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From: Stefano Garzarella <[email protected]>
To: Jens Axboe <[email protected]>
Cc: [email protected],
	Alexander Viro <[email protected]>,
	[email protected], [email protected]
Subject: [PATCH v2 1/2] io_uring: add 'cq_flags' field for the CQ ring
Date: Fri, 15 May 2020 18:38:04 +0200	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

This patch adds the new 'cq_flags' field that should be written by
the application and read by the kernel.

This new field is available to the userspace application through
'cq_off.flags'.
We are using 4-bytes previously reserved and set to zero. This means
that if the application finds this field to zero, then the new
functionality is not supported.

In the next patch we will introduce the first flag available.

Signed-off-by: Stefano Garzarella <[email protected]>
---
 fs/io_uring.c                 | 10 +++++++++-
 include/uapi/linux/io_uring.h |  4 +++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 979d9f977409..6e8158269f3c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -142,7 +142,7 @@ struct io_rings {
 	 */
 	u32			sq_dropped;
 	/*
-	 * Runtime flags
+	 * Runtime SQ flags
 	 *
 	 * Written by the kernel, shouldn't be modified by the
 	 * application.
@@ -151,6 +151,13 @@ struct io_rings {
 	 * for IORING_SQ_NEED_WAKEUP after updating the sq tail.
 	 */
 	u32			sq_flags;
+	/*
+	 * Runtime CQ flags
+	 *
+	 * Written by the application, shouldn't be modified by the
+	 * kernel.
+	 */
+	u32                     cq_flags;
 	/*
 	 * Number of completion events lost because the queue was full;
 	 * this should be avoided by the application by making sure
@@ -7834,6 +7841,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
 	p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
 	p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
 	p->cq_off.cqes = offsetof(struct io_rings, cqes);
+	p->cq_off.flags = offsetof(struct io_rings, cq_flags);
 
 	p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
 			IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index e48d746b8e2a..602bb0ece607 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -204,7 +204,9 @@ struct io_cqring_offsets {
 	__u32 ring_entries;
 	__u32 overflow;
 	__u32 cqes;
-	__u64 resv[2];
+	__u32 flags;
+	__u32 resv1;
+	__u64 resv2;
 };
 
 /*
-- 
2.25.4


  reply	other threads:[~2020-05-15 16:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-15 16:38 [PATCH v2 0/2] io_uring: add a CQ ring flag to enable/disable eventfd notification Stefano Garzarella
2020-05-15 16:38 ` Stefano Garzarella [this message]
2020-05-15 16:38 ` [PATCH v2 2/2] io_uring: add IORING_CQ_EVENTFD_DISABLED to the CQ ring flags Stefano Garzarella
2020-05-15 18:17 ` [PATCH v2 0/2] io_uring: add a CQ ring flag to enable/disable eventfd notification Jens Axboe

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