[PATCH v2 0/2] implement timeout update

[PATCH v2 0/2] implement timeout update

[Pavel Begunkov]

Timeout update is a IORING_OP_TIMEOUT_REMOVE request with timeout_flags
containing a new IORING_TIMEOUT_UPDATE flag. Even though naming may be
confusing, but update and remove are very similar both code and
functionality wise, so doesn't seem necessary to add a new opcode.

Updates don't support offsets, but I don't see a need either. Can
be implemented in the future by passing it in sqe->len.

v2: nits for [2/2] (Jens)

Pavel Begunkov (2):
  io_uring: restructure io_timeout_cancel()
  io_uring: add timeout update

 fs/io_uring.c                 | 93 +++++++++++++++++++++++++++--------
 include/uapi/linux/io_uring.h |  1 +
 2 files changed, 73 insertions(+), 21 deletions(-)

-- 
2.24.0

[PATCH v2 1/2] io_uring: restructure io_timeout_cancel()

[Pavel Begunkov]

Add io_timeout_extract() helper, which searches and disarms timeouts,
but doesn't complete them. No functional changes.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 42 +++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 12e641c61708..bffcbec6c9be 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5639,24 +5639,10 @@ static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-static int __io_timeout_cancel(struct io_kiocb *req)
-{
-	struct io_timeout_data *io = req->async_data;
-	int ret;
-
-	ret = hrtimer_try_to_cancel(&io->timer);
-	if (ret == -1)
-		return -EALREADY;
-	list_del_init(&req->timeout.list);
-
-	req_set_fail_links(req);
-	io_cqring_fill_event(req, -ECANCELED);
-	io_put_req_deferred(req, 1);
-	return 0;
-}
-
-static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
+static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
+					   __u64 user_data)
 {
+	struct io_timeout_data *io;
 	struct io_kiocb *req;
 	int ret = -ENOENT;
 
@@ -5668,9 +5654,27 @@ static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
 	}
 
 	if (ret == -ENOENT)
-		return ret;
+		return ERR_PTR(ret);
+
+	io = req->async_data;
+	ret = hrtimer_try_to_cancel(&io->timer);
+	if (ret == -1)
+		return ERR_PTR(-EALREADY);
+	list_del_init(&req->timeout.list);
+	return req;
+}
 
-	return __io_timeout_cancel(req);
+static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
+{
+	struct io_kiocb *req = io_timeout_extract(ctx, user_data);
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	req_set_fail_links(req);
+	io_cqring_fill_event(req, -ECANCELED);
+	io_put_req_deferred(req, 1);
+	return 0;
 }
 
 static int io_timeout_remove_prep(struct io_kiocb *req,
-- 
2.24.0

[PATCH v2 2/2] io_uring: add timeout update

[Pavel Begunkov]

Support timeout updates through IORING_OP_TIMEOUT_REMOVE with passed in
IORING_TIMEOUT_UPDATE. Updates doesn't support offset timeout mode.
Oirignal timeout.off will be ignored as well.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c                 | 55 ++++++++++++++++++++++++++++++++---
 include/uapi/linux/io_uring.h |  1 +
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index bffcbec6c9be..b811f14d1ce0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -453,6 +453,10 @@ struct io_timeout {
 struct io_timeout_rem {
 	struct file			*file;
 	u64				addr;
+
+	/* timeout update */
+	struct timespec64		ts;
+	u32				flags;
 };
 
 struct io_rw {
@@ -867,7 +871,10 @@ static const struct io_op_def io_op_defs[] = {
 		.async_size		= sizeof(struct io_timeout_data),
 		.work_flags		= IO_WQ_WORK_MM,
 	},
-	[IORING_OP_TIMEOUT_REMOVE] = {},
+	[IORING_OP_TIMEOUT_REMOVE] = {
+		/* used by timeout updates' prep() */
+		.work_flags		= IO_WQ_WORK_MM,
+	},
 	[IORING_OP_ACCEPT] = {
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
@@ -5677,17 +5684,49 @@ static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
 	return 0;
 }
 
+static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
+			     struct timespec64 *ts, enum hrtimer_mode mode)
+{
+	struct io_kiocb *req = io_timeout_extract(ctx, user_data);
+	struct io_timeout_data *data;
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	req->timeout.off = 0; /* noseq */
+	data = req->async_data;
+	list_add_tail(&req->timeout.list, &ctx->timeout_list);
+	hrtimer_init(&data->timer, CLOCK_MONOTONIC, mode);
+	data->timer.function = io_timeout_fn;
+	hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode);
+	return 0;
+}
+
 static int io_timeout_remove_prep(struct io_kiocb *req,
 				  const struct io_uring_sqe *sqe)
 {
+	struct io_timeout_rem *tr = &req->timeout_rem;
+	int ret;
+
 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
 		return -EINVAL;
 	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
 		return -EINVAL;
-	if (sqe->ioprio || sqe->buf_index || sqe->len || sqe->timeout_flags)
+	if (sqe->ioprio || sqe->buf_index || sqe->len)
 		return -EINVAL;
 
-	req->timeout_rem.addr = READ_ONCE(sqe->addr);
+	tr->addr = READ_ONCE(sqe->addr);
+	tr->flags = READ_ONCE(sqe->timeout_flags);
+	if (tr->flags & IORING_TIMEOUT_UPDATE) {
+		if (tr->flags & ~(IORING_TIMEOUT_UPDATE|IORING_TIMEOUT_ABS))
+			return -EINVAL;
+		if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2)))
+			return -EFAULT;
+	} else if (tr->flags) {
+		/* timeout removal doesn't support flags */
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -5696,11 +5735,19 @@ static int io_timeout_remove_prep(struct io_kiocb *req,
  */
 static int io_timeout_remove(struct io_kiocb *req)
 {
+	struct io_timeout_rem *tr = &req->timeout_rem;
 	struct io_ring_ctx *ctx = req->ctx;
 	int ret;
 
 	spin_lock_irq(&ctx->completion_lock);
-	ret = io_timeout_cancel(ctx, req->timeout_rem.addr);
+	if (req->timeout_rem.flags & IORING_TIMEOUT_UPDATE) {
+		enum hrtimer_mode mode = (tr->flags & IORING_TIMEOUT_ABS)
+					? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
+
+		ret = io_timeout_update(ctx, tr->addr, &tr->ts, mode);
+	} else {
+		ret = io_timeout_cancel(ctx, tr->addr);
+	}
 
 	io_cqring_fill_event(req, ret);
 	io_commit_cqring(ctx);
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 6bb8229de892..d31a2a1e8ef9 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -151,6 +151,7 @@ enum {
  * sqe->timeout_flags
  */
 #define IORING_TIMEOUT_ABS	(1U << 0)
+#define IORING_TIMEOUT_UPDATE	(1U << 1)
 
 /*
  * sqe->splice_flags
-- 
2.24.0

Re: [PATCH v2 0/2] implement timeout update

[Jens Axboe]

On 11/30/20 12:11 PM, Pavel Begunkov wrote:
> Timeout update is a IORING_OP_TIMEOUT_REMOVE request with timeout_flags
> containing a new IORING_TIMEOUT_UPDATE flag. Even though naming may be
> confusing, but update and remove are very similar both code and
> functionality wise, so doesn't seem necessary to add a new opcode.
> 
> Updates don't support offsets, but I don't see a need either. Can
> be implemented in the future by passing it in sqe->len.

Applied, thanks.

-- 
Jens Axboe