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| author | Ming Lei <tom.leiming@gmail.com> | 2014-05-11 01:01:48 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-05-10 15:41:42 -0600 |
| commit | 0289b2e110b7824b2f76d194ad6f8f0844e270ad (patch) | |
| tree | eac254d7cd5b82bda9cfb4cd8b489c6173b40659 /block/blk-mq-tag.c | |
| parent | 59d13bf5f57ded658c872fa22276f75ab8f12841 (diff) | |
| download | linux-0289b2e110b7824b2f76d194ad6f8f0844e270ad.tar.gz linux-0289b2e110b7824b2f76d194ad6f8f0844e270ad.tar.bz2 linux-0289b2e110b7824b2f76d194ad6f8f0844e270ad.zip | |
blk-mq: bitmap tag: use clear_bit_unlock in bt_clear_tag()
The unlock memory barrier need to order access to req in free
path and clearing tag bit, otherwise either request free path
may see a allocated request, or initialized request in allocate
path might be modified by the ongoing free path.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-mq-tag.c')
| -rw-r--r-- | block/blk-mq-tag.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 6c78c08865e3..a81b138e89fe 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -236,7 +236,11 @@ static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag) const int index = TAG_TO_INDEX(bt, tag); struct bt_wait_state *bs; - clear_bit(TAG_TO_BIT(bt, tag), &bt->map[index].word); + /* + * The unlock memory barrier need to order access to req in free + * path and clearing tag bit + */ + clear_bit_unlock(TAG_TO_BIT(bt, tag), &bt->map[index].word); bs = bt_wake_ptr(bt); if (bs && atomic_dec_and_test(&bs->wait_cnt)) { |