Re: [PATCH] mmc: block: Add new ioctl to send multi commands

Grant Grundler
2015-09-10T20:26:20Z

On Thu, Sep 10, 2015 at 11:20 AM, Jon Hunter <jonathanh@nvidia.com> wrote:
>
> On 10/09/15 18:10, Grant Grundler wrote:
...
>>>>>> struct mmc_ioc_multi_cmd {
>>>>>> __u64 num_of_cmds;
>>>>>> struct mmc_ioc_cmd cmds[0];
>>>>>> };
>>
>> I think this would work just as well. But doesn't "pointer to an
>> array" require 32-bit ioctl compat handling?
>> We were trying to avoid a 32-bit user space compatibility handler.
>
> I think that this is fine as it is a zero length array [0] and not a
> pointer.

Doh, yes. Thanks for correcting. I knew this was a gcc special but
forgot it's not actually allocating any space.

cheers,
grant

>
> Cheers
> Jon
>
> [0] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html