Subject: [PATCH] ipconfig: Inform user if carrier is not ready

From: Erwan Velu <[email-masked]>
Date: Thu, 13 Sep 2012 23:59:52 +0200

From: Erwan Velu <[email-masked]>

While using the ip= option at the cmdline, the kernel can hold the boot
process for 2 minutes (CONF_CARRIER_TIMEOUT) if the carrier is not
present.

While waiting the carrier, user is not informed about this situation and
so could think the kernel is frozen.

This patch is just adding a simple message every second telling we are
waiting the carrier to come up.
---
  net/ipv4/ipconfig.c |    8 ++++++++
  1 file changed, 8 insertions(+)

diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 67e8a6b..d9f34b7 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -205,6 +205,7 @@ static int __init ic_open_devs(void)
      struct net_device *dev;
      unsigned short oflags;
      unsigned long start;
+    unsigned int loops=0;

      last = &ic_first_dev;
      rtnl_lock();
@@ -266,6 +267,13 @@ static int __init ic_open_devs(void)
              if (ic_is_init_dev(dev) && netif_carrier_ok(dev))
                  goto have_carrier;

+        loops++;
+        /* This loop is blocking the boot process until we get the 
carrier or reach the timeout.
+         * We have to inform the user about the situation as it could 
look like a kernel freeze.
+         * Every second, we display a short message indicating we wait 
the carrier */
+        if ((loops % 1000) == 0) {
+            pr_info("IP-Config: Waiting Carrier (%d/%d):\n",loops / 
1000, CONF_CARRIER_TIMEOUT / 1000);
+        }
          msleep(1);
      }
  have_carrier:
-- 
1.7.10