Re: [PATCH v2 03/15] [media] adv7180: Use inline function instead of macro

[Lars-Peter Clausen <lars@metafoo.de>]

On 02/02/2015 02:36 PM, Mauro Carvalho Chehab wrote:
> Em Fri, 23 Jan 2015 16:52:22 +0100
> Lars-Peter Clausen <lars@metafoo.de> escreveu:
>
>> Use a inline function instead of a macro for the container_of helper for
>> getting the driver's state struct from a control. A inline function has the
>> advantage that it is more typesafe and nicer in general.
>
> I don't see any advantage on this.
>
> See: container_of is already a macro, and it is written in a way that, if
> you use it with inconsistent values, the compilation will break.

Yes, container_of is a macro, because it needs to be a macro. Compilation 
will also not always break if you pass in a incorrect type, it might succeed 
with even generating a warning. Furthermore if compilation breaks the error 
message is completely incomprehensible. Using a function instead makes sure 
that the error message you get is in the style of "passing argument of wrong 
type to function, expected typeX, got typeY".

>
> Also, there's the risk that, for whatever reason, gcc to decide to not
> inline this.

If the compiler does not inline this it probably has a good reason to do so. 
Not inlining this will not break the functionality, so it is not a problem.

- Lars