linux-kernel - [tip:x86/debug] printk: Make the printk*once() variants return a value

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Date:	Fri, 8 Jul 2016 05:08:01 -0700
From:	tip-bot for Borislav Petkov <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	hpa@...or.com, luto@...nel.org, mingo@...nel.org,
	peterz@...radead.org, brgerst@...il.com, tglx@...utronix.de,
	luto@...capital.net, torvalds@...ux-foundation.org,
	jpoimboe@...hat.com, fweisbec@...il.com, dvlasenk@...hat.com,
	bp@...e.de, bp@...en8.de
Subject: [tip:x86/debug] printk: Make the printk*once() variants return a
 value

Commit-ID:  069f0cd00df0abfb9252e0dbdc355e40e6ab75fc
Gitweb:     http://git.kernel.org/tip/069f0cd00df0abfb9252e0dbdc355e40e6ab75fc
Author:     Borislav Petkov <bp@...e.de>
AuthorDate: Tue, 5 Jul 2016 00:31:26 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 8 Jul 2016 11:33:18 +0200

printk: Make the printk*once() variants return a value

Have printk*once() return a bool which denotes whether the string was
printed or not so that calling code can react accordingly.

Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/1467671487-10344-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 include/linux/printk.h | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index f4da695..f136b22 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -108,11 +108,14 @@ struct va_format {
  * Dummy printk for disabled debugging statements to use whilst maintaining
  * gcc's format checking.
  */
-#define no_printk(fmt, ...)			\
-do {						\
-	if (0)					\
-		printk(fmt, ##__VA_ARGS__);	\
-} while (0)
+#define no_printk(fmt, ...)				\
+({							\
+	do {						\
+		if (0)					\
+			printk(fmt, ##__VA_ARGS__);	\
+	} while (0);					\
+	0;						\
+})
 
 #ifdef CONFIG_EARLY_PRINTK
 extern asmlinkage __printf(1, 2)
@@ -309,20 +312,24 @@ extern asmlinkage void dump_stack(void) __cold;
 #define printk_once(fmt, ...)					\
 ({								\
 	static bool __print_once __read_mostly;			\
+	bool __ret_print_once = !__print_once;			\
 								\
 	if (!__print_once) {					\
 		__print_once = true;				\
 		printk(fmt, ##__VA_ARGS__);			\
 	}							\
+	unlikely(__ret_print_once);				\
 })
 #define printk_deferred_once(fmt, ...)				\
 ({								\
 	static bool __print_once __read_mostly;			\
+	bool __ret_print_once = !__print_once;			\
 								\
 	if (!__print_once) {					\
 		__print_once = true;				\
 		printk_deferred(fmt, ##__VA_ARGS__);		\
 	}							\
+	unlikely(__ret_print_once);				\
 })
 #else
 #define printk_once(fmt, ...)					\