SUNRPC: Add refcounting to the struct rpc_xprt
In a subsequent patch, this will allow the portmapper to take a reference
to the rpc_xprt for which it is updating the port number, fixing an Oops.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index de4efea..bdeba85 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -12,6 +12,7 @@
#include <linux/uio.h>
#include <linux/socket.h>
#include <linux/in.h>
+#include <linux/kref.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/xdr.h>
@@ -129,6 +130,7 @@
};
struct rpc_xprt {
+ struct kref kref; /* Reference count */
struct rpc_xprt_ops * ops; /* transport methods */
struct socket * sock; /* BSD socket layer */
struct sock * inet; /* INET layer */
@@ -248,7 +250,8 @@
void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
void xprt_release(struct rpc_task *task);
-int xprt_destroy(struct rpc_xprt *xprt);
+struct rpc_xprt * xprt_get(struct rpc_xprt *xprt);
+void xprt_put(struct rpc_xprt *xprt);
static inline u32 *xprt_skip_transport_header(struct rpc_xprt *xprt, u32 *p)
{
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index ceadb72..084a0ad 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -177,7 +177,7 @@
kfree(clnt->cl_server);
kfree(clnt);
out_err:
- xprt_destroy(xprt);
+ xprt_put(xprt);
out_no_xprt:
return ERR_PTR(err);
}
@@ -261,6 +261,7 @@
atomic_set(&new->cl_users, 0);
new->cl_parent = clnt;
atomic_inc(&clnt->cl_count);
+ new->cl_xprt = xprt_get(clnt->cl_xprt);
/* Turn off autobind on clones */
new->cl_autobind = 0;
new->cl_oneshot = 0;
@@ -337,15 +338,12 @@
rpc_rmdir(clnt->cl_dentry);
rpc_put_mount();
}
- if (clnt->cl_xprt) {
- xprt_destroy(clnt->cl_xprt);
- clnt->cl_xprt = NULL;
- }
if (clnt->cl_server != clnt->cl_inline_name)
kfree(clnt->cl_server);
out_free:
rpc_free_iostats(clnt->cl_metrics);
clnt->cl_metrics = NULL;
+ xprt_put(clnt->cl_xprt);
kfree(clnt);
return 0;
}
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index a85f82b..1f786f6 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -926,6 +926,7 @@
return ERR_PTR(result);
}
+ kref_init(&xprt->kref);
spin_lock_init(&xprt->transport_lock);
spin_lock_init(&xprt->reserve_lock);
@@ -958,16 +959,37 @@
/**
* xprt_destroy - destroy an RPC transport, killing off all requests.
- * @xprt: transport to destroy
+ * @kref: kref for the transport to destroy
*
*/
-int xprt_destroy(struct rpc_xprt *xprt)
+static void xprt_destroy(struct kref *kref)
{
+ struct rpc_xprt *xprt = container_of(kref, struct rpc_xprt, kref);
+
dprintk("RPC: destroying transport %p\n", xprt);
xprt->shutdown = 1;
del_timer_sync(&xprt->timer);
xprt->ops->destroy(xprt);
kfree(xprt);
+}
- return 0;
+/**
+ * xprt_put - release a reference to an RPC transport.
+ * @xprt: pointer to the transport
+ *
+ */
+void xprt_put(struct rpc_xprt *xprt)
+{
+ kref_put(&xprt->kref, xprt_destroy);
+}
+
+/**
+ * xprt_get - return a reference to an RPC transport.
+ * @xprt: pointer to the transport
+ *
+ */
+struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
+{
+ kref_get(&xprt->kref);
+ return xprt;
}