| Message ID | 1454893743-6285-2-git-send-email-ddecotig@gmail.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
On Sun, 7 Feb 2016 17:08:45 -0800 David Decotigny <ddecotig@gmail.com> wrote: > From: David Decotigny <decot@googlers.com> > > 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.
thanks. done in v8 I am sending right now. On Mon, Feb 8, 2016 at 3:36 PM, Andrew Morton <akpm@linux-foundation.org> wrote: > On Sun, 7 Feb 2016 17:08:45 -0800 David Decotigny <ddecotig@gmail.com> wrote: > >> From: David Decotigny <decot@googlers.com> >> >> 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. > >
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 9653fdb..f7dc158 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -59,6 +59,8 @@ * bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region * bitmap_release_region(bitmap, pos, order) Free specified bit region * bitmap_allocate_region(bitmap, pos, order) Allocate specified bit region + * bitmap_from_u32array(dst, nbits, buf, nwords) *dst = *buf (nwords 32b words) + * bitmap_to_u32array(buf, nwords, src, nbits) *buf = *dst (nwords 32b words) */ /* @@ -163,6 +165,10 @@ extern void bitmap_fold(unsigned long *dst, const unsigned long *orig, extern int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order); extern void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order); extern int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order); +extern void bitmap_from_u32array(unsigned long *bitmap, unsigned int nbits, + const u32 *buf, unsigned int nwords); +extern void bitmap_to_u32array(u32 *buf, unsigned int nwords, + const unsigned long *bitmap, unsigned int nbits); #ifdef __BIG_ENDIAN extern void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits); #else diff --git a/lib/bitmap.c b/lib/bitmap.c index 8148143..e1cc648 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -12,6 +12,8 @@ #include <linux/bitmap.h> #include <linux/bitops.h> #include <linux/bug.h> +#include <linux/kernel.h> +#include <linux/string.h> #include <asm/page.h> #include <asm/uaccess.h> @@ -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. + */ +void bitmap_from_u32array(unsigned long *bitmap, unsigned int nbits, + const u32 *buf, unsigned int nwords) +{ + unsigned int k; + const u32 *src = buf; + + for (k = 0; k < BITS_TO_LONGS(nbits); ++k) { + unsigned long part = 0; + + if (nwords) { + part = *src++; + nwords--; + } + +#if BITS_PER_LONG == 64 + if (nwords) { + part |= ((unsigned long) *src++) << 32; + nwords--; + } +#endif + + if (k < nbits/BITS_PER_LONG) + bitmap[k] = part; + else { + unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); + + bitmap[k] = (bitmap[k] & ~mask) | (part & mask); + } + } +} +EXPORT_SYMBOL(bitmap_from_u32array); + +/** + * 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) +{ + unsigned int k = 0; + u32 *dst = buf; + + while (nwords) { + unsigned long part = 0; + + if (k < BITS_TO_LONGS(nbits)) { + part = bitmap[k]; + if (k >= nbits/BITS_PER_LONG) + part &= BITMAP_LAST_WORD_MASK(nbits); + k++; + } + + *dst++ = part & 0xffffffffUL; + nwords--; + +#if BITS_PER_LONG == 64 + if (nwords) { + part >>= 32; + *dst++ = part & 0xffffffffUL; + nwords--; + } +#endif + } +} +EXPORT_SYMBOL(bitmap_to_u32array); + +/** * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. * @dst: destination buffer * @src: bitmap to copy