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bitmap: introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_area

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This introduces new bitmap functions:

bitmap_set: Set specified bit area
bitmap_clear: Clear specified bit area
bitmap_find_next_zero_area: Find free bit area

These are mostly stolen from iommu helper. The differences are:

- Use find_next_bit instead of doing test_bit for each bit

- Rewrite bitmap_set and bitmap_clear

  Instead of setting or clearing for each bit.

- Check the last bit of the limit

  iommu-helper doesn't want to find such area

- The return value if there is no zero area

  find_next_zero_area in iommu helper: returns -1
  bitmap_find_next_zero_area: return >= bitmap size

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Lothar Wassmann <LW@KARO-electronics.de>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Akinobu Mita 2009-12-15 16:48:25 -08:00 • committed by Linus Torvalds
parent 868d64812a
commit c1a2a962a2
2 changed files with 92 additions and 0 deletions
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11
include/linux/bitmap.h
View file

@ -42,6 +42,9 @@
* bitmap_empty(src, nbits) Are all bits zero in *src?
* bitmap_full(src, nbits) Are all bits set in *src?
* bitmap_weight(src, nbits) Hamming Weight: number set bits
* bitmap_set(dst, pos, nbits) Set specified bit area
* bitmap_clear(dst, pos, nbits) Clear specified bit area
* bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area
* bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n
* bitmap_shift_left(dst, src, n, nbits) *dst = *src << n
* bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src)
@ -108,6 +111,14 @@ extern int __bitmap_subset(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
extern int __bitmap_weight(const unsigned long *bitmap, int bits);
extern void bitmap_set(unsigned long *map, int i, int len);
extern void bitmap_clear(unsigned long *map, int start, int nr);
extern unsigned long bitmap_find_next_zero_area(unsigned long *map,
unsigned long size,
unsigned long start,
unsigned int nr,
unsigned long align_mask);
extern int bitmap_scnprintf(char *buf, unsigned int len,
const unsigned long *src, int nbits);
extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,