From: Trond Myklebust <redacted>
Date: Fri, 30 Aug 2024 02:08:09 +0000

On Fri, 2024-08-30 at 09:42 +0800, Yan Zhen wrote:

quoted

Using ERR_CAST() is more reasonable and safer, When it is necessary
to convert the type of an error pointer and return it.

static inline void * __must_check ERR_CAST(__force const void *ptr)
{
        /* cast away the const */
        return (void *) ptr;
}

That function is literally just doing an implicit cast from whatever
pointer type it is now, to a 'const void *' and then to a 'void *',
which then gets implicitly cast to whatever type the caller is
expecting. Exactly how is that "safer" than the current explicit cast?

I think we might want to reimplement ERR_CAST() using _Generic() to not
cast away const when the argument itself is const.

While it is great that ERR_CAST() exists, and I agree that it should be
preferred in newer code for the (sole (!)) reason that it documents
that we expect this to be an error, I see no reason why it is
imperative to apply that change to existing code. Particularly not as a
standalone patch.

So NACK for now.

Thanks,
Olek