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Commit b004ff49 authored by Joe Perches's avatar Joe Perches Committed by Greg Kroah-Hartman
Browse files

netdev_printk/dynamic_netdev_dbg: Directly call printk_emit 



A lot of stack is used in recursive printks with %pV.

Using multiple levels of %pV (a logging function with %pV
that calls another logging function with %pV) can consume
more stack than necessary.

Avoid excessive stack use by not calling dev_printk from
netdev_printk and dynamic_netdev_dbg.  Duplicate the logic
and form of dev_printk instead.

Make __netdev_printk static.
Remove EXPORT_SYMBOL(__netdev_printk)
Whitespace and brace style neatening.

Signed-off-by: default avatarJoe Perches <joe@perches.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Tested-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 798efc60

include/linux/netdevice.h

+0 −3
Original line number Diff line number Diff line
@@ -2720,9 +2720,6 @@ 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,

			struct va_format *vaf);



extern __printf(3, 4)

int netdev_printk(const char *level, const struct net_device *dev,

		  const char *format, ...);

lib/dynamic_debug.c

+23 −3
Original line number Diff line number Diff line
@@ -616,15 +616,35 @@ 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);



	va_start(args, fmt);



	vaf.fmt = fmt;

	vaf.va = &args;

	res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);



	if (dev && dev->dev.parent) {

		char buf[PREFIX_SIZE];

		char dict[128];

		size_t dictlen;



		dictlen = create_syslog_header(dev->dev.parent,

					       dict, sizeof(dict));



		res = printk_emit(0, 7, dictlen ? dict : NULL, dictlen,

				  "%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);

	}



	va_end(args);



	return res;

net/core/dev.c

+17 −7
Original line number Diff line number Diff line
@@ -6423,22 +6423,30 @@ const char *netdev_drivername(const struct net_device *dev) 
	return empty;

}



int __netdev_printk(const char *level, const struct net_device *dev,

static int __netdev_printk(const char *level, const struct net_device *dev,

			   struct va_format *vaf)

{

	int r;



	if (dev && dev->dev.parent)

		r = dev_printk(level, dev->dev.parent, "%s: %pV",

	if (dev && dev->dev.parent) {

		char dict[128];

		size_t dictlen = create_syslog_header(dev->dev.parent,

						      dict, sizeof(dict));



		r = printk_emit(0, level[1] - '0',

				dictlen ? dict : NULL, dictlen,

				"%s %s: %s: %pV",

				dev_driver_string(dev->dev.parent),

				dev_name(dev->dev.parent),

				netdev_name(dev), vaf);

	else if (dev)

	} else if (dev) {

		r = printk("%s%s: %pV", level, netdev_name(dev), vaf);

	else

	} else {

		r = printk("%s(NULL net_device): %pV", level, vaf);

	}



	return r;

}

EXPORT_SYMBOL(__netdev_printk);



int netdev_printk(const char *level, const struct net_device *dev,

		  const char *format, ...)
@@ -6453,6 +6461,7 @@ int netdev_printk(const char *level, const struct net_device *dev, 
	vaf.va = &args;



	r = __netdev_printk(level, dev, &vaf);



	va_end(args);



	return r;
@@ -6472,6 +6481,7 @@ int func(const struct net_device *dev, const char *fmt, ...) \ 
	vaf.va = &args;						\

								\

	r = __netdev_printk(level, dev, &vaf);			\

								\

	va_end(args);						\

								\

	return r;						\