Add functions and macros as used upstream.

include/sys/sysmacros.h

@@ -150,6 +150,7 @@ extern unsigned long spl_hostid;
 
 /* Missing misc functions */
 extern int highbit(unsigned long i);
+extern int highbit64(uint64_t i);
 extern uint32_t zone_get_hostid(void *zone);
 extern void spl_setup(void);
 extern void spl_cleanup(void);
@@ -172,6 +173,9 @@ extern void spl_cleanup(void);
 #ifndef roundup
 #define roundup(x, y)		((((x) + ((y) - 1)) / (y)) * (y))
 #endif
+#ifndef howmany
+#define howmany(x, y)		(((x) + ((y) - 1)) / (y))
+#endif
 
 /*
  * Compatibility macros/typedefs needed for Solaris -> Linux port

module/spl/spl-generic.c

@@ -97,6 +97,36 @@ highbit(unsigned long i)
 }
 EXPORT_SYMBOL(highbit);
 
+int
+highbit64(uint64_t i)
+{
+        register int h = 1;
+        SENTRY;
+
+        if (i == 0)
+                SRETURN(0);
+        if (i & 0xffffffff00000000ull) {
+                h += 32; i >>= 32;
+        }
+        if (i & 0xffff0000) {
+                h += 16; i >>= 16;
+        }
+        if (i & 0xff00) {
+                h += 8; i >>= 8;
+        }
+        if (i & 0xf0) {
+                h += 4; i >>= 4;
+        }
+        if (i & 0xc) {
+                h += 2; i >>= 2;
+        }
+        if (i & 0x2) {
+                h += 1;
+        }
+        SRETURN(h);
+}
+EXPORT_SYMBOL(highbit64);
+
 #if BITS_PER_LONG == 32
 /*
  * Support 64/64 => 64 division on a 32-bit platform.  While the kernel