tools lib: Sync tools/lib/find_bit.c with the kernel

Need to move the bitmap.[ch] things from tools/perf/ to tools/lib, will
be done in the next patches.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: George Spelvin <linux@horizon.com
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yury Norov <yury.norov@gmail.com>
Link: http://lkml.kernel.org/n/tip-5fys65wkd7gu8j7a7xgukc5t@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 552eb975
/* find_next_bit.c: fallback find next bit implementation
/* bit search implementation
*
* Copied from lib/find_next_bit.c to tools/lib/find_bit.c
* Copied from lib/find_bit.c to tools/lib/find_bit.c
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* Copyright (C) 2008 IBM Corporation
* 'find_last_bit' is written by Rusty Russell <rusty@rustcorp.com.au>
* (Inspired by David Howell's find_next_bit implementation)
*
* Rewritten by Yury Norov <yury.norov@gmail.com> to decrease
* size and improve performance, 2015.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
......@@ -12,52 +19,50 @@
*/
#include <linux/bitops.h>
#include <asm/types.h>
#include <asm/byteorder.h>
#include <linux/bitmap.h>
#include <linux/kernel.h>
#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
#if !defined(find_next_bit)
#ifndef find_next_bit
/*
* Find the next set bit in a memory region.
* This is a common helper function for find_next_bit and
* find_next_zero_bit. The difference is the "invert" argument, which
* is XORed with each fetched word before searching it for one bits.
*/
unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
unsigned long offset)
static unsigned long _find_next_bit(const unsigned long *addr,
unsigned long nbits, unsigned long start, unsigned long invert)
{
const unsigned long *p = addr + BITOP_WORD(offset);
unsigned long result = offset & ~(BITS_PER_LONG-1);
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset %= BITS_PER_LONG;
if (offset) {
tmp = *(p++);
tmp &= (~0UL << offset);
if (size < BITS_PER_LONG)
goto found_first;
if (tmp)
goto found_middle;
size -= BITS_PER_LONG;
result += BITS_PER_LONG;
}
while (size & ~(BITS_PER_LONG-1)) {
if ((tmp = *(p++)))
goto found_middle;
result += BITS_PER_LONG;
size -= BITS_PER_LONG;
if (!nbits || start >= nbits)
return nbits;
tmp = addr[start / BITS_PER_LONG] ^ invert;
/* Handle 1st word. */
tmp &= BITMAP_FIRST_WORD_MASK(start);
start = round_down(start, BITS_PER_LONG);
while (!tmp) {
start += BITS_PER_LONG;
if (start >= nbits)
return nbits;
tmp = addr[start / BITS_PER_LONG] ^ invert;
}
if (!size)
return result;
tmp = *p;
found_first:
tmp &= (~0UL >> (BITS_PER_LONG - size));
if (tmp == 0UL) /* Are any bits set? */
return result + size; /* Nope. */
found_middle:
return result + __ffs(tmp);
return min(start + __ffs(tmp), nbits);
}
#endif
#ifndef find_next_bit
/*
* Find the next set bit in a memory region.
*/
unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
unsigned long offset)
{
return _find_next_bit(addr, size, offset, 0UL);
}
#endif
......@@ -67,23 +72,13 @@ unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
*/
unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
{
const unsigned long *p = addr;
unsigned long result = 0;
unsigned long tmp;
unsigned long idx;
while (size & ~(BITS_PER_LONG-1)) {
if ((tmp = *(p++)))
goto found;
result += BITS_PER_LONG;
size -= BITS_PER_LONG;
for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
if (addr[idx])
return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size);
}
if (!size)
return result;
tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
if (tmp == 0UL) /* Are any bits set? */
return result + size; /* Nope. */
found:
return result + __ffs(tmp);
return size;
}
#endif
......@@ -11,6 +11,8 @@ int __bitmap_weight(const unsigned long *bitmap, int bits);
void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
#define BITMAP_LAST_WORD_MASK(nbits) \
( \
((nbits) % BITS_PER_LONG) ? \
......
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