Re: [PATCH 18/20] staging/lustre/libcfs: get rid of debugfs/lnet/debug_mb

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jul 06, 2015 at 12:48:56PM -0400, green@linuxhacker.ru wrote:
> From: Oleg Drokin <green@linuxhacker.ru>
> 
> It's just a fancy libcfs_debug_mb module parameter wrapper,
> so just add debug buffer size check and resizing and the same
> functionality now would be accessible via
> /sys/module/libcfs/parameters/libcfs_debug_mb
> 
> Also add a symlink for backwards compatibility.
> 
> Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
> ---
>  drivers/staging/lustre/lustre/libcfs/debug.c     | 37 ++++++++++++++++++++++--
>  drivers/staging/lustre/lustre/libcfs/module.c    | 32 ++------------------
>  drivers/staging/lustre/lustre/libcfs/tracefile.c | 12 --------
>  drivers/staging/lustre/lustre/libcfs/tracefile.h |  1 -
>  4 files changed, 37 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/staging/lustre/lustre/libcfs/debug.c b/drivers/staging/lustre/lustre/libcfs/debug.c
> index 5ae7b65..e4c7129 100644
> --- a/drivers/staging/lustre/lustre/libcfs/debug.c
> +++ b/drivers/staging/lustre/lustre/libcfs/debug.c
> @@ -57,8 +57,39 @@ module_param(libcfs_debug, int, 0644);
>  MODULE_PARM_DESC(libcfs_debug, "Lustre kernel debug mask");
>  EXPORT_SYMBOL(libcfs_debug);
>  
> +static int libcfs_param_debug_mb_set(const char *val,
> +				     const struct kernel_param *kp)
> +{
> +	int rc;
> +	unsigned num;
> +
> +	rc = kstrtouint(val, 0, &num);
> +	if (rc == -EINVAL)
> +		return -EINVAL;
> +
> +	if (!*((unsigned int *)kp->arg)) {
> +		*((unsigned int *)kp->arg) = num;
> +		return 0;
> +	}
> +
> +	rc = cfs_trace_set_debug_mb(num);
> +
> +	if (!rc)
> +		*((unsigned int *)kp->arg) = cfs_trace_get_debug_mb();
> +
> +	return rc;
> +}
> +
> +static struct kernel_param_ops param_ops_debugmb = {
> +	.set = libcfs_param_debug_mb_set,
> +	.get = param_get_uint,
> +};
> +
> +#define param_check_debugmb(name, p) \
> +		__param_check(name, p, unsigned int)
> +
>  static unsigned int libcfs_debug_mb;
> -module_param(libcfs_debug_mb, uint, 0644);
> +module_param(libcfs_debug_mb, debugmb, 0644);

module_param wants a variable type as the second option, not a variable
name, how is this working?

thanks,

greg k-h