[PATCH 2/8] bitmap: Introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_area

Akinobu Mita
2009-10-09T08:29:15Z

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 stolen from iommu helper.

I changed the return value of bitmap_find_next_zero_area if there is
no zero area.

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

Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@ozlabs.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Lothar Wassmann <LW@KARO-electronics.de>
Cc: linux-usb@vger.kernel.org
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Cc: netdev@vger.kernel.org
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: linux-altix@sgi.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
include/linux/bitmap.h | 11 +++++++++++
lib/bitmap.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 58 insertions(+), 0 deletions(-)

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 756d78b..daf8c48 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -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,
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 7025658..95070fa 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -271,6 +271,53 @@ int __bitmap_weight(const unsigned long *bitmap, int bits)
}
EXPORT_SYMBOL(__bitmap_weight);

+void bitmap_set(unsigned long *map, int i, int len)
+{
+ int end = i + len;
+
+ while (i < end) {
+ __set_bit(i, map);
+ i++;
+ }
+}
+EXPORT_SYMBOL(bitmap_set);
+
+void bitmap_clear(unsigned long *map, int start, int nr)
+{
+ int end = start + nr;
+
+ while (start < end) {
+ __clear_bit(start, map);
+ start++;
+ }
+}
+EXPORT_SYMBOL(bitmap_clear);
+
+unsigned long bitmap_find_next_zero_area(unsigned long *map,
+ unsigned long size,
+ unsigned long start,
+ unsigned int nr,
+ unsigned long align_mask)
+{
+ unsigned long index, end, i;
+again:
+ index = find_next_zero_bit(map, size, start);
+
+ /* Align allocation */
+ index = (index + align_mask) & ~align_mask;
+
+ end = index + nr;
+ if (end >= size)
+ return end;
+ i = find_next_bit(map, end, index);
+ if (i < end) {
+ start = i + 1;
+ goto again;
+ }
+ return index;
+}
+EXPORT_SYMBOL(bitmap_find_next_zero_area);
+
/*
* Bitmap printing & parsing functions: first version by Bill Irwin,
* second version by Paul Jackson, third by Joe Korty.
--
1.5.4.3