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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2008-01-28 23:58:27 -0500
committerTheodore Ts'o <tytso@mit.edu>2008-01-28 23:58:27 -0500
commitaa02ad67d9b308290fde390682cd039b29f7ab85 (patch)
tree1ebf910ab16e6081b5dd3ca526973f09cfd065c4 /lib
parentc549a95d40efd83fc054785dd1634e8b71fba890 (diff)
ext4: Add ext4_find_next_bit()
This function is used by the ext4 multi block allocator patches. Also add generic_find_next_le_bit Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/find_next_bit.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
index bda0d71a2514..78ccd73a8841 100644
--- a/lib/find_next_bit.c
+++ b/lib/find_next_bit.c
@@ -178,4 +178,47 @@ found_middle_swap:
178 178
179EXPORT_SYMBOL(generic_find_next_zero_le_bit); 179EXPORT_SYMBOL(generic_find_next_zero_le_bit);
180 180
181unsigned long generic_find_next_le_bit(const unsigned long *addr, unsigned
182 long size, unsigned long offset)
183{
184 const unsigned long *p = addr + BITOP_WORD(offset);
185 unsigned long result = offset & ~(BITS_PER_LONG - 1);
186 unsigned long tmp;
187
188 if (offset >= size)
189 return size;
190 size -= result;
191 offset &= (BITS_PER_LONG - 1UL);
192 if (offset) {
193 tmp = ext2_swabp(p++);
194 tmp &= (~0UL << offset);
195 if (size < BITS_PER_LONG)
196 goto found_first;
197 if (tmp)
198 goto found_middle;
199 size -= BITS_PER_LONG;
200 result += BITS_PER_LONG;
201 }
202
203 while (size & ~(BITS_PER_LONG - 1)) {
204 tmp = *(p++);
205 if (tmp)
206 goto found_middle_swap;
207 result += BITS_PER_LONG;
208 size -= BITS_PER_LONG;
209 }
210 if (!size)
211 return result;
212 tmp = ext2_swabp(p);
213found_first:
214 tmp &= (~0UL >> (BITS_PER_LONG - size));
215 if (tmp == 0UL) /* Are any bits set? */
216 return result + size; /* Nope. */
217found_middle:
218 return result + __ffs(tmp);
219
220found_middle_swap:
221 return result + __ffs(ext2_swab(tmp));
222}
223EXPORT_SYMBOL(generic_find_next_le_bit);
181#endif /* __BIG_ENDIAN */ 224#endif /* __BIG_ENDIAN */