Re: [PATCH 1/3] xfs: create global stats and stats_clear in sysfs

[Dave Chinner <david@fromorbit.com>]

On Fri, Sep 04, 2015 at 03:54:08PM -0500, Bill O'Donnell wrote:
> Currently, xfs global stats are in procfs. This patch introduces
> (replicates) the global stats in sysfs. Additionally a stats_clear file
> is introduced in sysfs.
> 
....
>  
> +int xfs_stats_format(char *buf)
> +{
> +	int		i, j;
> +	int		len = 0;
> +	__uint64_t	xs_xstrat_bytes = 0;
> +	__uint64_t	xs_write_bytes = 0;
> +	__uint64_t	xs_read_bytes = 0;
....
> +	len += snprintf(buf+len, PATH_MAX-len, "xpc %Lu %Lu %Lu\n",
> +			xs_xstrat_bytes, xs_write_bytes, xs_read_bytes);
> +	len += snprintf(buf+len, PATH_MAX-len, "debug %u\n",
> +#if defined(DEBUG)
> +		1);
> +#else
> +		0);
> +#endif
> +
> +return len;
> +}

missing tab on return.

....
> +STATIC ssize_t
> +xfs_stats_show(
> +	struct kobject		*kobject,
> +	struct attribute	*attr,
> +	char			*buf)
> +{
> +	struct xfs_sysfs_attr *xfs_attr = to_attr(attr);
> +
> +	return xfs_attr->show ? xfs_attr->show(buf, NULL) : 0;
> +}
> +
> +STATIC ssize_t
> +xfs_stats_store(
> +	struct kobject		*kobject,
> +	struct attribute	*attr,
> +	const char		*buf,
> +	size_t			count)
> +{
> +	struct xfs_sysfs_attr *xfs_attr = to_attr(attr);
> +
> +	return xfs_attr->store ? xfs_attr->store(buf, count, NULL) : 0;
> +}
> +
> +static struct sysfs_ops xfs_stats_ops = {
> +	.show = xfs_stats_show,
> +	.store = xfs_stats_store,
> +};

Hmmm, I'm wondering if we can reduce this boiler plate code here.
It's basically indentical to xfs_log_show/store and
xfs_dbg_show/store. TO make them indentical, all we need to do is
pass the kobject through as the data object, and have the show/store
function decode it if necessary (i.e. call to_xlog() for the xfs log
attributes).  This them means that all the sysfs entries
attributes use the same sysfs_ops structure.

That can be done as a patch on top of this, though (i.e. patch #4).

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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