Re: [net-next PATCH v4 1/3] sysctl: refactor integer handling proc code

[Cong Wang <amwang@redhat.com>]

Octavian Purdila wrote:
> On Tuesday 16 February 2010 15:09:51 you wrote:
>> Octavian Purdila wrote:
>>> On Tuesday 16 February 2010 10:41:07 you wrote:
>>>>> +static int proc_skip_wspace(char __user **buf, size_t *size)
>>>>> +{
>>>>> +     char c;
>>>>> +
>>>>> +     while (*size) {
>>>>> +             if (get_user(c, *buf))
>>>>> +                     return -EFAULT;
>>>>> +             if (!isspace(c))
>>>>> +                     break;
>>>>> +             (*size)--; (*buf)++;
>>>>> +     }
>>>>> +
>>>>> +     return 0;
>>>>> +}
>>>> In lib/string.c we have skip_spaces(), I think we can use it
>>>> here instead of inventing another one.
>>> I'm afraid we can't, skip_spaces does not accept userspace buffers.
>> Well, you need to use copy_from_user() before call it.
>>
> 
> And how much would you copy? You need to either use a stack buffer and do a 
> loop copy or you would need to copy the whole userspace buffer which means we 
> need to allocate a kernel buffer. I think its much cleaner the way is currently 
> done.

Yeah, maybe just a personal preference. :-/