lib: bitmap: make the start index of bitmap_clear unsigned

The compiler can generate slightly smaller and simpler code when it
knows that "start" is non-negative.

Also, use the names "start" and "len" for the two parameters for
consistency with bitmap_set.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/bitmap.h

@@ -113,7 +113,7 @@ extern int __bitmap_subset(const unsigned long *bitmap1,
 extern int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
 
 extern void bitmap_set(unsigned long *map, unsigned int start, int len);
-extern void bitmap_clear(unsigned long *map, int start, int nr);
+extern void bitmap_clear(unsigned long *map, unsigned int start, int len);
 extern unsigned long bitmap_find_next_zero_area(unsigned long *map,
 					 unsigned long size,
 					 unsigned long start,

lib/bitmap.c

@@ -295,21 +295,21 @@ void bitmap_set(unsigned long *map, unsigned int start, int len)
 }
 EXPORT_SYMBOL(bitmap_set);
 
-void bitmap_clear(unsigned long *map, int start, int nr)
+void bitmap_clear(unsigned long *map, unsigned int start, int len)
 {
 	unsigned long *p = map + BIT_WORD(start);
-	const int size = start + nr;
+	const unsigned int size = start + len;
 	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) {
+	while (len - bits_to_clear >= 0) {
 		*p &= ~mask_to_clear;
-		nr -= bits_to_clear;
+		len -= bits_to_clear;
 		bits_to_clear = BITS_PER_LONG;
 		mask_to_clear = ~0UL;
 		p++;
 	}
-	if (nr) {
+	if (len) {
 		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
 		*p &= ~mask_to_clear;
 	}