[PATCH RFC] bonding: rate-limit bonding driver inspect messages

[Praveen Kumar Kannoju]

Rate limit bond driver log messages, to prevent a log flood in a run-away
situation, e.g couldn't get rtnl lock. Message flood leads to instability
of system and loss of other crucial messages.

Signed-off-by: Praveen Kumar Kannoju <praveen.kannoju@xxxxxxxxxx>
---
 drivers/net/bonding/bond_main.c | 34 +++++++++++++++++++---------------
 include/net/bonding.h           | 11 +++++++++++
 2 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 4e0600c..32098dd 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2610,12 +2610,13 @@ static int bond_miimon_inspect(struct bonding *bond)
 			commit++;
 			slave->delay = bond->params.downdelay;
 			if (slave->delay) {
-				slave_info(bond->dev, slave->dev, "link status down for %sinterface, disabling it in %d ms\n",
-					   (BOND_MODE(bond) ==
-					    BOND_MODE_ACTIVEBACKUP) ?
-					    (bond_is_active_slave(slave) ?
+				bond_info_rl(bond->dev, slave->dev,
+					     "link status down for %sinterface, disabling it in %d ms\n",
+					     (BOND_MODE(bond) ==
+					     BOND_MODE_ACTIVEBACKUP) ?
+					     (bond_is_active_slave(slave) ?
 					     "active " : "backup ") : "",
-					   bond->params.downdelay * bond->params.miimon);
+					     bond->params.downdelay * bond->params.miimon);
 			}
 			fallthrough;
 		case BOND_LINK_FAIL:
@@ -2623,9 +2624,10 @@ static int bond_miimon_inspect(struct bonding *bond)
 				/* recovered before downdelay expired */
 				bond_propose_link_state(slave, BOND_LINK_UP);
 				slave->last_link_up = jiffies;
-				slave_info(bond->dev, slave->dev, "link status up again after %d ms\n",
-					   (bond->params.downdelay - slave->delay) *
-					   bond->params.miimon);
+				bond_info_rl(bond->dev, slave->dev,
+					     "link status up again after %d ms\n",
+					     (bond->params.downdelay - slave->delay) *
+					     bond->params.miimon);
 				commit++;
 				continue;
 			}
@@ -2648,18 +2650,20 @@ static int bond_miimon_inspect(struct bonding *bond)
 			slave->delay = bond->params.updelay;
 
 			if (slave->delay) {
-				slave_info(bond->dev, slave->dev, "link status up, enabling it in %d ms\n",
-					   ignore_updelay ? 0 :
-					   bond->params.updelay *
-					   bond->params.miimon);
+				bond_info_rl(bond->dev, slave->dev,
+					     "link status up, enabling it in %d ms\n",
+					     ignore_updelay ? 0 :
+					     bond->params.updelay *
+					     bond->params.miimon);
 			}
 			fallthrough;
 		case BOND_LINK_BACK:
 			if (!link_state) {
 				bond_propose_link_state(slave, BOND_LINK_DOWN);
-				slave_info(bond->dev, slave->dev, "link status down again after %d ms\n",
-					   (bond->params.updelay - slave->delay) *
-					   bond->params.miimon);
+				bond_info_rl(bond->dev, slave->dev,
+					     "link status down again after %d ms\n",
+					     (bond->params.updelay - slave->delay) *
+					     bond->params.miimon);
 				commit++;
 				continue;
 			}
diff --git a/include/net/bonding.h b/include/net/bonding.h
index 5b8b1b6..ebdfaf0 100644
--- a/include/net/bonding.h
+++ b/include/net/bonding.h
@@ -39,8 +39,19 @@
 #define __long_aligned __attribute__((aligned((sizeof(long)))))
 #endif
 
+DEFINE_RATELIMIT_STATE(bond_rs, DEFAULT_RATELIMIT_INTERVAL,
+		       DEFAULT_RATELIMIT_BURST);
+
+#define bond_ratelimited_function(function, ...)	\
+do {							\
+	if (__ratelimit(&bond_rs))		\
+		function(__VA_ARGS__);			\
+} while (0)
+
 #define slave_info(bond_dev, slave_dev, fmt, ...) \
 	netdev_info(bond_dev, "(slave %s): " fmt, (slave_dev)->name, ##__VA_ARGS__)
+#define bond_info_rl(bond_dev, slave_dev, fmt, ...) \
+	bond_ratelimited_function(slave_info, fmt, ##__VA_ARGS__)
 #define slave_warn(bond_dev, slave_dev, fmt, ...) \
 	netdev_warn(bond_dev, "(slave %s): " fmt, (slave_dev)->name, ##__VA_ARGS__)
 #define slave_dbg(bond_dev, slave_dev, fmt, ...) \
-- 
1.8.3.1