printk: rename nmi.c and exported api

A preparation patch for printk_safe work. No functional change.
- rename nmi.c to print_safe.c
- add `printk_safe' prefix to some (which used both by printk-safe
  and printk-nmi) of the exported functions.

Link: http://lkml.kernel.org/r/20161227141611.940-3-sergey.senozhatsky@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Calvin Owens <calvinowens@fb.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

2 files changed, 10 insertions, 8 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 223b734..760b7d0 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -875,17 +875,19 @@ config LOG_CPU_MAX_BUF_SHIFT
 		     13 =>   8 KB for each CPU
 		     12 =>   4 KB for each CPU
 
-config NMI_LOG_BUF_SHIFT
-	int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)"
+config PRINTK_SAFE_LOG_BUF_SHIFT
+	int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
 	range 10 21
 	default 13
-	depends on PRINTK_NMI
+	depends on PRINTK
 	help
-	  Select the size of a per-CPU buffer where NMI messages are temporary
-	  stored. They are copied to the main log buffer in a safe context
-	  to avoid a deadlock. The value defines the size as a power of 2.
+	  Select the size of an alternate printk per-CPU buffer where messages
+	  printed from usafe contexts are temporary stored. One example would
+	  be NMI messages, another one - printk recursion. The messages are
+	  copied to the main log buffer in a safe context to avoid a deadlock.
+	  The value defines the size as a power of 2.
 
-	  NMI messages are rare and limited. The largest one is when
+	  Those messages are rare and limited. The largest one is when
 	  a backtrace is printed. It usually fits into 4KB. Select
 	  8KB if you want to be on the safe side.
 
diff --git a/init/main.c b/init/main.c
index b0c9d6f..b4ca17d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -580,7 +580,7 @@ asmlinkage __visible void __init start_kernel(void)
 	timekeeping_init();
 	time_init();
 	sched_clock_postinit();
-	printk_nmi_init();
+	printk_safe_init();
 	perf_event_init();
 	profile_init();
 	call_function_init();