[RFC for-next v2 1/4] bio: safeguard REQ_ALLOC_CACHE bio put

From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org
Cc: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Pavel Begunkov <asml.silence@gmail.com>
Subject: [RFC for-next v2 1/4] bio: safeguard REQ_ALLOC_CACHE bio put
Date: Tue, 18 Oct 2022 20:50:55 +0100	[thread overview]
Message-ID: <558d78313476c4e9c233902efa0092644c3d420a.1666122465.git.asml.silence@gmail.com> (raw)
In-Reply-To: <cover.1666122465.git.asml.silence@gmail.com>

bio_put() with REQ_ALLOC_CACHE assumes that it's executed not from
an irq context. Let's add a warning if the invariant is not respected,
especially since there is a couple of places removing REQ_POLLED by hand
without also clearing REQ_ALLOC_CACHE.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 block/bio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index 7cb7d2ff139b..5b4594daa259 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -741,7 +741,7 @@ void bio_put(struct bio *bio)
 			return;
 	}
 
-	if (bio->bi_opf & REQ_ALLOC_CACHE) {
+	if ((bio->bi_opf & REQ_ALLOC_CACHE) && !WARN_ON_ONCE(in_interrupt())) {
 		struct bio_alloc_cache *cache;
 
 		bio_uninit(bio);
-- 
2.38.0

