Re: compat ioctl32 for /dev/snapshot?

[Michael Tokarev <mjt@tls.msk.ru>]

Arnd Bergmann wrote:
> On Sunday 12 July 2009, Michael Tokarev wrote:
>> As I mentioned in my first email, I'm not the right person to
>> do the patch.  But regardless, I spent about a day understanding
>> this stuff (or trying to, anyway) - 100% useless day - and when
>> I thought I have a patch someone else spoken up and said this
>> way (compat_ioctl) is the wrong approach now.  And sent another,
>> also trivial patch, adding compat calls right to the proper
>> place in kernel/power.c.  Which (the patch) has been ignored
>> too.
> 
> I never got a reply from you saying whether or not the patch
> I sent actually worked. If you or someone else can confirm it,
> I'll resend with the fixes you mentioned.

In order to (try to) check if it works or not, another userspace
component has to be fixed to support 32/64 bit mode.  It's uswsusp,
which currently assumes swap space structures are all 32bits.  So
it isn't possible to immediately check if it works or not -- just
ioctl(s) aren't enough.  Complete fix (kernel+user space) requires
both, fixing all remaining (yet unknown) issues in old and new
code on the way.

For now, I think it's best to let Pavel or Rafael to decide what
to do with all this.

Thanks!

/mjt