[PATCH] kernel.h: Add printk_ratelimited and pr_<level>_rl

[Joe Perches]

Add a printk_ratelimited statement expression macro
that uses a per-call ratelimit_state so that multiple
subsystems output messages are not suppressed by a global
__ratelimit state.

Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index f4e3184..555560c 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -407,6 +407,50 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
 #endif
 
 /*
+ * ratelimited messages with local ratelimit_state,
+ * no local ratelimit_state used in the !PRINTK case
+ */
+#ifdef CONFIG_PRINTK
+#define printk_ratelimited(fmt, ...)  ({		\
+	static struct ratelimit_state _rs = {		\
+		.interval = DEFAULT_RATELIMIT_INTERVAL, \
+		.burst = DEFAULT_RATELIMIT_BURST,       \
+	};                                              \
+							\
+	if (!__ratelimit(&_rs))                         \
+		printk(fmt, ##__VA_ARGS__);		\
+})
+#else
+/* No effect, but we still get type checking even in the !PRINTK case: */
+#define printk_ratelimited printk
+#endif
+
+#define pr_emerg_rl(fmt, ...) \
+        printk_ratelimited(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_alert_rl(fmt, ...) \
+        printk_ratelimited(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_crit_rl(fmt, ...) \
+        printk_ratelimited(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_err_rl(fmt, ...) \
+        printk_ratelimited(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_warning_rl(fmt, ...) \
+        printk_ratelimited(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_notice_rl(fmt, ...) \
+        printk_ratelimited(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
+#define pr_info_rl(fmt, ...) \
+        printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
+/* no pr_cont_rl, don't do that... */
+/* If you are writing a driver, please use dev_dbg instead */
+#if defined(DEBUG)
+#define pr_debug_rl(fmt, ...) \
+	printk_ratelimited(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
+#else
+#define pr_debug_rl(fmt, ...) \
+	({ if (0) printk_ratelimited(KERN_DEBUG pr_fmt(fmt), \
+				     ##__VA_ARGS__); 0; })
+#endif
+
+/*
  * General tracing related utility functions - trace_printk(),
  * tracing_on/tracing_off and tracing_start()/tracing_stop
  *


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