x86/perf/amd: Resolve race condition when disabling PMC

[linux-2.6-microblaze.git] / block / blk-mq.c

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 70b210a..3ff3d7b 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -59,7 +59,8 @@ static int blk_mq_poll_stats_bkt(const struct request *rq)
 }
 
 /*
- * Check if any of the ctx's have pending work in this hardware queue
+ * Check if any of the ctx, dispatch list or elevator
+ * have pending work in this hardware queue.
  */
 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
 {
@@ -1071,7 +1072,13 @@ static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
        hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
 
        spin_lock(&hctx->dispatch_wait_lock);
-       list_del_init(&wait->entry);
+       if (!list_empty(&wait->entry)) {
+               struct sbitmap_queue *sbq;
+
+               list_del_init(&wait->entry);
+               sbq = &hctx->tags->bitmap_tags;
+               atomic_dec(&sbq->ws_active);
+       }
        spin_unlock(&hctx->dispatch_wait_lock);
 
        blk_mq_run_hw_queue(hctx, true);
@@ -1087,6 +1094,7 @@ static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
                                 struct request *rq)
 {
+       struct sbitmap_queue *sbq = &hctx->tags->bitmap_tags;
        struct wait_queue_head *wq;
        wait_queue_entry_t *wait;
        bool ret;
@@ -1109,7 +1117,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
        if (!list_empty_careful(&wait->entry))
                return false;
 
-       wq = &bt_wait_ptr(&hctx->tags->bitmap_tags, hctx)->wait;
+       wq = &bt_wait_ptr(sbq, hctx)->wait;
 
        spin_lock_irq(&wq->lock);
        spin_lock(&hctx->dispatch_wait_lock);
@@ -1119,6 +1127,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
                return false;
        }
 
+       atomic_inc(&sbq->ws_active);
        wait->flags &= ~WQ_FLAG_EXCLUSIVE;
        __add_wait_queue(wq, wait);
 
@@ -1139,6 +1148,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
         * someone else gets the wakeup.
         */
        list_del_init(&wait->entry);
+       atomic_dec(&sbq->ws_active);
        spin_unlock(&hctx->dispatch_wait_lock);
        spin_unlock_irq(&wq->lock);