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lib: bitmap: make the start index of bitmap_clear unsigned
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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: Rasmus Villemoes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Villemoes authored and torvalds committed Aug 7, 2014
1 parent fb5ac54 commit 154f5e3
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Showing 2 changed files with 6 additions and 6 deletions.
2 changes: 1 addition & 1 deletion include/linux/bitmap.h
Original file line number Diff line number Diff line change
Expand Up @@ -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,
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10 changes: 5 additions & 5 deletions lib/bitmap.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
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