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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/sparc/lib/bitext.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/sparc/lib/bitext.c')
-rw-r--r-- | arch/sparc/lib/bitext.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/arch/sparc/lib/bitext.c b/arch/sparc/lib/bitext.c new file mode 100644 index 000000000..32a5c1d94 --- /dev/null +++ b/arch/sparc/lib/bitext.c @@ -0,0 +1,128 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * bitext.c: kernel little helper (of bit shuffling variety). + * + * Copyright (C) 2002 Pete Zaitcev <zaitcev@yahoo.com> + * + * The algorithm to search a zero bit string is geared towards its application. + * We expect a couple of fixed sizes of requests, so a rotating counter, reset + * by align size, should provide fast enough search while maintaining low + * fragmentation. + */ + +#include <linux/string.h> +#include <linux/bitmap.h> + +#include <asm/bitext.h> + +/** + * bit_map_string_get - find and set a bit string in bit map. + * @t: the bit map. + * @len: requested string length + * @align: requested alignment + * + * Returns offset in the map or -1 if out of space. + * + * Not safe to call from an interrupt (uses spin_lock). + */ +int bit_map_string_get(struct bit_map *t, int len, int align) +{ + int offset, count; /* siamese twins */ + int off_new; + int align1; + int i, color; + + if (t->num_colors) { + /* align is overloaded to be the page color */ + color = align; + align = t->num_colors; + } else { + color = 0; + if (align == 0) + align = 1; + } + align1 = align - 1; + if ((align & align1) != 0) + BUG(); + if (align < 0 || align >= t->size) + BUG(); + if (len <= 0 || len > t->size) + BUG(); + color &= align1; + + spin_lock(&t->lock); + if (len < t->last_size) + offset = t->first_free; + else + offset = t->last_off & ~align1; + count = 0; + for (;;) { + off_new = find_next_zero_bit(t->map, t->size, offset); + off_new = ((off_new + align1) & ~align1) + color; + count += off_new - offset; + offset = off_new; + if (offset >= t->size) + offset = 0; + if (count + len > t->size) { + spin_unlock(&t->lock); +/* P3 */ printk(KERN_ERR + "bitmap out: size %d used %d off %d len %d align %d count %d\n", + t->size, t->used, offset, len, align, count); + return -1; + } + + if (offset + len > t->size) { + count += t->size - offset; + offset = 0; + continue; + } + + i = 0; + while (test_bit(offset + i, t->map) == 0) { + i++; + if (i == len) { + bitmap_set(t->map, offset, len); + if (offset == t->first_free) + t->first_free = find_next_zero_bit + (t->map, t->size, + t->first_free + len); + if ((t->last_off = offset + len) >= t->size) + t->last_off = 0; + t->used += len; + t->last_size = len; + spin_unlock(&t->lock); + return offset; + } + } + count += i + 1; + if ((offset += i + 1) >= t->size) + offset = 0; + } +} + +void bit_map_clear(struct bit_map *t, int offset, int len) +{ + int i; + + if (t->used < len) + BUG(); /* Much too late to do any good, but alas... */ + spin_lock(&t->lock); + for (i = 0; i < len; i++) { + if (test_bit(offset + i, t->map) == 0) + BUG(); + __clear_bit(offset + i, t->map); + } + if (offset < t->first_free) + t->first_free = offset; + t->used -= len; + spin_unlock(&t->lock); +} + +void bit_map_init(struct bit_map *t, unsigned long *map, int size) +{ + bitmap_zero(map, size); + memset(t, 0, sizeof *t); + spin_lock_init(&t->lock); + t->map = map; + t->size = size; +} |