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Subject[PATCH 2/5] netdev_printk/dynamic_netdev_dbg: Directly call printk_emit
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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: Joe Perches <joe@perches.com>
Acked-by: David S. Miller <davem@davemloft.net>
Tested-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@redhat.com>
---
include/linux/netdevice.h | 3 ---
lib/dynamic_debug.c | 26 +++++++++++++++++++++++---
net/core/dev.c | 24 +++++++++++++++++-------
3 files changed, 40 insertions(+), 13 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 59dc05f3..5f49cc0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -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, ...);
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 29ff2e4..2a29f4e 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -611,20 +611,40 @@ EXPORT_SYMBOL(__dynamic_dev_dbg);
#ifdef CONFIG_NET

int __dynamic_netdev_dbg(struct _ddebug *descriptor,
- const struct net_device *dev, const char *fmt, ...)
+ const struct net_device *dev, const char *fmt, ...)
{
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;
diff --git a/net/core/dev.c b/net/core/dev.c
index 8398836..a588145 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6422,22 +6422,30 @@ 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",
- netdev_name(dev), vaf);
- else if (dev)
+ 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) {
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, ...)
@@ -6452,6 +6460,7 @@ 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;
@@ -6471,6 +6480,7 @@ int func(const struct net_device *dev, const char *fmt, ...) \
vaf.va = &args; \
\
r = __netdev_printk(level, dev, &vaf); \
+ \
va_end(args); \
\
return r; \
--
1.7.8.111.gad25c.dirty



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