Re: [PATCH 2/3] introduce probe_slab_address()

[Kirill Tkhai <tkhai@yandex.ru>]

On 28.10.2014 18:01, Peter Zijlstra wrote:
> On Tue, Oct 28, 2014 at 08:44:51AM +0300, Kirill Tkhai wrote:
>> В Пн, 27/10/2014 в 20:54 +0100, Oleg Nesterov пишет:
> 
>>> +#define probe_slab_address(addr, retval)	\
>>> +	probe_kernel_address(addr, retval)
>>
>> probe_kernel_read() was arch-dependent on tree platforms:
>>
>> arch/blackfin/mm/maccess.c
>> arch/parisc/lib/memcpy.c
>> arch/um/kernel/maccess.c
>>
>> But now we skip these arch-dependent implementations. Is there no a problem?
>
> Nope, see the first patch, it makes probe_kernel_address use
> __probe_kernel_read().
> 

Yes, probe_kernel_read() is in [1/3], but it's not the same as
__probe_kernel_read() for blackfin, for example.

It's defined as

long __weak probe_kernel_read(void *dst, const void *src, size_t size)
    __attribute__((alias("__probe_kernel_read")));

But blackfin's probe_kernel_read() redefines this __weak function,
isn't it? Didn't get_freepointer_safe() use to call architecture's
probe_kernel_read() before?

I don't see how it is called now...