NFS: Fix the fix to Bugzilla #11061, when IPv6 isn't defined...

Stephen Rothwell reports:

Today's linux-next build (powerpc ppc64_defconfig) failed like this:

fs/built-in.o: In function `.nfs_get_client':
client.c:(.text+0x115010): undefined reference to `.__ipv6_addr_type'

Fix by moving the IPV6 specific parts of commit
d7371c41 ("Bug 11061, NFS mounts dropped")
into the '#ifdef IPV6..." section.

Also fix up a couple of formatting issues.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/client.c

@@ -255,6 +255,32 @@ static int nfs_sockaddr_match_ipaddr(const struct sockaddr *sa1,
 	}
 	return 0;
 }
+
+/*
+ * Test if two ip6 socket addresses refer to the same socket by
+ * comparing relevant fields. The padding bytes specifically, are not
+ * compared. sin6_flowinfo is not compared because it only affects QoS
+ * and sin6_scope_id is only compared if the address is "link local"
+ * because "link local" addresses need only be unique to a specific
+ * link. Conversely, ordinary unicast addresses might have different
+ * sin6_scope_id.
+ *
+ * The caller should ensure both socket addresses are AF_INET6.
+ */
+static int nfs_sockaddr_cmp_ip6(const struct sockaddr *sa1,
+				const struct sockaddr *sa2)
+{
+	const struct sockaddr_in6 *saddr1 = (const struct sockaddr_in6 *)sa1;
+	const struct sockaddr_in6 *saddr2 = (const struct sockaddr_in6 *)sa2;
+
+	if (!ipv6_addr_equal(&saddr1->sin6_addr,
+			     &saddr1->sin6_addr))
+		return 0;
+	if (ipv6_addr_scope(&saddr1->sin6_addr) == IPV6_ADDR_SCOPE_LINKLOCAL &&
+	    saddr1->sin6_scope_id != saddr2->sin6_scope_id)
+		return 0;
+	return saddr1->sin6_port == saddr2->sin6_port;
+}
 #else
 static int nfs_sockaddr_match_ipaddr4(const struct sockaddr_in *sa1,
 				 const struct sockaddr_in *sa2)
@@ -270,6 +296,12 @@ static int nfs_sockaddr_match_ipaddr(const struct sockaddr *sa1,
 	return nfs_sockaddr_match_ipaddr4((const struct sockaddr_in *)sa1,
 			(const struct sockaddr_in *)sa2);
 }
+
+static int nfs_sockaddr_cmp_ip6(const struct sockaddr * sa1,
+				const struct sockaddr * sa2)
+{
+	return 0;
+}
 #endif
 
 /*
@@ -279,37 +311,17 @@ static int nfs_sockaddr_match_ipaddr(const struct sockaddr *sa1,
  *
  * The caller should ensure both socket addresses are AF_INET.
  */
-static int nfs_sockaddr_cmp_ip4(const struct sockaddr_in * saddr1,
-				const struct sockaddr_in * saddr2)
+static int nfs_sockaddr_cmp_ip4(const struct sockaddr *sa1,
+				const struct sockaddr *sa2)
 {
+	const struct sockaddr_in *saddr1 = (const struct sockaddr_in *)sa1;
+	const struct sockaddr_in *saddr2 = (const struct sockaddr_in *)sa2;
+
 	if (saddr1->sin_addr.s_addr != saddr2->sin_addr.s_addr)
 		return 0;
 	return saddr1->sin_port == saddr2->sin_port;
 }
 
-/*
- * Test if two ip6 socket addresses refer to the same socket by
- * comparing relevant fields. The padding bytes specifically, are not
- * compared. sin6_flowinfo is not compared because it only affects QoS
- * and sin6_scope_id is only compared if the address is "link local"
- * because "link local" addresses need only be unique to a specific
- * link. Conversely, ordinary unicast addresses might have different
- * sin6_scope_id.
- *
- * The caller should ensure both socket addresses are AF_INET6.
- */
-static int nfs_sockaddr_cmp_ip6 (const struct sockaddr_in6 * saddr1,
-				 const struct sockaddr_in6 * saddr2)
-{
-	if (!ipv6_addr_equal(&saddr1->sin6_addr,
-			     &saddr1->sin6_addr))
-		return 0;
-	if (ipv6_addr_scope(&saddr1->sin6_addr) == IPV6_ADDR_SCOPE_LINKLOCAL &&
-	    saddr1->sin6_scope_id != saddr2->sin6_scope_id)
-		return 0;
-	return saddr1->sin6_port == saddr2->sin6_port;
-}
-
 /*
  * Test if two socket addresses represent the same actual socket,
  * by comparing (only) relevant fields.
@@ -322,11 +334,9 @@ static int nfs_sockaddr_cmp(const struct sockaddr *sa1,
 
 	switch (sa1->sa_family) {
 	case AF_INET:
-		return nfs_sockaddr_cmp_ip4((const struct sockaddr_in *) sa1,
-					    (const struct sockaddr_in *) sa2);
+		return nfs_sockaddr_cmp_ip4(sa1, sa2);
 	case AF_INET6:
-		return nfs_sockaddr_cmp_ip6((const struct sockaddr_in6 *) sa1,
-					    (const struct sockaddr_in6 *) sa2);
+		return nfs_sockaddr_cmp_ip6(sa1, sa2);
 	}
 	return 0;
 }