Subject: [PATCH 47/52] VSOCK: make af_vsock.ko removable again

From: Stefan Hajnoczi <[email-masked]>
Date: Tue, 17 Apr 2018 14:25:58 +0800

[ Upstream commit 05e489b1596f0aa1025a1fa572676631cd9665da ]

Commit c1eef220c1760762753b602c382127bfccee226d ("vsock: always call
vsock_init_tables()") introduced a module_init() function without a
corresponding module_exit() function.

Modules with an init function can only be removed if they also have an
exit function.  Therefore the vsock module was considered "permanent"
and could not be removed.

This patch adds an empty module_exit() function so that "rmmod vsock"
works.  No explicit cleanup is required because:

1. Transports call vsock_core_exit() upon exit and cannot be removed
   while sockets are still alive.
2. vsock_diag.ko does not perform any action that requires cleanup by
   vsock.ko.

Fixes: c1eef220c176 ("vsock: always call vsock_init_tables()")
Reported-by: Xiumei Mu <[email-masked]>
Cc: Cong Wang <[email-masked]>
Cc: Jorgen Hansen <[email-masked]>
Signed-off-by: Stefan Hajnoczi <[email-masked]>
Reviewed-by: Jorgen Hansen <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/vmw_vsock/af_vsock.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index e0fc84daed94..ad17a985f74e 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -2018,7 +2018,13 @@ const struct vsock_transport *vsock_core_get_transport(void)
 }
 EXPORT_SYMBOL_GPL(vsock_core_get_transport);
 
+static void __exit vsock_exit(void)
+{
+	/* Do nothing.  This function makes this module removable. */
+}
+
 module_init(vsock_init_tables);
+module_exit(vsock_exit);
 
 MODULE_AUTHOR("VMware, Inc.");
 MODULE_DESCRIPTION("VMware Virtual Socket Family");
-- 
2.14.3