On Sun, Aug 20, 2023 at 09:52:22PM +0200, Alejandro Colomar wrote: > On 2023-08-18 10:46, Andy Shevchenko wrote: > > On Fri, Aug 18, 2023 at 01:28:42PM +0800, Herbert Xu wrote: > >> On Thu, Aug 17, 2023 at 04:33:17PM +0200, Lucas Segarra Fernandez wrote: ... > Many xxxof_{member,field}() macros make use of the same construction to > refer to a member of a struct without needing a variable of the > structure type. > > memberof(T, m) simplifies all of those, avoids possible mistakes in > repetition, adds a meaningful name to the construction, and improves > readability by avoiding too many parentheses together. > > It uses a compound literal, which should optimized out by the compiler. > It's a bit simpler to read than the dereference of a casted null > pointer, due to having less parentheses in the implementation. > > Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > Cc: Lucas Segarra Fernandez <lucas.segarra.fernandez@xxxxxxxxx> > Cc: Giovanni Cabiddu <giovanni.cabiddu@xxxxxxxxx> > Signed-off-by: Alejandro Colomar <alx.manpages@xxxxxxxxx> > --- > include/linux/container_of.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/include/linux/container_of.h b/include/linux/container_of.h > index 713890c867be..5e762025c780 100644 > --- a/include/linux/container_of.h > +++ b/include/linux/container_of.h > @@ -5,7 +5,9 @@ > #include <linux/build_bug.h> > #include <linux/stddef.h> > > -#define typeof_member(T, m) typeof(((T*)0)->m) > + > +#define memberof(T, member) ((T){}.member) I'm not sure. This seems to me utilization of compound literal, while above uses direct struct member pointer calculations. > +#define typeof_member(T, m) typeof(memberof(T, m)) -- With Best Regards, Andy Shevchenko