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-rw-r--r--block/blk-mq-tag.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 6deb13055490..08fc6716d362 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -344,6 +344,7 @@ 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;
+ int wait_cnt;
/*
* The unlock memory barrier need to order access to req in free
@@ -352,10 +353,19 @@ static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag)
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)) {
- atomic_set(&bs->wait_cnt, bt->wake_cnt);
+ if (!bs)
+ return;
+
+ wait_cnt = atomic_dec_return(&bs->wait_cnt);
+ if (wait_cnt == 0) {
+wake:
+ atomic_add(bt->wake_cnt, &bs->wait_cnt);
bt_index_atomic_inc(&bt->wake_index);
wake_up(&bs->wait);
+ } else if (wait_cnt < 0) {
+ wait_cnt = atomic_inc_return(&bs->wait_cnt);
+ if (!wait_cnt)
+ goto wake;
}
}