netdev - Re: [PATCH net-next-2.6] net: Dont use netdev

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Date:	Fri, 09 Apr 2010 10:13:02 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Joe Perches <joe@...ches.com>
Cc:	netdev <netdev@...r.kernel.org>,
	David Miller <davem@...emloft.net>,
	Tom Herbert <therbert@...gle.com>
Subject: Re: [PATCH net-next-2.6] net: Dont use netdev_warn()

Le vendredi 09 avril 2010 à 00:53 -0700, Joe Perches a écrit :
> On Fri, 2010-04-09 at 09:26 +0200, Eric Dumazet wrote:
> > Dont use netdev_warn() in dev_cap_txqueue() and get_rps_cpu() so that we
> > can catch following warnings without crash.
> 
> Crash?  Can you describe the crash a bit please.
> 
> > bond0.2240 received packet on queue 6, but number of RX queues is 1
> > bond0.2240 received packet on queue 11, but number of RX queues is 1
> 
> Bond0 doesn't have a valid (netdev)->dev.parent?
> 
> 	dev_printk(level, (netdev)->dev.parent,			\
> 
> Maybe there should be some additional check on
> netdev->dev.parent.
> 
> 

CC again original CC, no need to have a private conversation about this
Joe...


Yes, bonding have a NULL dev->dev.parent, I suspect other virtual
network device also have this property.


You can see in following patch Arjan's intent, and the difference
between :

dev->name and netdev_drivername(dev, drivername, 64))


commit 6579e57b31d79d31d9b806e41ba48774e73257dc
Author: Arjan van de Ven <arjan@...ux.intel.com>
Date:   Mon Jul 21 13:31:48 2008 -0700

    net: Print the module name as part of the watchdog message
    
    As suggested by Dave:
    
    This patch adds a function to get the driver name from a struct net_device,
    and consequently uses this in the watchdog timeout handler to print as
    part of the message.
    
    Signed-off-by: Arjan van de Ven <arjan@...ux.intel.com>
    Signed-off-by: David S. Miller <davem@...emloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 812bcd8..f5ea445 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1645,6 +1645,8 @@ extern void dev_seq_stop(struct seq_file *seq, void *v);
 extern int netdev_class_create_file(struct class_attribute *class_attr);
 extern void netdev_class_remove_file(struct class_attribute *class_attr);
 
+extern char *netdev_drivername(struct net_device *dev, char *buffer, int len);
+
 extern void linkwatch_run_queue(void);
 
 extern int netdev_compute_features(unsigned long all, unsigned long one);
diff --git a/net/core/dev.c b/net/core/dev.c
index 1698b39..ad5598d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4686,6 +4686,26 @@ err_name:
        return -ENOMEM;
 }
 
+char *netdev_drivername(struct net_device *dev, char *buffer, int len)
+{
+       struct device_driver *driver;
+       struct device *parent;
+
+       if (len <= 0 || !buffer)
+               return buffer;
+       buffer[0] = 0;
+
+       parent = dev->dev.parent;
+
+       if (!parent)
+               return buffer;
+
+       driver = parent->driver;
+       if (driver && driver->name)
+               strlcpy(buffer, driver->name, len);
+       return buffer;
+}
+
 static void __net_exit netdev_exit(struct net *net)
 {
        kfree(net->dev_name_head);
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index cb625b4..4ac7e3a 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -212,9 +212,9 @@ static void dev_watchdog(unsigned long arg)
                        if (some_queue_stopped &&
                            time_after(jiffies, (dev->trans_start +
                                                 dev->watchdog_timeo))) {
-                               printk(KERN_INFO "NETDEV WATCHDOG: %s: "
-                                      "transmit timed out\n",
-                                      dev->name);
+                               char drivername[64];
+                               printk(KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit timed out\n",
+                                      dev->name, netdev_drivername(dev, drivername, 64));
                                dev->tx_timeout(dev);
                                WARN_ON_ONCE(1);
                        }



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