linux-ext4 - [KJ][PATCH] is_power_of

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Date:	Tue, 20 Feb 2007 13:19:30 +0530
From:	Vignesh Babu BM <vignesh.babu@...ro.com>
To:	Kernel Janitors List <kernel-janitors@...ts.osdl.org>
Cc:	sct@...hat.com, akpm@...l.org, adilger@...sterfs.com,
	linux-ext4@...r.kernel.org
Subject: [KJ][PATCH] is_power_of_2 in ext4

Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2

Signed-off-by: vignesh babu <vignesh.babu@...ro.com>
--- 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 486a641..e70172b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -35,6 +35,7 @@
 #include <linux/namei.h>
 #include <linux/quotaops.h>
 #include <linux/seq_file.h>
+#include <linux/log2.h>
 
 #include <asm/uaccess.h>
 
@@ -1624,7 +1625,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
-		    (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
+		    !is_power_of_2(sbi->s_inode_size) ||
 		    (sbi->s_inode_size > blocksize)) {
 			printk (KERN_ERR
 				"EXT4-fs: unsupported inode size: %d\n",
@@ -1644,7 +1645,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
 		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
 		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
-		    sbi->s_desc_size & (sbi->s_desc_size - 1)) {
+		    !is_power_of_2(sbi->s_desc_size)) {
 			printk(KERN_ERR
 			       "EXT4-fs: unsupported descriptor size %lu\n",
 			       sbi->s_desc_size);

-- 
Regards,  
Vignesh Babu BM  
_____________________________________________________________  
"Why is it that every time I'm with you, makes me believe in magic?"
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