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

Pavel Begunkov
2022-10-18T18:49:00Z

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