1 files changed, 88 insertions, 12 deletions

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 702565821c99..ffb78c916ccd 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);