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-rw-r--r--block/elevator.c35
1 files changed, 28 insertions, 7 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 9edba1b8323e..603b2c178740 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -100,14 +100,14 @@ static void elevator_put(struct elevator_type *e)
module_put(e->elevator_owner);
}
-static struct elevator_type *elevator_get(const char *name)
+static struct elevator_type *elevator_get(const char *name, bool try_loading)
{
struct elevator_type *e;
spin_lock(&elv_list_lock);
e = elevator_find(name);
- if (!e) {
+ if (!e && try_loading) {
spin_unlock(&elv_list_lock);
request_module("%s-iosched", name);
spin_lock(&elv_list_lock);
@@ -136,6 +136,22 @@ static int __init elevator_setup(char *str)
__setup("elevator=", elevator_setup);
+/* called during boot to load the elevator chosen by the elevator param */
+void __init load_default_elevator_module(void)
+{
+ struct elevator_type *e;
+
+ if (!chosen_elevator[0])
+ return;
+
+ spin_lock(&elv_list_lock);
+ e = elevator_find(chosen_elevator);
+ spin_unlock(&elv_list_lock);
+
+ if (!e)
+ request_module("%s-iosched", chosen_elevator);
+}
+
static struct kobj_type elv_ktype;
static struct elevator_queue *elevator_alloc(struct request_queue *q,
@@ -191,25 +207,30 @@ int elevator_init(struct request_queue *q, char *name)
q->boundary_rq = NULL;
if (name) {
- e = elevator_get(name);
+ e = elevator_get(name, true);
if (!e)
return -EINVAL;
}
+ /*
+ * Use the default elevator specified by config boot param or
+ * config option. Don't try to load modules as we could be running
+ * off async and request_module() isn't allowed from async.
+ */
if (!e && *chosen_elevator) {
- e = elevator_get(chosen_elevator);
+ e = elevator_get(chosen_elevator, false);
if (!e)
printk(KERN_ERR "I/O scheduler %s not found\n",
chosen_elevator);
}
if (!e) {
- e = elevator_get(CONFIG_DEFAULT_IOSCHED);
+ e = elevator_get(CONFIG_DEFAULT_IOSCHED, false);
if (!e) {
printk(KERN_ERR
"Default I/O scheduler not found. " \
"Using noop.\n");
- e = elevator_get("noop");
+ e = elevator_get("noop", false);
}
}
@@ -951,7 +972,7 @@ int elevator_change(struct request_queue *q, const char *name)
return -ENXIO;
strlcpy(elevator_name, name, sizeof(elevator_name));
- e = elevator_get(strstrip(elevator_name));
+ e = elevator_get(strstrip(elevator_name), true);
if (!e) {
printk(KERN_ERR "elevator: type %s not found\n", elevator_name);
return -EINVAL;