diff options
| author | Ming Lei <ming.lei@redhat.com> | 2019-01-22 16:20:17 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-01-22 10:24:08 -0700 |
| commit | 698cef173983b086977e633e46476e0f925ca01e (patch) | |
| tree | 57caf7c7c9ce231ce193c53ae663ac49bbe999c6 | |
| parent | 8b9433eb4de3c26a9226c981c283f9f4896ae030 (diff) | |
| download | linux-698cef173983b086977e633e46476e0f925ca01e.tar.bz2 | |
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 <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: NeilBrown <neilb@suse.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/blk-core.c | 11 | ||||
| -rw-r--r-- | block/blk-merge.c | 10 |
2 files changed, 11 insertions, 10 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 3c5f61ceeb67..1ccec27d20c3 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1083,7 +1083,18 @@ blk_qc_t generic_make_request(struct bio *bio) /* Create a fresh bio_list for all subordinate requests */ bio_list_on_stack[1] = bio_list_on_stack[0]; bio_list_init(&bio_list_on_stack[0]); + + /* + * 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); ret = q->make_request_fn(q, bio); + bio_clear_flag(bio, BIO_QUEUE_ENTERED); /* sort new bios into those for a lower level * and those for the same level 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); |