xprtrdma: Decode credits field in rpcrdma_reply_handler
We need to decode and save the incoming rdma_credits field _after_
we know that the direction of the message is "forward direction
Reply". Otherwise, the credits value in reverse direction Calls is
also used to update the forward direction credits.
It is safe to decode the rdma_credits field in rpcrdma_reply_handler
now that rpcrdma_reply_handler is single-threaded. Receives complete
in the same order as they were sent on the NFS server.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 430f8b5..b8818c09 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -1244,7 +1244,7 @@ void rpcrdma_complete_rqst(struct rpcrdma_rep *rep)
out:
spin_lock(&xprt->recv_lock);
cwnd = xprt->cwnd;
- xprt->cwnd = atomic_read(&r_xprt->rx_buf.rb_credits) << RPC_CWNDSHIFT;
+ xprt->cwnd = r_xprt->rx_buf.rb_credits << RPC_CWNDSHIFT;
if (xprt->cwnd > cwnd)
xprt_release_rqst_cong(rqst->rq_task);
@@ -1297,8 +1297,10 @@ void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
{
struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
+ struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_req *req;
struct rpc_rqst *rqst;
+ u32 credits;
__be32 *p;
dprintk("RPC: %s: incoming rep %p\n", __func__, rep);
@@ -1315,7 +1317,7 @@ void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
goto out_shortreply;
rep->rr_xid = *p++;
rep->rr_vers = *p++;
- p++; /* credits */
+ credits = be32_to_cpu(*p++);
rep->rr_proc = *p++;
if (rep->rr_vers != rpcrdma_version)
@@ -1332,7 +1334,15 @@ void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
if (!rqst)
goto out_norqst;
xprt_pin_rqst(rqst);
+
+ if (credits == 0)
+ credits = 1; /* don't deadlock */
+ else if (credits > buf->rb_max_requests)
+ credits = buf->rb_max_requests;
+ buf->rb_credits = credits;
+
spin_unlock(&xprt->recv_lock);
+
req = rpcr_to_rdmar(rqst);
req->rl_reply = rep;
rep->rr_rqst = rqst;