[PATCH] 13/15 Add one more pointer to struct request for IO scheduler usage

[Jens Axboe <axboe@suse.de>]

Then we have enough room in the request to get rid of the dynamic
allocations in CFQ/AS.

Signed-off-by: Jens Axboe <axboe@suse.de>
---
 block/ll_rw_blk.c      |    2 ++
 include/linux/blkdev.h |    6 ++++++
 2 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 08c1615..4018254 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -451,6 +451,7 @@ static void queue_flush(request_queue_t 
 	rq_init(q, rq);
 	rq->flags = REQ_HARDBARRIER;
 	rq->elevator_private = NULL;
+	rq->elevator_private2 = NULL;
 	rq->rq_disk = q->bar_rq.rq_disk;
 	rq->rl = NULL;
 	rq->end_io = end_io;
@@ -477,6 +478,7 @@ static inline struct request *start_orde
 	rq->flags = bio_data_dir(q->orig_bar_rq->bio);
 	rq->flags |= q->ordered & QUEUE_ORDERED_FUA ? REQ_FUA : 0;
 	rq->elevator_private = NULL;
+	rq->elevator_private2 = NULL;
 	rq->rl = NULL;
 	init_request_from_bio(rq, q->orig_bar_rq->bio);
 	rq->end_io = bar_end_io;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 78808a0..ba4378f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -151,7 +151,13 @@ struct request {
 	struct hlist_node hash;	/* merge hash */
 	struct rb_node rb_node;	/* sort/lookup */
 
+	/*
+	 * two pointers are available for the IO schedulers, if they need
+	 * more they have to dynamically allocate it.
+	 */
 	void *elevator_private;
+	void *elevator_private2;
+
 	void *completion_data;
 
 	int rq_status;	/* should split this into a few status bits */
-- 
1.4.1.ged0e0

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