bio: safeguard REQ_ALLOC_CACHE bio put

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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/558d78313476c4e9c233902efa0092644c3d420a.1666122465.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

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);