block, cfq: move cfqd->icq_list to request_queue and add request->elv.icq
Most of icq management is about to be moved out of cfq into blk-ioc.
This patch prepares for it.
* Move cfqd->icq_list to request_queue->icq_list
* Make request explicitly point to icq instead of through elevator
private data. ->elevator_private[3] is replaced with sub struct elv
which contains icq pointer and priv[2]. cfq is updated accordingly.
* Meaningless clearing of ->elevator_private[0] removed from
elv_set_request(). At that point in code, the field was guaranteed
to be %NULL anyway.
This patch doesn't introduce any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 65c2f8c..8bca048 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -111,10 +111,14 @@
* Three pointers are available for the IO schedulers, if they need
* more they have to dynamically allocate it. Flush requests are
* never put on the IO scheduler. So let the flush fields share
- * space with the three elevator_private pointers.
+ * space with the elevator data.
*/
union {
- void *elevator_private[3];
+ struct {
+ struct io_cq *icq;
+ void *priv[2];
+ } elv;
+
struct {
unsigned int seq;
struct list_head list;
@@ -357,6 +361,8 @@
struct timer_list timeout;
struct list_head timeout_list;
+ struct list_head icq_list;
+
struct queue_limits limits;
/*