blk-mq: introduce blk_mq_delay_kick_requeue_list()

blk_mq_delay_kick_requeue_list() provides the ability to kick the
q->requeue_list after a specified time.  To do this the request_queue's
'requeue_work' member was changed to a delayed_work.

blk_mq_delay_kick_requeue_list() allows DM to defer processing requeued
requests while it doesn't make sense to immediately requeue them
(e.g. when all paths in a DM multipath have failed).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

3 files changed, 14 insertions, 5 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index eea0d230faa1..7ddc7969fba4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -502,7 +502,7 @@ EXPORT_SYMBOL(blk_mq_requeue_request);
 static void blk_mq_requeue_work(struct work_struct *work)
 {
         struct request_queue *q =
-                container_of(work, struct request_queue, requeue_work);
+                container_of(work, struct request_queue, requeue_work.work);
         LIST_HEAD(rq_list);
         struct request *rq, *next;
         unsigned long flags;
@@ -557,16 +557,24 @@ EXPORT_SYMBOL(blk_mq_add_to_requeue_list);
 
 void blk_mq_cancel_requeue_work(struct request_queue *q)
 {
-        cancel_work_sync(&q->requeue_work);
+        cancel_delayed_work_sync(&q->requeue_work);
 }
 EXPORT_SYMBOL_GPL(blk_mq_cancel_requeue_work);
 
 void blk_mq_kick_requeue_list(struct request_queue *q)
 {
-        kblockd_schedule_work(&q->requeue_work);
+        kblockd_schedule_delayed_work(&q->requeue_work, 0);
 }
 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
 
+void blk_mq_delay_kick_requeue_list(struct request_queue *q,
+                                    unsigned long msecs)
+{
+        kblockd_schedule_delayed_work(&q->requeue_work,
+                                      msecs_to_jiffies(msecs));
+}
+EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
+
 void blk_mq_abort_requeue_list(struct request_queue *q)
 {
         unsigned long flags;
@@ -2084,7 +2092,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
 
         q->sg_reserved_size = INT_MAX;
 
-        INIT_WORK(&q->requeue_work, blk_mq_requeue_work);
+        INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
         INIT_LIST_HEAD(&q->requeue_list);
         spin_lock_init(&q->requeue_lock);
 
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index ff14f68067aa..60ef14cbcd2d 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -233,6 +233,7 @@ void blk_mq_requeue_request(struct request *rq);
 void blk_mq_add_to_requeue_list(struct request *rq, bool at_head);
 void blk_mq_cancel_requeue_work(struct request_queue *q);
 void blk_mq_kick_requeue_list(struct request_queue *q);
+void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs);
 void blk_mq_abort_requeue_list(struct request_queue *q);
 void blk_mq_complete_request(struct request *rq, int error);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 69aae720f4ef..c47c358ba052 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -449,7 +449,7 @@ struct request_queue {
 
         struct list_head        requeue_list;
         spinlock_t              requeue_lock;
-        struct work_struct      requeue_work;
+        struct delayed_work     requeue_work;
 
         struct mutex            sysfs_lock;