IB/qib: Use memdup_user() rather than duplicating its implementation

[cascardo/linux.git] / drivers / md / dm-rq.c

diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 7a96618..1ca7463 100644 (file)
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -78,6 +78,7 @@ void dm_start_queue(struct request_queue *q)
        if (!q->mq_ops)
                dm_old_start_queue(q);
        else {
+               queue_flag_clear_unlocked(QUEUE_FLAG_STOPPED, q);
                blk_mq_start_stopped_hw_queues(q, true);
                blk_mq_kick_requeue_list(q);
        }
@@ -101,8 +102,14 @@ void dm_stop_queue(struct request_queue *q)
 {
        if (!q->mq_ops)
                dm_old_stop_queue(q);
-       else
+       else {
+               spin_lock_irq(q->queue_lock);
+               queue_flag_set(QUEUE_FLAG_STOPPED, q);
+               spin_unlock_irq(q->queue_lock);
+
+               blk_mq_cancel_requeue_work(q);
                blk_mq_stop_hw_queues(q);
+       }
 }
 
 static struct dm_rq_target_io *alloc_old_rq_tio(struct mapped_device *md,
@@ -864,6 +871,17 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
                dm_put_live_table(md, srcu_idx);
        }
 
+       /*
+        * On suspend dm_stop_queue() handles stopping the blk-mq
+        * request_queue BUT: even though the hw_queues are marked
+        * BLK_MQ_S_STOPPED at that point there is still a race that
+        * is allowing block/blk-mq.c to call ->queue_rq against a
+        * hctx that it really shouldn't.  The following check guards
+        * against this rarity (albeit _not_ race-free).
+        */
+       if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
+               return BLK_MQ_RQ_QUEUE_BUSY;
+
        if (ti->type->busy && ti->type->busy(ti))
                return BLK_MQ_RQ_QUEUE_BUSY;