[PATCH] arm: fix undefined reference to generic_fls

This patch defines constant_fls() instead of removed generic_fls().
Signed-off-by: NAkinobu Mita <mita@miraclelinux.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

include/asm-arm/bitops.h

@@ -344,13 +344,42 @@ static inline unsigned long __ffs(unsigned long word)
 
 #else
 
+static inline int constant_fls(int x)
+{
+	int r = 32;
+
+	if (!x)
+		return 0;
+	if (!(x & 0xffff0000u)) {
+		x <<= 16;
+		r -= 16;
+	}
+	if (!(x & 0xff000000u)) {
+		x <<= 8;
+		r -= 8;
+	}
+	if (!(x & 0xf0000000u)) {
+		x <<= 4;
+		r -= 4;
+	}
+	if (!(x & 0xc0000000u)) {
+		x <<= 2;
+		r -= 2;
+	}
+	if (!(x & 0x80000000u)) {
+		x <<= 1;
+		r -= 1;
+	}
+	return r;
+}
+
 /*
  * On ARMv5 and above those functions can be implemented around
  * the clz instruction for much better code efficiency.
  */
 
 #define fls(x) \
-	( __builtin_constant_p(x) ? generic_fls(x) : \
+	( __builtin_constant_p(x) ? constant_fls(x) : \
 	  ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) )
 #define fls64(x)   generic_fls64(x)
 #define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })