From: Chuck Lever <chuck.lever@oracle.com>
Date: Mon, 19 Aug 2019 18:50:16 -0400
Subject: xprtrdma: Fix bc_max_slots return value
Patch-mainline: v5.4-rc1
Git-commit: 17d47f93bc69cc629aa6a20c0ac7b20c9965c116
References: jsc#SLE-8449

For the moment the returned value just happens to be correct because
the current backchannel server implementation does not vary the
number of credits it offers. The spec does permit this value to
change during the lifetime of a connection, however.

The actual maximum is fixed for all RPC/RDMA transports, because
each transport instance has to pre-allocate the resources for
processing BC requests. That's the value that should be returned.

Fixes: 7402a4fedc2b ("SUNRPC: Fix up backchannel slot table ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/sunrpc/xprtrdma/backchannel.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -54,9 +54,7 @@ size_t xprt_rdma_bc_maxpayload(struct rp
 
 unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *xprt)
 {
-	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
-
-	return r_xprt->rx_buf.rb_bc_srv_max_requests;
+	return RPCRDMA_BACKWARD_WRS >> 1;
 }
 
 static int rpcrdma_bc_marshal_reply(struct rpc_rqst *rqst)