SUNRPC: Ensure that we grab the XPRT_LOCK before calling xprt_alloc_slot

This throttles the allocation of new slots when the socket is busy
reconnecting and/or is out of buffer space.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 0867070bb5ca..674a49224450 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -452,9 +452,8 @@ xprt_rdma_connect(struct rpc_task *task)
 }
 
 static int
-xprt_rdma_reserve_xprt(struct rpc_task *task)
+xprt_rdma_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 {
-        struct rpc_xprt *xprt = task->tk_xprt;
         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
         int credits = atomic_read(&r_xprt->rx_buf.rb_credits);
 
@@ -466,7 +465,7 @@ xprt_rdma_reserve_xprt(struct rpc_task *task)
                 BUG_ON(r_xprt->rx_buf.rb_cwndscale <= 0);
         }
         xprt->cwnd = credits * r_xprt->rx_buf.rb_cwndscale;
-        return xprt_reserve_xprt_cong(task);
+        return xprt_reserve_xprt_cong(xprt, task);
 }
 
 /*