Merge branch 'netdev_print'

Veaceslav Falico says:

====================
net: print net_device name/state more often

Currently we use net_device->name only if it's the NETREG_REGISTERED
reg_state, otherwise we return "(unregistered device)".

However, we always populate net_device->name on creation, so it's always
available to us for use. The only caveat is that we might have a name like
"eth%d", in which case we cannot use it as it might change in the future.

Also, the net_device might not be NETREG_UNREGISTERED when the function is
called (_UNINITIALIZED, _UNREGISTERING, _RELEASED, _DUMMY), so it's
misleading.

So, a better way would be to always return the dev->name in netdev_name(),
unless it's in the form of "eth%d" or it's empty, then return
"unnamed net_device". This way we'll always return the name in
NETREG_REGISTERED reg_state, and also return it in other states, when
possible.

Also, to be more verbose on non-NETREG_REGISTERED states, add a function
netdev_reg_state(), which returns a string describing the state, and use it
in netdev_printk()-related functions. If the dev is in NETREG_REGISTERED
state then a void string is regurned and, thus, nothing changes.

After these two patches we'll have the same behaviour in the usual cases,
and more verbose in non-standardad/buggy ones.

v2->v3:
Correct the string for _UNINITIALIZED and warn on a bad reg_state,
per Joe Perches's comments.

v1->v2:
As Tom Gundersen suggested, there might be a case when we have an empty
string as a name for a device, so account this also and return "unnamed
device" for that case too.
====================

Signed-off-by: Veaceslav Falico <vfalico@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 29 insertions, 9 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 15ed750458a..8e8fb3ed574 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3383,11 +3383,26 @@ extern struct pernet_operations __net_initdata loopback_net_ops;
 
 static inline const char *netdev_name(const struct net_device *dev)
 {
-	if (dev->reg_state != NETREG_REGISTERED)
-		return "(unregistered net_device)";
+	if (!dev->name[0] || strchr(dev->name, '%'))
+		return "(unnamed net_device)";
 	return dev->name;
 }
 
+static inline const char *netdev_reg_state(const struct net_device *dev)
+{
+	switch (dev->reg_state) {
+	case NETREG_UNINITIALIZED: return " (uninitialized)";
+	case NETREG_REGISTERED: return "";
+	case NETREG_UNREGISTERING: return " (unregistering)";
+	case NETREG_UNREGISTERED: return " (unregistered)";
+	case NETREG_RELEASED: return " (released)";
+	case NETREG_DUMMY: return " (dummy)";
+	}
+
+	WARN_ONCE(1, "%s: unknown reg_state %d\n", dev->name, dev->reg_state);
+	return " (unknown)";
+}
+
 __printf(3, 4)
 int netdev_printk(const char *level, const struct net_device *dev,
 		  const char *format, ...);
@@ -3444,7 +3459,8 @@ do {								\
  * file/line information and a backtrace.
  */
 #define netdev_WARN(dev, format, args...)			\
-	WARN(1, "netdevice: %s\n" format, netdev_name(dev), ##args)
+	WARN(1, "netdevice: %s%s\n" format, netdev_name(dev),	\
+	     netdev_reg_state(dev), ##args)
 
 /* netif printk helpers, similar to netdev_printk */
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 7288e38e175..c9afbe2c445 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -614,13 +614,15 @@ int __dynamic_netdev_dbg(struct _ddebug *descriptor,
 		char buf[PREFIX_SIZE];
 
 		res = dev_printk_emit(7, dev->dev.parent,
-				      "%s%s %s %s: %pV",
+				      "%s%s %s %s%s: %pV",
 				      dynamic_emit_prefix(descriptor, buf),
 				      dev_driver_string(dev->dev.parent),
 				      dev_name(dev->dev.parent),
-				      netdev_name(dev), &vaf);
+				      netdev_name(dev), netdev_reg_state(dev),
+				      &vaf);
 	} else if (dev) {
-		res = printk(KERN_DEBUG "%s: %pV", netdev_name(dev), &vaf);
+		res = printk(KERN_DEBUG "%s%s: %pV", netdev_name(dev),
+			     netdev_reg_state(dev), &vaf);
 	} else {
 		res = printk(KERN_DEBUG "(NULL net_device): %pV", &vaf);
 	}
diff --git a/net/core/dev.c b/net/core/dev.c
index 239722af098..81d61014fd9 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6950,12 +6950,14 @@ static int __netdev_printk(const char *level, const struct net_device *dev,
 	if (dev && dev->dev.parent) {
 		r = dev_printk_emit(level[1] - '0',
 				    dev->dev.parent,
-				    "%s %s %s: %pV",
+				    "%s %s %s%s: %pV",
 				    dev_driver_string(dev->dev.parent),
 				    dev_name(dev->dev.parent),
-				    netdev_name(dev), vaf);
+				    netdev_name(dev), netdev_reg_state(dev),
+				    vaf);
 	} else if (dev) {
-		r = printk("%s%s: %pV", level, netdev_name(dev), vaf);
+		r = printk("%s%s%s: %pV", level, netdev_name(dev),
+			   netdev_reg_state(dev), vaf);
 	} else {
 		r = printk("%s(NULL net_device): %pV", level, vaf);
 	}