Subject: Re: [PATCH 0/5] dev_<level> and dynamic_debug cleanups

From: Jason Baron <[email-masked]>
Date: Fri, 7 Sep 2012 10:52:35 -0400

On Thu, Sep 06, 2012 at 11:43:46AM -0700, Joe Perches wrote:
> On Thu, 2012-09-06 at 13:51 -0400, Jason Baron wrote:
> > On Sun, Aug 26, 2012 at 04:25:25AM -0700, Joe Perches wrote:
> > > The recent commit to fix dynamic_debug was a bit unclean.
> > > Neaten the style for dynamic_debug.
> > > Reduce the stack use of message logging that uses netdev_printk
> > > Add utility functions dev_printk_emit and dev_vprintk_emit for /dev/kmsg.
> > > 
> > > Joe Perches (5):
> > >   dev_dbg/dynamic_debug: Update to use printk_emit, optimize stack
> > >   netdev_printk/dynamic_netdev_dbg: Directly call printk_emit
> > >   netdev_printk/netif_printk: Remove a superfluous logging colon
> > >   dev: Add dev_vprintk_emit and dev_printk_emit
> > >   device and dynamic_debug: Use dev_vprintk_emit and dev_printk_emit
> > > 
> > 
> > Looks Good.
> > 
> > The one thing that is bothering me though, is that for
> > __dynamic_dev_dbg(), __dynamic_netdev_dbg(), we are copying much of the core
> > logic of __dev_printk(), __netdev_printk(), respectively. I would prefer
> > have this in one place. Can we add a 'prefix' argument to __dev_printk(),
> > and __netdev_printk() that dynamic debug can use, but is simply empty
> > for dev_printk() and netdev_printk().
> 
> I don't think that's an improvement actually.
> Why don't you try it.
> 

Ok, below is what I was thinking. It winds up being more deletions than
insertions.

Thanks,

-Jason

dynamic debug: remove duplicate __netdev_printk() and  __dev_printk() logic 

Add an option prefix string argument to __netdev_printk() and __dev_printk().
In this way dynamic debug does not have to contain duplicate logic.

Signed-off-by: Jason Baron <[email-masked]>
---
 drivers/base/core.c       |   13 +++++++------
 include/linux/device.h    |    3 +++
 include/linux/netdevice.h |    3 +++
 lib/dynamic_debug.c       |   32 ++++++++------------------------
 net/core/dev.c            |   11 ++++++-----
 5 files changed, 27 insertions(+), 35 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 65f82e3..7b4ee6d 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1937,15 +1937,16 @@ int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
 }
 EXPORT_SYMBOL(dev_printk_emit);
 
-static int __dev_printk(const char *level, const struct device *dev,
-			struct va_format *vaf)
+int __dev_printk(const char *level, const struct device *dev,
+		 char *prefix, struct va_format *vaf)
 {
 	if (!dev)
 		return printk("%s(NULL device *): %pV", level, vaf);
 
 	return dev_printk_emit(level[1] - '0', dev,
-			       "%s %s: %pV",
-			       dev_driver_string(dev), dev_name(dev), vaf);
+			       "%s%s %s: %pV",
+			       prefix, dev_driver_string(dev),
+			       dev_name(dev), vaf);
 }
 
 int dev_printk(const char *level, const struct device *dev,
@@ -1960,7 +1961,7 @@ int dev_printk(const char *level, const struct device *dev,
 	vaf.fmt = fmt;
 	vaf.va = &args;
 
-	r = __dev_printk(level, dev, &vaf);
+	r = __dev_printk(level, dev, "", &vaf);
 
 	va_end(args);
 
@@ -1980,7 +1981,7 @@ int func(const struct device *dev, const char *fmt, ...)	\
 	vaf.fmt = fmt;						\
 	vaf.va = &args;						\
 								\
-	r = __dev_printk(kern_level, dev, &vaf);		\
+	r = __dev_printk(kern_level, dev, "", &vaf);		\
 								\
 	va_end(args);						\
 								\
diff --git a/include/linux/device.h b/include/linux/device.h
index 2da4589..573b15e 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -891,6 +891,9 @@ extern const char *dev_driver_string(const struct device *dev);
 
 #ifdef CONFIG_PRINTK
 
+extern int __dev_printk(const char *level, const struct device *dev,
+			char *prefix, struct va_format *vaf);
+
 extern int dev_vprintk_emit(int level, const struct device *dev,
 			    const char *fmt, va_list args);
 extern __printf(3, 4)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5f49cc0..63f6165 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2720,6 +2720,9 @@ static inline const char *netdev_name(const struct net_device *dev)
 	return dev->name;
 }
 
+extern int __netdev_printk(const char *level, const struct net_device *dev,
+			   char *prefix, struct va_format *vaf);
+
 extern __printf(3, 4)
 int netdev_printk(const char *level, const struct net_device *dev,
 		  const char *format, ...);
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index e7f7d99..83bf601 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -578,6 +578,7 @@ int __dynamic_dev_dbg(struct _ddebug *descriptor,
 	struct va_format vaf;
 	va_list args;
 	int res;
+	char buf[PREFIX_SIZE];
 
 	BUG_ON(!descriptor);
 	BUG_ON(!fmt);
@@ -587,16 +588,9 @@ int __dynamic_dev_dbg(struct _ddebug *descriptor,
 	vaf.fmt = fmt;
 	vaf.va = &args;
 
-	if (!dev) {
-		res = printk(KERN_DEBUG "(NULL device *): %pV", &vaf);
-	} else {
-		char buf[PREFIX_SIZE];
-
-		res = dev_printk_emit(7, dev, "%s%s %s: %pV",
-				      dynamic_emit_prefix(descriptor, buf),
-				      dev_driver_string(dev), dev_name(dev),
-				      &vaf);
-	}
+	res = __dev_printk(KERN_DEBUG, dev,
+			   dynamic_emit_prefix(descriptor, buf),
+			   &vaf);
 
 	va_end(args);
 
@@ -612,6 +606,7 @@ int __dynamic_netdev_dbg(struct _ddebug *descriptor,
 	struct va_format vaf;
 	va_list args;
 	int res;
+	char buf[PREFIX_SIZE];
 
 	BUG_ON(!descriptor);
 	BUG_ON(!fmt);
@@ -621,20 +616,9 @@ int __dynamic_netdev_dbg(struct _ddebug *descriptor,
 	vaf.fmt = fmt;
 	vaf.va = &args;
 
-	if (dev && dev->dev.parent) {
-		char buf[PREFIX_SIZE];
-
-		res = dev_printk_emit(7, dev->dev.parent,
-				      "%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);
-	} else if (dev) {
-		res = printk(KERN_DEBUG "%s: %pV", netdev_name(dev), &vaf);
-	} else {
-		res = printk(KERN_DEBUG "(NULL net_device): %pV", &vaf);
-	}
+	res = __netdev_printk(KERN_DEBUG, dev,
+			      dynamic_emit_prefix(descriptor, buf),
+			      &vaf);
 
 	va_end(args);
 
diff --git a/net/core/dev.c b/net/core/dev.c
index 8ad42fd..5fef0f6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6422,15 +6422,16 @@ const char *netdev_drivername(const struct net_device *dev)
 	return empty;
 }
 
-static int __netdev_printk(const char *level, const struct net_device *dev,
-			   struct va_format *vaf)
+int __netdev_printk(const char *level, const struct net_device *dev,
+		    char *prefix, struct va_format *vaf)
 {
 	int r;
 
 	if (dev && dev->dev.parent) {
 		r = dev_printk_emit(level[1] - '0',
 				    dev->dev.parent,
-				    "%s %s %s: %pV",
+				    "%s%s %s %s: %pV",
+				    prefix,
 				    dev_driver_string(dev->dev.parent),
 				    dev_name(dev->dev.parent),
 				    netdev_name(dev), vaf);
@@ -6455,7 +6456,7 @@ int netdev_printk(const char *level, const struct net_device *dev,
 	vaf.fmt = format;
 	vaf.va = &args;
 
-	r = __netdev_printk(level, dev, &vaf);
+	r = __netdev_printk(level, dev, "", &vaf);
 
 	va_end(args);
 
@@ -6475,7 +6476,7 @@ int func(const struct net_device *dev, const char *fmt, ...)	\
 	vaf.fmt = fmt;						\
 	vaf.va = &args;						\
 								\
-	r = __netdev_printk(level, dev, &vaf);			\
+	r = __netdev_printk(level, dev, "", &vaf);		\
 								\
 	va_end(args);						\
 								\
-- 
1.7.7.6