summaryrefslogtreecommitdiff
path: root/include/linux/blk-mq.h
diff options
context:
space:
mode:
authorJens Axboe <axboe@fb.com>2014-10-29 20:14:52 +0300
committerJens Axboe <axboe@fb.com>2014-10-29 20:14:52 +0300
commit74c450521dd8d245b982da62592a18aa6f88b045 (patch)
treeb45928c02f0ee9051cd5cb257ad4bf1e0df125a8 /include/linux/blk-mq.h
parent34b48db66e08ca1c1bc07cf305d672ac940268dc (diff)
downloadlinux-74c450521dd8d245b982da62592a18aa6f88b045.tar.xz
blk-mq: add a 'list' parameter to ->queue_rq()
Since we have the notion of a 'last' request in a chain, we can use this to have the hardware optimize the issuing of requests. Add a list_head parameter to queue_rq that the driver can use to temporarily store hw commands for issue when 'last' is true. If we are doing a chain of requests, pass in a NULL list for the first request to force issue of that immediately, then batch the remainder for deferred issue until the last request has been sent. Instead of adding yet another argument to the hot ->queue_rq path, encapsulate the passed arguments in a blk_mq_queue_data structure. This is passed as a constant, and has been tested as faster than passing 4 (or even 3) args through ->queue_rq. Update drivers for the new ->queue_rq() prototype. There are no functional changes in this patch for drivers - if they don't use the passed in list, then they will just queue requests individually like before. Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include/linux/blk-mq.h')
-rw-r--r--include/linux/blk-mq.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index c9be1589415a..be01d7a687d4 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -79,7 +79,13 @@ struct blk_mq_tag_set {
struct list_head tag_list;
};
-typedef int (queue_rq_fn)(struct blk_mq_hw_ctx *, struct request *, bool);
+struct blk_mq_queue_data {
+ struct request *rq;
+ struct list_head *list;
+ bool last;
+};
+
+typedef int (queue_rq_fn)(struct blk_mq_hw_ctx *, const struct blk_mq_queue_data *);
typedef struct blk_mq_hw_ctx *(map_queue_fn)(struct request_queue *, const int);
typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);