diff options
Diffstat (limited to 'block/blk-core.c')
| -rw-r--r-- | block/blk-core.c | 33 |
1 files changed, 25 insertions, 8 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 09b262811ff..5e413933bc3 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -295,7 +295,8 @@ EXPORT_SYMBOL(blk_sync_queue); * * Description: * See @blk_run_queue. This variant must be called with the queue lock - * held and interrupts disabled. + * held and interrupts disabled. If force_kblockd is true, then it is + * safe to call this without holding the queue lock. * */ void __blk_run_queue(struct request_queue *q, bool force_kblockd) @@ -2671,9 +2672,23 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) */ static void queue_unplugged(struct request_queue *q, unsigned int depth, bool from_schedule) + __releases(q->queue_lock) { trace_block_unplug(q, depth, !from_schedule); - __blk_run_queue(q, from_schedule); + + /* + * If we are punting this to kblockd, then we can safely drop + * the queue_lock before waking kblockd (which needs to take + * this lock). + */ + if (from_schedule) { + spin_unlock(q->queue_lock); + __blk_run_queue(q, true); + } else { + __blk_run_queue(q, false); + spin_unlock(q->queue_lock); + } + } static void flush_plug_callbacks(struct blk_plug *plug) @@ -2729,10 +2744,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) BUG_ON(!(rq->cmd_flags & REQ_ON_PLUG)); BUG_ON(!rq->q); if (rq->q != q) { - if (q) { + /* + * This drops the queue lock + */ + if (q) queue_unplugged(q, depth, from_schedule); - spin_unlock(q->queue_lock); - } q = rq->q; depth = 0; spin_lock(q->queue_lock); @@ -2750,10 +2766,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) depth++; } - if (q) { + /* + * This drops the queue lock + */ + if (q) queue_unplugged(q, depth, from_schedule); - spin_unlock(q->queue_lock); - } local_irq_restore(flags); } |