Commit 7e55a19c authored May 15, 2020 by Stefano Garzarella Committed by Jens Axboe May 15, 2020

io_uring: add IORING_CQ_EVENTFD_DISABLED to the CQ ring flags



This new flag should be set/clear from the application to
disable/enable eventfd notifications when a request is completed
and queued to the CQ ring.

Before this patch, notifications were always sent if an eventfd is
registered, so IORING_CQ_EVENTFD_DISABLED is not set during the
initialization.

It will be up to the application to set the flag after initialization
if no notifications are required at the beginning.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 0d9b5b3a

fs/io_uring.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1153,6 +1153,8 @@ static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx)
		{
		if (!ctx->cq_ev_fd)
		return false;
		if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
		return false;
		if (!ctx->eventfd_async)
		return true;
		return io_wq_current_is_worker();

include/uapi/linux/io_uring.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -209,6 +209,13 @@ struct io_cqring_offsets {
		__u64 resv2;
		};

		/*
		* cq_ring->flags
		*/

		/* disable eventfd notifications */
		#define IORING_CQ_EVENTFD_DISABLED (1U << 0)

		/*
		* io_uring_enter(2) flags
		*/

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