blk-mq: add tag allocation policy
This is the blk-mq part to support tag allocation policy. The default
allocation policy isn't changed (though it's not a strict FIFO). The new
policy is round-robin for libata. But it's a try-best implementation. If
multiple tasks are competing, the tags returned will be mixed (which is
unavoidable even with !mq, as requests from different tasks can be
mixed in queue)
Cc: Jens Axboe <axboe@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a7d4a98..eb8e694 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1374,7 +1374,8 @@
size_t rq_size, left;
tags = blk_mq_init_tags(set->queue_depth, set->reserved_tags,
- set->numa_node);
+ set->numa_node,
+ BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
if (!tags)
return NULL;
