nfsd: provide callbacks on svc_xprt deletion
NFSv4.1 needs warning when a client tcp connection goes down, if that
connection is being used as a backchannel, so that it can warn the
client that it has lost the backchannel connection.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index bb18297..bbdb680 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -33,6 +33,16 @@
u32 xcl_max_payload;
};
+/*
+ * This is embedded in an object that wants a callback before deleting
+ * an xprt; intended for use by NFSv4.1, which needs to know when a
+ * client's tcp connection (and hence possibly a backchannel) goes away.
+ */
+struct svc_xpt_user {
+ struct list_head list;
+ void (*callback)(struct svc_xpt_user *);
+};
+
struct svc_xprt {
struct svc_xprt_class *xpt_class;
struct svc_xprt_ops *xpt_ops;
@@ -67,10 +77,25 @@
struct sockaddr_storage xpt_remote; /* remote peer's address */
size_t xpt_remotelen; /* length of address */
struct rpc_wait_queue xpt_bc_pending; /* backchannel wait queue */
+ struct list_head xpt_users; /* callbacks on free */
struct net *xpt_net;
};
+static inline void register_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u)
+{
+ spin_lock(&xpt->xpt_lock);
+ list_add(&u->list, &xpt->xpt_users);
+ spin_unlock(&xpt->xpt_lock);
+}
+
+static inline void unregister_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u)
+{
+ spin_lock(&xpt->xpt_lock);
+ list_del_init(&u->list);
+ spin_unlock(&xpt->xpt_lock);
+}
+
int svc_reg_xprt_class(struct svc_xprt_class *);
void svc_unreg_xprt_class(struct svc_xprt_class *);
void svc_xprt_init(struct svc_xprt_class *, struct svc_xprt *,