[IPCONFIG]: ip_auto_config fix

The following commandline:

 root=/dev/mtdblock6 rw rootfstype=jffs2 ip=192.168.1.10:::255.255.255.0:localhost.localdomain:eth1:off console=ttyS0,115200

makes ip_auto_config fall back to DHCP and complain "IP-Config: Incomplete
network configuration information." depending on if CONFIG_IP_PNP_DHCP is
set or not.

The only way I can make ip_auto_config accept my IP config is to add an
entry for the server IP:

ip=192.168.1.10:192.168.1.15::255.255.255.0:localhost.localdomain:eth1:off

I think this is a bug since I am not using a NFS root FS.

The following patch fixes the above problem.

From: Andrew Morton <akpm@linux-foundation.org>

Davem said (in February!):

  Well, first of all the change in question is not in 2.4.x either.  I just
  checked the current 2.4.x GIT tree and the test is exactly:

	if (ic_myaddr == INADDR_NONE ||
#ifdef CONFIG_ROOT_NFS
	    (MAJOR(ROOT_DEV) == UNNAMED_MAJOR
	     && root_server_addr == INADDR_NONE
	     && ic_servaddr == INADDR_NONE) ||
#endif
	    ic_first_dev->next) {

  which matches 2.6.x

  I even checked 2.4.x when it was branched for 2.5.x and the test was the
  same at the point in time too.

  Looking at the proposed change a bit it appears that it is probably
  correct, as it's trying to check that ROOT_DEV is nfs root.  But if it is
  correct then the UNNAMED_MAJOR comparison in the same code block should be
  removed as it becomes superfluous.

  I'm happy to apply this patch with that modification made.

Signed-off-by: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ipconfig.c

@@ -1281,9 +1281,9 @@ static int __init ip_auto_config(void)
 	 */
 	if (ic_myaddr == NONE ||
 #ifdef CONFIG_ROOT_NFS
-	    (MAJOR(ROOT_DEV) == UNNAMED_MAJOR
-	     && root_server_addr == NONE
-	     && ic_servaddr == NONE) ||
+	    (root_server_addr == NONE
+	     && ic_servaddr == NONE
+	     && ROOT_DEV == Root_NFS) ||
 #endif
 	    ic_first_dev->next) {
 #ifdef IPCONFIG_DYNAMIC