SUNRPC: Convert rpc_clnt->cl_users to a kref

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

fs/lockd/host.c

@@ -161,15 +161,9 @@ nlm_destroy_host(struct nlm_host *host)
 	 */
 	nsm_unmonitor(host);
 
-	if ((clnt = host->h_rpcclnt) != NULL) {
-		if (atomic_read(&clnt->cl_users)) {
-			printk(KERN_WARNING
-				"lockd: active RPC handle\n");
-			clnt->cl_dead = 1;
-		} else {
-			rpc_destroy_client(host->h_rpcclnt);
-		}
-	}
+	clnt = host->h_rpcclnt;
+	if (clnt != NULL)
+		rpc_shutdown_client(clnt);
 	kfree(host);
 }
 

include/linux/sunrpc/clnt.h

@@ -24,8 +24,8 @@ struct rpc_inode;
  * The high-level client handle
  */
 struct rpc_clnt {
+	struct kref		cl_kref;	/* Number of references */
 	atomic_t		cl_count;	/* Number of clones */
-	atomic_t		cl_users;	/* number of references */
 	struct list_head	cl_clients;	/* Global list of clients */
 	struct list_head	cl_tasks;	/* List of tasks */
 	spinlock_t		cl_lock;	/* spinlock */

net/sunrpc/clnt.c

@@ -121,7 +121,6 @@ static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, s
 	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 	if (!clnt)
 		goto out_err;
-	atomic_set(&clnt->cl_users, 0);
 	atomic_set(&clnt->cl_count, 1);
 	clnt->cl_parent = clnt;
 
@@ -157,6 +156,8 @@ static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, s
 	clnt->cl_rtt = &clnt->cl_rtt_default;
 	rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 
+	kref_init(&clnt->cl_kref);
+
 	err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 	if (err < 0)
 		goto out_no_path;
@@ -272,10 +273,10 @@ rpc_clone_client(struct rpc_clnt *clnt)
 	if (!new)
 		goto out_no_clnt;
 	atomic_set(&new->cl_count, 1);
-	atomic_set(&new->cl_users, 0);
 	new->cl_metrics = rpc_alloc_iostats(clnt);
 	if (new->cl_metrics == NULL)
 		goto out_no_stats;
+	kref_init(&new->cl_kref);
 	err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 	if (err != 0)
 		goto out_no_path;
@@ -311,40 +312,28 @@ out_no_clnt:
 int
 rpc_shutdown_client(struct rpc_clnt *clnt)
 {
-	dprintk("RPC:       shutting down %s client for %s, tasks=%d\n",
-			clnt->cl_protname, clnt->cl_server,
-			atomic_read(&clnt->cl_users));
+	dprintk("RPC:       shutting down %s client for %s\n",
+			clnt->cl_protname, clnt->cl_server);
 
-	while (atomic_read(&clnt->cl_users) > 0) {
+	while (!list_empty(&clnt->cl_tasks)) {
 		/* Don't let rpc_release_client destroy us */
 		clnt->cl_oneshot = 0;
 		clnt->cl_dead = 0;
 		rpc_killall_tasks(clnt);
 		wait_event_timeout(destroy_wait,
-			!atomic_read(&clnt->cl_users), 1*HZ);
-	}
-
-	if (atomic_read(&clnt->cl_users) < 0) {
-		printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
-				clnt, atomic_read(&clnt->cl_users));
-#ifdef RPC_DEBUG
-		rpc_show_tasks();
-#endif
-		BUG();
+			list_empty(&clnt->cl_tasks), 1*HZ);
 	}
 
 	return rpc_destroy_client(clnt);
 }
 
 /*
- * Delete an RPC client
+ * Free an RPC client
  */
-int
-rpc_destroy_client(struct rpc_clnt *clnt)
+static void
+rpc_free_client(struct kref *kref)
 {
-	if (!atomic_dec_and_test(&clnt->cl_count))
-		return 1;
-	BUG_ON(atomic_read(&clnt->cl_users) != 0);
+	struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 
 	dprintk("RPC:       destroying %s client for %s\n",
 			clnt->cl_protname, clnt->cl_server);
@@ -368,23 +357,33 @@ out_free:
 	clnt->cl_metrics = NULL;
 	xprt_put(clnt->cl_xprt);
 	kfree(clnt);
-	return 0;
 }
 
 /*
- * Release an RPC client
+ * Release reference to the RPC client
  */
 void
 rpc_release_client(struct rpc_clnt *clnt)
 {
-	dprintk("RPC:       rpc_release_client(%p, %d)\n",
-			clnt, atomic_read(&clnt->cl_users));
+	dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 
-	if (!atomic_dec_and_test(&clnt->cl_users))
-		return;
-	wake_up(&destroy_wait);
+	if (list_empty(&clnt->cl_tasks))
+		wake_up(&destroy_wait);
 	if (clnt->cl_oneshot || clnt->cl_dead)
 		rpc_destroy_client(clnt);
+	kref_put(&clnt->cl_kref, rpc_free_client);
+}
+
+/*
+ * Delete an RPC client
+ */
+int
+rpc_destroy_client(struct rpc_clnt *clnt)
+{
+	if (!atomic_dec_and_test(&clnt->cl_count))
+		return 1;
+	kref_put(&clnt->cl_kref, rpc_free_client);
+	return 0;
 }
 
 /**

net/sunrpc/rpc_pipe.c

@@ -344,7 +344,7 @@ rpc_info_open(struct inode *inode, struct file *file)
 		mutex_lock(&inode->i_mutex);
 		clnt = RPC_I(inode)->private;
 		if (clnt) {
-			atomic_inc(&clnt->cl_users);
+			kref_get(&clnt->cl_kref);
 			m->private = clnt;
 		} else {
 			single_release(inode, file);

net/sunrpc/sched.c

@@ -846,7 +846,7 @@ void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, int flags, cons
 	task->tk_workqueue = rpciod_workqueue;
 
 	if (clnt) {
-		atomic_inc(&clnt->cl_users);
+		kref_get(&clnt->cl_kref);
 		if (clnt->cl_softrtry)
 			task->tk_flags |= RPC_TASK_SOFT;
 		if (!clnt->cl_intr)
@@ -898,9 +898,7 @@ out:
 cleanup:
 	/* Check whether to release the client */
 	if (clnt) {
-		printk("rpc_new_task: failed, users=%d, oneshot=%d\n",
-			atomic_read(&clnt->cl_users), clnt->cl_oneshot);
-		atomic_inc(&clnt->cl_users); /* pretend we were used ... */
+		kref_get(&clnt->cl_kref); /* pretend we were used ... */
 		rpc_release_client(clnt);
 	}
 	goto out;