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path: root/drivers/block/elevator.c
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Diffstat (limited to 'drivers/block/elevator.c')
-rw-r--r--drivers/block/elevator.c24
1 files changed, 14 insertions, 10 deletions
diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c
index 98f0126a2deb..4144f30d82a9 100644
--- a/drivers/block/elevator.c
+++ b/drivers/block/elevator.c
@@ -97,7 +97,6 @@ static struct elevator_type *elevator_find(const char *name)
97 struct elevator_type *e = NULL; 97 struct elevator_type *e = NULL;
98 struct list_head *entry; 98 struct list_head *entry;
99 99
100 spin_lock_irq(&elv_list_lock);
101 list_for_each(entry, &elv_list) { 100 list_for_each(entry, &elv_list) {
102 struct elevator_type *__e; 101 struct elevator_type *__e;
103 102
@@ -108,7 +107,6 @@ static struct elevator_type *elevator_find(const char *name)
108 break; 107 break;
109 } 108 }
110 } 109 }
111 spin_unlock_irq(&elv_list_lock);
112 110
113 return e; 111 return e;
114} 112}
@@ -120,12 +118,15 @@ static void elevator_put(struct elevator_type *e)
120 118
121static struct elevator_type *elevator_get(const char *name) 119static struct elevator_type *elevator_get(const char *name)
122{ 120{
123 struct elevator_type *e = elevator_find(name); 121 struct elevator_type *e;
124 122
125 if (!e) 123 spin_lock_irq(&elv_list_lock);
126 return NULL; 124
127 if (!try_module_get(e->elevator_owner)) 125 e = elevator_find(name);
128 return NULL; 126 if (e && !try_module_get(e->elevator_owner))
127 e = NULL;
128
129 spin_unlock_irq(&elv_list_lock);
129 130
130 return e; 131 return e;
131} 132}
@@ -153,11 +154,15 @@ static char chosen_elevator[16];
153 154
154static void elevator_setup_default(void) 155static void elevator_setup_default(void)
155{ 156{
157 struct elevator_type *e;
158
156 /* 159 /*
157 * check if default is set and exists 160 * check if default is set and exists
158 */ 161 */
159 if (chosen_elevator[0] && elevator_find(chosen_elevator)) 162 if (chosen_elevator[0] && (e = elevator_get(chosen_elevator))) {
163 elevator_put(e);
160 return; 164 return;
165 }
161 166
162#if defined(CONFIG_IOSCHED_AS) 167#if defined(CONFIG_IOSCHED_AS)
163 strcpy(chosen_elevator, "anticipatory"); 168 strcpy(chosen_elevator, "anticipatory");
@@ -555,10 +560,9 @@ void elv_unregister_queue(struct request_queue *q)
555 560
556int elv_register(struct elevator_type *e) 561int elv_register(struct elevator_type *e)
557{ 562{
563 spin_lock_irq(&elv_list_lock);
558 if (elevator_find(e->elevator_name)) 564 if (elevator_find(e->elevator_name))
559 BUG(); 565 BUG();
560
561 spin_lock_irq(&elv_list_lock);
562 list_add_tail(&e->list, &elv_list); 566 list_add_tail(&e->list, &elv_list);
563 spin_unlock_irq(&elv_list_lock); 567 spin_unlock_irq(&elv_list_lock);
564 568