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-rw-r--r--block/blk-mq-tag.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 336dde07b230..a4e58fc28a06 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -134,6 +134,8 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
ws = bt_wait_ptr(bt, data->hctx);
drop_ctx = data->ctx == NULL;
do {
+ struct sbitmap_queue *bt_prev;
+
/*
* We're out of tags on this hardware queue, kick any
* pending IO submits before going to sleep waiting for
@@ -159,6 +161,7 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
if (data->ctx)
blk_mq_put_ctx(data->ctx);
+ bt_prev = bt;
io_schedule();
data->ctx = blk_mq_get_ctx(data->q);
@@ -170,6 +173,15 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
bt = &tags->bitmap_tags;
finish_wait(&ws->wait, &wait);
+
+ /*
+ * If destination hw queue is changed, fake wake up on
+ * previous queue for compensating the wake up miss, so
+ * other allocations on previous queue won't be starved.
+ */
+ if (bt != bt_prev)
+ sbitmap_queue_wake_up(bt_prev);
+
ws = bt_wait_ptr(bt, data->hctx);
} while (1);