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

[Jon Hunter <jonathanh@nvidia.com>]

On 04/09/15 02:14, Grant Grundler wrote:
> On Thu, Sep 3, 2015 at 8:10 AM, Jon Hunter <jonathanh@nvidia.com> wrote:
> 
>>
>> On 02/09/15 23:08, Grant Grundler wrote:
>>> [resending text-only]
>>>
>>> On Wed, Sep 2, 2015 at 3:07 PM, Grant Grundler <grundler@google.com>
>> wrote:
>>>>
>>>>
>>>> On Wed, Sep 2, 2015 at 11:28 AM, Olof Johansson <olof@lixom.net> wrote:
>>>> ...
>>>>>> +/**
>>>>>> + * struct mmc_ioc_combo_cmd - combo command information
>>>>>> + * @num_of_cmds: number of commands to send
>>>>>> + * @mmc_ioc_cmd_list: pointer to list of commands
>>>>>> + */
>>>>>> +struct mmc_ioc_combo_cmd {
>>>>>> +       uint8_t num_of_cmds;
>>>>>> +       struct mmc_ioc_cmd *mmc_ioc_cmd_list;
>>>>>> +};
>>>>>
>>>>> The size of this struct will depend on the pointer size of userspace.
>>>>>
>>>>> It might be better to use a u64 for the pointer instead. Otherwise
>>>>> you'd need a compat ioctl wrapper to copy a 32-bit pointer over on a
>>>>> 64-bit kernel.
>>>>
>>>> If alignment matters, then maybe swap the fields?
>>>> Or declare num_of_cmds as u64 as well?
>>
>> Thanks. I did swap them in the updated version as this seems to make
>> sense. However, I left num_of_cmds as an 8-bit value unless someone has
>> a need for more than 256 commands ;-)
>>
> 
> Awesome - thanks! I saw that in the new version you posted. LGTM.
> You or Ulf can add my "Reviewed by: Grant Grundler <grundler@chromium.org"
> 
> (I just switched the "reply-from:" on you ;)
> 
> Ulf, anything else stand out?
> 
> I normally don't like to rush but we'd at least like confirmation that
> struct mmc_ioc_combo_cmd is acceptable as is (since it's the main part of
> the API).

Ulf,

Sorry to pester you, but we wanted to get some feedback on whether this
proposal is ok or not.

Cheers
Jon