printk: Add printk_deferred_once

Two of the three prink_deferred uses are really printk_once style
uses, so add a printk_deferred_once macro to simplify those call
sites.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/printk.h b/include/linux/printk.h
index 7847301e2837..f086d6c99dbc 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -266,9 +266,20 @@ extern asmlinkage void dump_stack(void) __cold;
                 printk(fmt, ##__VA_ARGS__);                     \
         }                                                       \
 })
+#define printk_deferred_once(fmt, ...)                          \
+({                                                              \
+        static bool __print_once __read_mostly;                 \
+                                                                \
+        if (!__print_once) {                                    \
+                __print_once = true;                            \
+                printk_deferred(fmt, ##__VA_ARGS__);            \
+        }                                                       \
+})
 #else
 #define printk_once(fmt, ...)                                   \
         no_printk(fmt, ##__VA_ARGS__)
+#define printk_deferred_once(fmt, ...)                          \
+        no_printk(fmt, ##__VA_ARGS__)
 #endif
 
 #define pr_emerg_once(fmt, ...)                                 \