@@ -53,6 +53,8 @@ static LIST_HEAD(elv_list);
*/
#define rq_hash_key(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
+static int elevator_change(struct request_queue *q, const char *name);
+
/*
* Query io scheduler to see if the current process issuing bio may be
* merged with rq.
@@ -681,10 +683,6 @@ int __elevator_change(struct request_queue *q, const char *elevator_name,
struct elevator_type *e;
int ret;
- /* Make sure queue is not in the middle of being removed */
- if (!blk_queue_registered(q))
- return -ENOENT;
-
if (!strncmp(elevator_name, "none", 4)) {
if (q->elevator)
elevator_disable(q);
@@ -703,6 +701,29 @@ int __elevator_change(struct request_queue *q, const char *elevator_name,
return ret;
}
+static int elevator_change(struct request_queue *q, const char *name)
+{
+ int ret, idx;
+ unsigned int memflags;
+ struct blk_mq_tag_set *set = q->tag_set;
+
+ idx = srcu_read_lock(&set->update_nr_hwq_srcu);
+
+ if (set->flags & BLK_MQ_F_UPDATE_HW_QUEUES) {
+ ret = -EBUSY;
+ goto exit;
+ }
+
+ memflags = blk_mq_freeze_queue(q);
+ mutex_lock(&q->elevator_lock);
+ ret = __elevator_change(q, name, false);
+ mutex_unlock(&q->elevator_lock);
+ blk_mq_unfreeze_queue(q, memflags);
+exit:
+ srcu_read_unlock(&set->update_nr_hwq_srcu, idx);
+ return ret;
+}
+
static void elv_iosched_load_module(char *elevator_name)
{
struct elevator_type *found;
@@ -718,12 +739,10 @@ static void elv_iosched_load_module(char *elevator_name)
ssize_t elv_iosched_store(struct gendisk *disk, const char *buf,
size_t count)
{
+ struct request_queue *q = disk->queue;
char elevator_name[ELV_NAME_MAX];
char *name;
- int ret, idx;
- unsigned int memflags;
- struct request_queue *q = disk->queue;
- struct blk_mq_tag_set *set = q->tag_set;
+ int ret;
/*
* If the attribute needs to load a module, do it before freezing the
@@ -735,22 +754,13 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf,
elv_iosched_load_module(name);
- idx = srcu_read_lock(&set->update_nr_hwq_srcu);
-
- if (set->flags & BLK_MQ_F_UPDATE_HW_QUEUES) {
- ret = -EBUSY;
- goto exit;
- }
+ /* Make sure queue is not in the middle of being removed */
+ if (!blk_queue_registered(q))
+ return -ENOENT;
- memflags = blk_mq_freeze_queue(q);
- mutex_lock(&q->elevator_lock);
- ret = __elevator_change(q, name, false);
+ ret = elevator_change(q, name);
if (!ret)
ret = count;
- mutex_unlock(&q->elevator_lock);
- blk_mq_unfreeze_queue(q, memflags);
-exit:
- srcu_read_unlock(&set->update_nr_hwq_srcu, idx);
return ret;
}
Add elevator_change() to simplify elv_iosched_store() a bit, and the new helper will be used for unifying all scheduler change. Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/elevator.c | 52 +++++++++++++++++++++++++++++------------------- 1 file changed, 31 insertions(+), 21 deletions(-)