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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sparc/lib/bitext.c | |
download | kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/sparc/lib/bitext.c')
-rw-r--r-- | arch/sparc/lib/bitext.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/arch/sparc/lib/bitext.c b/arch/sparc/lib/bitext.c new file mode 100644 index 0000000..94b05e8 --- /dev/null +++ b/arch/sparc/lib/bitext.c @@ -0,0 +1,132 @@ +/* + * 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/smp_lock.h> +#include <linux/bitops.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) { + for (i = 0; i < len; i++) + __set_bit(offset + i, t->map); + 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) +{ + + if ((size & 07) != 0) + BUG(); + memset(map, 0, size>>3); + + memset(t, 0, sizeof *t); + spin_lock_init(&t->lock); + t->map = map; + t->size = size; +} |