Re: [PATCH 03/34] brcmfmac: firmware: Support having multiple alt paths

[Dmitry Osipenko]

03.01.2022 03:41, Hector Martin пишет:
>> There is indeed no need for the castings in such cases, it's a typical
>> code pattern in kernel. You would need to do the casting for the other
>> way around, i.e. if char ** was returned and **alt_paths was a const.
> You do need to do the cast. Try it.
> 
> $ cat test.c
> int main() {
>         char *foo[1];
>         const char **bar = foo;
> 
>         return 0;
> }
> 
> $ gcc test.c
> test.c: In function ‘main’:
> test.c:4:28: warning: initialization of ‘const char **’ from
> incompatible pointer type ‘char **’ [-Wincompatible-pointer-types]
>     4 |         const char **bar = foo;
>       |
> 
> You can implicitly cast char* to const char*, but you *cannot*
> impliclicitly cast char** to const char** for the reason I explained. It
> requires a cast.

Right, I read it as "char * const *". The "const char **" vs "char *
const *" always confuses me.

Hence you should've written "const char **alt_paths;" in
brcm_alt_fw_paths() in the first place and then casting wouldn't have
been needed.