1 files changed, 88 insertions, 12 deletions

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 702565821c9..ffb78c916cc 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -271,6 +271,87 @@ int __bitmap_weight(const unsigned long *bitmap, int bits)
 }
 EXPORT_SYMBOL(__bitmap_weight);
 
+#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG))
+
+void bitmap_set(unsigned long *map, int start, int nr)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const int size = start + nr;
+	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+	while (nr - bits_to_set >= 0) {
+		*p |= mask_to_set;
+		nr -= bits_to_set;
+		bits_to_set = BITS_PER_LONG;
+		mask_to_set = ~0UL;
+		p++;
+	}
+	if (nr) {
+		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+		*p |= mask_to_set;
+	}
+}
+EXPORT_SYMBOL(bitmap_set);
+
+void bitmap_clear(unsigned long *map, int start, int nr)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const int size = start + nr;
+	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+	while (nr - bits_to_clear >= 0) {
+		*p &= ~mask_to_clear;
+		nr -= bits_to_clear;
+		bits_to_clear = BITS_PER_LONG;
+		mask_to_clear = ~0UL;
+		p++;
+	}
+	if (nr) {
+		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+		*p &= ~mask_to_clear;
+	}
+}
+EXPORT_SYMBOL(bitmap_clear);
+
+/*
+ * bitmap_find_next_zero_area - find a contiguous aligned zero area
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @align_mask: Alignment mask for zero area
+ *
+ * The @align_mask should be one less than a power of 2; the effect is that
+ * the bit offset of all zero areas this function finds is multiples of that
+ * power of 2. A @align_mask of 0 means no alignment is required.
+ */
+unsigned long bitmap_find_next_zero_area(unsigned long *map,
+					 unsigned long size,
+					 unsigned long start,
+					 unsigned int nr,
+					 unsigned long align_mask)
+{
+	unsigned long index, end, i;
+again:
+	index = find_next_zero_bit(map, size, start);
+
+	/* Align allocation */
+	index = __ALIGN_MASK(index, align_mask);
+
+	end = index + nr;
+	if (end > size)
+		return end;
+	i = find_next_bit(map, end, index);
+	if (i < end) {
+		start = i + 1;
+		goto again;
+	}
+	return index;
+}
+EXPORT_SYMBOL(bitmap_find_next_zero_area);
+
 /*
  * Bitmap printing & parsing functions: first version by Bill Irwin,
  * second version by Paul Jackson, third by Joe Korty.
@@ -406,7 +487,7 @@ int __bitmap_parse(const char *buf, unsigned int buflen,
 EXPORT_SYMBOL(__bitmap_parse);
 
 /**
- * bitmap_parse_user()
+ * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
  *
  * @ubuf: pointer to user buffer containing string.
  * @ulen: buffer size in bytes.  If string is smaller than this
@@ -538,7 +619,7 @@ int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
 EXPORT_SYMBOL(bitmap_parselist);
 
 /**
- * bitmap_pos_to_ord(buf, pos, bits)
+ * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
  *	@buf: pointer to a bitmap
  *	@pos: a bit position in @buf (0 <= @pos < @bits)
  *	@bits: number of valid bit positions in @buf
@@ -574,7 +655,7 @@ static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
 }
 
 /**
- * bitmap_ord_to_pos(buf, ord, bits)
+ * bitmap_ord_to_pos - find position of n-th set bit in bitmap
  *	@buf: pointer to bitmap
  *	@ord: ordinal bit position (n-th set bit, n >= 0)
  *	@bits: number of valid bit positions in @buf
@@ -652,10 +733,9 @@ void bitmap_remap(unsigned long *dst, const unsigned long *src,
 	bitmap_zero(dst, bits);
 
 	w = bitmap_weight(new, bits);
-	for (oldbit = find_first_bit(src, bits);
-	     oldbit < bits;
-	     oldbit = find_next_bit(src, bits, oldbit + 1)) {
+	for_each_set_bit(oldbit, src, bits) {
 	     	int n = bitmap_pos_to_ord(old, oldbit, bits);
+
 		if (n < 0 || w == 0)
 			set_bit(oldbit, dst);	/* identity map */
 		else
@@ -822,9 +902,7 @@ void bitmap_onto(unsigned long *dst, const unsigned long *orig,
 	 */
 
 	m = 0;
-	for (n = find_first_bit(relmap, bits);
-	     n < bits;
-	     n = find_next_bit(relmap, bits, n + 1)) {
+	for_each_set_bit(n, relmap, bits) {
 		/* m == bitmap_pos_to_ord(relmap, n, bits) */
 		if (test_bit(m, orig))
 			set_bit(n, dst);
@@ -853,9 +931,7 @@ void bitmap_fold(unsigned long *dst, const unsigned long *orig,
 		return;
 	bitmap_zero(dst, bits);
 
-	for (oldbit = find_first_bit(orig, bits);
-	     oldbit < bits;
-	     oldbit = find_next_bit(orig, bits, oldbit + 1))
+	for_each_set_bit(oldbit, orig, bits)
 		set_bit(oldbit % sz, dst);
 }
 EXPORT_SYMBOL(bitmap_fold);