[PATCH 1/2] nptl: Remove __ASSUME_SET_ROBUST_LIST

[Florian Weimer]

On 04/19/2017 07:38 PM, Adhemerval Zanella wrote:
> On Wed, Apr 19, 2017 at 12:28 PM, Florian Weimer <fweimer@redhat.com> wrote:
>> On 04/19/2017 04:17 PM, Adhemerval Zanella wrote:
>>>
>>> The problem is kernel supports for some architecture depends of kernel
>>> config
>>> and the underlying hardware revision/model.
>>
>>
>> I understand that.  But I have seen a lot of use of robust mutexes lately,
>> and I'm sure these developers aren't aware that the mutexes aren't portable
>> across GNU/Linux (the Linux architecture subset supported by glibc).
>>
>> I expect it's like the missing accept4 system call—you need to provide the
>> set_robust_list system call in the kernel if you want to a working, modern
>> system.
> 
> But my point is with current minimum supported kernel version for some
> architectures
> we can't simple assume set_robust_list support and even bumping minimum kernel
> version for some architectures also do not solve the issue (on mips
> for instance).

Hmm, maybe you are right, and we have to keep things this way for now.

But I don't like that your patch reintroduces the conditional code.  You 
could use

#define __set_robust_list_avail 1

for the __ASSUME_SET_ROBUST_LIST case to reduce clutter, and let GCC do 
the rest.

Thanks,
Florian