1 files changed, 42 insertions, 34 deletions

diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 7acfc83087d5..7ee4fea93637 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -13,39 +13,24 @@
 extern char bpfilter_umh_start;
 extern char bpfilter_umh_end;
 
-static struct umh_info info;
-/* since ip_getsockopt() can run in parallel, serialize access to umh */
-static DEFINE_MUTEX(bpfilter_lock);
-
-static void shutdown_umh(struct umh_info *info)
+static void shutdown_umh(void)
 {
 	struct task_struct *tsk;
 
-	if (!info->pid)
+	if (bpfilter_ops.stop)
 		return;
-	tsk = get_pid_task(find_vpid(info->pid), PIDTYPE_PID);
+
+	tsk = get_pid_task(find_vpid(bpfilter_ops.info.pid), PIDTYPE_PID);
 	if (tsk) {
 		force_sig(SIGKILL, tsk);
 		put_task_struct(tsk);
 	}
-	fput(info->pipe_to_umh);
-	fput(info->pipe_from_umh);
-	info->pid = 0;
 }
 
 static void __stop_umh(void)
 {
-	if (IS_ENABLED(CONFIG_INET)) {
-		bpfilter_process_sockopt = NULL;
-		shutdown_umh(&info);
-	}
-}
-
-static void stop_umh(void)
-{
-	mutex_lock(&bpfilter_lock);
-	__stop_umh();
-	mutex_unlock(&bpfilter_lock);
+	if (IS_ENABLED(CONFIG_INET))
+		shutdown_umh();
 }
 
 static int __bpfilter_process_sockopt(struct sock *sk, int optname,
@@ -63,10 +48,10 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname,
 	req.cmd = optname;
 	req.addr = (long __force __user)optval;
 	req.len = optlen;
-	mutex_lock(&bpfilter_lock);
-	if (!info.pid)
+	if (!bpfilter_ops.info.pid)
 		goto out;
-	n = __kernel_write(info.pipe_to_umh, &req, sizeof(req), &pos);
+	n = __kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req),
+			   &pos);
 	if (n != sizeof(req)) {
 		pr_err("write fail %zd\n", n);
 		__stop_umh();
@@ -74,7 +59,8 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname,
 		goto out;
 	}
 	pos = 0;
-	n = kernel_read(info.pipe_from_umh, &reply, sizeof(reply), &pos);
+	n = kernel_read(bpfilter_ops.info.pipe_from_umh, &reply, sizeof(reply),
+			&pos);
 	if (n != sizeof(reply)) {
 		pr_err("read fail %zd\n", n);
 		__stop_umh();
@@ -83,37 +69,59 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname,
 	}
 	ret = reply.status;
 out:
-	mutex_unlock(&bpfilter_lock);
 	return ret;
 }
 
-static int __init load_umh(void)
+static int start_umh(void)
 {
 	int err;
 
 	/* fork usermode process */
-	info.cmdline = "bpfilter_umh";
 	err = fork_usermode_blob(&bpfilter_umh_start,
 				 &bpfilter_umh_end - &bpfilter_umh_start,
-				 &info);
+				 &bpfilter_ops.info);
 	if (err)
 		return err;
-	pr_info("Loaded bpfilter_umh pid %d\n", info.pid);
+	bpfilter_ops.stop = false;
+	pr_info("Loaded bpfilter_umh pid %d\n", bpfilter_ops.info.pid);
 
 	/* health check that usermode process started correctly */
 	if (__bpfilter_process_sockopt(NULL, 0, NULL, 0, 0) != 0) {
-		stop_umh();
+		shutdown_umh();
 		return -EFAULT;
 	}
-	if (IS_ENABLED(CONFIG_INET))
-		bpfilter_process_sockopt = &__bpfilter_process_sockopt;
 
 	return 0;
 }
 
+static int __init load_umh(void)
+{
+	int err;
+
+	mutex_lock(&bpfilter_ops.lock);
+	if (!bpfilter_ops.stop) {
+		err = -EFAULT;
+		goto out;
+	}
+	err = start_umh();
+	if (!err && IS_ENABLED(CONFIG_INET)) {
+		bpfilter_ops.sockopt = &__bpfilter_process_sockopt;
+		bpfilter_ops.start = &start_umh;
+	}
+out:
+	mutex_unlock(&bpfilter_ops.lock);
+	return err;
+}
+
 static void __exit fini_umh(void)
 {
-	stop_umh();
+	mutex_lock(&bpfilter_ops.lock);
+	if (IS_ENABLED(CONFIG_INET)) {
+		shutdown_umh();
+		bpfilter_ops.start = NULL;
+		bpfilter_ops.sockopt = NULL;
+	}
+	mutex_unlock(&bpfilter_ops.lock);
 }
 module_init(load_umh);
 module_exit(fini_umh);