[PATCH 01/24] block: disable elevator for reserved tags

[Hannes Reinecke]

Reserved requests are internal to the driver and we wouldn't know
if and how they should be merged.
So disable the elevator for reserved tags.

Signed-off-by: Hannes Reinecke <h...@suse.com>
---
 block/blk-mq.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 08a6248d8536..f6711a61ba3b 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -368,17 +368,18 @@ static struct request *blk_mq_get_request(struct 
request_queue *q,
        if (data->cmd_flags & REQ_NOWAIT)
                data->flags |= BLK_MQ_REQ_NOWAIT;
 
+       if (data->flags & BLK_MQ_REQ_RESERVED)
+               e = NULL;
+
        if (e) {
                data->flags |= BLK_MQ_REQ_INTERNAL;
 
                /*
                 * Flush requests are special and go directly to the
-                * dispatch list. Don't include reserved tags in the
-                * limiting, as it isn't useful.
+                * dispatch list.
                 */
                if (!op_is_flush(data->cmd_flags) &&
-                   e->type->ops.limit_depth &&
-                   !(data->flags & BLK_MQ_REQ_RESERVED))
+                   e->type->ops.limit_depth)
                        e->type->ops.limit_depth(data->cmd_flags, data);
        } else {
                blk_mq_tag_busy(data->hctx);
-- 
2.16.4