blk-mq: Make it safe to quiesce and unquiesce from an interrupt handler

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>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 1c4f1f4978c6f0934a04c6a4e493e17a2b9c60f9..2caac30e128a2a989d717a6e668dc3402ec25de4 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -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);

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 366b83cee9550e1b490317ba758938b13ebf520e..23d32ff0b4629f6ae441ca6f697ee17f490fd9f7 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -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