const: make block_device_operations const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/block/umem.c b/drivers/block/umem.c
index 858c34d..ad1ba39 100644
--- a/drivers/block/umem.c
+++ b/drivers/block/umem.c
@@ -140,7 +140,6 @@
 };
 
 static struct cardinfo cards[MM_MAXCARDS];
-static struct block_device_operations mm_fops;
 static struct timer_list battery_timer;
 
 static int num_cards;
@@ -789,7 +788,7 @@
 	return 0;
 }
 
-static struct block_device_operations mm_fops = {
+static const struct block_device_operations mm_fops = {
 	.owner		= THIS_MODULE,
 	.getgeo		= mm_getgeo,
 	.revalidate_disk = mm_revalidate,