Messages in this thread Patch in this message | | | Subject | Re: [PATCH] mfd: Fix MACRO for commonly declared MFD cell attributes | From | Rhyland Klein <> | Date | Fri, 19 Feb 2016 11:28:52 -0500 |
| |
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.jones@linaro.org> >> cc: Laxman Dewangan <ldewangan@nvidia.com> >> Signed-off-by: Rhyland Klein <rklein@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
| |