[PATCH] Add printk_timed_ratelimit()
printk_ratelimit() has global state which makes it not useful for callers
which wish to perform ratelimiting at a particular frequency.
Add a printk_timed_ratelimit() which utilises caller-provided state storage to
permit more flexibility.
This function can in fact be used for things other than printk ratelimiting
and is perhaps poorly named.
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/printk.c b/kernel/printk.c
index f7d427e..6642655 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -31,6 +31,7 @@
#include <linux/security.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
+#include <linux/jiffies.h>
#include <asm/uaccess.h>
@@ -1101,3 +1102,23 @@
printk_ratelimit_burst);
}
EXPORT_SYMBOL(printk_ratelimit);
+
+/**
+ * printk_timed_ratelimit - caller-controlled printk ratelimiting
+ * @caller_jiffies: pointer to caller's state
+ * @interval_msecs: minimum interval between prints
+ *
+ * printk_timed_ratelimit() returns true if more than @interval_msecs
+ * milliseconds have elapsed since the last time printk_timed_ratelimit()
+ * returned true.
+ */
+bool printk_timed_ratelimit(unsigned long *caller_jiffies,
+ unsigned int interval_msecs)
+{
+ if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) {
+ *caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs);
+ return true;
+ }
+ return false;
+}
+EXPORT_SYMBOL(printk_timed_ratelimit);
