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 *,
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 678b6ee..12025ee 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -156,6 +156,7 @@
INIT_LIST_HEAD(&xprt->xpt_list);
INIT_LIST_HEAD(&xprt->xpt_ready);
INIT_LIST_HEAD(&xprt->xpt_deferred);
+ INIT_LIST_HEAD(&xprt->xpt_users);
mutex_init(&xprt->xpt_mutex);
spin_lock_init(&xprt->xpt_lock);
set_bit(XPT_BUSY, &xprt->xpt_flags);
@@ -881,6 +882,19 @@
mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
}
+static void call_xpt_users(struct svc_xprt *xprt)
+{
+ struct svc_xpt_user *u;
+
+ spin_lock(&xprt->xpt_lock);
+ while (!list_empty(&xprt->xpt_users)) {
+ u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
+ list_del(&u->list);
+ u->callback(u);
+ }
+ spin_unlock(&xprt->xpt_lock);
+}
+
/*
* Remove a dead transport
*/
@@ -913,6 +927,7 @@
while ((dr = svc_deferred_dequeue(xprt)) != NULL)
kfree(dr);
+ call_xpt_users(xprt);
svc_xprt_put(xprt);
}