check privileges before setting mount propagation

[deliverable/linux.git] / fs / block_dev.c

diff --git a/fs/block_dev.c b/fs/block_dev.c
index f02b7bdd9864874c5f038c792c20763a1bfa7437..742899240872ffb59e7329f6dabef624798c2fbb 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -22,6 +22,7 @@
 #include <linux/mount.h>
 #include <linux/uio.h>
 #include <linux/namei.h>
+#include <linux/log2.h>
 #include <asm/uaccess.h>
 #include "internal.h"
 
@@ -67,7 +68,7 @@ static void kill_bdev(struct block_device *bdev)
 int set_blocksize(struct block_device *bdev, int size)
 {
        /* Size must be a power of two, and between 512 and PAGE_SIZE */
-       if (size > PAGE_SIZE || size < 512 || (size & (size-1)))
+       if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
                return -EINVAL;
 
        /* Size cannot be smaller than the size supported by the device */