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 <jpi...@redhat.com>
---
 include/linux/netdevice.h |   51 +++++++++-
 net/core/dev.c            |  264 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 313 insertions(+), 2 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ff8db51..8cf62f1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -210,6 +210,12 @@ struct dev_addr_list
 #define dmi_users      da_users
 #define dmi_gusers     da_gusers
 
+struct hw_addr {
+       struct list_head        list;
+       unsigned char           addr[MAX_ADDR_LEN];
+       int                     refcount;
+};
+
 struct hh_cache
 {
        struct hh_cache *hh_next;       /* Next entry                        */
@@ -776,8 +782,12 @@ 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 */
+       spinlock_t              dev_addr_list_lock;
 
        unsigned char           broadcast[MAX_ADDR_LEN];        /* hw bcast add 
*/
 
@@ -1779,6 +1789,32 @@ static inline void netif_addr_unlock_bh(struct 
net_device *dev)
        spin_unlock_bh(&dev->addr_list_lock);
 }
 
+/* Locking helpers for spinlock guarding dev_addr_list */
+
+static inline void netif_dev_addr_lock(struct net_device *dev)
+{
+       spin_lock(&dev->dev_addr_list_lock);
+}
+
+static inline void netif_dev_addr_lock_bh(struct net_device *dev)
+{
+       spin_lock_bh(&dev->dev_addr_list_lock);
+}
+
+static inline void netif_dev_addr_unlock(struct net_device *dev)
+{
+       spin_unlock(&dev->dev_addr_list_lock);
+}
+
+static inline void netif_dev_addr_unlock_bh(struct net_device *dev)
+{
+       spin_unlock_bh(&dev->dev_addr_list_lock);
+}
+
+/* dev_addr_list walker */
+#define for_each_dev_addr(dev, ha) \
+               list_for_each_entry(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);
@@ -1791,6 +1827,17 @@ 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 1adc89b..0b154b3 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3437,6 +3437,263 @@ 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 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 = kzalloc(sizeof(*ha), GFP_ATOMIC);
+       if (!ha)
+               return -ENOMEM;
+       memcpy(ha->addr, addr, addr_len);
+       ha->refcount = 1;
+       list_add_tail(&ha->list, list);
+       return 0;
+}
+
+static inline 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 int __hw_addr_del_ii(struct list_head *list, unsigned char *addr,
+                           int addr_len, int ignore_index)
+{
+       struct 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(&ha->list);
+                       kfree(ha);
+                       return 0;
+               }
+       }
+       return -ENOENT;
+}
+
+static inline 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 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 inline 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 hw_addr *ha;
+
+       list_for_each_entry(ha, from_list, list) {
+               __hw_addr_del_ii(to_list, ha->addr, addr_len, 0);
+       }
+}
+
+static inline 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 hw_addr *ha, *tmp;
+
+       list_for_each_entry_safe(ha, tmp, list, list) {
+               list_del(&ha->list);
+       }
+}
+
+/* Device addresses handling functions */
+
+static void dev_addr_flush(struct net_device *dev)
+{
+       netif_dev_addr_lock_bh(dev);
+       __hw_addr_flush(&dev->dev_addr_list);
+       dev->dev_addr = NULL;
+       netif_dev_addr_unlock_bh(dev);
+}
+
+static int dev_addr_init(struct net_device *dev)
+{
+       unsigned char addr[MAX_ADDR_LEN];
+       struct hw_addr *ha;
+       int err;
+
+       spin_lock_init(&dev->dev_addr_list_lock);
+       INIT_LIST_HEAD(&dev->dev_addr_list);
+       memset(addr, 0, sizeof(*addr));
+       netif_dev_addr_lock_bh(dev);
+       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 hw_addr, list);
+               dev->dev_addr = ha->addr;
+       }
+       netif_dev_addr_unlock_bh(dev);
+       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();
+
+       netif_dev_addr_lock_bh(dev);
+       err = __hw_addr_add_ii(&dev->dev_addr_list, addr, dev->addr_len, 0);
+       netif_dev_addr_unlock_bh(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();
+
+       netif_dev_addr_lock_bh(dev);
+       err = __hw_addr_del_ii(&dev->dev_addr_list, addr, dev->addr_len, 0);
+       netif_dev_addr_unlock_bh(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;
+
+       netif_dev_addr_lock_bh(from_dev);
+       netif_dev_addr_lock_bh(to_dev);
+       err = __hw_addr_add_multiple_ii(&to_dev->dev_addr_list,
+                                       &from_dev->dev_addr_list,
+                                       to_dev->addr_len, 0);
+       netif_dev_addr_unlock_bh(to_dev);
+       netif_dev_addr_unlock_bh(from_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;
+
+       netif_dev_addr_lock_bh(from_dev);
+       netif_dev_addr_lock_bh(to_dev);
+       __hw_addr_add_multiple_ii(&to_dev->dev_addr_list,
+                                 &from_dev->dev_addr_list,
+                                 to_dev->addr_len, 0);
+       netif_dev_addr_unlock_bh(to_dev);
+       netif_dev_addr_unlock_bh(from_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)
 {
@@ -4269,6 +4526,9 @@ static void rollback_registered(struct net_device *dev)
         */
        dev_addr_discard(dev);
 
+       /* Flush device addresses */
+       dev_addr_flush(dev);
+
        if (dev->netdev_ops->ndo_uninit)
                dev->netdev_ops->ndo_uninit(dev);
 
@@ -4791,6 +5051,7 @@ 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);
@@ -4977,6 +5238,9 @@ int dev_change_net_namespace(struct net_device *dev, 
struct net *net, const char
         */
        dev_addr_discard(dev);
 
+       /* Flush device addresses */
+       dev_addr_flush(dev);
+
        netdev_unregister_kobject(dev);
 
        /* Actually switch the network namespace */
-- 
1.6.0.6

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