On Wed, 24 Nov 2021 09:03:24 +0100 Johannes Berg wrote: > On Tue, 2021-11-23 at 15:49 -0800, Jakub Kicinski wrote: > > > Indeed. > > > > > > Also as I said in my other mail, the le32/be32/... variants are > > > tremendously useful, and they fundamentally cannot be expressed with the > > > FIELD_GET() or field_get() macros. IMHO this is a clear advantage to the > > > > Can you elaborate? > > Well, the way I see it, the only advantage of FIELD_GET() is that it > will auto-determine the type (based on the mask type.) This cannot work > if you need be/le conversions, because the be/le type annotations are > invisible to the compiler. > > So obviously you could write a BE32_FIELD_GET(), but then really that's > equivalent to be32_get_bits() - note you you have to actually specify > the type in the macro name. I guess in theory you could make macros > where the type is an argument (like FIELD_GET_TYPE(be32, ...)), but I > don't see how that gains anything. Ah, that's what you meant! Thanks for spelling it out. FWIW I never found the be/le versions useful. Most of the time the data comes from bus accessors which swap or is unaligned so you have to do be/le_get_unaligned, which swaps. Plus if you access/set multiple fields you'd swap them one by one which seems wasteful. > > > typed versions, and if you ask me we should get rid of the FIELD_GETand > > > FIELD_PREP entirely - difficult now, but at least let's not propagate > > > that? > > > > I don't see why. > > Just for being more regular, in the spirit of "there's exactly one > correct way of doing it" :) Right now it seems the uppercase macros are more prevalent. Could just be because of the way the "swapping ones" are defined.
