Re: build failure with mason/for-linus tree

[Miao Xie <miaox@cn.fujitsu.com>]

On Wed, 2 Jul 2014 08:41:54 +0900, Satoru Takeuchi wrote:
> Hi Chris,
> 
> (2014/07/01 23:30), Chris Mason wrote:
>> On 07/01/2014 01:43 AM, Satoru Takeuchi wrote:
>>> Hi Chris,
>>>
>>> FYI, today I failed to build mason/for-linus tree as follows.
>>>
>>
>> You were building for 3.15?
> 
> I just run the following command to confirm whether the latest
> for-linux tree can build or not.
> 
> $ git checkout -b mason-for-linus mason/for-linus
> $ make
> 
> Then that error happens and It's just FYI.

It is because for-linus was built on v3.15 kernel, but the code of for-linus
is based on v3.16-rc1.

If you merge for-linus to upstream kernel, then you will compile the kernel successfully.

Thanks
Miao

> 
> Thanks,
> Satoru
> 
>>
>>> ===============================================================================
>>> ...
>>> /home/sat/src/linux-2.6/fs/btrfs/transaction.c: In function 'record_root_in_trans':
>>> /home/sat/src/linux-2.6/fs/btrfs/transaction.c:293:3: error: implicit declaration of function 'smp_mb__before_atomic' [-Werror=implicit-function-declaration]
>>>     smp_mb__before_atomic();
>>>     ^
>>> /home/sat/src/linux-2.6/fs/btrfs/transaction.c: In function 'commit_fs_roots':
>>> /home/sat/src/linux-2.6/fs/btrfs/transaction.c:1065:4: error: implicit declaration of function 'smp_mb__after_atomic' [-Werror=implicit-function-declaration]
>>>      smp_mb__after_atomic();
>>>      ^
>>> cc1: some warnings being treated as errors
>>> ...
>>> ===============================================================================
>>>
>>> It can be solved by cherry-picking febdbfe.
>>>
>>> ===
>>> commit febdbfe8a91ce0d11939d4940b592eb0dba8d663
>>> Author: Peter Zijlstra <peterz@infradead.org>
>>> Date:   Thu Feb 6 18:16:07 2014 +0100
>>>
>>>      arch: Prepare for smp_mb__{before,after}_atomic()
>>>      
>>>      Since the smp_mb__{before,after}*() ops are fundamentally dependent on
>>>      how an arch can implement atomics it doesn't make sense to have 3
>>>      variants of them. They must all be the same.
>>
>> Yes, or revert:
>>
>> commit c7548af69d9ef71512eb52d8009521eba3e768fd
>> Author: Chris Mason <clm@fb.com>
>> Date:   Tue Jun 10 13:06:56 2014 -0700
>>
>>      Btrfs: convert smp_mb__{before,after}_clear_bit
>>
>>      The new call is smp_mb__{before,after}_atomic.  The __ gives us extra
>>      protection from the atomic rays.
>>
>>      Signed-off-by: Chris Mason <clm@fb.com>
>>
>> Which is only needed on 3.16+
>>
>> I should have put this one into a 3.16 only branch, it was a mistake on
>> my end.
>>
>> -chris
>>
> 
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