On 2/19/2016 3:50 AM, Lee Jones wrote:
> On Thu, 18 Feb 2016, Rhyland Klein wrote:
>
>> MFD_ARRAY_SIZE() would not accurately return 0 if the passed
>> parameter was NULL. Fix this so that num_resources will
>> accurately be 0 in the case that _res is NULL.
>>
>> cc: Lee Jones <lee.jo...@linaro.org>
>> cc: Laxman Dewangan <ldewan...@nvidia.com>
>> Signed-off-by: Rhyland Klein <rkl...@nvidia.com>
>> ---
>> include/linux/mfd/core.h | 15 +++++++++------
>> 1 file changed, 9 insertions(+), 6 deletions(-)
>>
>> diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
>> index 1a5a87f3cd38..62136ccff1df 100644
>> --- a/include/linux/mfd/core.h
>> +++ b/include/linux/mfd/core.h
>> @@ -18,11 +18,11 @@
>>
>> #define MFD_ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
>>
>> -#define MFD_CELL_ALL(_name, _res, _pdata, _id, _compat, _match)
>> \
>> +#define MFD_CELL_ALL(_name, _nres, _res, _pdata, _id, _compat, _match)
>> \
>> { \
>> .name = (_name), \
>> .resources = (_res), \
>> - .num_resources = MFD_ARRAY_SIZE((_res)), \
>> + .num_resources = (_nres), \
>> .platform_data = (_pdata), \
>> .pdata_size = MFD_ARRAY_SIZE((_pdata)), \
>> .of_compatible = (_compat), \
>> @@ -31,16 +31,19 @@
>> }
>>
>> #define OF_MFD_CELL(_name, _res, _pdata, _id, _compat)
>> \
>> - MFD_CELL_ALL(_name, _res, _pdata, _id, _compat, NULL) \
>> + MFD_CELL_ALL(_name, MFD_ARRAY_SIZE((_res)), _res, \
>> + _pdata, _id, _compat, NULL) \
>
> I'm confused. Why would it be any different just by changing the call
> site of MFD_ARRAY_SIZE?
It isn't different, but for MFD_CELL_NAME, it explicitly passes 0
instead of using MFD_ARRAY_SIZE, as its the only place that doesn't
expect to have resources.
>
> And what about .platform_data?
This crashed for me (without the change) at :
mfd_add_device():
for (r = 0; r < cell->num_resources; r++) {
res[r].name = cell->resources[r].name;
res[r].flags = cell->resources[r].flags;
where dereferencing cell->resources[0] when there are no resources. I
guess the platform_data could do the same, but I didn't run into it.
>
> How about this change instead?
>
> diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
> index 1a5a87f..8440f42 100644
> --- a/include/linux/mfd/core.h
> +++ b/include/linux/mfd/core.h
> @@ -16,7 +16,7 @@
>
> #include <linux/platform_device.h>
>
> -#define MFD_ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
> +#define MFD_ARRAY_SIZE(arr) (arr ? (sizeof(arr) / sizeof((arr)[0])) : 0)
>
> #define MFD_CELL_ALL(_name, _res, _pdata, _id, _compat, _match)
> \
> { \
>
That was my first thought too. However, I see this when I try to compile
that:
In file included from drivers/mfd/max77620.c:18:0:
include/linux/mfd/core.h:19:34: warning: the address of ‘gpio_resources’
will always evaluate as ‘true’ [-Waddress]
#define MFD_ARRAY_SIZE(arr) (arr ? (sizeof(arr) / sizeof((arr)[0])) : 0)
7 different times. This patch was the only way I seemed to be able to
WAR around compile time warnings.
-rhyland
--
nvpublic
