On Tue, 23 Nov 2021 09:36:22 +0100 Geert Uytterhoeven wrote: > > > Also, you're using __ffs(), which doesn't work for 64-bit on 32-bit > > > architectures (afaict), so that seems a bit awkward. > > > > > > Maybe we can make {u32,...}_get_bits() be doing compile-time only checks > > > if it is indeed a constant? The __field_overflow() usage is already only > > > done if __builtin_constant_p(v), so I guess we can do the same with > > > __bad_mask()? > > > > Either that or add decomposition macros. Are compilers still really bad > > at passing small structs by value? > > Sorry, I don't get what you mean by adding decomposition macros. > Can you please elaborate? #define DECOMPOSE(_mask) \ (struct bf){ .mask = _mask, .shf = __bf_shf(_mask), } Then drivers can save or pass around the mask and shift params broken apart as a small struct.