[PATCH 1/3] Deadline iosched: Factor out finding latter request

Aaron Carroll
2007-10-30T04:05:26Z

Factor finding the next request in sector-sorted order into
a function deadline_latter_request.

Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au>
---
block/deadline-iosched.c | 28 +++++++++++++++++-----------
1 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index 1a511ff..a44437e 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -55,6 +55,20 @@ static void deadline_move_request(struct deadline_data *, struct request *);

#define RQ_RB_ROOT(dd, rq) (&(dd)->sort_list[rq_data_dir((rq))])

+/*
+ * get the request after `rq' in sector-sorted order
+ */
+static inline struct request *
+deadline_latter_request(struct request *rq)
+{
+ struct rb_node *node = rb_next(&rq->rb_node);
+
+ if (node)
+ return rb_entry_rq(node);
+
+ return NULL;
+}
+
static void
deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
{
@@ -74,13 +88,8 @@ deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
{
const int data_dir = rq_data_dir(rq);

- if (dd->next_rq[data_dir] == rq) {
- struct rb_node *rbnext = rb_next(&rq->rb_node);
-
- dd->next_rq[data_dir] = NULL;
- if (rbnext)
- dd->next_rq[data_dir] = rb_entry_rq(rbnext);
- }
+ if (dd->next_rq[data_dir] == rq)
+ dd->next_rq[data_dir] = deadline_latter_request(rq);

elv_rb_del(RQ_RB_ROOT(dd, rq), rq);
}
@@ -198,14 +207,11 @@ static void
deadline_move_request(struct deadline_data *dd, struct request *rq)
{
const int data_dir = rq_data_dir(rq);
- struct rb_node *rbnext = rb_next(&rq->rb_node);

dd->next_rq[READ] = NULL;
dd->next_rq[WRITE] = NULL;
+ dd->next_rq[data_dir] = deadline_latter_request(rq);

- if (rbnext)
- dd->next_rq[data_dir] = rb_entry_rq(rbnext);
-
dd->last_sector = rq->sector + rq->nr_sectors;

/*