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authorDamien Le Moal <damien.lemoal@wdc.com>2017-12-21 09:43:41 +0300
committerJens Axboe <axboe@kernel.dk>2018-01-05 19:22:17 +0300
commitc117bac70133dbff9ed7fcbd91ef82b4ee518797 (patch)
treec7ce23c0147bfc758e15f367881edbdba325d67e /block/deadline-iosched.c
parent5700f69178e91a6b21250049b86148ed5e9550c1 (diff)
downloadlinux-c117bac70133dbff9ed7fcbd91ef82b4ee518797.tar.xz
deadline-iosched: Introduce dispatch helpers
Avoid directly referencing the next_rq and fifo_list arrays using the helper functions deadline_next_request() and deadline_fifo_request() to facilitate changes in the dispatch request selection in deadline_dispatch_requests() for zoned block devices. While at it, also remove the unnecessary forward declaration of the function deadline_move_request(). Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/deadline-iosched.c')
-rw-r--r--block/deadline-iosched.c47
1 files changed, 37 insertions, 10 deletions
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index b83f77460d28..81e3f0897457 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -50,8 +50,6 @@ struct deadline_data {
int front_merges;
};
-static void deadline_move_request(struct deadline_data *, struct request *);
-
static inline struct rb_root *
deadline_rb_root(struct deadline_data *dd, struct request *rq)
{
@@ -231,6 +229,35 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
}
/*
+ * For the specified data direction, return the next request to dispatch using
+ * arrival ordered lists.
+ */
+static struct request *
+deadline_fifo_request(struct deadline_data *dd, int data_dir)
+{
+ if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
+ return NULL;
+
+ if (list_empty(&dd->fifo_list[data_dir]))
+ return NULL;
+
+ return rq_entry_fifo(dd->fifo_list[data_dir].next);
+}
+
+/*
+ * For the specified data direction, return the next request to dispatch using
+ * sector position sorted lists.
+ */
+static struct request *
+deadline_next_request(struct deadline_data *dd, int data_dir)
+{
+ if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
+ return NULL;
+
+ return dd->next_rq[data_dir];
+}
+
+/*
* deadline_dispatch_requests selects the best request according to
* read/write expire, fifo_batch, etc
*/
@@ -239,16 +266,15 @@ static int deadline_dispatch_requests(struct request_queue *q, int force)
struct deadline_data *dd = q->elevator->elevator_data;
const int reads = !list_empty(&dd->fifo_list[READ]);
const int writes = !list_empty(&dd->fifo_list[WRITE]);
- struct request *rq;
+ struct request *rq, *next_rq;
int data_dir;
/*
* batches are currently reads XOR writes
*/
- if (dd->next_rq[WRITE])
- rq = dd->next_rq[WRITE];
- else
- rq = dd->next_rq[READ];
+ rq = deadline_next_request(dd, WRITE);
+ if (!rq)
+ rq = deadline_next_request(dd, READ);
if (rq && dd->batching < dd->fifo_batch)
/* we have a next request are still entitled to batch */
@@ -291,19 +317,20 @@ dispatch_find_request:
/*
* we are not running a batch, find best request for selected data_dir
*/
- if (deadline_check_fifo(dd, data_dir) || !dd->next_rq[data_dir]) {
+ next_rq = deadline_next_request(dd, data_dir);
+ if (deadline_check_fifo(dd, data_dir) || !next_rq) {
/*
* A deadline has expired, the last request was in the other
* direction, or we have run out of higher-sectored requests.
* Start again from the request with the earliest expiry time.
*/
- rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
+ rq = deadline_fifo_request(dd, data_dir);
} else {
/*
* The last req was the same dir and we have a next request in
* sort order. No expired requests so continue on from here.
*/
- rq = dd->next_rq[data_dir];
+ rq = next_rq;
}
dd->batching = 0;