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    Subject[PATCH 1/3] net: introduce a list of device addresses dev_addr_list (v3)
    v2 -> v3 (current):
    -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@redhat.com>
    ---
    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..b4503ac 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 = kzalloc(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)
    +{
    + ASSERT_RTNL();
    +
    + __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;
    +
    + ASSERT_RTNL();
    +
    + 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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