[PATCH 5.17 389/772] io_uring: avoid io-wq -EAGAIN looping for !IOPOLL

[Greg Kroah-Hartman]

From: Pavel Begunkov <asml.silence@xxxxxxxxx>

[ Upstream commit e0deb6a025ae8c850dc8685be39fb27b06c88736 ]

If an opcode handler semi-reliably returns -EAGAIN, io_wq_submit_work()
might continue busily hammer the same handler over and over again, which
is not ideal. The -EAGAIN handling in question was put there only for
IOPOLL, so restrict it to IOPOLL mode only where there is no other
recourse than to retry as we cannot wait.

Fixes: def596e9557c9 ("io_uring: support for IO polling")
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Link: https://lore.kernel.org/r/f168b4f24181942f3614dd8ff648221736f572e6.1652433740.git.asml.silence@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/io_uring.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a0680046ff3c..26bf488096b2 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6939,6 +6939,8 @@ static void io_wq_submit_work(struct io_wq_work *work)
 		 * wait for request slots on the block side.
 		 */
 		if (!needs_poll) {
+			if (!(req->ctx->flags & IORING_SETUP_IOPOLL))
+				break;
 			cond_resched();
 			continue;
 		}
-- 
2.35.1