Re: [PATCH] hw_breakpoint: Fix build warnings with clang

[Michael Ellerman <mpe@ellerman.id.au>]

Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> Le 02/06/2020 à 06:12, Ravi Bangoria a écrit :
>> kbuild test robot reported few build warnings with hw_breakpoint code
>> when compiled with clang[1]. Fix those.
>> 
>> [1]: https://lore.kernel.org/linuxppc-dev/202005192233.oi9CjRtA%25lkp@intel.com/
>> 

This should have mentioned that some of the errors were recently
introduced by your commit.

>> Reported-by: kbuild test robot <lkp@intel.com>
>> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
>> ---
>> Note: Prepared on top of powerpc/next.
>> 
>>   arch/powerpc/include/asm/hw_breakpoint.h | 3 ---
>>   include/linux/hw_breakpoint.h            | 4 ++++
>>   2 files changed, 4 insertions(+), 3 deletions(-)
>> 
>> diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
>> index f42a55eb77d2..cb424799da0d 100644
>> --- a/arch/powerpc/include/asm/hw_breakpoint.h
>> +++ b/arch/powerpc/include/asm/hw_breakpoint.h
>> @@ -70,9 +70,6 @@ extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
>>   						unsigned long val, void *data);
>>   int arch_install_hw_breakpoint(struct perf_event *bp);
>>   void arch_uninstall_hw_breakpoint(struct perf_event *bp);
>> -int arch_reserve_bp_slot(struct perf_event *bp);
>> -void arch_release_bp_slot(struct perf_event *bp);
>> -void arch_unregister_hw_breakpoint(struct perf_event *bp);
>>   void hw_breakpoint_pmu_read(struct perf_event *bp);
>>   extern void flush_ptrace_hw_breakpoint(struct task_struct *tsk);
>>   
>> diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h
>> index 6058c3844a76..521481f0d320 100644
>> --- a/include/linux/hw_breakpoint.h
>> +++ b/include/linux/hw_breakpoint.h
>> @@ -80,6 +80,10 @@ extern int dbg_reserve_bp_slot(struct perf_event *bp);
>>   extern int dbg_release_bp_slot(struct perf_event *bp);
>>   extern int reserve_bp_slot(struct perf_event *bp);
>>   extern void release_bp_slot(struct perf_event *bp);
>> +extern int hw_breakpoint_weight(struct perf_event *bp);
>> +extern int arch_reserve_bp_slot(struct perf_event *bp);
>> +extern void arch_release_bp_slot(struct perf_event *bp);
>> +extern void arch_unregister_hw_breakpoint(struct perf_event *bp);
>
> Please no new 'extern'. In the old days 'extern' keyword was used, but 
> new code shall not introduce new unnecessary usage of 'extern' keyword. 
> See report from Checkpatch below:
>
> WARNING:COMMIT_LOG_LONG_LINE: Possible unwrapped commit description 
> (prefer a maximum 75 chars per line)
> #9:
> [1]: 
> https://lore.kernel.org/linuxppc-dev/202005192233.oi9CjRtA%25lkp@intel.com/
>
> CHECK:AVOID_EXTERNS: extern prototypes should be avoided in .h files
> #40: FILE: include/linux/hw_breakpoint.h:83:
> +extern int hw_breakpoint_weight(struct perf_event *bp);

I fixed it up when applying.

cheers