Re: [patch 3/4] make pr_debug() dynamic - sysctl support

[Stephen Hemminger <shemminger@linux-foundation.org>]

On Thu, 7 Feb 2008 16:12:29 -0500
Jason Baron <jbaron@redhat.com> wrote:

> 
> -add /proc/sys/debug/pr_debug, to toggle pr_debug() on/off
> 
> Signed-off-by: Jason Baron <jbaron@redhat.com>
> ---
> 
>  kernel/sysctl.c |   41 +++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 41 insertions(+), 0 deletions(-)
> 
> 
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 7cb1ac3..73508d7 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -155,6 +155,11 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, struct file *filp
>  static int proc_dointvec_taint(struct ctl_table *table, int write, struct file *filp,
>  			       void __user *buffer, size_t *lenp, loff_t *ppos);
>  #endif
> +#ifdef CONFIG_PR_DEBUG_DYNAMIC
> +static int proc_pr_debug_handler(struct ctl_table *table, int write,
> +				 struct file *filp, void __user *buffer,
> +				 size_t *lenp, loff_t *ppos);
> +#endif
>  
>  static struct ctl_table root_table[];
>  static struct ctl_table_root sysctl_table_root;
> @@ -1312,6 +1317,16 @@ static struct ctl_table debug_table[] = {
>  		.proc_handler	= proc_dointvec
>  	},
>  #endif
> +#ifdef CONFIG_PR_DEBUG_DYNAMIC
> +	{
> +		.ctl_name       = CTL_UNNUMBERED,
> +		.procname       = "pr_debug",
> +		.data           = NULL,
> +		.maxlen         = sizeof(int),
> +		.mode           = 0644,
> +		.proc_handler   = &proc_pr_debug_handler
> +	},
> +#endif
>  	{ .ctl_name = 0 }
>  };
>  
> @@ -2499,6 +2514,32 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, struct file *filp
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PR_DEBUG_DYNAMIC
> +
> +static int proc_pr_debug_handler(struct ctl_table *table, int write,
> +				 struct file *filp, void __user *buffer,
> +				 size_t *lenp, loff_t *ppos)
> +{
> +	int tmp, r;
> +
> +	if (!write)
> +		tmp = imv_read(pr_debug_on);
> +	r = __do_proc_dointvec(&tmp, table, write, filp, buffer,
> +				lenp, ppos, NULL, NULL);
> +	if (r)
> +		return r;
> +
> +	if (write) {
> +		if (tmp)
> +			imv_set(pr_debug_on, 1);
> +		else
> +			imv_set(pr_debug_on, 0);
> +	}
> +	return 0;
> +}
> +
> +#endif
> +
>  #else /* CONFIG_PROC_FS */
>  
>  int proc_dostring(struct ctl_table *table, int write, struct file *filp,

Please no, there are many pr_debug calls that are only intended for debugging that
particular subsystem, not a global enable/disable. It also adds to kernel bloat.

-- 
Stephen Hemminger <stephen.hemminger@vyatta.com>