Subject: Convert net_msg_warn, NETDEBUG, & LIMIT_NETDEBUG?

From: Joe Perches <[email-masked]>
Date: Tue, 04 Nov 2014 12:46:40 -0800

net_msg_warn is a sysctl used to control the printk
of a bundle of mostly ipv4/ipv6 logging messages.

Does anyone use it?

NETDEBUG is used 4 times, 2 of which seem senseless
as they are allocation failures messages after an
alloc_skb.  These already get stack dumps.

The other NETDEBUG uses are ESP crypto descriptions.

LIMIT_NETDEBUG is used a lot more.

include/net/sock.h:#define LIMIT_NETDEBUG(fmt, args...) \
include/net/sock.h-     do { if (net_msg_warn && net_ratelimit()) printk(fmt,##args); } while(0)

Most of the LIMIT_NETDEBUG uses are emitted at KERN_DEBUG.

Here is the count of each type of use:
     31 KERN_DEBUG
      2 KERN_ERR
      3 KERN_INFO
     11 KERN_WARNING

Should those KERN_DEBUG uses be converted to
net_dbg_ratelimited so that these uses could be
controlled via dynamic_debug instead of the
net_msg_warn sysctl?

net/dccp/ uses LIMIT_NETDEBUG via DCCP_WARN to
control another 38 KERN_WARNING messages.

The others LIMIT_NETDEBUG uses could be converted
to net_<level>_ratelimited if appropriate.