Re: [PATCH 2/4] blk-mq: introduce blk_mq_get_queue_depth()

On Wed, May 03, 2017 at 09:55:30AM -0700, Omar Sandoval wrote:

On Fri, Apr 28, 2017 at 11:15:37PM +0800, Ming Lei wrote:

quoted

The hardware queue depth can be resized via blk_mq_update_nr_requests(),
so introduce this helper for retrieving queue's depth easily.

One nit below. If the per-hardware queue tag space situation changes, we
can revisit this and the similar thing in Kyber.

OK, will add comment about this situation in V3. 

Reviewed-by: Omar Sandoval <redacted>

quoted

Signed-off-by: Ming Lei <redacted>
---
 block/blk-mq.c | 12 ++++++++++++
 block/blk-mq.h |  1 +
 2 files changed, 13 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index e530bc54f0d9..04761fb76ab4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c

@@ -2637,6 +2637,18 @@ void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
 }
 EXPORT_SYMBOL(blk_mq_free_tag_set);
 
+/*
+ * Queue depth can be changed via blk_mq_update_nr_requests(),
+ * so use this helper to retrieve queue's depth.
+ */
+int blk_mq_get_queue_depth(struct request_queue *q)
+{
+	/* All queues have same queue depth */
+	struct blk_mq_tags	*tags = q->tag_set->tags[0];

Not sure what's going on with the spacing here. Tab instead of a space?

Either one should be fine, and I am sure this patch is warning/error
free when checking with ./scripts/checkpatch.pl, :-)

Thanks,
Ming