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

Message ID 558d78313476c4e9c233902efa0092644c3d420a.1666122465.git.asml.silence@gmail.com
State New
Headers
Series enable pcpu bio caching for IRQ I/O |

Commit Message

Pavel Begunkov Oct. 18, 2022, 7:50 p.m. UTC
  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(-)
  

Comments

Christoph Hellwig Oct. 20, 2022, 8:26 a.m. UTC | #1
On Tue, Oct 18, 2022 at 08:50:55PM +0100, Pavel Begunkov wrote:
> 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.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
  

Patch

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);