[PATCH 1/9] drivers/gpu/drm/drm_stub.c: Use printf extension %pV

[Kristian Høgsberg]

On Tue, Nov 9, 2010 at 7:35 PM, Joe Perches <joe at perches.com> wrote:
> Using %pV reduces the number of printk calls and
> eliminates any possible message interleaving from
> other printk calls.
>
> Signed-off-by: Joe Perches <joe at perches.com>
> ---
> ?drivers/gpu/drm/drm_stub.c | ? 14 +++++++++++---
> ?1 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
> index cdc89ee..e632527 100644
> --- a/drivers/gpu/drm/drm_stub.c
> +++ b/drivers/gpu/drm/drm_stub.c
> @@ -57,13 +57,21 @@ void drm_ut_debug_printk(unsigned int request_level,
> ? ? ? ? ? ? ? ? ? ? ? ? const char *function_name,
> ? ? ? ? ? ? ? ? ? ? ? ? const char *format, ...)
> ?{
> + ? ? ? struct va_format vaf;
> ? ? ? ?va_list args;
>
> ? ? ? ?if (drm_debug & request_level) {
> - ? ? ? ? ? ? ? if (function_name)
> - ? ? ? ? ? ? ? ? ? ? ? printk(KERN_DEBUG "[%s:%s], ", prefix, function_name);
> ? ? ? ? ? ? ? ?va_start(args, format);
> - ? ? ? ? ? ? ? vprintk(format, args);
> +
> + ? ? ? ? ? ? ? vaf.fmt = format;
> + ? ? ? ? ? ? ? vaf.va = &args;
> +
> + ? ? ? ? ? ? ? if (function_name)
> + ? ? ? ? ? ? ? ? ? ? ? printk(KERN_DEBUG "[%s:%s], %pV",
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?prefix, function_name, &vaf);
> + ? ? ? ? ? ? ? else
> + ? ? ? ? ? ? ? ? ? ? ? printk(KERN_DEBUG "%pV", &vaf);

Wouldn't it be easier and more convenient to just make the %pV format
specifier just expect a format string and the va_arg list?  Like this

  printk(KERN_DEBUG "%pV", format, &args);

I mean, the %pV is kernel specific and we can just change how it works.

Kristian