3 files changed, 81 insertions, 0 deletions

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index c7a1095ed84..2559fb53983 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -15,6 +15,7 @@
 #include <linux/igmp.h>
 #include <linux/jhash.h>
 #include <linux/kernel.h>
+#include <linux/log2.h>
 #include <linux/netdevice.h>
 #include <linux/netfilter_bridge.h>
 #include <linux/random.h>
@@ -1261,3 +1262,43 @@ unlock:
 
 	return err;
 }
+
+int br_multicast_set_hash_max(struct net_bridge *br, unsigned long val)
+{
+	int err = -ENOENT;
+	u32 old;
+
+	spin_lock(&br->multicast_lock);
+	if (!netif_running(br->dev))
+		goto unlock;
+
+	err = -EINVAL;
+	if (!is_power_of_2(val))
+		goto unlock;
+	if (br->mdb && val < br->mdb->size)
+		goto unlock;
+
+	err = 0;
+
+	old = br->hash_max;
+	br->hash_max = val;
+
+	if (br->mdb) {
+		if (br->mdb->old) {
+			err = -EEXIST;
+rollback:
+			br->hash_max = old;
+			goto unlock;
+		}
+
+		err = br_mdb_rehash(&br->mdb, br->hash_max,
+				    br->hash_elasticity);
+		if (err)
+			goto rollback;
+	}
+
+unlock:
+	spin_unlock(&br->multicast_lock);
+
+	return err;
+}
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index bf162fa6b23..9191198c4f1 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -301,6 +301,7 @@ extern int br_multicast_set_router(struct net_bridge *br, unsigned long val);
 extern int br_multicast_set_port_router(struct net_bridge_port *p,
 					unsigned long val);
 extern int br_multicast_toggle(struct net_bridge *br, unsigned long val);
+extern int br_multicast_set_hash_max(struct net_bridge *br, unsigned long val);
 #else
 static inline int br_multicast_rcv(struct net_bridge *br,
 				   struct net_bridge_port *port,
diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 0ab288332fc..d2ee53b3ad7 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -378,6 +378,43 @@ static ssize_t store_multicast_snooping(struct device *d,
 }
 static DEVICE_ATTR(multicast_snooping, S_IRUGO | S_IWUSR,
 		   show_multicast_snooping, store_multicast_snooping);
+
+static ssize_t show_hash_elasticity(struct device *d,
+				    struct device_attribute *attr, char *buf)
+{
+	struct net_bridge *br = to_bridge(d);
+	return sprintf(buf, "%u\n", br->hash_elasticity);
+}
+
+static int set_elasticity(struct net_bridge *br, unsigned long val)
+{
+	br->hash_elasticity = val;
+	return 0;
+}
+
+static ssize_t store_hash_elasticity(struct device *d,
+				     struct device_attribute *attr,
+				     const char *buf, size_t len)
+{
+	return store_bridge_parm(d, buf, len, set_elasticity);
+}
+static DEVICE_ATTR(hash_elasticity, S_IRUGO | S_IWUSR, show_hash_elasticity,
+		   store_hash_elasticity);
+
+static ssize_t show_hash_max(struct device *d, struct device_attribute *attr,
+			     char *buf)
+{
+	struct net_bridge *br = to_bridge(d);
+	return sprintf(buf, "%u\n", br->hash_max);
+}
+
+static ssize_t store_hash_max(struct device *d, struct device_attribute *attr,
+			      const char *buf, size_t len)
+{
+	return store_bridge_parm(d, buf, len, br_multicast_set_hash_max);
+}
+static DEVICE_ATTR(hash_max, S_IRUGO | S_IWUSR, show_hash_max,
+		   store_hash_max);
 #endif
 
 static struct attribute *bridge_attrs[] = {
@@ -402,6 +439,8 @@ static struct attribute *bridge_attrs[] = {
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	&dev_attr_multicast_router.attr,
 	&dev_attr_multicast_snooping.attr,
+	&dev_attr_hash_elasticity.attr,
+	&dev_attr_hash_max.attr,
 #endif
 	NULL
 };