From: Stefano Garzarella sgarzare@redhat.com
mainline inclusion from mainline-5.8-rc1 commit 7e55a19cf6e70ce08964b46dbbfbdb07fbc995fc category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA ---------------------------
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 Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/io_uring.c | 2 ++ include/uapi/linux/io_uring.h | 7 +++++++ 2 files changed, 9 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c index dfb1a9e9a9b9..e0dd69d9d0c6 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1152,6 +1152,8 @@ 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(); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 94e3359249ab..15aed20c6789 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -208,6 +208,13 @@ struct io_cqring_offsets { __u64 resv2; };
+/* + * cq_ring->flags + */ + +/* disable eventfd notifications */ +#define IORING_CQ_EVENTFD_DISABLED (1U << 0) + /* * io_uring_enter(2) flags */