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Diffstat (limited to 'block/blk-mq-tag.c')
-rw-r--r--block/blk-mq-tag.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 4bc701b32ce2..89bb6250633d 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -336,6 +336,13 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
struct blk_mq_hw_ctx *hctx;
int i;
+ /*
+ * __blk_mq_update_nr_hw_queues will update the nr_hw_queues and
+ * queue_hw_ctx after freeze the queue, so we use q_usage_counter
+ * to avoid race with it.
+ */
+ if (!percpu_ref_tryget(&q->q_usage_counter))
+ return;
queue_for_each_hw_ctx(q, hctx, i) {
struct blk_mq_tags *tags = hctx->tags;
@@ -351,7 +358,7 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
bt_for_each(hctx, &tags->breserved_tags, fn, priv, true);
bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false);
}
-
+ blk_queue_exit(q);
}
static unsigned int bt_unused_tags(const struct sbitmap_queue *bt)