block: Stop abusing csd.list for fifo_time

Block layer currently abuses rq->csd.list.next for storing fifo_time.
That is a terrible hack and completely unnecessary as well. Union
achieves the same space saving in a cleaner way.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

2 files changed, 1 insertions, 6 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 4afa4f8f6090..1e1fa3f93d5f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -99,6 +99,7 @@ struct request {
         union {
                 struct call_single_data csd;
                 struct work_struct mq_flush_work;
+                unsigned long fifo_time;
         };
 
         struct request_queue *q;
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 306dd8cd0b6f..0bdfd46f4735 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -202,12 +202,6 @@ enum {
 #define rq_end_sector(rq)       (blk_rq_pos(rq) + blk_rq_sectors(rq))
 #define rb_entry_rq(node)       rb_entry((node), struct request, rb_node)
 
-/*
- * Hack to reuse the csd.list list_head as the fifo time holder while
- * the request is in the io scheduler. Saves an unsigned long in rq.
- */
-#define rq_fifo_time(rq)        ((unsigned long) (rq)->csd.list.next)
-#define rq_set_fifo_time(rq,exp)        ((rq)->csd.list.next = (void *) (exp))
 #define rq_entry_fifo(ptr)      list_entry((ptr), struct request, queuelist)
 #define rq_fifo_clear(rq)       do {            \
         list_del_init(&(rq)->queuelist);        \