Hi,
Am 10.10.2012 17:52, schrieb Joe Perches:
> On Wed, 2012-10-10 at 16:44 +0100, David Laight wrote:
>>> On Wed, 2012-10-10 at 15:59 +0100, David Laight wrote:
>>>> Seems to me the code is expecting 256 bits of data, not any multiple of int,
>>>> long or anything else.
>>>
>>> include/linux/isdn_ppp.h:#define PPPIOCGCOMPRESSORS _IOR('t',134,unsigned long [8])
>>
>> That doesn't mean the whole thing makes any sense on 64bit systems.
>> A whole load of historic code used 'long' to ensure 32bit.
>> Some of that might have crept into Linux sources.
>
> Very true, but it's exported via copy_to_user.
>
>> Since I suspect there are a maximum of 256 bits on both 32 and 64bit
>> systems, I wouldn't like to guess exactly how any particular 64bit
>> application chooses to check the bitmap.
>>
>> The ioctl constant may be wrong on 64 bit systems.
>
> shrug. Not much to do about it now.
> isdn isn't very active.
>
> Karsten? What do you think?
>
I use ipppd as testbench to test remote connections via different PPP
clients running on a 64 bit system without problems so far - but I did
not use any compressions for some years, so maybe this code was never
tested on 64 bit and at least not on mixed 32/64 bit systems.
If I will find some time, I will check if the compression works.
I did not wrote this part, so I cannot say how the code should work
correctly out of the box, I need to analyze this first by myself.
Karsten
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