Re: [PATCH v4] mmc: Add ioctl to let userspace apps send ACMDs

Arnd Bergmann
2011-04-18T14:40:00Z

On Wednesday 13 April 2011, John Calixto wrote:
> Gah! OK, so much for the v5 I just sent then. What do you think about
> the compat_ioctl that I sent in v2? It means having the extra 32-bit
> compat structure, but at least all the compat overhead is conditional
> upon CONFIG_COMPAT. If you're not using CONFIG_COMPAT, you don't get
> any compat cruft.
>

A single __u64 is sufficient, because the user space will do the correct
conversion from pointer to 64-bit integer then. The only conversion
you need to worry about is the actual pointer to the main structure,
which needs the compat_ptr() magic.

Arnd