[PATCH 16/21] blk-mq: Set flush_start_tag to BLK_MQ_MAX_DEPTH

[Alexander Gordeev]

We need flush tags unique across hardware contexts and do
not overlap with normal tags. BLK_MQ_MAX_DEPTH as a base
number seems better choise than a queue's depth.

CC: Jens Axboe <ax...@kernel.dk>
CC: linux-n...@lists.infradead.org
Signed-off-by: Alexander Gordeev <agord...@redhat.com>
---
 block/blk-mq.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index e14f7e8..c27e64e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1661,14 +1661,12 @@ static void blk_mq_exit_hctx(struct request_queue *q,
                struct blk_mq_tag_set *set,
                struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
 {
-       unsigned flush_start_tag = set->queue_depth;
-
        blk_mq_tag_idle(hctx);
 
        if (set->ops->exit_request)
                set->ops->exit_request(set->driver_data,
                                       hctx->fq->flush_rq, hctx_idx,
-                                      flush_start_tag + hctx_idx);
+                                      BLK_MQ_MAX_DEPTH + hctx_idx);
 
        if (set->ops->exit_hctx)
                set->ops->exit_hctx(hctx, hctx_idx);
@@ -1697,7 +1695,6 @@ static void blk_mq_exit_hw_queues(struct request_queue *q,
 static struct blk_mq_hw_ctx *blk_mq_init_hctx(struct request_queue *q,
                struct blk_mq_tag_set *set, unsigned hctx_idx)
 {
-       unsigned flush_start_tag = set->queue_depth;
        struct blk_mq_hw_ctx *hctx;
        int node;
 
@@ -1751,7 +1748,7 @@ static struct blk_mq_hw_ctx *blk_mq_init_hctx(struct 
request_queue *q,
        if (set->ops->init_request &&
            set->ops->init_request(set->driver_data,
                                   hctx->fq->flush_rq, hctx_idx,
-                                  flush_start_tag + hctx_idx, node))
+                                  BLK_MQ_MAX_DEPTH + hctx_idx, node))
                goto exit_hctx;
 
        return hctx;
-- 
1.8.3.1