blk-mq: let blk_mq_tag_to_rq() take blk_mq_tags as the main parameter

We currently pass in the hardware queue, and get the tags from there.
But from scsi-mq, with a shared tag space, it's a lot more convenient
to pass in the blk_mq_tags instead as the hardware queue isn't always
directly available. So instead of having to re-map to a given
hardware queue from rq->mq_ctx, just pass in the tags structure.

Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 12 insertions, 7 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4e8e8cf00815..4e4cd6208052 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -529,15 +529,20 @@ void blk_mq_kick_requeue_list(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
 
-struct request *blk_mq_tag_to_rq(struct blk_mq_hw_ctx *hctx, unsigned int tag)
+static inline bool is_flush_request(struct request *rq, unsigned int tag)
 {
-        struct request_queue *q = hctx->queue;
+        return ((rq->cmd_flags & REQ_FLUSH_SEQ) &&
+                        rq->q->flush_rq->tag == tag);
+}
 
-        if ((q->flush_rq->cmd_flags & REQ_FLUSH_SEQ) &&
-            q->flush_rq->tag == tag)
-                return q->flush_rq;
+struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
+{
+        struct request *rq = tags->rqs[tag];
+
+        if (!is_flush_request(rq, tag))
+                return rq;
 
-        return hctx->tags->rqs[tag];
+        return rq->q->flush_rq;
 }
 EXPORT_SYMBOL(blk_mq_tag_to_rq);
 
@@ -566,7 +571,7 @@ static void blk_mq_timeout_check(void *__data, unsigned long *free_tags)
                 if (tag >= hctx->tags->nr_tags)
                         break;
 
-                rq = blk_mq_tag_to_rq(hctx, tag++);
+                rq = blk_mq_tag_to_rq(hctx->tags, tag++);
                 if (rq->q != hctx->queue)
                         continue;
                 if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))