blk-mq: Make it safe to quiesce and unquiesce from an interrupt handler
authorBart Van Assche <bart.vanassche@wdc.com>
Wed, 21 Jun 2017 17:55:47 +0000 (10:55 -0700)
committerJens Axboe <axboe@kernel.dk>
Wed, 21 Jun 2017 18:01:15 +0000 (12:01 -0600)
Since blk_mq_quiesce_queue_nowait() can be called from interrupt
context, make this safe. Since this function is not in the hot
path, uninline it.

Fixes: commit f4560ffe8cec ("blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/blk-mq.c
include/linux/blk-mq.h

index 1c4f1f4..2caac30 100644 (file)
@@ -153,6 +153,20 @@ void blk_mq_unfreeze_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
 
+/*
+ * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
+ * mpt3sas driver such that this function can be removed.
+ */
+void blk_mq_quiesce_queue_nowait(struct request_queue *q)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(q->queue_lock, flags);
+       queue_flag_set(QUEUE_FLAG_QUIESCED, q);
+       spin_unlock_irqrestore(q->queue_lock, flags);
+}
+EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
+
 /**
  * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
  * @q: request queue.
@@ -190,9 +204,11 @@ EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
  */
 void blk_mq_unquiesce_queue(struct request_queue *q)
 {
-       spin_lock_irq(q->queue_lock);
+       unsigned long flags;
+
+       spin_lock_irqsave(q->queue_lock, flags);
        queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
-       spin_unlock_irq(q->queue_lock);
+       spin_unlock_irqrestore(q->queue_lock, flags);
 
        /* dispatch requests which are inserted during quiescing */
        blk_mq_run_hw_queues(q, true);
index 366b83c..23d32ff 100644 (file)
@@ -266,15 +266,7 @@ int blk_mq_reinit_tagset(struct blk_mq_tag_set *set);
 int blk_mq_map_queues(struct blk_mq_tag_set *set);
 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
 
-/*
- * FIXME: this helper is just for working around mpt3sas.
- */
-static inline void blk_mq_quiesce_queue_nowait(struct request_queue *q)
-{
-       spin_lock_irq(q->queue_lock);
-       queue_flag_set(QUEUE_FLAG_QUIESCED, q);
-       spin_unlock_irq(q->queue_lock);
-}
+void blk_mq_quiesce_queue_nowait(struct request_queue *q);
 
 /*
  * Driver command data is immediately after the request. So subtract request