Add UNPLUG traces to all appropriate places

Added blk_unplug interface, allowing all invocations of unplugs to result
in a generated blktrace UNPLUG.

Signed-off-by: Alan D. Brunelle <Alan.Brunelle@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 15 insertions, 9 deletions

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 3d489915fd22..3b927be03850 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1621,15 +1621,7 @@ static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
 {
         struct request_queue *q = bdi->unplug_io_data;
 
-        /*
-         * devices don't necessarily have an ->unplug_fn defined
-         */
-        if (q->unplug_fn) {
-                blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
-                                        q->rq.count[READ] + q->rq.count[WRITE]);
-
-                q->unplug_fn(q);
-        }
+        blk_unplug(q);
 }
 
 static void blk_unplug_work(struct work_struct *work)
@@ -1653,6 +1645,20 @@ static void blk_unplug_timeout(unsigned long data)
         kblockd_schedule_work(&q->unplug_work);
 }
 
+void blk_unplug(struct request_queue *q)
+{
+        /*
+         * devices don't necessarily have an ->unplug_fn defined
+         */
+        if (q->unplug_fn) {
+                blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
+                                        q->rq.count[READ] + q->rq.count[WRITE]);
+
+                q->unplug_fn(q);
+        }
+}
+EXPORT_SYMBOL(blk_unplug);
+
 /**
  * blk_start_queue - restart a previously stopped queue
  * @q:    The &struct request_queue in question