Received-SPF: pass (google.com: domain of linux-nfs+bounces-1552-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Subject: [PATCH v1 01/11] svcrdma: Reserve an extra WQE for ib_drain_rq()
From: Chuck Lever <cel@kernel.org>
To: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org
Date: Mon, 29 Jan 2024 09:50:37 -0500
Message-ID: 
 <170653983726.24162.15894483608296911955.stgit@manet.1015granger.net>
In-Reply-To: 
 <170653967395.24162.4661804176845293777.stgit@manet.1015granger.net>
References: 
 <170653967395.24162.4661804176845293777.stgit@manet.1015granger.net>
User-Agent: StGit/1.5
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit

From: Chuck Lever <chuck.lever@oracle.com>

Do as other ULPs already do: ensure there is an extra Receive WQE
reserved for the tear-down drain WR. I haven't heard reports of
problems but it can't hurt.

Note that rq_depth is used to compute the Send Queue depth as well,
so this fix should affect both the SQ and RQ.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma_transport.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 4f27325ace4a..4a038c7e86f9 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -415,7 +415,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 	if (newxprt->sc_max_send_sges > dev->attrs.max_send_sge)
 		newxprt->sc_max_send_sges = dev->attrs.max_send_sge;
 	rq_depth = newxprt->sc_max_requests + newxprt->sc_max_bc_requests +
-		   newxprt->sc_recv_batch;
+		   newxprt->sc_recv_batch + 1 /* drain */;
 	if (rq_depth > dev->attrs.max_qp_wr) {
 		rq_depth = dev->attrs.max_qp_wr;
 		newxprt->sc_recv_batch = 1;