[PATCH] Adds a new ioctl32 syscall for backwards compatibility layers

[David Laight]

From: Christoph Hellwig
> Sent: 16 January 2021 09:07
...
> > I personally would like to see in_compat_syscall() go away,
> > but some other people (Hi, Christoph!) disagree, and usage seems to be
> > increasing, not decreasing.
> 
> I'm absolutely against it going away.  in_compat_syscall helped to
> remove so much crap compared to the explicit compat syscalls.

The only other real option is to pass the 'syscall type' explicitly
through all the layers into every piece of code that might need it.

So passing it as a 'parameter' that is (probably) current->syscall_type
does make sense.

It might even make sense have separate bits for the required emulations.
So you'd have separate bits for '32bit pointers' and '64bit items 32bit
aligned' (etc).

	David

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