[PATCH 4/5] NETDEV: Wait for autoconfigurable network devices to become available

[David VomLehn <dvomlehn@cisco.com>]

Delay IP autoconfiguration until network boot devices have been initialized.
This depends on the boot device discovery code and on the asynchronous
function call infrastructure.

Signed-off-by: David VomLehn <dvomlehn@cisco.com>
---
 net/core/dev.c      |    2 +
 net/ipv4/ipconfig.c |   56 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 57 insertions(+), 1 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 308a7d0..73cb282 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -93,6 +93,7 @@
 #include <linux/ethtool.h>
 #include <linux/notifier.h>
 #include <linux/skbuff.h>
+#include <linux/device.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <linux/rtnetlink.h>
@@ -4497,6 +4498,7 @@ int register_netdevice(struct net_device *dev)
 		dev->reg_state = NETREG_UNREGISTERED;
 	}
 
+	bootdev_registered(BOOTDEV_NETDEV);
 out:
 	return ret;
 
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 90d22ae..65a7ecd 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -53,6 +53,7 @@
 #include <linux/root_dev.h>
 #include <linux/delay.h>
 #include <linux/nfs_fs.h>
+#include <linux/async.h>
 #include <net/net_namespace.h>
 #include <net/arp.h>
 #include <net/ip.h>
@@ -182,12 +183,48 @@ struct ic_device {
 static struct ic_device *ic_first_dev __initdata = NULL;/* List of open device */
 static struct net_device *ic_dev __initdata = NULL;	/* Selected device */
 
+/*
+ * Wait for required network devices to come up
+ * If the networking device name was specified on the kernel command line
+ * and that device is now registered, we have the device we want to configure
+ * and we return true. Otherwise, we return false. So, if no device was
+ * specified on the command line, we wait for all possible network devices to
+ * be initialized.
+ */
+static bool have_all_netdevs(void)
+{
+	struct net_device *dev;
+	bool	result = false;
+
+	rtnl_lock();
+
+	for_each_netdev(&init_net, dev) {
+		if (dev->flags & IFF_LOOPBACK)
+			continue;
+
+		/* If a specific device name was specified and that name is
+		 * registered, we have the device we need. */
+		if (user_dev_name[0] && !strcmp(dev->name, user_dev_name)) {
+			result = true;
+			break;
+		}
+	}
+
+	rtnl_unlock();
+
+	return result;
+
+}
+
 static int __init ic_open_devs(void)
 {
 	struct ic_device *d, **last;
 	struct net_device *dev;
 	unsigned short oflags;
 
+	/* Wait for networking devices */
+	bootdev_wait(BOOTDEV_NETDEV, have_all_netdevs);
+
 	last = &ic_first_dev;
 	rtnl_lock();
 
@@ -1263,6 +1300,7 @@ __be32 __init root_nfs_parse_addr(char *name)
 
 /*
  *	IP Autoconfig dispatcher.
+ *	Return zero on success, negative one on failure
  */
 
 static int __init ip_auto_config(void)
@@ -1397,7 +1435,23 @@ static int __init ip_auto_config(void)
 	return 0;
 }
 
-late_initcall(ip_auto_config);
+static void __init ip_auto_config_async(void *data, async_cookie_t cookie)
+{
+	ip_auto_config();
+}
+
+static async_cookie_t ic_cookie;
+/*
+ * Start a thread to do IP autoconfiguration
+ */
+static int __init ip_auto_configurator(void)
+{
+	ic_cookie = async_schedule(ip_auto_config_async, NULL);
+
+	return 0;
+}
+
+late_initcall(ip_auto_configurator);
 
 
 /*