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-rw-r--r--block/elevator.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 02d4390afee..6d765f7e2b2 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -965,7 +965,7 @@ fail_init:
/*
* Switch this queue to the given IO scheduler.
*/
-int elevator_change(struct request_queue *q, const char *name)
+static int __elevator_change(struct request_queue *q, const char *name)
{
char elevator_name[ELV_NAME_MAX];
struct elevator_type *e;
@@ -987,6 +987,18 @@ int elevator_change(struct request_queue *q, const char *name)
return elevator_switch(q, e);
}
+
+int elevator_change(struct request_queue *q, const char *name)
+{
+ int ret;
+
+ /* Protect q->elevator from elevator_init() */
+ mutex_lock(&q->sysfs_lock);
+ ret = __elevator_change(q, name);
+ mutex_unlock(&q->sysfs_lock);
+
+ return ret;
+}
EXPORT_SYMBOL(elevator_change);
ssize_t elv_iosched_store(struct request_queue *q, const char *name,
@@ -997,7 +1009,7 @@ ssize_t elv_iosched_store(struct request_queue *q, const char *name,
if (!q->elevator)
return count;
- ret = elevator_change(q, name);
+ ret = __elevator_change(q, name);
if (!ret)
return count;