[PATCH 1/2] io_uring/poll: flag request with REQ_F_POLL_TRIGGERED if it went through poll

[Jens Axboe <axboe@kernel.dk>]

If a request targeting a pollable file cannot get executed without
needing to wait for a POLLIN/POLLOUT trigger, then flag it with
REQ_F_POLL_TRIGGERED. Only supported for non-multishot requests, as it's
fully expected that multishot will always end up going through poll.

No functional changes in this patch, just in preparation for using this
information elsewhere.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 include/linux/io_uring_types.h | 3 +++
 io_uring/poll.c                | 1 +
 2 files changed, 4 insertions(+)

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 92780764d5fa..ef1af730193a 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -521,6 +521,7 @@ enum {
 	REQ_F_HAS_METADATA_BIT,
 	REQ_F_IMPORT_BUFFER_BIT,
 	REQ_F_SQE_COPIED_BIT,
+	REQ_F_POLL_TRIGGERED_BIT,
 
 	/* not a real bit, just to check we're not overflowing the space */
 	__REQ_F_LAST_BIT,
@@ -612,6 +613,8 @@ enum {
 	REQ_F_IMPORT_BUFFER	= IO_REQ_FLAG(REQ_F_IMPORT_BUFFER_BIT),
 	/* ->sqe_copy() has been called, if necessary */
 	REQ_F_SQE_COPIED	= IO_REQ_FLAG(REQ_F_SQE_COPIED_BIT),
+	/* poll was triggered at least once for this request */
+	REQ_F_POLL_TRIGGERED	= IO_REQ_FLAG(REQ_F_POLL_TRIGGERED_BIT),
 };
 
 struct io_tw_req {
diff --git a/io_uring/poll.c b/io_uring/poll.c
index 8aa4e3a31e73..d6f7cddf36d0 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -419,6 +419,7 @@ static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
 				req->flags &= ~REQ_F_DOUBLE_POLL;
 			else
 				req->flags &= ~REQ_F_SINGLE_POLL;
+			req->flags |= REQ_F_POLL_TRIGGERED;
 		}
 		__io_poll_execute(req, mask);
 	}
-- 
2.51.0