From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH 2/4] blk-mq: introduce blk_mq_get_queue_depth() To: Ming Lei , linux-block@vger.kernel.org References: <20170428151539.25514-1-ming.lei@redhat.com> <20170428151539.25514-3-ming.lei@redhat.com> Cc: Christoph Hellwig , Omar Sandoval From: Jens Axboe Message-ID: <01993bcb-da07-a8f5-1f00-09b808f9efc9@fb.com> Date: Fri, 28 Apr 2017 12:23:38 -0600 MIME-Version: 1.0 In-Reply-To: <20170428151539.25514-3-ming.lei@redhat.com> Content-Type: text/plain; charset=windows-1252 List-ID: On 04/28/2017 09:15 AM, Ming Lei wrote: > The hardware queue depth can be resized via blk_mq_update_nr_requests(), > so introduce this helper for retrieving queue's depth easily. > > Signed-off-by: Ming Lei > --- > 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]; > + > + return tags->bitmap_tags.sb.depth; > +} What about the per-hw queue tag space? q->nr_requests is device side, this might not be. -- Jens Axboe