Re: [PATCH 18/25] dynamic_debug: Introduce global fake module param module.ddebug

[Rusty Russell <rusty@rustcorp.com.au>]

On Wed, 30 Nov 2011 12:56:47 -0700, jim.cromie@gmail.com wrote:
> From: Jim Cromie <jim.cromie@gmail.com>
> 
> Rework Thomas Renninger's $module.ddebug boot-time debugging feature,
> from https://lkml.org/lkml/2010/9/15/397
> 
> Dynamic Debug allows enabling of pr_debug and dev_dbg messages at
> runtime.  This is controlled via $DBGFS/dynamic_debug/control.  One
> major drawback is that the whole initialization of a module cannot be
> tracked, because ddebug is only aware of debug strings of loaded
> modules.  But this is the most interesting part...
> 
> This patch introduces a fake module parameter module.ddebug (not shown
> in /sys/module/*/parameters, thus it does not use any resources).  If
> a module passes ddebug as a module parameter (e.g. via module.ddebug
> kernel boot param or via "modprobe module ddebug"), all debug strings
> of this module get activated by issuing "module module_name +p"
> internally (not via sysfs) when the module gets loaded.
> A later patch extends this with an arg: module.ddebug="+mfp"

I think you're missing a neat trick here: we should be able to handle
ddebug in the handle_unknown parameter to parse_args().

Or am I missing something?

Thanks,
Rusty.