Re: device-mapper: use dynamic debug instead of compile-time config option

[Mike Snitzer <snitzer@redhat.com>]

On Wed, May 13 2020 at  7:10am -0400,
Hannes Reinecke <hare@suse.de> wrote:

> On 5/13/20 11:41 AM, Damien Le Moal wrote:
> >On 2020/05/13 16:10, Hannes Reinecke wrote:
> >>Switch to use dynamic debug to avoid having recompile the kernel
> >>just to enable debugging messages.
> >>
> >>Signed-off-by: Hannes Reinecke <hare@suse.de>
> >>---
> >>  include/linux/device-mapper.h | 7 +------
> >>  1 file changed, 1 insertion(+), 6 deletions(-)
> >>
> >>diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
> >>index e2d506dd805e..3d4365fd3001 100644
> >>--- a/include/linux/device-mapper.h
> >>+++ b/include/linux/device-mapper.h
> >>@@ -556,13 +556,8 @@ void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
> >>  #define DMINFO(fmt, ...) pr_info(DM_FMT(fmt), ##__VA_ARGS__)
> >>  #define DMINFO_LIMIT(fmt, ...) pr_info_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
> >>-#ifdef CONFIG_DM_DEBUG
> >
> >Can we remove this from Kconfig as a config option ?
> >
> No, we can't, it's being used by dm-snap and dm-integrity.

Yeah, they provide additional debugging if its set.

But shouldn't we preserve old-style DMDEBUG if CONFIG_DM_DEBUG is set
(compile time printing of debugging) but if not set, use dynamic
debugging?

Think I'd prefer that as the incremental improvement... thoughts?

Mike