Re: [PATCH] cgroup: reorder flexible array members of struct cgroup_root

[Tejun Heo]

On Sun, Oct 22, 2017 at 02:59:33AM +1100, Aleksa Sarai wrote:
> >Here, not necessarily but I don't want to move it for a bogus reason.
> >Why would we disallow embedding structs with flexible members in the
> >middle when it can be done and is useful?  If we want to discuss
> >whether we want to avoid such usages in the kernel (but why?), sure,
> >let's have that discussion but we can't decide that on "clang warns on
> >it by default".
> 
> There was a talk a few years ago by the clang folks[1] saying that
> while trying to build a kernel with clang, they discovered that
> several places in the kernel uses "VLAIS" (variable Length Arrays In
> Structs") and argued that this is a violation of the C
> specification, despite it being a GNU extension. They also submitted
> several patches that removed this code (even working around a
> user-space visible usage of VLAIS).

The kernel is explicitly using GNU extended version of C and has
always from the beginning, so not-std-c isn't a valid argument.

Thanks.

-- 
tejun