blk-mq: check on cpu id when there is only one ctx mapping

commit f168420c62e7 ("blk-mq: don't redirect completion for hctx withs
only one ctx mapping") When nvme applies a 1:1 mapping of hctx and ctx,
there will be no remote request.

But for ufs, the submission and completion queues could be asymmetric.
(e.g. Multiple SQs share one CQ) Therefore, 1:1 mapping of hctx and
ctx won't complete request on the submission cpu. In this situation,
this nr_ctx check could violate the QUEUE_FLAG_SAME_FORCE, as a result,
check on cpu id when there is only one ctx mapping.

Signed-off-by: Ed Tsai <ed.tsai@mediatek.com>
Signed-off-by: Po-Wen Kao <powen.kao@mediatek.com>
Suggested-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230614002529.6636-1-ed.tsai@mediatek.com
[axboe: fixed up indentation]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 1749f58..24dc8fe 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1185,8 +1185,9 @@ bool blk_mq_complete_request_remote(struct request *rq)
         * or a polled request, always complete locally,
         * it's pointless to redirect the completion.
         */
-       if (rq->mq_hctx->nr_ctx == 1 ||
-               rq->cmd_flags & REQ_POLLED)
+       if ((rq->mq_hctx->nr_ctx == 1 &&
+            rq->mq_ctx->cpu == raw_smp_processor_id()) ||
+            rq->cmd_flags & REQ_POLLED)
                return false;
 
        if (blk_mq_complete_need_ipi(rq)) {