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authorRasmus Villemoes <linux@rasmusvillemoes.dk>2015-02-12 15:02:10 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-12 18:54:14 -0800
commitf6a1f5db8d7a7a94ff07251996959d27daba4ee7 (patch)
tree60e8d219664966cab66732850ac0e40f9aa5dc5e /lib
parentdf1d80a9eb16d98002673f68a7ebbe881f6e6946 (diff)
lib/bitmap.c: simplify bitmap_ord_to_pos
Make the return value and the ord and nbits parameters of bitmap_ord_to_pos unsigned. Also, simplify the implementation and as a side effect make the result fully defined, returning nbits for ord >= weight, in analogy with what find_{first,next}_bit does. This is a better sentinel than the former ("unofficial") 0. No current users are affected by this change. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/bitmap.c28
1 files changed, 11 insertions, 17 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 84d20b5c6bf1..e8a38bde7af9 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -771,34 +771,28 @@ static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigne
* 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
+ * @nbits: number of valid bit positions in @buf
*
* Map the ordinal offset of bit @ord in @buf to its position in @buf.
- * Value of @ord should be in range 0 <= @ord < weight(buf), else
- * results are undefined.
+ * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord
+ * >= weight(buf), returns @nbits.
*
* If for example, just bits 4 through 7 are set in @buf, then @ord
* values 0 through 3 will get mapped to 4 through 7, respectively,
- * and all other @ord values return undefined values. When @ord value 3
+ * and all other @ord values returns @nbits. When @ord value 3
* gets mapped to (returns) @pos value 7 in this example, that means
* that the 3rd set bit (starting with 0th) is at position 7 in @buf.
*
- * The bit positions 0 through @bits are valid positions in @buf.
+ * The bit positions 0 through @nbits-1 are valid positions in @buf.
*/
-int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
+unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits)
{
- int pos = 0;
+ unsigned int pos;
- if (ord >= 0 && ord < bits) {
- int i;
-
- for (i = find_first_bit(buf, bits);
- i < bits && ord > 0;
- i = find_next_bit(buf, bits, i + 1))
- ord--;
- if (i < bits && ord == 0)
- pos = i;
- }
+ for (pos = find_first_bit(buf, nbits);
+ pos < nbits && ord;
+ pos = find_next_bit(buf, nbits, pos + 1))
+ ord--;
return pos;
}