From f6f371f7db42917c7b2a861c4fc923cb352ce5a1 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Sun, 6 Dec 2020 14:04:39 +0000
Subject: blk-mq: skip hybrid polling if iopoll doesn't spin

If blk_poll() is not going to spin (i.e. @spin=false), it also must not
sleep in hybrid polling, otherwise it might be pretty suprising for
users trying to do a quick check and expecting no-wait behaviour.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 block/blk-mq.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'block')

diff --git a/block/blk-mq.c b/block/blk-mq.c
index cf3916e2852f..2881a457de83 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3865,9 +3865,10 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
 	 * the state. Like for the other success return cases, the
 	 * caller is responsible for checking if the IO completed. If
 	 * the IO isn't complete, we'll get called again and will go
-	 * straight to the busy poll loop.
+	 * straight to the busy poll loop. If specified not to spin,
+	 * we also should not sleep.
 	 */
-	if (blk_mq_poll_hybrid(q, hctx, cookie))
+	if (spin && blk_mq_poll_hybrid(q, hctx, cookie))
 		return 1;
 
 	hctx->poll_considered++;
-- 
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