Re: [PATCH wireless-drivers] mt76x0: Remove VLA usage

Stanislaw Gruszka
2018-08-09T10:41:48Z

On Wed, Aug 08, 2018 at 08:41:28AM -0700, Kees Cook wrote:
> >> I thought SPDX line is needed only if file has no license and eeprom.c
> >> file and other mt76x0 files have specified the license. Is SPDX still
> >> needed in that case ?
>
> I thought all source files needed SPDX: https://lwn.net/Articles/739183/

Ok, goal is to have all kernel source files with SPDX header.

> >>> +#define MT_MAP_READS DIV_ROUND_UP(MT_EFUSE_USAGE_MAP_SIZE, 16)
> >>> static int
> >>> mt76x0_efuse_physical_size_check(struct mt76x0_dev *dev)
> >>> {
> >>> - const int map_reads = DIV_ROUND_UP(MT_EFUSE_USAGE_MAP_SIZE, 16);
> >>> - u8 data[map_reads * 16];
> >>
> >> Why this is variable length array? DIV_ROUND_UP can not be calculated
> >> at compile time? But if so, macro do not change the situation either.
> >
> > The commit log mentioned:
> >
> > "Even with "const" variables, the compiler will generate warnings about
> > VLA usage."
> >
> > So I guess the compiler (gcc?) is just not smart enough in this case?
>
> Correct. This is technically a false positive, but with the goal of
> adding -Wvla to the build globally, we have to get rid of these as
> well. It's a little frustrating, I agree, but with all others fixed
> now, these stand out. :)

Then:
Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>