Re: [PATCH v2] seqlock: Fix build errors

[Xingxing Su]

On 08/14/2020 04:35 PM, Peter Zijlstra wrote:

> On Fri, Aug 14, 2020 at 12:12:38PM +0800, Xingxing Su wrote:
> > Fix the following build errors:
> >
> > In file included from ./include/linux/time.h:6:0,
> >                   from ./include/linux/compat.h:10,
> >                   from arch/mips/kernel/asm-offsets.c:12:
> > ./include/linux/seqlock.h: In function ‘write_seqcount_begin_nested’:
> > ./include/linux/seqlock.h:286:2: error: implicit declaration of function
> >   ‘raw_smp_processor_id’ [-Werror=implicit-function-declaration]
> >    lockdep_assert_preemption_disabled();
> >    ^
> > ./arch/mips/include/asm/smp.h: At top level:
> > ./arch/mips/include/asm/smp.h:28:19: error: static declaration of
> >   ‘raw_smp_processor_id’ follows non-static declaration
> >   static inline int raw_smp_processor_id(void)
> >                   ^
> > cc1: some warnings being treated as errors
> > scripts/Makefile.build:117: recipe for target 'arch/mips/kernel/asm-offsets.s' failed
> > make[1]: *** [arch/mips/kernel/asm-offsets.s] Error 1
> > arch/mips/Makefile:396: recipe for target 'archprepare' failed
> > make: *** [archprepare] Error 2
> What kernel are you building?
>
> Commit 0cd39f4600ed ("locking/seqlock, headers: Untangle the spaghetti monster")
>
> should have solved that I think.
>
> > Signed-off-by: Xingxing Su <suxingxing@xxxxxxxxxxx>
> > ---
> >   v2:  update the commit message
> >
> >   include/linux/seqlock.h | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
> > index 54bc204..4763c13 100644
> > --- a/include/linux/seqlock.h
> > +++ b/include/linux/seqlock.h
> > @@ -17,6 +17,7 @@
> >   #include <linux/lockdep.h>
> >   #include <linux/compiler.h>
> >   #include <linux/kcsan-checks.h>
> > +#include <linux/smp.h>
> >   #include <asm/processor.h>
> Wrong place, it's lockdep_assert_preemption_disabled() that requires
> asm/percpu.h, and thus lockdep.h should include linux/smp. before
> asm/percpu.h

Thanks for your reply, I will check it.