Subject: [PATCH v1 23/23] SUNRPC: Use au_rslack when computing reply buffer
 size
From:   Chuck Lever <chuck.lever@oracle.com>
To:     anna.schumaker@netapp.com
Cc:     linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org
Date:   Mon, 11 Feb 2019 11:25:41 -0500
Message-ID: <20190211162541.2817.96724.stgit@manet.1015granger.net>
In-Reply-To: <20190211161920.2817.20881.stgit@manet.1015granger.net>
References: <20190211161920.2817.20881.stgit@manet.1015granger.net>
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au_rslack is significantly smaller than (au_cslack << 2). Using
that value results in smaller receive buffers. In some cases this
eliminates an extra segment in Reply chunks (RPC/RDMA).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/clnt.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 99bfeb1..241e842 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1690,7 +1690,7 @@ void rpc_force_rebind(struct rpc_clnt *clnt)
 static void
 call_allocate(struct rpc_task *task)
 {
-	unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
+	const struct rpc_auth *auth = task->tk_rqstp->rq_cred->cr_auth;
 	struct rpc_rqst *req = task->tk_rqstp;
 	struct rpc_xprt *xprt = req->rq_xprt;
 	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
@@ -1715,9 +1715,10 @@ void rpc_force_rebind(struct rpc_clnt *clnt)
 	 * and reply headers, and convert both values
 	 * to byte sizes.
 	 */
-	req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
+	req->rq_callsize = RPC_CALLHDRSIZE + (auth->au_cslack << 1) +
+			   proc->p_arglen;
 	req->rq_callsize <<= 2;
-	req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
+	req->rq_rcvsize = RPC_REPHDRSIZE + auth->au_rslack + proc->p_replen;
 	req->rq_rcvsize <<= 2;
 
 	status = xprt->ops->buf_alloc(task);