[patch 40/47] m68k: Add ext2_find_{first,next}_bit() for ext4

Greg KH
2008-06-14T00:25:51Z

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-stable review patch. If anyone has any objections, please let us know.

------------------
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 69c5ddf58a03da3686691ad2f293bc79fd977c10 upstream

Add ext2_find_{first,next}_bit(), which are needed for ext4.
They're derived out of the ext2_find_next_zero_bit found in the same file.
Compile tested with crosstools

[Reworked to preserve all symmetry with ext2_find_{first,next}_zero_bit()]

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=10393

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
include/asm-m68k/bitops.h | 46 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 44 insertions(+), 2 deletions(-)

--- a/include/asm-m68k/bitops.h
+++ b/include/asm-m68k/bitops.h
@@ -410,8 +410,50 @@ static inline int ext2_find_next_zero_bi
res = ext2_find_first_zero_bit (p, size - 32 * (p - addr));
return (p - addr) * 32 + res;
}
-#define ext2_find_next_bit(addr, size, off) \
- generic_find_next_le_bit((unsigned long *)(addr), (size), (off))
+
+static inline int ext2_find_first_bit(const void *vaddr, unsigned size)
+{
+ const unsigned long *p = vaddr, *addr = vaddr;
+ int res;
+
+ if (!size)
+ return 0;
+
+ size = (size >> 5) + ((size & 31) > 0);
+ while (*p++ == 0UL)
+ {
+ if (--size == 0)
+ return (p - addr) << 5;
+ }
+
+ --p;
+ for (res = 0; res < 32; res++)
+ if (ext2_test_bit(res, p))
+ break;
+ return (p - addr) * 32 + res;
+}
+
+static inline int ext2_find_next_bit(const void *vaddr, unsigned size,
+ unsigned offset)
+{
+ const unsigned long *addr = vaddr;
+ const unsigned long *p = addr + (offset >> 5);
+ int bit = offset & 31UL, res;
+
+ if (offset >= size)
+ return size;
+
+ if (bit) {
+ /* Look for one in first longword */
+ for (res = bit; res < 32; res++)
+ if (ext2_test_bit(res, p))
+ return (p - addr) * 32 + res;
+ p++;
+ }
+ /* No set bit yet, search remaining full bytes for a set bit */
+ res = ext2_find_first_bit(p, size - 32 * (p - addr));
+ return (p - addr) * 32 + res;
+}

#endif /* __KERNEL__ */

--