Merge branch 'MCTP-flow-support'

Jeremy Kerr says:

====================
MCTP flow support

For certain MCTP transport bindings, the binding driver will need to be
aware of request/response pairing. For example, the i2c binding may need
to set multiplexer configuration when expecting a response from a device
behind a mux.

This series implements a mechanism for informing the driver about these
flows, so it can implement transport-specific behaviour when a flow is
in progress (ie, a response is expected, and/or we time-out on that
expectation). We use a skb extension to notify the driver about the
presence of a flow, and a new dev->ops callback to notify about a flow's
destruction.
====================

Signed-off-by: David S. Miller <[email protected]>

3 files changed, 32 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index cb96f1e6460c..0bd6520329f6 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4244,6 +4244,9 @@ enum skb_ext_id {
 #if IS_ENABLED(CONFIG_MPTCP)
 	SKB_EXT_MPTCP,
 #endif
+#if IS_ENABLED(CONFIG_MCTP_FLOWS)
+	SKB_EXT_MCTP,
+#endif
 	SKB_EXT_NUM, /* must be last */
 };
 
diff --git a/include/net/mctp.h b/include/net/mctp.h
index 23bec708f4c7..7e35ec79b909 100644
--- a/include/net/mctp.h
+++ b/include/net/mctp.h
@@ -152,6 +152,12 @@ struct mctp_sk_key {
 
 	/* expiry timeout; valid (above) cleared on expiry */
 	unsigned long	expiry;
+
+	/* free to use for device flow state tracking. Initialised to
+	 * zero on initial key creation
+	 */
+	unsigned long	dev_flow_state;
+	struct mctp_dev	*dev;
 };
 
 struct mctp_skb_cb {
@@ -189,6 +195,13 @@ static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb)
 	return (void *)(skb->cb);
 }
 
+/* If CONFIG_MCTP_FLOWS, we may add one of these as a SKB extension,
+ * indicating the flow to the device driver.
+ */
+struct mctp_flow {
+	struct mctp_sk_key *key;
+};
+
 /* Route definition.
  *
  * These are held in the pernet->mctp.routes list, with RCU protection for
diff --git a/include/net/mctpdevice.h b/include/net/mctpdevice.h
index 3a439463f055..5c0d04b5c12c 100644
--- a/include/net/mctpdevice.h
+++ b/include/net/mctpdevice.h
@@ -14,6 +14,8 @@
 #include <linux/types.h>
 #include <linux/refcount.h>
 
+struct mctp_sk_key;
+
 struct mctp_dev {
 	struct net_device	*dev;
 
@@ -21,6 +23,8 @@ struct mctp_dev {
 
 	unsigned int		net;
 
+	const struct mctp_netdev_ops *ops;
+
 	/* Only modified under RTNL. Reads have addrs_lock held */
 	u8			*addrs;
 	size_t			num_addrs;
@@ -29,12 +33,24 @@ struct mctp_dev {
 	struct rcu_head		rcu;
 };
 
+struct mctp_netdev_ops {
+	void			(*release_flow)(struct mctp_dev *dev,
+						struct mctp_sk_key *key);
+};
+
 #define MCTP_INITIAL_DEFAULT_NET	1
 
 struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev);
 struct mctp_dev *__mctp_dev_get(const struct net_device *dev);
 
+int mctp_register_netdev(struct net_device *dev,
+			 const struct mctp_netdev_ops *ops);
+void mctp_unregister_netdev(struct net_device *dev);
+
 void mctp_dev_hold(struct mctp_dev *mdev);
 void mctp_dev_put(struct mctp_dev *mdev);
 
+void mctp_dev_set_key(struct mctp_dev *dev, struct mctp_sk_key *key);
+void mctp_dev_release_key(struct mctp_dev *dev, struct mctp_sk_key *key);
+
 #endif /* __NET_MCTPDEVICE_H */