Messages in this thread | | | Subject | Re: [PATCH v1] kunit: fix failure to build without printk | From | shuah <> | Date | Tue, 27 Aug 2019 16:00:55 -0600 |
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On 8/27/19 3:36 PM, Brendan Higgins wrote: > On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins > <brendanhiggins@google.com> wrote: >> >> On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins >> <brendanhiggins@google.com> wrote: >>> >>> On Tue, Aug 27, 2019 at 1:21 PM shuah <shuah@kernel.org> 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@infradead.org> >>>>> Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df@kernel.org/T/#t >>>>> Cc: Stephen Rothwell <sfr@canb.auug.org.au> >>>>> Signed-off-by: Brendan Higgins <brendanhiggins@google.com> >>>>> --- >>>>> 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.
Let me see if we are on the same page first. I am asking if you can just include printk.h for vprintk_emit() define for both CONFIG_PRINTK and !CONFIG_PRINTK cases.
I am not asking you to use printk() in place of vprintk_emit(). It is perfectly fine to use vprintk_emit()
> > So it appears that we have to weigh the following trade-offs: > > Using vprintk_emit: > > Pros: > - That's what dev_printk uses.
Not sure what you mean by this. I am suggesting if you can just call vprintk_emit() and include printk.h and not have to ifdef around all the other callers of kunit_vprintk_emit()
Yes. There is the other issue of why do you need the complexity of having kunit_vprintk_emit() at all.
thanks, -- Shuah
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