On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins <brendanhiggins@xxxxxxxxxx> wrote: > > On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins > <brendanhiggins@xxxxxxxxxx> wrote: > > > > On Tue, Aug 27, 2019 at 1:21 PM shuah <shuah@xxxxxxxxxx> wrote: > > > > > > On 8/27/19 11:49 AM, Brendan Higgins wrote: > > > > Previously KUnit assumed that printk would always be present, which is > > > > not a valid assumption to make. Fix that by ifdefing out functions which > > > > directly depend on printk core functions similar to what dev_printk > > > > does. > > > > > > > > Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> > > > > Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df@xxxxxxxxxx/T/#t > > > > Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> > > > > Signed-off-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx> > > > > --- > > > > include/kunit/test.h | 7 +++++++ > > > > kunit/test.c | 41 ++++++++++++++++++++++++----------------- > > > > 2 files changed, 31 insertions(+), 17 deletions(-) > > > > > > > > diff --git a/include/kunit/test.h b/include/kunit/test.h > > > > index 8b7eb03d4971..339af5f95c4a 100644 > > > > --- a/include/kunit/test.h > > > > +++ b/include/kunit/test.h > > > > @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp) > > [...] > > > Okay after reviewing this, I am not sure why you need to do all > > > this. > > > > > > Why can't you just change the root function that throws the warn: > > > > > > static int kunit_vprintk_emit(int level, const char *fmt, va_list args) > > > { > > > return vprintk_emit(0, level, NULL, 0, fmt, args); > > > } > > > > > > You aren'r really doing anything extra here, other than calling > > > vprintk_emit() > > > > Yeah, I did that a while ago. I think it was a combination of trying > > to avoid an extra layer of adding and then removing the log level, and > > that's what dev_printk and friends did. > > > > But I think you are probably right. It's a lot of maintenance overhead > > to get rid of that. Probably best to just use what the printk people > > have. > > > > > Unless I am missing something, can't you solve this problem by including > > > printk.h and let it handle the !CONFIG_PRINTK case? > > > > Randy, I hope you don't mind, but I am going to ask you to re-ack my > > next revision since it basically addresses the problem in a totally > > different way. > > Actually, scratch that. Checkpatch doesn't like me calling printk > without using a KERN_<LEVEL>. > > Now that I am thinking back to when I wrote this. I think it also > might not like using a dynamic KERN_<LEVEL> either (printk("%s my > message", KERN_INFO)). > > I am going to have to do some more investigation. Alright, I am pretty sure it is safe to do printk("%smessage", KERN_<LEVEL>); Looking at the printk implementation, it appears to do the format before it checks the log level: https://elixir.bootlin.com/linux/v5.2.10/source/kernel/printk/printk.c#L1907 So I am pretty sure we can do it either with the vprintk_emit or with printk. So it appears that we have to weigh the following trade-offs: Using vprintk_emit: Pros: - That's what dev_printk uses. - No checkpatch warnings. Cons: - Harder to maintain (requires ifdefery). Using printk: Pros: - Easier to maintain. Cons: - I am less confident that it is correct (I am not 100% certain that printk is intended to be used this way). - Checkpatch warnings. - Extra layer of string formatting. My preference is to go the vprintk_emit route since I am more confident that it is right, but I don't have a strong preference.
