Re: [PATCH] [v2] iwlwifi: pcie: fix constant-conversion warning

[Arnd Bergmann]

On Thu, Nov 11, 2021 at 8:31 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> clang points out a potential issue with integer overflow when
> the iwl_dev_info_table[] array is empty:
>
> drivers/net/wireless/intel/iwlwifi/pcie/drv.c:1344:42: error: implicit conversion from 'unsigned long' to 'int' changes value from 18446744073709551615 to -1 [-Werror,-Wconstant-conversion]
>         for (i = ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
>                ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
>
> This is still harmless, as the loop correctly terminates, but adding
> an extra range check makes that obvious to both readers and to the
> compiler.
>
> Fixes: 3f7320428fa4 ("iwlwifi: pcie: simplify iwl_pci_find_dev_info()")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Something went wrong on my end: I thought this was a clang warning and
that I had
fixed it because it didn't come back with my v2 patch. However I now see it in
my gcc-11 test builds, so I assume this was a gcc warning all along, and that
my patch does nothing. Please disregard it if you have not already applied it.

       Arnd