lib/bitmap.c: conversion routines to/from u32 array (e52bc7c2) · Commits · 戴 / test

include/linux/bitmap.h

+10 −0

Original line number	Diff line number	Diff line
		@@ -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

lib/bitmap.c

+89 −0

Original line number	Diff line number	Diff line
		@@ -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>
		@@ -1059,6 +1061,93 @@ 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

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