On Wed, 2017-06-14 at 12:18 +0200, Greg Kroah-Hartman wrote:
> On Tue, Jun 13, 2017 at 02:12:56PM -0700, Joe Perches wrote:
> > These are similar macros so use the normal kernel one.
> > 
> > As well, there are odd games being played with casting a plist to
> > a union recv_frame by using LIST_CONTAINOR.  Just use a direct cast
> > to union recv_frame instead.
[]
> > diff --git a/drivers/staging/rtl8723bs/core/rtw_recv.c 
> > b/drivers/staging/rtl8723bs/core/rtw_recv.c
[]
> > @@ -129,7 +129,7 @@ union recv_frame *_rtw_alloc_recvframe(struct __queue 
> > *pfree_recv_queue)
> >  
> >             plist = get_next(phead);
> >  
> > -           precvframe = LIST_CONTAINOR(plist, union recv_frame, u);
> > +           precvframe = (union recv_frame *)plist;
> 
> No, you are "assuming" that the list_head is going to stay the first
> object of this structure, and what if it isn't?
> 
> Just use container_of, that way at least you get the type safeness of
> the call, and if something changes in the future, you don't instantly
> break the code everywhere without knowing it.

It's a named union u and it's exactly at the beginning.
It's unlikely to change.

The container_of macro doesn't work here as there it has
a BUILD_BUG_ON_MSG and there are pointer type mismatches
on those uses.

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