netlink: mmaped netlink: ring setup

Add support for mmap'ed RX and TX ring setup and teardown based on the
af_packet.c code. The following patches will use this to add the real
mmap'ed receive and transmit functionality.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 0 deletions

diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h
index d9acb2a1d855..ed8522265f4e 100644
--- a/net/netlink/af_netlink.h
+++ b/net/netlink/af_netlink.h
@@ -6,6 +6,20 @@
 #define NLGRPSZ(x)      (ALIGN(x, sizeof(unsigned long) * 8) / 8)
 #define NLGRPLONGS(x)   (NLGRPSZ(x)/sizeof(unsigned long))
 
+struct netlink_ring {
+        void                    **pg_vec;
+        unsigned int            head;
+        unsigned int            frames_per_block;
+        unsigned int            frame_size;
+        unsigned int            frame_max;
+
+        unsigned int            pg_vec_order;
+        unsigned int            pg_vec_pages;
+        unsigned int            pg_vec_len;
+
+        atomic_t                pending;
+};
+
 struct netlink_sock {
         /* struct sock has to be the first member of netlink_sock */
         struct sock             sk;
@@ -24,6 +38,12 @@ struct netlink_sock {
         void                    (*netlink_rcv)(struct sk_buff *skb);
         void                    (*netlink_bind)(int group);
         struct module           *module;
+#ifdef CONFIG_NETLINK_MMAP
+        struct mutex            pg_vec_lock;
+        struct netlink_ring     rx_ring;
+        struct netlink_ring     tx_ring;
+        atomic_t                mapped;
+#endif /* CONFIG_NETLINK_MMAP */
 };
 
 static inline struct netlink_sock *nlk_sk(struct sock *sk)