Re: [PATCH 1/3] net: introduce a list of device addressesdev_addr_list (v4)

[Jiri Pirko]

Mon, Apr 20, 2009 at 06:11:56PM CEST, jpirko@xxxxxxxxxx wrote:
>How about this (and another 2 patches in patchset)? What's your opinion guys?

Eric, Stephen, Patrick? Can you please look at this? Any objections?
>
>Thanks,
>
>Jirka
>
>Sat, Apr 18, 2009 at 10:58:49AM CEST, jpirko@xxxxxxxxxx wrote:
>>v3 -> v4 (current):
>>-changed kzalloc to kmalloc in __hw_addr_add_ii()
>>-ASSERT_RTNL() avoided in dev_addr_flush() and dev_addr_init()
>>
>>v2 -> v3:
>>-removed unnecessary rcu read locking
>>-moved dev_addr_flush() calling to ensure no null dereference of dev_addr
>>
>>v1 -> v2:
>>-added forgotten ASSERT_RTNL to dev_addr_init and dev_addr_flush
>>-removed unnecessary rcu_read locking in dev_addr_init
>>-use compare_ether_addr_64bits instead of compare_ether_addr
>>-use L1_CACHE_BYTES as size for allocating struct netdev_hw_addr
>>-use call_rcu instead of rcu_synchronize
>>-moved is_etherdev_addr into __KERNEL__ ifdef
>>
>>This patch introduces a new list in struct net_device and brings a set of
>>functions to handle the work with device address list. The list is a replacement
>>for the original dev_addr field and because in some situations there is need to
>>carry several device addresses with the net device. To be backward compatible,
>>dev_addr is made to point to the first member of the list so original drivers
>>sees no difference.
>>
>>Signed-off-by: Jiri Pirko <jpirko@xxxxxxxxxx>
>>---
>> include/linux/etherdevice.h |   27 +++++
>> include/linux/netdevice.h   |   32 +++++-
>> net/core/dev.c              |  261 +++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 318 insertions(+), 2 deletions(-)
>>
>>diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
>>index a1f17ab..3d7a668 100644
>>--- a/include/linux/etherdevice.h
>>+++ b/include/linux/etherdevice.h
>>@@ -182,6 +182,33 @@ static inline unsigned compare_ether_addr_64bits(const u8 addr1[6+2],
>> 	return compare_ether_addr(addr1, addr2);
>> #endif
>> }
>>+
>>+/**
>>+ * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
>>+ * @dev: Pointer to a device structure
>>+ * @addr: Pointer to a six-byte array containing the Ethernet address
>>+ *
>>+ * Compare passed address with all addresses of the device. Return true if the
>>+ * address if one of the device addresses.
>>+ *
>>+ * Note that this function calls compare_ether_addr_64bits() so take care of
>>+ * the right padding.
>>+ */
>>+static inline bool is_etherdev_addr(const struct net_device *dev,
>>+				    const u8 addr[6 + 2])
>>+{
>>+	struct netdev_hw_addr *ha;
>>+	int res = 1;
>>+
>>+	rcu_read_lock();
>>+	for_each_dev_addr(dev, ha) {
>>+		res = compare_ether_addr_64bits(addr, ha->addr);
>>+		if (!res)
>>+			break;
>>+	}
>>+	rcu_read_unlock();
>>+	return !res;
>>+}
>> #endif	/* __KERNEL__ */
>> 
>> /**
>>diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>>index 2e7783f..89ad6d2 100644
>>--- a/include/linux/netdevice.h
>>+++ b/include/linux/netdevice.h
>>@@ -210,6 +210,13 @@ struct dev_addr_list
>> #define dmi_users	da_users
>> #define dmi_gusers	da_gusers
>> 
>>+struct netdev_hw_addr {
>>+	struct list_head	list;
>>+	unsigned char		addr[MAX_ADDR_LEN];
>>+	int			refcount;
>>+	struct rcu_head		rcu_head;
>>+};
>>+
>> struct hh_cache
>> {
>> 	struct hh_cache *hh_next;	/* Next entry			     */
>>@@ -776,8 +783,11 @@ struct net_device
>>  */
>> 	unsigned long		last_rx;	/* Time of last Rx	*/
>> 	/* Interface address info used in eth_type_trans() */
>>-	unsigned char		dev_addr[MAX_ADDR_LEN];	/* hw address, (before bcast
>>-							   because most packets are unicast) */
>>+	unsigned char		*dev_addr;	/* hw address, (before bcast
>>+						   because most packets are
>>+						   unicast) */
>>+
>>+	struct list_head	dev_addr_list; /* list of device hw addresses */
>> 
>> 	unsigned char		broadcast[MAX_ADDR_LEN];	/* hw bcast add	*/
>> 
>>@@ -1778,6 +1788,13 @@ static inline void netif_addr_unlock_bh(struct net_device *dev)
>> 	spin_unlock_bh(&dev->addr_list_lock);
>> }
>> 
>>+/*
>>+ * dev_addr_list walker. Should be used only for read access. Call with
>>+ * rcu_read_lock held.
>>+ */
>>+#define for_each_dev_addr(dev, ha) \
>>+		list_for_each_entry_rcu(ha, &dev->dev_addr_list, list)
>>+
>> /* These functions live elsewhere (drivers/net/net_init.c, but related) */
>> 
>> extern void		ether_setup(struct net_device *dev);
>>@@ -1790,6 +1807,17 @@ extern struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
>> 	alloc_netdev_mq(sizeof_priv, name, setup, 1)
>> extern int		register_netdev(struct net_device *dev);
>> extern void		unregister_netdev(struct net_device *dev);
>>+
>>+/* Functions used for device addresses handling */
>>+extern int		dev_addr_add(struct net_device *dev,
>>+				     unsigned char *addr);
>>+extern int		dev_addr_del(struct net_device *dev,
>>+				     unsigned char *addr);
>>+extern int		dev_addr_add_multiple(struct net_device *to_dev,
>>+					      struct net_device *from_dev);
>>+extern int		dev_addr_del_multiple(struct net_device *to_dev,
>>+					      struct net_device *from_dev);
>>+
>> /* Functions used for secondary unicast and multicast support */
>> extern void		dev_set_rx_mode(struct net_device *dev);
>> extern void		__dev_set_rx_mode(struct net_device *dev);
>>diff --git a/net/core/dev.c b/net/core/dev.c
>>index 343883f..2274294 100644
>>--- a/net/core/dev.c
>>+++ b/net/core/dev.c
>>@@ -3438,6 +3438,263 @@ void dev_set_rx_mode(struct net_device *dev)
>> 	netif_addr_unlock_bh(dev);
>> }
>> 
>>+/* hw addresses list handling functions */
>>+
>>+static int __hw_addr_add_ii(struct list_head *list, unsigned char *addr,
>>+			    int addr_len, int ignore_index)
>>+{
>>+	struct netdev_hw_addr *ha;
>>+	int i = 0;
>>+
>>+	if (addr_len > MAX_ADDR_LEN)
>>+		return -EINVAL;
>>+
>>+	list_for_each_entry(ha, list, list) {
>>+		if (i++ != ignore_index &&
>>+		    !memcmp(ha->addr, addr, addr_len)) {
>>+			ha->refcount++;
>>+			return 0;
>>+		}
>>+	}
>>+
>>+	ha = kmalloc(max(sizeof(*ha), L1_CACHE_BYTES), GFP_ATOMIC);
>>+	if (!ha)
>>+		return -ENOMEM;
>>+	memcpy(ha->addr, addr, addr_len);
>>+	ha->refcount = 1;
>>+	list_add_tail_rcu(&ha->list, list);
>>+	return 0;
>>+}
>>+
>>+static int __hw_addr_add(struct list_head *list, unsigned char *addr,
>>+			 int addr_len)
>>+{
>>+	return __hw_addr_add_ii(list, addr, addr_len, -1);
>>+}
>>+
>>+static void ha_rcu_free(struct rcu_head *head)
>>+{
>>+	struct netdev_hw_addr *ha;
>>+
>>+	ha = container_of(head, struct netdev_hw_addr, rcu_head);
>>+	kfree(ha);
>>+}
>>+
>>+static int __hw_addr_del_ii(struct list_head *list, unsigned char *addr,
>>+			    int addr_len, int ignore_index)
>>+{
>>+	struct netdev_hw_addr *ha;
>>+	int i = 0;
>>+
>>+	list_for_each_entry(ha, list, list) {
>>+		if (i++ != ignore_index &&
>>+		    !memcmp(ha->addr, addr, addr_len)) {
>>+			if (--ha->refcount)
>>+				return 0;
>>+			list_del_rcu(&ha->list);
>>+			call_rcu(&ha->rcu_head, ha_rcu_free);
>>+			return 0;
>>+		}
>>+	}
>>+	return -ENOENT;
>>+}
>>+
>>+static int __hw_addr_del(struct list_head *list, unsigned char *addr,
>>+			 int addr_len)
>>+{
>>+	return __hw_addr_del_ii(list, addr, addr_len, -1);
>>+}
>>+
>>+static int __hw_addr_add_multiple_ii(struct list_head *to_list,
>>+				     struct list_head *from_list,
>>+				     int addr_len, int ignore_index)
>>+{
>>+	int err;
>>+	struct netdev_hw_addr *ha, *ha2;
>>+
>>+	list_for_each_entry(ha, from_list, list) {
>>+		err = __hw_addr_add_ii(to_list, ha->addr, addr_len, 0);
>>+		if (err)
>>+			goto unroll;
>>+	}
>>+	return 0;
>>+
>>+unroll:
>>+	list_for_each_entry(ha2, from_list, list) {
>>+		if (ha2 == ha)
>>+			break;
>>+		__hw_addr_del_ii(to_list, ha2->addr, addr_len, 0);
>>+	}
>>+	return err;
>>+}
>>+
>>+static int __hw_addr_add_multiple(struct list_head *to_list,
>>+					 struct list_head *from_list,
>>+					 int addr_len)
>>+{
>>+	return __hw_addr_add_multiple_ii(to_list, from_list, addr_len, -1);
>>+}
>>+
>>+static void __hw_addr_del_multiple_ii(struct list_head *to_list,
>>+				      struct list_head *from_list,
>>+				      int addr_len, int ignore_index)
>>+{
>>+	struct netdev_hw_addr *ha;
>>+
>>+	list_for_each_entry(ha, from_list, list) {
>>+		__hw_addr_del_ii(to_list, ha->addr, addr_len, 0);
>>+	}
>>+}
>>+
>>+static void __hw_addr_del_multiple(struct list_head *to_list,
>>+					 struct list_head *from_list,
>>+					 int addr_len)
>>+{
>>+	__hw_addr_del_multiple_ii(to_list, from_list, addr_len, -1);
>>+}
>>+
>>+static void __hw_addr_flush(struct list_head *list)
>>+{
>>+	struct netdev_hw_addr *ha, *tmp;
>>+
>>+	list_for_each_entry_safe(ha, tmp, list, list) {
>>+		list_del_rcu(&ha->list);
>>+		call_rcu(&ha->rcu_head, ha_rcu_free);
>>+	}
>>+}
>>+
>>+/* Device addresses handling functions */
>>+
>>+static void dev_addr_flush(struct net_device *dev)
>>+{
>>+	/* rtnl_mutex must be held here */
>>+
>>+	__hw_addr_flush(&dev->dev_addr_list);
>>+	dev->dev_addr = NULL;
>>+}
>>+
>>+static int dev_addr_init(struct net_device *dev)
>>+{
>>+	unsigned char addr[MAX_ADDR_LEN];
>>+	struct netdev_hw_addr *ha;
>>+	int err;
>>+
>>+	/* rtnl_mutex must be held here */
>>+
>>+	INIT_LIST_HEAD(&dev->dev_addr_list);
>>+	memset(addr, 0, sizeof(*addr));
>>+	err = __hw_addr_add(&dev->dev_addr_list, addr, sizeof(*addr));
>>+	if (!err) {
>>+		/*
>>+		 * Get the first (previously created) address from the list
>>+		 * and set dev_addr pointer to this location.
>>+		 */
>>+		ha = list_first_entry(&dev->dev_addr_list,
>>+				      struct netdev_hw_addr, list);
>>+		dev->dev_addr = ha->addr;
>>+	}
>>+	return err;
>>+}
>>+
>>+/**
>>+ *	dev_addr_add	- Add a device address
>>+ *	@dev: device
>>+ *	@addr: address to add
>>+ *
>>+ *	Add a device address to the device or increase the reference count if
>>+ *	it already exists.
>>+ *
>>+ *	The caller must hold the rtnl_mutex.
>>+ */
>>+int dev_addr_add(struct net_device *dev, unsigned char *addr)
>>+{
>>+	int err;
>>+
>>+	ASSERT_RTNL();
>>+
>>+	err = __hw_addr_add_ii(&dev->dev_addr_list, addr, dev->addr_len, 0);
>>+	if (!err)
>>+		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
>>+	return err;
>>+}
>>+EXPORT_SYMBOL(dev_addr_add);
>>+
>>+/**
>>+ *	dev_addr_del	- Release a device address.
>>+ *	@dev: device
>>+ *	@addr: address to delete
>>+ *
>>+ *	Release reference to a device address and remove it from the device
>>+ *	if the reference count drops to zero.
>>+ *
>>+ *	The caller must hold the rtnl_mutex.
>>+ */
>>+int dev_addr_del(struct net_device *dev, unsigned char *addr)
>>+{
>>+	int err;
>>+
>>+	ASSERT_RTNL();
>>+
>>+	err = __hw_addr_del_ii(&dev->dev_addr_list, addr, dev->addr_len, 0);
>>+	if (!err)
>>+		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
>>+	return err;
>>+}
>>+EXPORT_SYMBOL(dev_addr_del);
>>+
>>+/**
>>+ *	dev_addr_add_multiple	- Add device addresses from another device
>>+ *	@to_dev: device to which addresses will be added
>>+ *	@from_dev: device from which addresses will be added
>>+ *
>>+ *	Add device addresses of the one device to another.
>>+ *
>>+ *	The caller must hold the rtnl_mutex.
>>+ */
>>+int dev_addr_add_multiple(struct net_device *to_dev,
>>+			  struct net_device *from_dev)
>>+{
>>+	int err;
>>+
>>+	ASSERT_RTNL();
>>+
>>+	if (from_dev->addr_len != to_dev->addr_len)
>>+		return -EINVAL;
>>+	err = __hw_addr_add_multiple_ii(&to_dev->dev_addr_list,
>>+					&from_dev->dev_addr_list,
>>+					to_dev->addr_len, 0);
>>+	if (!err)
>>+		call_netdevice_notifiers(NETDEV_CHANGEADDR, to_dev);
>>+	return err;
>>+}
>>+EXPORT_SYMBOL(dev_addr_add_multiple);
>>+
>>+/**
>>+ *	dev_addr_del_multiple	- Delete device addresses by another device
>>+ *	@to_dev: device where the addresses will be deleted
>>+ *	@from_dev: device by which addresses the addresses will be deleted
>>+ *
>>+ *	Deletes addresses in to device by the list of addresses in from device.
>>+ *
>>+ *	The caller must hold the rtnl_mutex.
>>+ */
>>+int dev_addr_del_multiple(struct net_device *to_dev,
>>+			  struct net_device *from_dev)
>>+{
>>+	ASSERT_RTNL();
>>+
>>+	if (from_dev->addr_len != to_dev->addr_len)
>>+		return -EINVAL;
>>+	__hw_addr_add_multiple_ii(&to_dev->dev_addr_list,
>>+				  &from_dev->dev_addr_list,
>>+				  to_dev->addr_len, 0);
>>+	call_netdevice_notifiers(NETDEV_CHANGEADDR, to_dev);
>>+	return 0;
>>+}
>>+EXPORT_SYMBOL(dev_addr_del_multiple);
>>+
>>+/* unicast and multicast addresses handling functions */
>>+
>> int __dev_addr_delete(struct dev_addr_list **list, int *count,
>> 		      void *addr, int alen, int glbl)
>> {
>>@@ -4780,6 +5037,7 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
>> 
>> 	dev->gso_max_size = GSO_MAX_SIZE;
>> 
>>+	dev_addr_init(dev);
>> 	netdev_init_queues(dev);
>> 
>> 	INIT_LIST_HEAD(&dev->napi_list);
>>@@ -4805,6 +5063,9 @@ void free_netdev(struct net_device *dev)
>> 
>> 	kfree(dev->_tx);
>> 
>>+	/* Flush device addresses */
>>+	dev_addr_flush(dev);
>>+
>> 	list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
>> 		netif_napi_del(p);
>> 
>>-- 
>>1.6.0.6
>>
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