blk-mq: Always complete remote completions requests in softirq

Controllers with multiple queues have their IRQ-handelers pinned to a
CPU. The core shouldn't need to complete the request on a remote CPU.

Remove this case and always raise the softirq to complete the request.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index f285a9123a8b081deeae72282306948aeec928b4..90348ae518461270646abbbd2e4b485ef73fc144 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -628,19 +628,7 @@ static void __blk_mq_complete_request_remote(void *data)
 {
        struct request *rq = data;
 
-       /*
-        * For most of single queue controllers, there is only one irq vector
-        * for handling I/O completion, and the only irq's affinity is set
-        * to all possible CPUs.  On most of ARCHs, this affinity means the irq
-        * is handled on one specific CPU.
-        *
-        * So complete I/O requests in softirq context in case of single queue
-        * devices to avoid degrading I/O performance due to irqsoff latency.
-        */
-       if (rq->q->nr_hw_queues == 1)
-               blk_mq_trigger_softirq(rq);
-       else
-               rq->q->mq_ops->complete(rq);
+       blk_mq_trigger_softirq(rq);
 }
 
 static inline bool blk_mq_complete_need_ipi(struct request *rq)