[XFS] Use the generic bitops rather than implementing them ourselves.
This keeps xfs_lowbit64 as it was since there aren't good generic helpers
there ... Patch inspired by Andi Kleen.
SGI-PV: 981498
SGI-Modid: xfs-linux-melb:xfs-kern:31472a
Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Donald Douwsma <donaldd@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
diff --git a/fs/xfs/xfs_bit.h b/fs/xfs/xfs_bit.h
index 082641a..8e0e463 100644
--- a/fs/xfs/xfs_bit.h
+++ b/fs/xfs/xfs_bit.h
@@ -47,13 +47,39 @@
}
/* Get high bit set out of 32-bit argument, -1 if none set */
-extern int xfs_highbit32(__uint32_t v);
-
-/* Get low bit set out of 64-bit argument, -1 if none set */
-extern int xfs_lowbit64(__uint64_t v);
+static inline int xfs_highbit32(__uint32_t v)
+{
+ return fls(v) - 1;
+}
/* Get high bit set out of 64-bit argument, -1 if none set */
-extern int xfs_highbit64(__uint64_t);
+static inline int xfs_highbit64(__uint64_t v)
+{
+ return fls64(v) - 1;
+}
+
+/* Get low bit set out of 32-bit argument, -1 if none set */
+static inline int xfs_lowbit32(__uint32_t v)
+{
+ unsigned long t = v;
+ return (v) ? find_first_bit(&t, 32) : -1;
+}
+
+/* Get low bit set out of 64-bit argument, -1 if none set */
+static inline int xfs_lowbit64(__uint64_t v)
+{
+ __uint32_t w = (__uint32_t)v;
+ int n = 0;
+
+ if (w) { /* lower bits */
+ n = ffs(w);
+ } else { /* upper bits */
+ w = (__uint32_t)(v >> 32);
+ if (w && (n = ffs(w)))
+ n += 32;
+ }
+ return n - 1;
+}
/* Return whether bitmap is empty (1 == empty) */
extern int xfs_bitmap_empty(uint *map, uint size);