block: add a blk_plug_device_unlocked() that grabs the queue lock

blk_plug_device() must be called with the queue lock held, so callers
often just grab and release the lock for that purpose. Add a helper
that does just that.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index fef79cc..4889eb8 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -212,6 +212,24 @@ void blk_plug_device(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_plug_device);
 
+/**
+ * blk_plug_device_unlocked - plug a device without queue lock held
+ * @q:    The &struct request_queue to plug
+ *
+ * Description:
+ *   Like @blk_plug_device(), but grabs the queue lock and disables
+ *   interrupts.
+ **/
+void blk_plug_device_unlocked(struct request_queue *q)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	blk_plug_device(q);
+	spin_unlock_irqrestore(q->queue_lock, flags);
+}
+EXPORT_SYMBOL(blk_plug_device_unlocked);
+
 /*
  * remove the queue from the plugged list, if present. called with
  * queue lock held and interrupts disabled.