[PATCH V2] IB/ipoib: Leave stale send-only multicast groups

[Moni Shoua <monis-hKgKHo2Ms0F+cjeuK/JdrQ@public.gmane.org>]

Unlike with send/receive multicast groups, there is no indication for IPoIB
that a send-only multicast group is useless. Therefore, even a single packet
to a multicast destination leaves a multicast entry on the fabric until the
host interface is down. This causes an MGID leakage in the SM.

Here, a garbage-collection task will be scheduled once a minute and will leave
stale multicast groups.

V1 of the patch below was sent to the list a long ago by Yossi Etigin and from some
reason the discussion about it was stopped without a conclusion.

Link to V1:
 - http://www.mail-archive.com/general-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org/msg18928.html

Changes from V1:
 - Add a module parameter to control the amount of time that an idle send-only
   group is allowed to stay joined.

Signed-off-by: Yossi Etigin <yosefe-smomgflXvOZWk0Htik3J/w@public.gmane.org>
Signed-off-by: Moni Shoua <monis-smomgflXvOZWk0Htik3J/w@public.gmane.org>

--
 drivers/infiniband/ulp/ipoib/ipoib.h           |    8 +++-
 drivers/infiniband/ulp/ipoib/ipoib_main.c      |    8 +++-
 drivers/infiniband/ulp/ipoib/ipoib_multicast.c |   50 +++++++++++++++++++++----
 3 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index ab97f92..fb1714f 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -92,6 +92,7 @@ enum {
 	IPOIB_FLAG_ADMIN_CM	  = 9,
 	IPOIB_FLAG_UMCAST	  = 10,
 	IPOIB_FLAG_CSUM		  = 11,
+	IPOIB_MCAST_RUN_GC	  = 12,
 
 	IPOIB_MAX_BACKOFF_SECONDS = 16,
 
@@ -132,6 +133,7 @@ struct ipoib_mcast {
 	struct list_head  list;
 
 	unsigned long created;
+	unsigned long used;
 	unsigned long backoff;
 
 	unsigned long flags;
@@ -283,7 +285,8 @@ struct ipoib_dev_priv {
 	struct rb_root multicast_tree;
 
 	struct delayed_work pkey_poll_task;
-	struct delayed_work mcast_task;
+	struct delayed_work mcast_join_task;
+	struct delayed_work mcast_leave_task;
 	struct work_struct carrier_on_task;
 	struct work_struct flush_light;
 	struct work_struct flush_normal;
@@ -411,6 +414,8 @@ void ipoib_neigh_free(struct net_device *dev, struct ipoib_neigh *neigh);
 
 extern struct workqueue_struct *ipoib_workqueue;
 
+extern int ipoib_mc_sendonly_timeout;
+
 /* functions */
 
 int ipoib_poll(struct napi_struct *napi, int budget);
@@ -453,6 +458,7 @@ int ipoib_dev_init(struct net_device *dev, struct ib_device *ca, int port);
 void ipoib_dev_cleanup(struct net_device *dev);
 
 void ipoib_mcast_join_task(struct work_struct *work);
+void ipoib_mcast_leave_task(struct work_struct *work);
 void ipoib_mcast_carrier_on_task(struct work_struct *work);
 void ipoib_mcast_send(struct net_device *dev, void *mgid, struct sk_buff *skb);
 
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index 7a07a72..563370e 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -67,6 +67,11 @@ module_param_named(debug_level, ipoib_debug_level, int, 0644);
 MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0");
 #endif
 
+int ipoib_mc_sendonly_timeout;
+
+module_param_named(mc_sendonly_timeout, ipoib_mc_sendonly_timeout, int, 0644);
+MODULE_PARM_DESC(mc_sendonly_timeout, "Enable debug tracing if > 0");
+
 struct ipoib_path_iter {
 	struct net_device *dev;
 	struct ipoib_path  path;
@@ -1020,7 +1025,8 @@ static void ipoib_setup(struct net_device *dev)
 	INIT_LIST_HEAD(&priv->multicast_list);
 
 	INIT_DELAYED_WORK(&priv->pkey_poll_task, ipoib_pkey_poll);
-	INIT_DELAYED_WORK(&priv->mcast_task,   ipoib_mcast_join_task);
+	INIT_DELAYED_WORK(&priv->mcast_join_task,   ipoib_mcast_join_task);
+	INIT_DELAYED_WORK(&priv->mcast_leave_task, ipoib_mcast_leave_task);
 	INIT_WORK(&priv->carrier_on_task, ipoib_mcast_carrier_on_task);
 	INIT_WORK(&priv->flush_light,   ipoib_ib_dev_flush_light);
 	INIT_WORK(&priv->flush_normal,   ipoib_ib_dev_flush_normal);
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 3871ac6..87928c1 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -117,6 +117,7 @@ static struct ipoib_mcast *ipoib_mcast_alloc(struct net_device *dev,
 
 	mcast->dev = dev;
 	mcast->created = jiffies;
+	mcast->used = jiffies;
 	mcast->backoff = 1;
 
 	INIT_LIST_HEAD(&mcast->list);
@@ -403,7 +404,7 @@ static int ipoib_mcast_join_complete(int status,
 		mutex_lock(&mcast_mutex);
 		if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
 			queue_delayed_work(ipoib_workqueue,
-					   &priv->mcast_task, 0);
+					   &priv->mcast_join_task, 0);
 		mutex_unlock(&mcast_mutex);
 
 		/*
@@ -436,7 +437,7 @@ static int ipoib_mcast_join_complete(int status,
 	mutex_lock(&mcast_mutex);
 	spin_lock_irq(&priv->lock);
 	if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
-		queue_delayed_work(ipoib_workqueue, &priv->mcast_task,
+		queue_delayed_work(ipoib_workqueue, &priv->mcast_join_task,
 				   mcast->backoff * HZ);
 	spin_unlock_irq(&priv->lock);
 	mutex_unlock(&mcast_mutex);
@@ -505,7 +506,7 @@ static void ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast,
 		mutex_lock(&mcast_mutex);
 		if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
 			queue_delayed_work(ipoib_workqueue,
-					   &priv->mcast_task,
+					   &priv->mcast_join_task,
 					   mcast->backoff * HZ);
 		mutex_unlock(&mcast_mutex);
 	}
@@ -514,7 +515,7 @@ static void ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast,
 void ipoib_mcast_join_task(struct work_struct *work)
 {
 	struct ipoib_dev_priv *priv =
-		container_of(work, struct ipoib_dev_priv, mcast_task.work);
+		container_of(work, struct ipoib_dev_priv, mcast_join_task.work);
 	struct net_device *dev = priv->dev;
 
 	if (!test_bit(IPOIB_MCAST_RUN, &priv->flags))
@@ -546,7 +547,7 @@ void ipoib_mcast_join_task(struct work_struct *work)
 			mutex_lock(&mcast_mutex);
 			if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
 				queue_delayed_work(ipoib_workqueue,
-						   &priv->mcast_task, HZ);
+						   &priv->mcast_join_task, HZ);
 			mutex_unlock(&mcast_mutex);
 			return;
 		}
@@ -610,7 +611,9 @@ int ipoib_mcast_start_thread(struct net_device *dev)
 
 	mutex_lock(&mcast_mutex);
 	if (!test_and_set_bit(IPOIB_MCAST_RUN, &priv->flags))
-		queue_delayed_work(ipoib_workqueue, &priv->mcast_task, 0);
+		queue_delayed_work(ipoib_workqueue, &priv->mcast_join_task, 0);
+	if (!test_and_set_bit(IPOIB_MCAST_RUN_GC, &priv->flags))
+		queue_delayed_work(ipoib_workqueue, &priv->mcast_leave_task, 0);
 	mutex_unlock(&mcast_mutex);
 
 	return 0;
@@ -624,7 +627,9 @@ int ipoib_mcast_stop_thread(struct net_device *dev, int flush)
 
 	mutex_lock(&mcast_mutex);
 	clear_bit(IPOIB_MCAST_RUN, &priv->flags);
-	cancel_delayed_work(&priv->mcast_task);
+	clear_bit(IPOIB_MCAST_RUN_GC, &priv->flags);
+	cancel_delayed_work(&priv->mcast_join_task);
+	cancel_delayed_work(&priv->mcast_leave_task);
 	mutex_unlock(&mcast_mutex);
 
 	if (flush)
@@ -727,7 +732,7 @@ out:
 				list_add_tail(&neigh->list, &mcast->neigh_list);
 			}
 		}
-
+		mcast->used = jiffies;
 		spin_unlock_irqrestore(&priv->lock, flags);
 		ipoib_send(dev, skb, mcast->ah, IB_MULTICAST_QPN);
 		return;
@@ -888,6 +893,35 @@ void ipoib_mcast_restart_task(struct work_struct *work)
 		ipoib_mcast_start_thread(dev);
 }
 
+void ipoib_mcast_leave_task(struct work_struct *work)
+{
+	struct ipoib_dev_priv *priv =
+		container_of(work, struct ipoib_dev_priv, mcast_leave_task.work);
+	struct net_device *dev = priv->dev;
+	struct ipoib_mcast *mcast, *tmcast;
+	LIST_HEAD(remove_list);
+
+	if (!test_bit(IPOIB_MCAST_RUN_GC, &priv->flags))
+		return;
+
+	if (ipoib_mc_sendonly_timeout > 0) {
+		list_for_each_entry_safe(mcast, tmcast, &priv->multicast_list, list) {
+			if (test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags) &&
+			    time_before(mcast->used, jiffies - ipoib_mc_sendonly_timeout * HZ)) {
+				rb_erase(&mcast->rb_node, &priv->multicast_tree);
+				list_move_tail(&mcast->list, &remove_list);
+			}
+		}
+
+		list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {
+			ipoib_mcast_leave(dev, mcast);
+			ipoib_mcast_free(mcast);
+		}
+	}
+
+	queue_delayed_work(ipoib_workqueue, &priv->mcast_leave_task, 60 * HZ);
+}
+
 #ifdef CONFIG_INFINIBAND_IPOIB_DEBUG
 
 struct ipoib_mcast_iter *ipoib_mcast_iter_init(struct net_device *dev)
--
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