printk: allow setting DEFAULT_MESSAGE_LEVEL via Kconfig

We've been burned by regressions/bugs which we later realized could have
been triaged quicker if only we'd paid closer attention to dmesg.  To make
it easier to audit dmesg, we'd like to make DEFAULT_MESSAGE_LEVEL
Kconfig-settable.  That way we can set it to KERN_NOTICE and audit any
messages <= KERN_WARNING.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Cc: Olof Johansson <olofj@chromium.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index fb0afef..bef5faa 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -9,6 +9,17 @@
 	  operations.  This is useful for identifying long delays
 	  in kernel startup.
 
+config DEFAULT_MESSAGE_LOGLEVEL
+	int "Default message log level (1-7)"
+	range 1 7
+	default "4"
+	help
+	  Default log level for printk statements with no specified priority.
+
+	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
+	  that are auditing their logs closely may want to set it to a lower
+	  priority.
+
 config ENABLE_WARN_DEPRECATED
 	bool "Enable __deprecated logic"
 	default y