linux-kernel - [KJ][PATCH] is_power_of

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 20 Feb 2007 13:19:54 +0530
From:	Vignesh Babu BM <vignesh.babu@...ro.com>
To:	Kernel Janitors List <kernel-janitors@...ts.osdl.org>
Cc:	hirofumi@...l.parknet.co.jp, linux-kernel@...r.kernel.org
Subject: [KJ][PATCH] is_power_of_2 in fat

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/fat/inode.c b/fs/fat/inode.c
index a9e4688..8437190 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -25,6 +25,7 @@
 #include <linux/parser.h>
 #include <linux/uio.h>
 #include <linux/writeback.h>
+#include <linux/log2.h>
 #include <asm/unaligned.h>
 
 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
@@ -1216,8 +1217,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
 	}
 	logical_sector_size =
 		le16_to_cpu(get_unaligned((__le16 *)&b->sector_size));
-	if (!logical_sector_size
-	    || (logical_sector_size & (logical_sector_size - 1))
+	if (!is_power_of_2(logical_sector_size)
 	    || (logical_sector_size < 512)
 	    || (PAGE_CACHE_SIZE < logical_sector_size)) {
 		if (!silent)
@@ -1227,8 +1227,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
 		goto out_invalid;
 	}
 	sbi->sec_per_clus = b->sec_per_clus;
-	if (!sbi->sec_per_clus
-	    || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) {
+	if (!is_power_of_2(sbi->sec_per_clus)) {
 		if (!silent)
 			printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
 			       sbi->sec_per_clus);

-- 
Regards,  
Vignesh Babu BM  
_____________________________________________________________  
"Why is it that every time I'm with you, makes me believe in magic?"
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/