cifs: have cifs parse scope_id out of IPv6 addresses and use it

This patch has CIFS look for a '%' in an IPv6 address. If one is
present then it will try to treat that value as a numeric interface
index suitable for stuffing into the sin6_scope_id field.

This should allow people to mount servers on IPv6 link-local addresses.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: David Holder <david@erion.co.uk>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/dns_resolve.c b/fs/cifs/dns_resolve.c
index 91b5500..8794814 100644
--- a/fs/cifs/dns_resolve.c
+++ b/fs/cifs/dns_resolve.c
@@ -35,7 +35,7 @@
  * 		0 - name is not IP
  */
 static int
-is_ip(const char *name)
+is_ip(char *name)
 {
 	struct sockaddr_storage ss;
 
@@ -57,7 +57,7 @@
 	ip[datalen] = '\0';
 
 	/* make sure this looks like an address */
-	if (!is_ip((const char *) ip)) {
+	if (!is_ip(ip)) {
 		kfree(ip);
 		return -EINVAL;
 	}