blk-mq: fix dispatch from sw queue

When a request is added to rq list of sw queue(ctx), the rq may be from
a different type of hctx, especially after multi queue mapping is
introduced.

So when dispach request from sw queue via blk_mq_flush_busy_ctxs() or
blk_mq_dequeue_from_ctx(), one request belonging to other queue type of
hctx can be dispatched to current hctx in case that read queue or poll
queue is enabled.

This patch fixes this issue by introducing per-queue-type list.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>

Changed by me to not use separately cacheline aligned lists, just
place them all in the same cacheline where we had just the one list
and lock before.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 2 insertions, 2 deletions

diff --git a/block/blk-mq.h b/block/blk-mq.h
index d1ed096723fb..d943d46b0785 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -18,8 +18,8 @@ struct blk_mq_ctxs {
 struct blk_mq_ctx {
 	struct {
 		spinlock_t		lock;
-		struct list_head	rq_list;
-	}  ____cacheline_aligned_in_smp;
+		struct list_head	rq_lists[HCTX_MAX_TYPES];
+	} ____cacheline_aligned_in_smp;
 
 	unsigned int		cpu;
 	unsigned short		index_hw[HCTX_MAX_TYPES];