[IPV4]: Fix ip command line processing.

Recently the documentation in Documentation/nfsroot.txt was
update to note that in fact ip=off and ip=::::::off as the
latter is ignored and the default (on) is used.

This was certainly a step in the direction of reducing confusion.
But it seems to me that the code ought to be fixed up so that
ip=::::::off actually turns off ip autoconfiguration.

This patch also notes more specifically that ip=on (aka ip=::::::on)
is the default.

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/nfsroot.txt

@@ -97,10 +97,6 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
   autoconfiguration will take place.  The most common way to use this
   is "ip=dhcp".
 
-  Note that "ip=off" is not the same thing as "ip=::::::off", because in
-  the latter autoconfiguration will take place if any of DHCP, BOOTP or RARP
-  are compiled in the kernel.
-
   <client-ip>	IP address of the client.
 
   		Default:  Determined using autoconfiguration.
@@ -150,6 +146,7 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
 
                   off or none: don't use autoconfiguration
 		  on or any:   use any protocol available in the kernel
+			       (default)
 		  dhcp:        use DHCP
 		  bootp:       use BOOTP
 		  rarp:        use RARP

net/ipv4/ipconfig.c

@@ -1403,6 +1403,10 @@ static int __init ic_proto_name(char *name)
 	if (!strcmp(name, "on") || !strcmp(name, "any")) {
 		return 1;
 	}
+	if (!strcmp(name, "off") || !strcmp(name, "none")) {
+		ic_enable = 0;
+		return 1;
+	}
 #ifdef CONFIG_IP_PNP_DHCP
 	else if (!strcmp(name, "dhcp")) {
 		ic_proto_enabled &= ~IC_RARP;
@@ -1437,12 +1441,6 @@ static int __init ip_auto_config_setup(char *addrs)
 
 	ic_set_manually = 1;
 
-	ic_enable = (*addrs &&
-		(strcmp(addrs, "off") != 0) &&
-		(strcmp(addrs, "none") != 0));
-	if (!ic_enable)
-		return 1;
-
 	if (ic_proto_name(addrs))
 		return 1;