[PATCH v2 1/6] blk-mq: introduce blk_mq_delay_kick_requeue_list()

[Mike Snitzer]

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 <snit...@redhat.com>
---
 block/blk-mq.c         | 15 +++++++++++----
 include/linux/blk-mq.h |  1 +
 include/linux/blkdev.h |  2 +-
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 13f5a6c..4ff96b7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -501,7 +501,7 @@ 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;
@@ -556,16 +556,23 @@ 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 delay)
+{
+       kblockd_schedule_delayed_work(&q->requeue_work, delay);
+}
+EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
+
 void blk_mq_abort_requeue_list(struct request_queue *q)
 {
        unsigned long flags;
@@ -2082,7 +2089,7 @@ 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 e43bbff..bac01bb 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -232,6 +232,7 @@ 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 
delay);
 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 e79055c..b0a6189 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;
 
-- 
2.7.4 (Apple Git-66)

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