diff options
| -rw-r--r-- | include/linux/bitmap.h | 10 | ||||
| -rw-r--r-- | lib/bitmap.c | 89 |
2 files changed, 99 insertions, 0 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 9653fdb76a42..e9b0b9ab07e5 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 +165,14 @@ 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 unsigned int bitmap_from_u32array(unsigned long *bitmap, + unsigned int nbits, + const u32 *buf, + unsigned int nwords); +extern unsigned int 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 814814397cce..c66da508cbf7 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 +1062,93 @@ 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. + * + * Return the number of bits effectively copied. + */ +unsigned int +bitmap_from_u32array(unsigned long *bitmap, unsigned int nbits, + const u32 *buf, unsigned int nwords) +{ + unsigned int dst_idx, src_idx; + + for (src_idx = dst_idx = 0; dst_idx < BITS_TO_LONGS(nbits); ++dst_idx) { + unsigned long part = 0; + + if (src_idx < nwords) + part = buf[src_idx++]; + +#if BITS_PER_LONG == 64 + if (src_idx < nwords) + part |= ((unsigned long) buf[src_idx++]) << 32; +#endif + + if (dst_idx < nbits/BITS_PER_LONG) + bitmap[dst_idx] = part; + else { + unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); + + bitmap[dst_idx] = (bitmap[dst_idx] & ~mask) + | (part & mask); + } + } + + return min_t(unsigned int, nbits, 32*nwords); +} +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. + * + * Return the number of bits effectively copied. + */ +unsigned int +bitmap_to_u32array(u32 *buf, unsigned int nwords, + const unsigned long *bitmap, unsigned int nbits) +{ + unsigned int dst_idx = 0, src_idx = 0; + + while (dst_idx < nwords) { + unsigned long part = 0; + + if (src_idx < BITS_TO_LONGS(nbits)) { + part = bitmap[src_idx]; + if (src_idx >= nbits/BITS_PER_LONG) + part &= BITMAP_LAST_WORD_MASK(nbits); + src_idx++; + } + + buf[dst_idx++] = part & 0xffffffffUL; + +#if BITS_PER_LONG == 64 + if (dst_idx < nwords) { + part >>= 32; + buf[dst_idx++] = part & 0xffffffffUL; + } +#endif + } + + return min_t(unsigned int, nbits, 32*nwords); +} +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 |