Re: [PATCH v2 03/15] xfs: mount-api - refactor suffix_kstrtoint()

[Brian Foster <bfoster@redhat.com>]

On Fri, Aug 23, 2019 at 08:59:33AM +0800, Ian Kent wrote:
> The mount-api doesn't have a "human unit" parse type yet so
> the options that have values like "10k" etc. still need to
> be converted by the fs.
> 
> But the value comes to the fs as a string (not a substring_t
> type) so there's a need to change the conversion function to
> take a character string instead.
> 
> After refactoring xfs_parseargs() and changing it to use
> xfs_parse_param() match_kstrtoint() will no longer be used
> and will be removed.
> 
> Signed-off-by: Ian Kent <raven@themaw.net>
> ---
>  fs/xfs/xfs_super.c |   22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 74c88b92ce22..49c87fb921f1 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -153,13 +153,13 @@ static const struct fs_parameter_description xfs_fs_parameters = {
>  };
>  
>  STATIC int
> -suffix_kstrtoint(const substring_t *s, unsigned int base, int *res)
> +suffix_kstrtoint(const char *s, unsigned int base, int *res)
>  {
>  	int	last, shift_left_factor = 0, _res;
>  	char	*value;
>  	int	ret = 0;
>  
> -	value = match_strdup(s);
> +	value = kstrdup(s, GFP_KERNEL);
>  	if (!value)
>  		return -ENOMEM;
>  
> @@ -184,6 +184,20 @@ suffix_kstrtoint(const substring_t *s, unsigned int base, int *res)
>  	return ret;
>  }
>  
> +STATIC int
> +match_kstrtoint(const substring_t *s, unsigned int base, int *res)
> +{
> +	const char	*value;
> +	int ret;
> +
> +	value = match_strdup(s);
> +	if (!value)
> +		return -ENOMEM;
> +	ret = suffix_kstrtoint(value, base, res);
> +	kfree(value);
> +	return ret;
> +}
> +

I guess the use case isn't clear to me yet and it's not critical if this
code is going away by the end of the series, but why not refactor into a
__suffix_kstrtoint(char *s, ...) variant that accepts an already
duplicated string so we don't have to duplicate each string twice in the
match_kstrtoint() case?

Brian

>  /*
>   * This function fills in xfs_mount_t fields based on mount args.
>   * Note: the superblock has _not_ yet been read in.
> @@ -255,7 +269,7 @@ xfs_parseargs(
>  				return -EINVAL;
>  			break;
>  		case Opt_logbsize:
> -			if (suffix_kstrtoint(args, 10, &mp->m_logbsize))
> +			if (match_kstrtoint(args, 10, &mp->m_logbsize))
>  				return -EINVAL;
>  			break;
>  		case Opt_logdev:
> @@ -272,7 +286,7 @@ xfs_parseargs(
>  			break;
>  		case Opt_allocsize:
>  		case Opt_biosize:
> -			if (suffix_kstrtoint(args, 10, &iosize))
> +			if (match_kstrtoint(args, 10, &iosize))
>  				return -EINVAL;
>  			iosizelog = ffs(iosize) - 1;
>  			break;
>