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Diffstat (limited to 'block/blk-mq-tag.c')
-rw-r--r--block/blk-mq-tag.c32
1 files changed, 21 insertions, 11 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 1aab39f71d95..6deb13055490 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -43,9 +43,16 @@ bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
return bt_has_free_tags(&tags->bitmap_tags);
}
-static inline void bt_index_inc(unsigned int *index)
+static inline int bt_index_inc(int index)
{
- *index = (*index + 1) & (BT_WAIT_QUEUES - 1);
+ return (index + 1) & (BT_WAIT_QUEUES - 1);
+}
+
+static inline void bt_index_atomic_inc(atomic_t *index)
+{
+ int old = atomic_read(index);
+ int new = bt_index_inc(old);
+ atomic_cmpxchg(index, old, new);
}
/*
@@ -69,14 +76,14 @@ static void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags)
int i, wake_index;
bt = &tags->bitmap_tags;
- wake_index = bt->wake_index;
+ wake_index = atomic_read(&bt->wake_index);
for (i = 0; i < BT_WAIT_QUEUES; i++) {
struct bt_wait_state *bs = &bt->bs[wake_index];
if (waitqueue_active(&bs->wait))
wake_up(&bs->wait);
- bt_index_inc(&wake_index);
+ wake_index = bt_index_inc(wake_index);
}
}
@@ -212,12 +219,14 @@ static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt,
struct blk_mq_hw_ctx *hctx)
{
struct bt_wait_state *bs;
+ int wait_index;
if (!hctx)
return &bt->bs[0];
- bs = &bt->bs[hctx->wait_index];
- bt_index_inc(&hctx->wait_index);
+ wait_index = atomic_read(&hctx->wait_index);
+ bs = &bt->bs[wait_index];
+ bt_index_atomic_inc(&hctx->wait_index);
return bs;
}
@@ -313,18 +322,19 @@ static struct bt_wait_state *bt_wake_ptr(struct blk_mq_bitmap_tags *bt)
{
int i, wake_index;
- wake_index = bt->wake_index;
+ wake_index = atomic_read(&bt->wake_index);
for (i = 0; i < BT_WAIT_QUEUES; i++) {
struct bt_wait_state *bs = &bt->bs[wake_index];
if (waitqueue_active(&bs->wait)) {
- if (wake_index != bt->wake_index)
- bt->wake_index = wake_index;
+ int o = atomic_read(&bt->wake_index);
+ if (wake_index != o)
+ atomic_cmpxchg(&bt->wake_index, o, wake_index);
return bs;
}
- bt_index_inc(&wake_index);
+ wake_index = bt_index_inc(wake_index);
}
return NULL;
@@ -344,7 +354,7 @@ static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag)
bs = bt_wake_ptr(bt);
if (bs && atomic_dec_and_test(&bs->wait_cnt)) {
atomic_set(&bs->wait_cnt, bt->wake_cnt);
- bt_index_inc(&bt->wake_index);
+ bt_index_atomic_inc(&bt->wake_index);
wake_up(&bs->wait);
}
}