[PATCH] fat: silence warning for 64KB PAGE_SIZE builds

[PATCH] fat: silence warning for 64KB PAGE_SIZE builds

[Olof Johansson]

Annoying gcc warning:

fs/fat/inode.c: In function 'fat_fill_super':
fs/fat/inode.c:1222: warning: comparison is always false due to limited range of data type

logical_sector_size can never be more than 16 bits worth, but switching
it to an int silences gcc. It's a sanity check that can never fail with
64KB PAGE_SIZE but it seems like it'd still be useful for other page
sizes, so it's worth keeping:

        if (!is_power_of_2(logical_sector_size)
            || (logical_sector_size < 512)
            || (PAGE_CACHE_SIZE < logical_sector_size)) {
                if (!silent)
                        printk(KERN_ERR "FAT: bogus logical sector size %u\n",
                               logical_sector_size);
                brelse(bh);
                goto out_invalid;
        }


Signed-off-by: Olof Johansson <olof@lixom.net>

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 920a576..6aae680 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -1158,7 +1158,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
 	struct buffer_head *bh;
 	struct fat_boot_sector *b;
 	struct msdos_sb_info *sbi;
-	u16 logical_sector_size;
+	int logical_sector_size;
 	u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
 	int debug;
 	unsigned int media;

Re: [PATCH] fat: silence warning for 64KB PAGE_SIZE builds

[OGAWA Hirofumi]

Olof Johansson <olof@lixom.net> writes:

> logical_sector_size can never be more than 16 bits worth, but switching
> it to an int silences gcc. It's a sanity check that can never fail with
> 64KB PAGE_SIZE but it seems like it'd still be useful for other page
> sizes, so it's worth keeping:
>
>         if (!is_power_of_2(logical_sector_size)
>             || (logical_sector_size < 512)
>             || (PAGE_CACHE_SIZE < logical_sector_size)) {
>                 if (!silent)
>                         printk(KERN_ERR "FAT: bogus logical sector size %u\n",
>                                logical_sector_size);
>                 brelse(bh);
>                 goto out_invalid;
>         }

Please use 4096 instead of allowing it, at least for now.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Re: [PATCH] fat: silence warning for 64KB PAGE_SIZE builds

[Olof Johansson]

Annoying gcc warning:

fs/fat/inode.c: In function 'fat_fill_super':
fs/fat/inode.c:1222: warning: comparison is always false due to limited range of data type

Change it to compare with 4K instead of PAGE_CACHE_SIZE, as suggested
by OGAWA-san.


Signed-off-by: Olof Johansson <olof@lixom.net>

---

On Wed, Nov 07, 2007 at 11:39:01PM +0900, OGAWA Hirofumi wrote:
> Olof Johansson <olof@lixom.net> writes:
> 
> > logical_sector_size can never be more than 16 bits worth, but switching
> > it to an int silences gcc. It's a sanity check that can never fail with
> > 64KB PAGE_SIZE but it seems like it'd still be useful for other page
> > sizes, so it's worth keeping:
[...]
> 
> Please use 4096 instead of allowing it, at least for now.

Sure. New patch.


Thanks,

-Olof

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 920a576..61e2874 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -1219,7 +1219,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
 		le16_to_cpu(get_unaligned((__le16 *)&b->sector_size));
 	if (!is_power_of_2(logical_sector_size)
 	    || (logical_sector_size < 512)
-	    || (PAGE_CACHE_SIZE < logical_sector_size)) {
+	    || (logical_sector_size > 4096)) {
 		if (!silent)
 			printk(KERN_ERR "FAT: bogus logical sector size %u\n",
 			       logical_sector_size);

Re: [PATCH] fat: silence warning for 64KB PAGE_SIZE builds

[OGAWA Hirofumi]

Olof Johansson <olof@lixom.net> writes:

> Annoying gcc warning:
>
> fs/fat/inode.c: In function 'fat_fill_super':
> fs/fat/inode.c:1222: warning: comparison is always false due to limited range of data type
>
> Change it to compare with 4K instead of PAGE_CACHE_SIZE, as suggested
> by OGAWA-san.
>
>
> Signed-off-by: Olof Johansson <olof@lixom.net>
>
> ---
>
> On Wed, Nov 07, 2007 at 11:39:01PM +0900, OGAWA Hirofumi wrote:
>> Olof Johansson <olof@lixom.net> writes:
>> 
>> > logical_sector_size can never be more than 16 bits worth, but switching
>> > it to an int silences gcc. It's a sanity check that can never fail with
>> > 64KB PAGE_SIZE but it seems like it'd still be useful for other page
>> > sizes, so it's worth keeping:
> [...]
>> 
>> Please use 4096 instead of allowing it, at least for now.
>
> Sure. New patch.
>
>
> Thanks,
>
> -Olof
>
> diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> index 920a576..61e2874 100644
> --- a/fs/fat/inode.c
> +++ b/fs/fat/inode.c
> @@ -1219,7 +1219,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
>  		le16_to_cpu(get_unaligned((__le16 *)&b->sector_size));
>  	if (!is_power_of_2(logical_sector_size)
>  	    || (logical_sector_size < 512)
> -	    || (PAGE_CACHE_SIZE < logical_sector_size)) {
> +	    || (logical_sector_size > 4096)) {
>  		if (!silent)
>  			printk(KERN_ERR "FAT: bogus logical sector size %u\n",
>  			       logical_sector_size);

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

Thanks a lot.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>