[PATCH] 7/15 elevator: introduce a way to reuse rq for internal FIFO handling

From: Jens Axboe
Date: Thu Jul 13 2006 - 08:42:49 EST


The io schedulers can use this instead of having to allocate space for
it themselves.

Signed-off-by: Jens Axboe <axboe@xxxxxxx>
---
include/linux/elevator.h | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 95b2a04..0e7b1a7 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -166,4 +166,16 @@ enum {
#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)

+/*
+ * Hack to reuse the donelist 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)->donelist.next)
+#define rq_set_fifo_time(rq,exp) ((rq)->donelist.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); \
+ INIT_LIST_HEAD(&(rq)->donelist); \
+ } while (0)
+
#endif
--
1.4.1.ged0e0

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/