rd: use is_power_of_2() in drivers/block/rd.c.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/block/rd.c b/drivers/block/rd.c
index 82f4eecc8699..06e23be70904 100644
--- a/drivers/block/rd.c
+++ b/drivers/block/rd.c
@@ -56,6 +56,7 @@
 #include <linux/backing-dev.h>
 #include <linux/blkpg.h>
 #include <linux/writeback.h>
+#include <linux/log2.h>
 
 #include <asm/uaccess.h>
 
@@ -450,7 +451,7 @@ static int __init rd_init(void)
         err = -ENOMEM;
 
         if (rd_blocksize > PAGE_SIZE || rd_blocksize < 512 ||
-                        (rd_blocksize & (rd_blocksize-1))) {
+                        !is_power_of_2(rd_blocksize)) {
                 printk("RAMDISK: wrong blocksize %d, reverting to defaults\n",
                        rd_blocksize);
                 rd_blocksize = BLOCK_SIZE;