afs: Wait for outstanding async calls before closing rxrpc socket
The afs filesystem needs to wait for any outstanding asynchronous calls
(such as FS.GiveUpCallBacks cleaning up the callbacks lodged with a server)
to complete before closing the AF_RXRPC socket when unloading the module.
This may occur if the module is removed too quickly after unmounting all
filesystems. This will produce an error report that looks like:
AFS: Assertion failed
1 == 0 is false
0x1 == 0x0 is false
------------[ cut here ]------------
kernel BUG at ../fs/afs/rxrpc.c:135!
...
RIP: 0010:[<
ffffffffa004111c>] afs_close_socket+0xec/0x107 [kafs]
...
Call Trace:
[<
ffffffffa004a160>] afs_exit+0x1f/0x57 [kafs]
[<
ffffffff810c30a0>] SyS_delete_module+0xec/0x17d
[<
ffffffff81610417>] entry_SYSCALL_64_fastpath+0x12/0x6b
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>