@ static int vfio_pci_core_runtime_resume(struct device *dev)
>>           */
>>          down_write(&vdev->memory_lock);
>>          if (vdev->pm_wake_eventfd_ctx) {
>> -               eventfd_signal(vdev->pm_wake_eventfd_ctx, 1);
>> +               eventfd_signal(vdev->pm_wake_eventfd_ctx);
>>                  __vfio_pci_runtime_pm_exit(vdev);
>>          }
>>          up_write(&vdev->memory_lock);
>> @@ -1883,7 +1883,7 @@ void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count)
>>                          pci_notice_ratelimited(pdev,
>>                                  "Relaying device request to user (#%u)\n",
>>                                  count);
>> -               eventfd_signal(vdev->req_trigger, 1);
>> +               eventfd_signal(vdev->req_trigger);
>>          } else if (count == 0) {
>>                  pci_warn(pdev,
>>                          "No device request channel registered, blocked until released by user\n");
>> @@ -2302,7 +2302,7 @@ pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
>>          mutex_lock(&vdev->igate);
>>
>>          if (vdev->err_trigger)
>> -               eventfd_signal(vdev->err_trigger, 1);
>> +               eventfd_signal(vdev->err_trigger);
>>
>>          mutex_unlock(&vdev->igate);
>>
>> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
>> index cbb4bcbfbf83..237beac83809 100644
>> --- a/drivers/vfio/pci/vfio_pci_intrs.c
>> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
>> @@ -94,7 +94,7 @@ static void vfio_send_intx_eventfd(void *opaque, void *unused)
>>                  ctx = vfio_irq_ctx_get(vdev, 0);
>>                  if (WARN_ON_ONCE(!ctx))
>>                          return;
>> -               eventfd_signal(ctx->trigger, 1);
>> +               eventfd_signal(ctx->trigger);
>>          }
>>   }
>>
>> @@ -342,7 +342,7 @@ static irqreturn_t vfio_msihandler(int irq, void *arg)
>>   {
>>          struct eventfd_ctx *trigger = arg;
>>
>> -       eventfd_signal(trigger, 1);
>> +       eventfd_signal(trigger);
>>          return IRQ_HANDLED;
>>   }
>>
>> @@ -689,11 +689,11 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_core_device *vdev,
>>                  if (!ctx)
>>                          continue;
>>                  if (flags & VFIO_IRQ_SET_DATA_NONE) {
>> -                       eventfd_signal(ctx->trigger, 1);
>> +                       eventfd_signal(ctx->trigger);
>>                  } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
>>                          uint8_t *bools = data;
>>                          if (bools[i - start])
>> -                               eventfd_signal(ctx->trigger, 1);
>> +                               eventfd_signal(ctx->trigger);
>>                  }
>>          }
>>          return 0;
>> @@ -707,7 +707,7 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
>>          if (flags & VFIO_IRQ_SET_DATA_NONE) {
>>                  if (*ctx) {
>>                          if (count) {
>> -                               eventfd_signal(*ctx, 1);
>> +                               eventfd_signal(*ctx);
>>                          } else {
>>                                  eventfd_ctx_put(*ctx);
>>                                  *ctx = NULL;
>> @@ -722,7 +722,7 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
>>
>>                  trigger = *(uint8_t *)data;
>>                  if (trigger && *ctx)
>> -                       eventfd_signal(*ctx, 1);
>> +                       eventfd_signal(*ctx);
>>
>>                  return 0;
>>          } else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
>> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
>> index 665197caed89..61a1bfb68ac7 100644
>> --- a/drivers/vfio/platform/vfio_platform_irq.c
>> +++ b/drivers/vfio/platform/vfio_platform_irq.c
>> @@ -155,7 +155,7 @@ static irqreturn_t vfio_automasked_irq_handler(int irq, void *dev_id)
>>          spin_unlock_irqrestore(&irq_ctx->lock, flags);
>>
>>          if (ret == IRQ_HANDLED)
>> -               eventfd_signal(irq_ctx->trigger, 1);
>> +               eventfd_signal(irq_ctx->trigger);
>>
>>          return ret;
>>   }
>> @@ -164,7 +164,7 @@ static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
>>   {
>>          struct vfio_platform_irq *irq_ctx = dev_id;
>>
>> -       eventfd_signal(irq_ctx->trigger, 1);
>> +       eventfd_signal(irq_ctx->trigger);
>>
>>          return IRQ_HANDLED;
>>   }
>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>> index 30df5c58db73..8d9f958946d6 100644
>> --- a/drivers/vhost/vdpa.c
>> +++ b/drivers/vhost/vdpa.c
>> @@ -178,7 +178,7 @@ static irqreturn_t vhost_vdpa_virtqueue_cb(void *private)
>>          struct eventfd_ctx *call_ctx = vq->call_ctx.ctx;
>>
>>          if (call_ctx)
>> -               eventfd_signal(call_ctx, 1);
>> +               eventfd_signal(call_ctx);
>>
>>          return IRQ_HANDLED;
>>   }
>> @@ -189,7 +189,7 @@ static irqreturn_t vhost_vdpa_config_cb(void *private)
>>          struct eventfd_ctx *config_ctx = v->config_ctx;
>>
>>          if (config_ctx)
>> -               eventfd_signal(config_ctx, 1);
>> +               eventfd_signal(config_ctx);
>>
>>          return IRQ_HANDLED;
>>   }
>> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>> index e0c181ad17e3..045f666b4f12 100644
>> --- a/drivers/vhost/vhost.c
>> +++ b/drivers/vhost/vhost.c
>> @@ -2248,7 +2248,7 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
>>                  len -= l;
>>                  if (!len) {
>>                          if (vq->log_ctx)
>> -                               eventfd_signal(vq->log_ctx, 1);
>> +                               eventfd_signal(vq->log_ctx);
>>                          return 0;
>>                  }
>>          }
>> @@ -2271,7 +2271,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
>>                  log_used(vq, (used - (void __user *)vq->used),
>>                           sizeof vq->used->flags);
>>                  if (vq->log_ctx)
>> -                       eventfd_signal(vq->log_ctx, 1);
>> +                       eventfd_signal(vq->log_ctx);
>>          }
>>          return 0;
>>   }
>> @@ -2289,7 +2289,7 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq)
>>                  log_used(vq, (used - (void __user *)vq->used),
>>                           sizeof *vhost_avail_event(vq));
>>                  if (vq->log_ctx)
>> -                       eventfd_signal(vq->log_ctx, 1);
>> +                       eventfd_signal(vq->log_ctx);
>>          }
>>          return 0;
>>   }
>> @@ -2715,7 +2715,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
>>                  log_used(vq, offsetof(struct vring_used, idx),
>>                           sizeof vq->used->idx);
>>                  if (vq->log_ctx)
>> -                       eventfd_signal(vq->log_ctx, 1);
>> +                       eventfd_signal(vq->log_ctx);
>>          }
>>          return r;
>>   }
>> @@ -2763,7 +2763,7 @@ void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
>>   {
>>          /* Signal the Guest tell them we used something up. */
>>          if (vq->call_ctx.ctx && vhost_notify(dev, vq))
>> -               eventfd_signal(vq->call_ctx.ctx, 1);
>> +               eventfd_signal(vq->call_ctx.ctx);
>>   }
>>   EXPORT_SYMBOL_GPL(vhost_signal);
>>
>> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
>> index f60d5f7bef94..9e942fcda5c3 100644
>> --- a/drivers/vhost/vhost.h
>> +++ b/drivers/vhost/vhost.h
>> @@ -249,7 +249,7 @@ void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
>>   #define vq_err(vq, fmt, ...) do {                                  \
>>                  pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
>>                  if ((vq)->error_ctx)                               \
>> -                               eventfd_signal((vq)->error_ctx, 1);\
>> +                               eventfd_signal((vq)->error_ctx);\
>>          } while (0)
>>
>>   enum {
>> diff --git a/drivers/virt/acrn/ioeventfd.c b/drivers/virt/acrn/ioeventfd.c
>> index ac4037e9f947..4e845c6ca0b5 100644
>> --- a/drivers/virt/acrn/ioeventfd.c
>> +++ b/drivers/virt/acrn/ioeventfd.c
>> @@ -223,7 +223,7 @@ static int acrn_ioeventfd_handler(struct acrn_ioreq_client *client,
>>          mutex_lock(&client->vm->ioeventfds_lock);
>>          p = hsm_ioeventfd_match(client->vm, addr, val, size, req->type);
>>          if (p)
>> -               eventfd_signal(p->eventfd, 1);
>> +               eventfd_signal(p->eventfd);
>>          mutex_unlock(&client->vm->ioeventfds_lock);
>>
>>          return 0;
>> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
>> index 1ce7f3c7a950..7efc0c62e984 100644
>> --- a/drivers/xen/privcmd.c
>> +++ b/drivers/xen/privcmd.c
>> @@ -1147,7 +1147,7 @@ static irqreturn_t ioeventfd_interrupt(int irq, void *dev_id)
>>                  if (ioreq->addr == kioeventfd->addr + VIRTIO_MMIO_QUEUE_NOTIFY &&
>>                      ioreq->size == kioeventfd->addr_len &&
>>                      (ioreq->data & QUEUE_NOTIFY_VQ_MASK) == kioeventfd->vq) {
>> -                       eventfd_signal(kioeventfd->eventfd, 1);
>> +                       eventfd_signal(kioeventfd->eventfd);
>>                          state = STATE_IORESP_READY;
>>                          break;
>>                  }
>> diff --git a/fs/aio.c b/fs/aio.c
>> index f8589caef9c1..5c5b09e52d75 100644
>> --- a/fs/aio.c
>> +++ b/fs/aio.c
>> @@ -1166,7 +1166,7 @@ static void aio_complete(struct aio_kiocb *iocb)
>>           * from IRQ context.
>>           */
>>          if (iocb->ki_eventfd)
>> -               eventfd_signal(iocb->ki_eventfd, 1);
>> +               eventfd_signal(iocb->ki_eventfd);
>>
>>          /*
>>           * We have to order our ring_info tail store above and test
>> diff --git a/fs/eventfd.c b/fs/eventfd.c
>> index 33a918f9566c..dc9e01053235 100644
>> --- a/fs/eventfd.c
>> +++ b/fs/eventfd.c
>> @@ -74,20 +74,17 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
>>   /**
>>    * eventfd_signal - Adds @n to the eventfd counter.
>>    * @ctx: [in] Pointer to the eventfd context.
>> - * @n: [in] Value of the counter to be added to the eventfd internal counter.
>> - *          The value cannot be negative.
>>    *
>>    * This function is supposed to be called by the kernel in paths that do not
>>    * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
>>    * value, and we signal this as overflow condition by returning a EPOLLERR
>>    * to poll(2).
>>    *
>> - * Returns the amount by which the counter was incremented.  This will be less
>> - * than @n if the counter has overflowed.
>> + * Returns the amount by which the counter was incremented.
>>    */
>> -__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
>> +__u64 eventfd_signal(struct eventfd_ctx *ctx)
>>   {
>> -       return eventfd_signal_mask(ctx, n, 0);
>> +       return eventfd_signal_mask(ctx, 1, 0);
>>   }
>>   EXPORT_SYMBOL_GPL(eventfd_signal);
>>
>> diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
>> index b9d83652c097..562089431551 100644
>> --- a/include/linux/eventfd.h
>> +++ b/include/linux/eventfd.h
>> @@ -35,7 +35,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
>>   struct file *eventfd_fget(int fd);
>>   struct eventfd_ctx *eventfd_ctx_fdget(int fd);
>>   struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
>> -__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
>> +__u64 eventfd_signal(struct eventfd_ctx *ctx);
>>   __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask);
>>   int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
>>                                    __u64 *cnt);
>> @@ -58,7 +58,7 @@ static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
>>          return ERR_PTR(-ENOSYS);
>>   }
>>
>> -static inline int eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
>> +static inline int eventfd_signal(struct eventfd_ctx *ctx)
>>   {
>>          return -ENOSYS;
>>   }
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 774bd6e21e27..dfbb1d3b77b7 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -4378,7 +4378,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
>>           * only one element of the array here.
>>           */
>>          for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
>> -               eventfd_signal(t->entries[i].eventfd, 1);
>> +               eventfd_signal(t->entries[i].eventfd);
>>
>>          /* i = current_threshold + 1 */
>>          i++;
>> @@ -4390,7 +4390,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
>>           * only one element of the array here.
>>           */
>>          for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
>> -               eventfd_signal(t->entries[i].eventfd, 1);
>> +               eventfd_signal(t->entries[i].eventfd);
>>
>>          /* Update current_threshold */
>>          t->current_threshold = i - 1;
>> @@ -4430,7 +4430,7 @@ static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
>>          spin_lock(&memcg_oom_lock);
>>
>>          list_for_each_entry(ev, &memcg->oom_notify, list)
>> -               eventfd_signal(ev->eventfd, 1);
>> +               eventfd_signal(ev->eventfd);
>>
>>          spin_unlock(&memcg_oom_lock);
>>          return 0;
>> @@ -4649,7 +4649,7 @@ static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
>>
>>          /* already in OOM ? */
>>          if (memcg->under_oom)
>> -               eventfd_signal(eventfd, 1);
>> +               eventfd_signal(eventfd);
>>          spin_unlock(&memcg_oom_lock);
>>
>>          return 0;
>> @@ -4941,7 +4941,7 @@ static void memcg_event_remove(struct work_struct *work)
>>          event->unregister_event(memcg, event->eventfd);
>>
>>          /* Notify userspace the event is going away. */
>> -       eventfd_signal(event->eventfd, 1);
>> +       eventfd_signal(event->eventfd);
>>
>>          eventfd_ctx_put(event->eventfd);
>>          kfree(event);
>> diff --git a/mm/vmpressure.c b/mm/vmpressure.c
>> index 22c6689d9302..bd5183dfd879 100644
>> --- a/mm/vmpressure.c
>> +++ b/mm/vmpressure.c
>> @@ -169,7 +169,7 @@ static bool vmpressure_event(struct vmpressure *vmpr,
>>                          continue;
>>                  if (level < ev->level)
>>                          continue;
>> -               eventfd_signal(ev->efd, 1);
>> +               eventfd_signal(ev->efd);
>>                  ret = true;
>>          }
>>          mutex_unlock(&vmpr->events_lock);
>> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
>> index 69ba0281f9e0..2284b3751240 100644
>> --- a/samples/vfio-mdev/mtty.c
>> +++ b/samples/vfio-mdev/mtty.c
>> @@ -234,10 +234,10 @@ static void mtty_trigger_interrupt(struct mdev_state *mdev_state)
>>
>>          if (is_msi(mdev_state)) {
>>                  if (mdev_state->msi_evtfd)
>> -                       eventfd_signal(mdev_state->msi_evtfd, 1);
>> +                       eventfd_signal(mdev_state->msi_evtfd);
>>          } else if (is_intx(mdev_state)) {
>>                  if (mdev_state->intx_evtfd && !mdev_state->intx_mask) {
>> -                       eventfd_signal(mdev_state->intx_evtfd, 1);
>> +                       eventfd_signal(mdev_state->intx_evtfd);
>>                          mdev_state->intx_mask = true;
>>                  }
>>          }
>> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
>> index 89912a17f5d5..c0e230f4c3e9 100644
>> --- a/virt/kvm/eventfd.c
>> +++ b/virt/kvm/eventfd.c
>> @@ -61,7 +61,7 @@ static void irqfd_resampler_notify(struct kvm_kernel_irqfd_resampler *resampler)
>>
>>          list_for_each_entry_srcu(irqfd, &resampler->list, resampler_link,
>>                                   srcu_read_lock_held(&resampler->kvm->irq_srcu))
>> -               eventfd_signal(irqfd->resamplefd, 1);
>> +               eventfd_signal(irqfd->resamplefd);
>>   }
>>
>>   /*
>> @@ -786,7 +786,7 @@ ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,
>>          if (!ioeventfd_in_range(p, addr, len, val))
>>                  return -EOPNOTSUPP;
>>
>> -       eventfd_signal(p->eventfd, 1);
>> +       eventfd_signal(p->eventfd);
>>          return 0;
>>   }
>>
>>
>> --
>> 2.42.0
>>
>>

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Paolo Bonzini]

On Wed, Nov 22, 2023 at 1:49 PM Christian Brauner <brauner@kernel.org> wrote:
>
> Ever since the evenfd type was introduced back in 2007 in commit
> e1ad7468c77d ("signal/timer/event: eventfd core") the eventfd_signal()
> function only ever passed 1 as a value for @n. There's no point in
> keeping that additional argument.
>
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> ---
>  arch/x86/kvm/hyperv.c                     |  2 +-
>  arch/x86/kvm/xen.c                        |  2 +-
>  virt/kvm/eventfd.c                        |  4 ++--
>  30 files changed, 60 insertions(+), 63 deletions(-)

For KVM:

Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Re: [PATCH v2 2/4] eventfd: simplify eventfd_signal()

[Christian Brauner]

On Wed, Feb 07, 2024 at 03:34:59PM +0100, Paolo Bonzini wrote:
> On Wed, Nov 22, 2023 at 1:49 PM Christian Brauner <brauner@kernel.org> wrote:
> >
> > Ever since the evenfd type was introduced back in 2007 in commit
> > e1ad7468c77d ("signal/timer/event: eventfd core") the eventfd_signal()
> > function only ever passed 1 as a value for @n. There's no point in
> > keeping that additional argument.
> >
> > Signed-off-by: Christian Brauner <brauner@kernel.org>
> > ---
> >  arch/x86/kvm/hyperv.c                     |  2 +-
> >  arch/x86/kvm/xen.c                        |  2 +-
> >  virt/kvm/eventfd.c                        |  4 ++--
> >  30 files changed, 60 insertions(+), 63 deletions(-)
> 
> For KVM:
> 
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>

I really appreciate all of the ACKs but just fyi that this was merged
for v6.8-rc1. Just so that there's no confusion!