Messages in this thread | | | Subject | Re: [RFC PATCH] mmc: block: Add new ioctl to send combo commands | From | Jon Hunter <> | Date | Thu, 3 Sep 2015 16:10:18 +0100 |
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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 ;-)
Jon
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