[PATCH v2] seqlock: Fix build errors

[PATCH v2] seqlock: Fix build errors

[Xingxing Su]

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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


Signed-off-by: Xingxing Su <suxingxing@loongson.cn>
---
 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>
 
 /*
-- 
2.1.0

Re: [PATCH v2] seqlock: Fix build errors

[Peter Zijlstra]

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@loongson.cn>
> ---
>  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

Re: [PATCH v2] seqlock: Fix build errors

[Ingo Molnar]

* Peter Zijlstra <peterz@infradead.org> wrote:

> > Signed-off-by: Xingxing Su <suxingxing@loongson.cn>
> > ---
> >  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

It already does that upstream:

 #ifndef __LINUX_LOCKDEP_H
 #define __LINUX_LOCKDEP_H

 #include <linux/lockdep_types.h>
 #include <linux/smp.h>
 #include <asm/percpu.h>

So it would be interesting to know what kernel version the build error 
occurs on.

Thanks,

	Ingo

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@loongson.cn>
>> ---
>>   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.