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

From: Grant Grundler
Date: Wed Sep 02 2015 - 18:08:59 EST


[resending text-only]

On Wed, Sep 2, 2015 at 3:07 PM, Grant Grundler <grundler@xxxxxxxxxx> wrote:
>
>
> On Wed, Sep 2, 2015 at 11:28 AM, Olof Johansson <olof@xxxxxxxxx> 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?
>
> grant
>
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