[PATCH v3 net-next 0/2] net: print net_device name/state more often

[PATCH v3 net-next 0/2] net: print net_device name/state more often

[Veaceslav Falico]

Hi,

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.

CC: "David S. Miller" <davem@davemloft.net>
CC: Jason Baron <jbaron@akamai.com>
CC: Eric Dumazet <edumazet@google.com>
CC: Vlad Yasevich <vyasevic@redhat.com>
CC: stephen hemminger <stephen@networkplumber.org>
CC: Jerry Chu <hkchu@google.com>
CC: Ben Hutchings <bhutchings@solarflare.com>
CC: Joe Perches <joe@perches.com>
Signed-off-by: Veaceslav Falico <vfalico@gmail.com>

---
 include/linux/netdevice.h | 22 +++++++++++++++++++---
 lib/dynamic_debug.c       |  8 +++++---
 net/core/dev.c            |  8 +++++---
 3 files changed, 29 insertions(+), 9 deletions(-)

[PATCH v3 net-next 1/2] net: use dev->name in netdev_pr* when it's available

[Veaceslav Falico]

netdev_name() returns dev->name only when the net_device is in
NETREG_REGISTERED state.

However, dev->name is always populated on creation, so we can easily use
it.

There are two cases when there's no real name - when it's an empty string
or when the name is in form of "eth%d", then netdev_name() returns "unnamed
net_device".

CC: "David S. Miller" <davem@davemloft.net>
CC: Tom Gundersen <teg@jklm.no>
Signed-off-by: Veaceslav Falico <vfalico@gmail.com>
---

Notes:
    v1->v2:
    Also account for an empty string, as Tom Gundersen suggested.

 include/linux/netdevice.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 15ed750..70256aa 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3383,8 +3383,8 @@ 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;
 }
 
-- 
1.8.4

[PATCH v3 net-next 2/2] net: print net_device reg_state in netdev_* unless it's registered

[Veaceslav Falico]

This way we'll always know in what status the device is, unless it's
running normally (i.e. NETDEV_REGISTERED).

Also, emit a warning once in case of a bad reg_state.

CC: "David S. Miller" <davem@davemloft.net>
CC: Jason Baron <jbaron@akamai.com>
CC: Eric Dumazet <edumazet@google.com>
CC: Vlad Yasevich <vyasevic@redhat.com>
CC: stephen hemminger <stephen@networkplumber.org>
CC: Jerry Chu <hkchu@google.com>
CC: Ben Hutchings <bhutchings@solarflare.com>
CC: Joe Perches <joe@perches.com>
Signed-off-by: Veaceslav Falico <vfalico@gmail.com>
---

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

 include/linux/netdevice.h | 18 +++++++++++++++++-
 lib/dynamic_debug.c       |  8 +++++---
 net/core/dev.c            |  8 +++++---
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 70256aa..8e8fb3e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3388,6 +3388,21 @@ static inline const char *netdev_name(const struct net_device *dev)
 	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 7288e38..c9afbe2 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 239722a..81d6101 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);
 	}
-- 
1.8.4

Re: [PATCH v3 net-next 2/2] net: print net_device reg_state in netdev_* unless it's registered

[Joe Perches]

On Thu, 2014-07-17 at 19:46 +0200, Veaceslav Falico wrote:
[]
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
[]
> @@ -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)

trivia:

My preference for style here is to have the format
and args on one line when it fits and separate
the format and args lines when they don't.

	WARN(1, "netdevice: %s%s\n" format,
	     netdev_name(dev), netdev_reg_state(dev), ##args)

Unrelated:  maybe it'd be better to change the '\n' to ": "

> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
[]
> -		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);

etc...

Re: [PATCH v3 net-next 2/2] net: print net_device reg_state in netdev_* unless it's registered

[Veaceslav Falico]

On Thu, Jul 17, 2014 at 12:21:39PM -0700, Joe Perches wrote:
>On Thu, 2014-07-17 at 19:46 +0200, Veaceslav Falico wrote:
>[]
>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>[]
>> @@ -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)
>
>trivia:
>
>My preference for style here is to have the format
>and args on one line when it fits and separate
>the format and args lines when they don't.
>
>	WARN(1, "netdevice: %s%s\n" format,
>	     netdev_name(dev), netdev_reg_state(dev), ##args)
>
>Unrelated:  maybe it'd be better to change the '\n' to ": "

Good points, but I guess they're minor. If I'll send v4 I'll include them.

>
>> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
>[]
>> -		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);
>
>etc...
>
>

Re: [PATCH v3 net-next 1/2] net: use dev->name in netdev_pr* when it's available

[Tom Gundersen]

On Thu, Jul 17, 2014 at 7:46 PM, Veaceslav Falico <vfalico@gmail.com> wrote:
> netdev_name() returns dev->name only when the net_device is in
> NETREG_REGISTERED state.
>
> However, dev->name is always populated on creation, so we can easily use
> it.
>
> There are two cases when there's no real name - when it's an empty string
> or when the name is in form of "eth%d", then netdev_name() returns "unnamed
> net_device".
>
> CC: "David S. Miller" <davem@davemloft.net>
> CC: Tom Gundersen <teg@jklm.no>

Acked-by: Tom Gundersen <teg@jklm.no>

> Signed-off-by: Veaceslav Falico <vfalico@gmail.com>
> ---
>
> Notes:
>     v1->v2:
>     Also account for an empty string, as Tom Gundersen suggested.
>
>  include/linux/netdevice.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 15ed750..70256aa 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -3383,8 +3383,8 @@ 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;
>  }
>
> --
> 1.8.4
>

Re: [PATCH v3 net-next 0/2] net: print net_device name/state more often

[David Miller]

From: Veaceslav Falico <vfalico@gmail.com>
Date: Thu, 17 Jul 2014 19:46:08 +0200

> 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.

Series applied, thanks.