xfs: Add ratelimited printk for different alert levels

Ratelimited printk will be useful in printing xfs messages which are otherwise
not required to be printed always due to their high rate (to prevent kernel ring
buffer from overflowing), while at the same time required to be printed.

Signed-off-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
Reviewed-by: Rich Johnston <rjohnston@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_linux.h

@@ -72,6 +72,7 @@
 #include <linux/kthread.h>
 #include <linux/freezer.h>
 #include <linux/list_sort.h>
+#include <linux/ratelimit.h>
 
 #include <asm/page.h>
 #include <asm/div64.h>

fs/xfs/xfs_message.h

@@ -30,6 +30,32 @@ void xfs_debug(const struct xfs_mount *mp, const char *fmt, ...)
 }
 #endif
 
+#define xfs_printk_ratelimited(func, dev, fmt, ...)		\
+do {									\
+	static DEFINE_RATELIMIT_STATE(_rs,				\
+				      DEFAULT_RATELIMIT_INTERVAL,	\
+				      DEFAULT_RATELIMIT_BURST);		\
+	if (__ratelimit(&_rs))						\
+		func(dev, fmt, ##__VA_ARGS__);			\
+} while (0)
+
+#define xfs_emerg_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_emerg, dev, fmt, ##__VA_ARGS__)
+#define xfs_alert_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_alert, dev, fmt, ##__VA_ARGS__)
+#define xfs_crit_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_crit, dev, fmt, ##__VA_ARGS__)
+#define xfs_err_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_err, dev, fmt, ##__VA_ARGS__)
+#define xfs_warn_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_warn, dev, fmt, ##__VA_ARGS__)
+#define xfs_notice_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_notice, dev, fmt, ##__VA_ARGS__)
+#define xfs_info_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_info, dev, fmt, ##__VA_ARGS__)
+#define xfs_debug_ratelimited(dev, fmt, ...)				\
+	xfs_printk_ratelimited(xfs_debug, dev, fmt, ##__VA_ARGS__)
+
 extern void assfail(char *expr, char *f, int l);
 
 extern void xfs_hex_dump(void *p, int length);