Re: [PATCH 5/6] cachefiles: Fix signed/unsigned mixup

[Gao Xiang]

On 2024/1/9 19:20, David Howells wrote:
> In __cachefiles_prepare_write(), the start and pos variables were made
> unsigned 64-bit so that the casts in the checking could be got rid of -
> which should be fine since absolute file offsets can't be negative, except
> that an error code may be obtained from vfs_llseek(), which *would* be
> negative.  This breaks the error check.
>
> Fix this for now by reverting pos and start to be signed and putting back
> the casts.  Unfortunately, the error value checks cannot be replaced with
> IS_ERR_VALUE() as long might be 32-bits.
>
> Fixes: 7097c96411d2 ("cachefiles: Fix __cachefiles_prepare_write()")
> Reported-by: Simon Horman <horms@xxxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202401071152.DbKqMQMu-lkp@xxxxxxxxx/
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
> cc: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
> cc: Yiqun Leng <yqleng@xxxxxxxxxxxxxxxxx>
> cc: Jia Zhu <zhujia.zj@xxxxxxxxxxxxx>
> cc: Jeff Layton <jlayton@xxxxxxxxxx>
> cc: linux-cachefs@xxxxxxxxxx
> cc: linux-erofs@xxxxxxxxxxxxxxxx
> cc: linux-fsdevel@xxxxxxxxxxxxxxx
> cc: linux-mm@xxxxxxxxx

It looks good to me,
Reviewed-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>

Thanks,
Gao Xiang