From: Bart Van Assche <bart.vanassche@wdc.com>
Date: Wed, 9 Aug 2017 18:32:11 +0000 (-0700)
Subject: dm: fix printk() rate limiting code
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=62b3046afa78f34d1e05997ce86e4ce6f2f060d1

dm: fix printk() rate limiting code

commit 604407890ecf624c2fb41013c82b22aade59b455 upstream.

Using the same rate limiting state for different kinds of messages
is wrong because this can cause a high frequency message to suppress
a report of a low frequency message. Hence use a unique rate limiting
state per message type.

Fixes: 71a16736a15e ("dm: use local printk ratelimit")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c00bcdcd36de..ca688a28e219 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -25,16 +25,6 @@
 
 #define DM_MSG_PREFIX "core"
 
-#ifdef CONFIG_PRINTK
-/*
- * ratelimit state to be used in DMXXX_LIMIT().
- */
-DEFINE_RATELIMIT_STATE(dm_ratelimit_state,
-		       DEFAULT_RATELIMIT_INTERVAL,
-		       DEFAULT_RATELIMIT_BURST);
-EXPORT_SYMBOL(dm_ratelimit_state);
-#endif
-
 /*
  * Cookies are numeric values sent with CHANGE and REMOVE
  * uevents while resuming, removing or renaming the device.
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index e1e1842c5ce9..45bf2ddf43e8 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -398,46 +398,29 @@ void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
  *---------------------------------------------------------------*/
 #define DM_NAME "device-mapper"
 
-#ifdef CONFIG_PRINTK
-extern struct ratelimit_state dm_ratelimit_state;
-
-#define dm_ratelimit()	__ratelimit(&dm_ratelimit_state)
-#else
-#define dm_ratelimit()	0
-#endif
+#define DM_RATELIMIT(pr_func, fmt, ...)					\
+do {									\
+	static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,	\
+				      DEFAULT_RATELIMIT_BURST);		\
+									\
+	if (__ratelimit(&rs))						\
+		pr_func(DM_FMT(fmt), ##__VA_ARGS__);			\
+} while (0)
 
 #define DM_FMT(fmt) DM_NAME ": " DM_MSG_PREFIX ": " fmt "\n"
 
 #define DMCRIT(fmt, ...) pr_crit(DM_FMT(fmt), ##__VA_ARGS__)
 
 #define DMERR(fmt, ...) pr_err(DM_FMT(fmt), ##__VA_ARGS__)
-#define DMERR_LIMIT(fmt, ...)						\
-do {									\
-	if (dm_ratelimit())						\
-		DMERR(fmt, ##__VA_ARGS__);				\
-} while (0)
-
+#define DMERR_LIMIT(fmt, ...) DM_RATELIMIT(pr_err, fmt, ##__VA_ARGS__)
 #define DMWARN(fmt, ...) pr_warn(DM_FMT(fmt), ##__VA_ARGS__)
-#define DMWARN_LIMIT(fmt, ...)						\
-do {									\
-	if (dm_ratelimit())						\
-		DMWARN(fmt, ##__VA_ARGS__);				\
-} while (0)
-
+#define DMWARN_LIMIT(fmt, ...) DM_RATELIMIT(pr_warn, fmt, ##__VA_ARGS__)
 #define DMINFO(fmt, ...) pr_info(DM_FMT(fmt), ##__VA_ARGS__)
-#define DMINFO_LIMIT(fmt, ...)						\
-do {									\
-	if (dm_ratelimit())						\
-		DMINFO(fmt, ##__VA_ARGS__);				\
-} while (0)
+#define DMINFO_LIMIT(fmt, ...) DM_RATELIMIT(pr_info, fmt, ##__VA_ARGS__)
 
 #ifdef CONFIG_DM_DEBUG
 #define DMDEBUG(fmt, ...) printk(KERN_DEBUG DM_FMT(fmt), ##__VA_ARGS__)
-#define DMDEBUG_LIMIT(fmt, ...)						\
-do {									\
-	if (dm_ratelimit())						\
-		DMDEBUG(fmt, ##__VA_ARGS__);				\
-} while (0)
+#define DMDEBUG_LIMIT(fmt, ...) DM_RATELIMIT(pr_debug, fmt, ##__VA_ARGS__)
 #else
 #define DMDEBUG(fmt, ...) no_printk(fmt, ##__VA_ARGS__)
 #define DMDEBUG_LIMIT(fmt, ...) no_printk(fmt, ##__VA_ARGS__)