Re: [B.A.T.M.A.N.] [PATCH] batman-adv: add compat code for kstrtou32

[Matthias Schiffer <mschiffer@universe-factory.net>]

[-- Attachment #1: Type: text/plain, Size: 1335 bytes --]

On 11/21/2013 03:20 PM, Antonio Quartulli wrote:
> On Thu, Nov 21, 2013 at 02:57:50PM +0100, Matthias Schiffer wrote:
>> On 11/21/2013 08:21 AM, Antonio Quartulli wrote:
>>> On Thu, Nov 21, 2013 at 04:45:14AM +0100, Matthias Schiffer wrote:
>>>> You are casting a u32 * to unsigned long *? Won't this break horribly
>>>> when sizeof(u32) != sizeof(unsigned long)?
>>>>
>>>
>>> It will break when sizeof(unsigned long) > sizeof(uint32). For example on
>>> x86_64. Hopefully nobody would use such ancient kernel on his machine. But you
>>> are right.
>>>
>>> What do you think of the attached patch?
>>>
>>
>> That's better, but if you care about overflow, you should add something like
>>
>> if (_v != (unsigned long)v)
>> 	_r = -ERANGE;
> 
> yeah, thanks! I'll add this!
> 
>>
>> Also, the comment in the line above doesn't make sense anymore...
> 
> yeah, I removed that already.
> 
> 

Ah, and I overlooked that you have to dereference v and take the address
of _v; adding parantheses around the parameters might also be a good
idea as it is a macro.

So I'd recommend something like this (not even compile tested...):

({\
	unsigned long _v;\
	int _r;\
	_r = strict_strtoul((cp), (base), &_v);\
	if (_v == (unsigned long)(u32)_v)\
		*(v) = (u32)_v;\
	else\
		_r = -ERANGE;\
	_r;\
})



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 263 bytes --]