2007-02-20 07:51:41

by vignesh babu

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 <[email protected]>
---
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?"

2007-02-20 13:12:54

by OGAWA Hirofumi

Subject: Re: [KJ][PATCH] is_power_of_2 in fat

Vignesh Babu BM <[email protected]> writes:

> Replacing (n & (n-1)) in the context of power of 2 checks
> with is_power_of_2
>
> Signed-off-by: vignesh babu <[email protected]>

Acked-by: OGAWA Hirofumi <[email protected]>

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 <[email protected]>