On Fri, Sep 28, 2018 at 09:20:30AM -0700, Christoph Hellwig wrote: > > +unsigned long long notrace __bswapdi2(unsigned long long u) > > +{ > > + return (((u) & 0xff00000000000000ull) >> 56) | > > + (((u) & 0x00ff000000000000ull) >> 40) | > > + (((u) & 0x0000ff0000000000ull) >> 24) | > > + (((u) & 0x000000ff00000000ull) >> 8) | > > + (((u) & 0x00000000ff000000ull) << 8) | > > + (((u) & 0x0000000000ff0000ull) << 24) | > > + (((u) & 0x000000000000ff00ull) << 40) | > > + (((u) & 0x00000000000000ffull) << 56); > > +} > > How is this any better than using the generic byteswap helpers? OK. #include <uapi/linux/swab.h> unsigned long long notrace __bswapdi2(unsigned long long u) { return ___constant_swab64(u); > > > +unsigned int notrace __bswapsi2(unsigned int u) > > +{ > > + return (((u) & 0xff000000) >> 24) | > > + (((u) & 0x00ff0000) >> 8) | > > + (((u) & 0x0000ff00) << 8) | > > + (((u) & 0x000000ff) << 24); > > +} > > Same here. OK. #include <uapi/linux/swab.h> unsigned int notrace __bswapsi2(unsigned int u) { return ___constant_swab32(u); } Thx Guo Ren