xprtrdma: Don't wake pending tasks until disconnect is done

Transport disconnect processing does a "wake pending tasks" at
various points.

Suppose an RPC Reply is being processed. The RPC task that Reply
goes with is waiting on the pending queue. If a disconnect wake-up
happens before reply processing is done, that reply, even if it is
good, is thrown away, and the RPC has to be sent again.

This window apparently does not exist for socket transports because
there is a lock held while a reply is being received which prevents
the wake-up call until after reply processing is done.

To resolve this, all RPC replies being processed on an RPC-over-RDMA
transport have to complete before pending tasks are awoken due to a
transport disconnect.

Callers that already hold the transport write lock may invoke
->ops->close directly. Others use a generic helper that schedules
a close when the write lock can be taken safely.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 7c1b5191a5fe..99b7f8ea66b0 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -647,6 +647,7 @@ static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len)
 extern unsigned int xprt_rdma_max_inline_read;
 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
+void xprt_rdma_close(struct rpc_xprt *xprt);
 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
 int xprt_rdma_init(void);
 void xprt_rdma_cleanup(void);