Re: [RFC][PATCH] new byteorder primitives - ..._{replace,get}_bits()

Al Viro
2017-12-13T17:46:05Z

On Wed, Dec 13, 2017 at 02:22:12PM +0000, Al Viro wrote:

> Next question: where do we put that bunch? I've put it into
> linux/byteorder/generic.h, so that anything picking fixed-endian primitives
> would pick those as well; I hadn't thought of linux/bitfield.h at the time.
> We certainly could put it there instead - it's never pulled by other headers,
> so adding #include <asm/byteorder.h> into linux/bitfield.h is not going to
> cause header order problems. Not sure...
>
> Linus, do you have any preferences in that area?

After looking at some of the callers of bitfield.h stuff: it might be useful
to add

static inline void le64p_replace_bits(__le64 *p, u64 v, u64 mask)
{
__le64 m = cpu_to_le64(mask);
*p = (*p & ~m) | (cpu_to_le64(v * mask_to_multiplier(mask)) & m);
}

and similar for other types. Not sure what would be a good name for
host-endian variants - u64p_replace_bits() sounds a bit clumsy. Suggestions?