block layer: elv_iosched_show should get elv_list_lock

elv_iosched_show function iterates other elv_list,
hence elv_list_lock should be got.

Also the question is: in elv_iosched_show, elv_iosched_store
q->elevator->elevator_type construction is used without locking q->queue_lock.
Is it expected?..

Signed-off-by: Vasily Tarasov <vtaras@openvz.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/block/elevator.c b/block/elevator.c
index 9b72dc7c8a5c98dcde87dc0d7e42d9a56f447776..8ed284691c0bc69aa3be19d1db52b6b9f3c768da 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -892,7 +892,7 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name)
        struct list_head *entry;
        int len = 0;
 
-       spin_lock_irq(q->queue_lock);
+       spin_lock_irq(&elv_list_lock);
        list_for_each(entry, &elv_list) {
                struct elevator_type *__e;
 
@@ -902,7 +902,7 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name)
                else
                        len += sprintf(name+len, "%s ", __e->elevator_name);
        }
-       spin_unlock_irq(q->queue_lock);
+       spin_unlock_irq(&elv_list_lock);
 
        len += sprintf(len+name, "\n");
        return len;