make elv_register() output atomic

Booting 2.6.21-rc3-g45592145 I noticed the following on one of my
machines in the bootlog:

io scheduler noop registered<6>Time: jiffies clocksource has been installed.

io scheduler deadline registered (default)

Looking at block/elevator.c, it appears that elv_register() uses two
consecutive printks in a non-atomic way, leading to the above glitch. The
attached trivial patch fixes this issue, by using a single printk.

Signed-off-by: Thibaut VARENE <varenet@parisc-linux.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/block/elevator.c b/block/elevator.c
index 25f6ef28e3bb..96a00c822748 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -964,17 +964,18 @@ void elv_unregister_queue(struct request_queue *q)
 
 int elv_register(struct elevator_type *e)
 {
+        char *def = "";
         spin_lock_irq(&elv_list_lock);
         BUG_ON(elevator_find(e->elevator_name));
         list_add_tail(&e->list, &elv_list);
         spin_unlock_irq(&elv_list_lock);
 
-        printk(KERN_INFO "io scheduler %s registered", e->elevator_name);
         if (!strcmp(e->elevator_name, chosen_elevator) ||
                         (!*chosen_elevator &&
                          !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED)))
-                                printk(" (default)");
-        printk("\n");
+                                def = " (default)";
+
+        printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name, def);
         return 0;
 }
 EXPORT_SYMBOL_GPL(elv_register);