SUNRPC: Allow rpc_auth to run clean up before the rpc_client is destroyed

RPCSEC_GSS needs to be able to send NULL RPC calls to the server in order
to free up any remaining GSS contexts.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 25 insertions, 5 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 98df44e453f..28a789419f6 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -352,10 +352,6 @@ rpc_free_client(struct kref *kref)
 
         dprintk("RPC:       destroying %s client for %s\n",
                         clnt->cl_protname, clnt->cl_server);
-        if (clnt->cl_auth) {
-                rpcauth_release(clnt->cl_auth);
-                clnt->cl_auth = NULL;
-        }
         if (!IS_ERR(clnt->cl_dentry)) {
                 rpc_rmdir(clnt->cl_dentry);
                 rpc_put_mount();
@@ -376,6 +372,30 @@ out_free:
 }
 
 /*
+ * Free an RPC client
+ */
+static void
+rpc_free_auth(struct kref *kref)
+{
+        struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
+
+        if (clnt->cl_auth == NULL) {
+                rpc_free_client(kref);
+                return;
+        }
+
+        /*
+         * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
+         *       release remaining GSS contexts. This mechanism ensures
+         *       that it can do so safely.
+         */
+        kref_init(kref);
+        rpcauth_release(clnt->cl_auth);
+        clnt->cl_auth = NULL;
+        kref_put(kref, rpc_free_client);
+}
+
+/*
  * Release reference to the RPC client
  */
 void
@@ -385,7 +405,7 @@ rpc_release_client(struct rpc_clnt *clnt)
 
         if (list_empty(&clnt->cl_tasks))
                 wake_up(&destroy_wait);
-        kref_put(&clnt->cl_kref, rpc_free_client);
+        kref_put(&clnt->cl_kref, rpc_free_auth);
 }
 
 /**