[PATCH -v2 2/3] printk: Make the printk*once() variants return a value

From: Borislav Petkov
Date: Mon Jul 04 2016 - 18:31:58 EST


From: Borislav Petkov <bp@xxxxxxx>

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@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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 f4da695fd615..f136b22c7772 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, ...) \
--
2.7.3