[PATCH] Introduce ext4_find_next_bit

Aneesh Kumar K.V
2007-09-21T05:25:28Z

Also add generic_find_next_le_bit

This gets used by the ext4 multi block allocator patches.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
include/asm-generic/bitops/ext2-non-atomic.h | 2 +
include/asm-generic/bitops/le.h | 4 ++
include/asm-powerpc/bitops.h | 4 ++
include/linux/ext4_fs.h | 1 +
lib/find_next_bit.c | 44 ++++++++++++++++++++++++++
5 files changed, 55 insertions(+), 0 deletions(-)

diff --git a/include/asm-generic/bitops/ext2-non-atomic.h b/include/asm-generic/bitops/ext2-non-atomic.h
index 1697404..63cf822 100644
--- a/include/asm-generic/bitops/ext2-non-atomic.h
+++ b/include/asm-generic/bitops/ext2-non-atomic.h
@@ -14,5 +14,7 @@
generic_find_first_zero_le_bit((unsigned long *)(addr), (size))
#define ext2_find_next_zero_bit(addr, size, off) \
generic_find_next_zero_le_bit((unsigned long *)(addr), (size), (off))
+#define ext2_find_next_bit(addr, size, off) \
+ generic_find_next_le_bit((unsigned long *)(addr), (size), (off))

#endif /* _ASM_GENERIC_BITOPS_EXT2_NON_ATOMIC_H_ */
diff --git a/include/asm-generic/bitops/le.h b/include/asm-generic/bitops/le.h
index b9c7e5d..80e3bf1 100644
--- a/include/asm-generic/bitops/le.h
+++ b/include/asm-generic/bitops/le.h
@@ -20,6 +20,8 @@
#define generic___test_and_clear_le_bit(nr, addr) __test_and_clear_bit(nr, addr)

#define generic_find_next_zero_le_bit(addr, size, offset) find_next_zero_bit(addr, size, offset)
+#define generic_find_next_le_bit(addr, size, offset) \
+ find_next_bit(addr, size, offset)

#elif defined(__BIG_ENDIAN)

@@ -42,6 +44,8 @@

extern unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,
unsigned long size, unsigned long offset);
+extern unsigned long generic_find_next_le_bit(const unsigned long *addr,
+ unsigned long size, unsigned long offset);

#else
#error "Please fix <asm/byteorder.h>"
diff --git a/include/asm-powerpc/bitops.h b/include/asm-powerpc/bitops.h
index 8144a27..60652a3 100644
--- a/include/asm-powerpc/bitops.h
+++ b/include/asm-powerpc/bitops.h
@@ -310,6 +310,8 @@ static __inline__ int test_le_bit(unsigned long nr,
unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,
unsigned long size, unsigned long offset);

+unsigned long generic_find_next_le_bit(const unsigned long *addr,
+ unsigned long size, unsigned long offset);
/* Bitmap functions for the ext2 filesystem */

#define ext2_set_bit(nr,addr) \
@@ -329,6 +331,8 @@ unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,
#define ext2_find_next_zero_bit(addr, size, off) \
generic_find_next_zero_le_bit((unsigned long*)addr, size, off)

+#define ext2_find_next_bit(addr, size, off) \
+ generic_find_next_le_bit((unsigned long *)addr, size, off)
/* Bitmap functions for the minix filesystem. */

#define minix_test_and_set_bit(nr,addr) \
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index cdee7aa..c7b9bb2 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -502,6 +502,7 @@ do { \
#define ext4_test_bit ext2_test_bit
#define ext4_find_first_zero_bit ext2_find_first_zero_bit
#define ext4_find_next_zero_bit ext2_find_next_zero_bit
+#define ext4_find_next_bit ext2_find_next_bit

/*
* Maximal mount counts between two filesystem checks
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
index bda0d71..0306c04 100644
--- a/lib/find_next_bit.c
+++ b/lib/find_next_bit.c
@@ -178,4 +178,48 @@ found_middle_swap:

EXPORT_SYMBOL(generic_find_next_zero_le_bit);

+unsigned long generic_find_next_le_bit(const unsigned long *addr, unsigned
+ long size, unsigned long offset)
+{
+ const unsigned long *p = addr + BITOP_WORD(offset);
+ unsigned long result = offset & ~(BITS_PER_LONG - 1);
+ unsigned long tmp;
+
+ if (offset >= size)
+ return size;
+ size -= result;
+ offset &= (BITS_PER_LONG - 1UL);
+ if (offset) {
+ tmp = ext2_swabp(p++);
+ tmp &= (~0UL << offset);
+ if (size < BITS_PER_LONG)
+ goto found_first;
+ if (tmp)
+ goto found_middle;
+ size -= BITS_PER_LONG;
+ result += BITS_PER_LONG;
+ }
+
+ while (size & ~(BITS_PER_LONG - 1)) {
+ tmp = *(p++);
+ if (tmp)
+ goto found_middle_swap;
+ result += BITS_PER_LONG;
+ size -= BITS_PER_LONG;
+ }
+ if (!size)
+ return result;
+ tmp = ext2_swabp(p);
+found_first:
+ tmp &= (~0UL >> (BITS_PER_LONG - size));
+ if (tmp == 0UL) /* Are any bits set? */
+ return result + size; /* Nope. */
+found_middle:
+ return result + __ffs(tmp);
+
+found_middle_swap:
+ return result + __ffs(ext2_swab(tmp));
+}
+EXPORT_SYMBOL(generic_find_next_le_bit);
+
#endif /* __BIG_ENDIAN */
--
1.5.3.1.91.gd3392-dirty