On Sun, 7 Feb 2016 17:08:45 -0800 David Decotigny <ddecotig@xxxxxxxxx> wrote: > From: David Decotigny <decot@xxxxxxxxxxxx> > > Aimed at transferring bitmaps to/from user-space in a 32/64-bit agnostic > way. > > Tested: > unit tests (next patch) on qemu i386, x86_64, ppc, ppc64 BE and LE, > ARM. > > @@ -1060,6 +1062,90 @@ int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) > EXPORT_SYMBOL(bitmap_allocate_region); > > /** > + * bitmap_from_u32array - copy the contents of a u32 array of bits to bitmap > + * @bitmap: array of unsigned longs, the destination bitmap, non NULL > + * @nbits: number of bits in @bitmap > + * @buf: array of u32 (in host byte order), the source bitmap, non NULL > + * @nwords: number of u32 words in @buf > + * > + * copy min(nbits, 32*nwords) bits from @buf to @bitmap, remaining > + * bits between nword and nbits in @bitmap (if any) are cleared. In > + * last word of @bitmap, the bits beyond nbits (if any) are kept > + * unchanged. > + */ This will leave the caller not knowing how many valid bits are actually present in the resulting bitmap. To determine that, the caller will need to perform (duplicated) math on `nbits' and `nwords'. > +void bitmap_from_u32array(unsigned long *bitmap, unsigned int nbits, > + const u32 *buf, unsigned int nwords) So how about we make this return the number of valid bits in *bitmap? > +/** > + * bitmap_to_u32array - copy the contents of bitmap to a u32 array of bits > + * @buf: array of u32 (in host byte order), the dest bitmap, non NULL > + * @nwords: number of u32 words in @buf > + * @bitmap: array of unsigned longs, the source bitmap, non NULL > + * @nbits: number of bits in @bitmap > + * > + * copy min(nbits, 32*nwords) bits from @bitmap to @buf. Remaining > + * bits after nbits in @buf (if any) are cleared. > + */ > +void bitmap_to_u32array(u32 *buf, unsigned int nwords, > + const unsigned long *bitmap, unsigned int nbits) Ditto.
