[PATCH 1/2] Use generic routines for xfs_next_bit

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

We can use find_next_bit, which is assembly on some arches,
to implement xfs_next_bit.  Tested on x86.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxxx>

Index: linux-2.6.22.i386/fs/xfs/xfs_bit.c
===================================================================
--- linux-2.6.22.i386.orig/fs/xfs/xfs_bit.c
+++ linux-2.6.22.i386/fs/xfs/xfs_bit.c
@@ -192,32 +192,16 @@ found:
  */
 int xfs_next_bit(uint *map, uint size, uint start_bit)
 {
-       uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
-       uint result = start_bit & ~(NBWORD - 1);
-       uint tmp;
+       int result;
 
-       size <<= BIT_TO_WORD_SHIFT;
+       size <<= BIT_TO_WORD_SHIFT;
+       if (start_bit >= size)  /* beyond end of bitmap */
+               return -1;
 
-       if (start_bit >= size)
-               return -1;
-       size -= result;
-       start_bit &= (NBWORD - 1);
-       if (start_bit) {
-               tmp = *p++;
-               /* set to zero first offset bits prior to start */
-               tmp &= (~0U << start_bit);
-               if (tmp != 0U)
-                       goto found;
-               result += NBWORD;
-               size -= NBWORD;
-       }
-       while (size) {
-               if ((tmp = *p++) != 0U)
-                       goto found;
-               result += NBWORD;
-               size -= NBWORD;
-       }
-       return -1;
-found:
-       return result + ffs(tmp) - 1;
+       result = find_next_bit((unsigned long *)map, size, start_bit);
+
+       if (result == size)     /* no bits set */
+               return -1;
+
+       return result;
 }