[KJ][PATCH] is_power_of_2 in fat

[KJ][PATCH] is_power_of_2 in fat

[Vignesh Babu BM]

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

Signed-off-by: vignesh babu <vignesh.babu@wipro.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?"

Re: [KJ][PATCH] is_power_of_2 in fat

[OGAWA Hirofumi]

Vignesh Babu BM <vignesh.babu@wipro.com> writes:

> Replacing (n & (n-1)) in the context of power of 2 checks
> with is_power_of_2
>
> Signed-off-by: vignesh babu <vignesh.babu@wipro.com>

Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Thanks.

> --- 
> 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);
>
> -- 
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>