Re: [PATCH v1] printk: add dummy vprintk_emit for when CONFIG_PRINTK=n

[Brendan Higgins <brendanhiggins@google.com>]

On Tue, Aug 27, 2019 at 10:24 PM Sergey Senozhatsky
<sergey.senozhatsky.work@gmail.com> wrote:
>
> On (08/27/19 21:45), Brendan Higgins wrote:
> [..]
> > I actually use it in a very similar way as dev_printk() does. I am using
> > it to define an equivalent kunit_printk(), which takes a log level, and
> > adds its own test information to the log.
> >
> > What I have now is:
> >
> > static int kunit_vprintk_emit(int level, const char *fmt, va_list args)
> > {
> >       return vprintk_emit(0, level, NULL, 0, fmt, args);
> > }
> >
> > static int kunit_printk_emit(int level, const char *fmt, ...)
> > {
> >       va_list args;
> >       int ret;
> >
> >       va_start(args, fmt);
> >       ret = kunit_vprintk_emit(level, fmt, args);
> >       va_end(args);
> >
> >       return ret;
> > }
> >
> > static void kunit_vprintk(const struct kunit *test,
> >                         const char *level,
> >                         struct va_format *vaf)
> > {
> >       kunit_printk_emit(level[1] - '0', "\t# %s: %pV", test->name, vaf);
> > }
>
> Basically, for prefixes we have pr_fmt().
>
> #define pr_fmt(fmt) "module name: " fmt
>
> but pr_fmt() is mostly for static prefixes. If that doesn't work for
> you, then maybe you can tweak kunit_foo() macros?

That doesn't work. The prefix is dynamic.

> E.g. something like this
>
> #define kunit_info(test, fmt, ...)                                   \
>         printk(KERN_INFO "\t# %s: " pr_fmt(fmt), (test)->name, ##__VA_ARGS__)
>
> #define kunit_err(test, fmt, ...)                                    \
>         printk(KERN_ERR "\t# %s: " pr_fmt(fmt), (test)->name, ##__VA_ARGS__)
>
> #define kunit_debug(test, fmt, ...)                                  \
>         printk(KERN_DEBUG "\t# %s: " pr_fmt(fmt), (test)->name, ##__VA_ARGS__)
>
> Would that do the trick? Am I missing something?

This appears to work. I will send out a patch that incorporates this.

Thanks!