[IPV4] ipconfig: Fix regression in ip command line processing

The recent changes for ip command line processing fixed some problems
but unfortunately broke some common usage scenarios.  In current
2.6.24-rc6 the following command line results in no IP address
assignment, which is surely a regression:

 ip=10.0.2.15::10.0.2.2:255.255.255.0::eth0:off

Please find below a patch that works for all cases I can find.

Signed-off-by: Amos Waterland <apw@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 19 insertions, 4 deletions

diff --git a/Documentation/nfsroot.txt b/Documentation/nfsroot.txt
index c86dd38e2281..31b329172343 100644
--- a/Documentation/nfsroot.txt
+++ b/Documentation/nfsroot.txt
@@ -145,6 +145,7 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
                 this option.
 
                   off or none: don't use autoconfiguration
+                                (do static IP assignment instead)
                   on or any:   use any protocol available in the kernel
                                (default)
                   dhcp:        use DHCP
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 56a675734ea5..b8f7763b2261 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -1404,8 +1404,7 @@ static int __init ic_proto_name(char *name)
                 return 1;
         }
         if (!strcmp(name, "off") || !strcmp(name, "none")) {
-                ic_enable = 0;
-                return 1;
+                return 0;
         }
 #ifdef CONFIG_IP_PNP_DHCP
         else if (!strcmp(name, "dhcp")) {
@@ -1442,10 +1441,22 @@ static int __init ip_auto_config_setup(char *addrs)
         ic_set_manually = 1;
         ic_enable = 1;
 
+        /*
+         * If any dhcp, bootp etc options are set, leave autoconfig on
+         * and skip the below static IP processing.
+         */
         if (ic_proto_name(addrs))
                 return 1;
 
-        /* Parse the whole string */
+        /* If no static IP is given, turn off autoconfig and bail.  */
+        if (*addrs == 0 ||
+            strcmp(addrs, "off") == 0 ||
+            strcmp(addrs, "none") == 0) {
+                ic_enable = 0;
+                return 1;
+        }
+
+        /* Parse string for static IP assignment.  */
         ip = addrs;
         while (ip && *ip) {
                 if ((cp = strchr(ip, ':')))
@@ -1483,7 +1494,10 @@ static int __init ip_auto_config_setup(char *addrs)
                                 strlcpy(user_dev_name, ip, sizeof(user_dev_name));
                                 break;
                         case 6:
-                                ic_proto_name(ip);
+                                if (ic_proto_name(ip) == 0 &&
+                                    ic_myaddr == NONE) {
+                                        ic_enable = 0;
+                                }
                                 break;
                         }
                 }