net: Add generic packet offload infrastructure.

Create a new data structure to contain the GRO/GSO callbacks and add
a new registration mechanism.

Singed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7bf867c970432af72255fa7c32542746309f8124..d45a58db4ba3a8bf317b6810650d981926661e69 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1521,6 +1521,17 @@ struct packet_type {
        struct list_head        list;
 };
 
+struct packet_offload {
+       __be16                  type;   /* This is really htons(ether_type). */
+       struct sk_buff          *(*gso_segment)(struct sk_buff *skb,
+                                               netdev_features_t features);
+       int                     (*gso_send_check)(struct sk_buff *skb);
+       struct sk_buff          **(*gro_receive)(struct sk_buff **head,
+                                              struct sk_buff *skb);
+       int                     (*gro_complete)(struct sk_buff *skb);
+       struct list_head        list;
+};
+
 #include <linux/notifier.h>
 
 /* netdevice notifier chain. Please remember to update the rtnetlink
@@ -1615,6 +1626,9 @@ extern struct net_device *__dev_getfirstbyhwtype(struct net *net, unsigned short
 extern void            dev_add_pack(struct packet_type *pt);
 extern void            dev_remove_pack(struct packet_type *pt);
 extern void            __dev_remove_pack(struct packet_type *pt);
+extern void            dev_add_offload(struct packet_offload *po);
+extern void            dev_remove_offload(struct packet_offload *po);
+extern void            __dev_remove_offload(struct packet_offload *po);
 
 extern struct net_device       *dev_get_by_flags_rcu(struct net *net, unsigned short flags,
                                                      unsigned short mask);

diff --git a/net/core/dev.c b/net/core/dev.c
index 83232a1be1e774192964ad7dea88b302aba2fdea..6884f8783bdd058e004cba477284cddc6214509f 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -176,8 +176,10 @@
 #define PTYPE_HASH_MASK        (PTYPE_HASH_SIZE - 1)
 
 static DEFINE_SPINLOCK(ptype_lock);
+static DEFINE_SPINLOCK(offload_lock);
 static struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly;
 static struct list_head ptype_all __read_mostly;       /* Taps */
+static struct list_head offload_base __read_mostly;
 
 /*
  * The @dev_base_head list is protected by @dev_base_lock and the rtnl
@@ -470,6 +472,82 @@ void dev_remove_pack(struct packet_type *pt)
 }
 EXPORT_SYMBOL(dev_remove_pack);
 
+
+/**
+ *     dev_add_offload - register offload handlers
+ *     @po: protocol offload declaration
+ *
+ *     Add protocol offload handlers to the networking stack. The passed
+ *     &proto_offload is linked into kernel lists and may not be freed until
+ *     it has been removed from the kernel lists.
+ *
+ *     This call does not sleep therefore it can not
+ *     guarantee all CPU's that are in middle of receiving packets
+ *     will see the new offload handlers (until the next received packet).
+ */
+void dev_add_offload(struct packet_offload *po)
+{
+       struct list_head *head = &offload_base;
+
+       spin_lock(&offload_lock);
+       list_add_rcu(&po->list, head);
+       spin_unlock(&offload_lock);
+}
+EXPORT_SYMBOL(dev_add_offload);
+
+/**
+ *     __dev_remove_offload     - remove offload handler
+ *     @po: packet offload declaration
+ *
+ *     Remove a protocol offload handler that was previously added to the
+ *     kernel offload handlers by dev_add_offload(). The passed &offload_type
+ *     is removed from the kernel lists and can be freed or reused once this
+ *     function returns.
+ *
+ *      The packet type might still be in use by receivers
+ *     and must not be freed until after all the CPU's have gone
+ *     through a quiescent state.
+ */
+void __dev_remove_offload(struct packet_offload *po)
+{
+       struct list_head *head = &offload_base;
+       struct packet_offload *po1;
+
+       spin_lock(&ptype_lock);
+
+       list_for_each_entry(po1, head, list) {
+               if (po == po1) {
+                       list_del_rcu(&po->list);
+                       goto out;
+               }
+       }
+
+       pr_warn("dev_remove_offload: %p not found\n", po);
+out:
+       spin_unlock(&ptype_lock);
+}
+EXPORT_SYMBOL(__dev_remove_offload);
+
+/**
+ *     dev_remove_offload       - remove packet offload handler
+ *     @po: packet offload declaration
+ *
+ *     Remove a packet offload handler that was previously added to the kernel
+ *     offload handlers by dev_add_offload(). The passed &offload_type is
+ *     removed from the kernel lists and can be freed or reused once this
+ *     function returns.
+ *
+ *     This call sleeps to guarantee that no CPU is looking at the packet
+ *     type after return.
+ */
+void dev_remove_offload(struct packet_offload *po)
+{
+       __dev_remove_offload(po);
+
+       synchronize_net();
+}
+EXPORT_SYMBOL(dev_remove_offload);
+
 /******************************************************************************
 
                      Device Boot-time Settings Routines
@@ -6661,6 +6739,8 @@ static int __init net_dev_init(void)
        for (i = 0; i < PTYPE_HASH_SIZE; i++)
                INIT_LIST_HEAD(&ptype_base[i]);
 
+       INIT_LIST_HEAD(&offload_base);
+
        if (register_pernet_subsys(&netdev_net_ops))
                goto out;