From: Yu Kuai <[email protected]> cached_dev_cache_miss() allocates cache_bio with GFP_NOWAIT. Passing a bdev to bio_alloc_bioset() can attach blkcg state and sleep to create a missing blkg after blkg lookup is protected by q->blkcg_mutex.
Use the nowait bio allocation/association path. If the cache bio needs a missing blkg to be created, fail the association and fall back to the existing miss submission path. journal_write_unlocked() also resets journal bios while holding the journal spinlock. Reset those bios without a bdev, set bi_bdev while still under the lock, and associate blkcg after dropping the lock. Signed-off-by: Yu Kuai <[email protected]> --- drivers/md/bcache/journal.c | 9 ++++++--- drivers/md/bcache/request.c | 2 ++ 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c index 144693b7c46a..49d2fb9a5f20 100644 --- a/drivers/md/bcache/journal.c +++ b/drivers/md/bcache/journal.c @@ -714,8 +714,9 @@ static CLOSURE_CALLBACK(journal_write_unlocked) atomic_long_add(sectors, &ca->meta_sectors_written); - bio_reset(bio, ca->bdev, REQ_OP_WRITE | - REQ_SYNC | REQ_META | REQ_PREFLUSH | REQ_FUA); + bio_reset(bio, NULL, REQ_OP_WRITE | REQ_SYNC | REQ_META | + REQ_PREFLUSH | REQ_FUA); + bio->bi_bdev = ca->bdev; bio->bi_iter.bi_sector = PTR_OFFSET(k, i); bio->bi_iter.bi_size = sectors << 9; @@ -740,8 +741,10 @@ static CLOSURE_CALLBACK(journal_write_unlocked) spin_unlock(&c->journal.lock); - while ((bio = bio_list_pop(&list))) + while ((bio = bio_list_pop(&list))) { + bio_associate_blkg(bio, false); closure_bio_submit(c, bio, cl); + } continue_at(cl, journal_write_done, NULL); } diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index c2b7a694ea99..647ca5018d07 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -932,6 +932,8 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, if (!cache_bio) goto out_submit; + if (!bio_clone_blkg_association(cache_bio, miss, true)) + goto out_put; cache_bio->bi_iter.bi_sector = miss->bi_iter.bi_sector; cache_bio->bi_iter.bi_size = s->insert_bio_sectors << 9; -- 2.51.0
