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@xxxxxxxxxx>
---
v1 -> v2:
- changed the flag name and behaviour from IORING_CQ_NEED_EVENT to
IORING_CQ_EVENTFD_DISABLED [Jens]
---
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 6e8158269f3c..a9b194e9b5bd 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 602bb0ece607..8c5775df08b8 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -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
*/
--
2.25.4
