On (03/14/19 02:19), Steve French wrote: > All of those uses of __constant_cpu_to_le32 apparently (at least > according to checkpatch) should be changed (someday) to cpu_to_le32 > but I didn't research why the change from __constant_cpu_to_le32 > ---> cpu_to_le32 Probably historic reasons. Looking at linux 2.4.21 /* * Allow constant folding */ #if defined(__GNUC__) && (__GNUC__ >= 2) && defined(__OPTIMIZE__) # define __swahw32(x) \ (__builtin_constant_p((__u32)(x)) ? \ ___swahw32((x)) : \ __fswahw32((x))) My assumption would be that __GNUC__ < 2 did no support __builtin_constant_p? > If it has benefit - and checkpatch is right (it warned about > __constant_cpu_to_le32 being no longer preferred) ... perhaps would be > worth a followup patch to clean the rest of them up? If you have any > context on why kernel code has moved away from using the older format > of __constant_cpu_to_.... would be useful to know if any benefit to > the change Right, that's what I'm going to do - send out patches and update the rest of __constant_cpu_to_XX users; so, eventually, __constant_cpu_to_XX can be removed. -ss
