From 698cef173983b086977e633e46476e0f925ca01e Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 22 Jan 2019 16:20:17 +0800 Subject: block: cover another queue enter recursion via BIO_QUEUE_ENTERED Except for blk_queue_split(), bio_split() is used for splitting bio too, then the remained bio is often resubmit to queue via generic_make_request(). So the same queue enter recursion exits in this case too. Unfortunatley commit cd4a4ae4683dc2 doesn't help this case. This patch covers the above case by setting BIO_QUEUE_ENTERED before calling q->make_request_fn. In theory the per-bio flag is used to simulate one stack variable, it is just fine to clear it after q->make_request_fn is returned. Especially the same bio can't be submitted from another context. Fixes: cd4a4ae4683dc2 ("block: don't use blocking queue entered for recursive bio submits") Cc: Tetsuo Handa Cc: NeilBrown Reviewed-by: Mike Snitzer Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-merge.c | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'block/blk-merge.c') diff --git a/block/blk-merge.c b/block/blk-merge.c index 71e9ac03f621..d79a22f111d1 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -272,16 +272,6 @@ void blk_queue_split(struct request_queue *q, struct bio **bio) /* there isn't chance to merge the splitted bio */ split->bi_opf |= REQ_NOMERGE; - /* - * Since we're recursing into make_request here, ensure - * that we mark this bio as already having entered the queue. - * If not, and the queue is going away, we can get stuck - * forever on waiting for the queue reference to drop. But - * that will never happen, as we're already holding a - * reference to it. - */ - bio_set_flag(*bio, BIO_QUEUE_ENTERED); - bio_chain(split, *bio); trace_block_split(q, split, (*bio)->bi_iter.bi_sector); generic_make_request(*bio); -- cgit v1.2.3