SUNRPC: The RDMA back channel mustn't disappear while requests are outstanding
If there are RDMA back channel requests being processed by the
server threads, then we should hold a reference to the transport
to ensure it doesn't get freed from underneath us.
Reported-by: Neil Brown <email@example.com>
Fixes: 63cae47005af ("xprtrdma: Handle incoming backward direction RPC calls")
Signed-off-by: Trond Myklebust <firstname.lastname@example.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>