[PATCH] Make RPCRDMA_MAX_RECV_BATCH configurable.

[Gaurav Gangalwar <gaurav.gangalwar@gmail.com>]

Bumped up rpcrdma_max_recv_batch to 64.
Added param to change to it, it becomes handy to use higher value
to avoid hung.

Signed-off-by: Gaurav Gangalwar <gaurav.gangalwar@gmail.com>
---
 net/sunrpc/xprtrdma/frwr_ops.c           | 2 +-
 net/sunrpc/xprtrdma/module.c             | 6 ++++++
 net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 +-
 net/sunrpc/xprtrdma/verbs.c              | 2 +-
 net/sunrpc/xprtrdma/xprt_rdma.h          | 4 +---
 5 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index 31434aeb8e29..863a0c567915 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -246,7 +246,7 @@ int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device)
 	ep->re_attr.cap.max_send_wr += 1; /* for ib_drain_sq */
 	ep->re_attr.cap.max_recv_wr = ep->re_max_requests;
 	ep->re_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
-	ep->re_attr.cap.max_recv_wr += RPCRDMA_MAX_RECV_BATCH;
+	ep->re_attr.cap.max_recv_wr += rpcrdma_max_recv_batch;
 	ep->re_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */
 
 	ep->re_max_rdma_segs =
diff --git a/net/sunrpc/xprtrdma/module.c b/net/sunrpc/xprtrdma/module.c
index 697f571d4c01..afeec5a68151 100644
--- a/net/sunrpc/xprtrdma/module.c
+++ b/net/sunrpc/xprtrdma/module.c
@@ -27,6 +27,12 @@ MODULE_ALIAS("svcrdma");
 MODULE_ALIAS("xprtrdma");
 MODULE_ALIAS("rpcrdma6");
 
+unsigned int rpcrdma_max_recv_batch = 64;
+module_param_named(max_recv_batch, rpcrdma_max_recv_batch, uint, 0644);
+MODULE_PARM_DESC(max_recv_batch,
+		 "Maximum number of Receive WRs to post in a batch "
+		 "(default: 64, set to 0 to disable batching)");
+
 static void __exit rpc_rdma_cleanup(void)
 {
 	xprt_rdma_cleanup();
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 3d7f1413df02..32a9ceb18389 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -440,7 +440,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 	newxprt->sc_max_req_size = svcrdma_max_req_size;
 	newxprt->sc_max_requests = svcrdma_max_requests;
 	newxprt->sc_max_bc_requests = svcrdma_max_bc_requests;
-	newxprt->sc_recv_batch = RPCRDMA_MAX_RECV_BATCH;
+	newxprt->sc_recv_batch = rpcrdma_max_recv_batch;
 	newxprt->sc_fc_credits = cpu_to_be32(newxprt->sc_max_requests);
 
 	/* Qualify the transport's resource defaults with the
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 63262ef0c2e3..7cd0a2c152e6 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1359,7 +1359,7 @@ void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, int needed)
 	if (likely(ep->re_receive_count > needed))
 		goto out;
 	needed -= ep->re_receive_count;
-	needed += RPCRDMA_MAX_RECV_BATCH;
+	needed += rpcrdma_max_recv_batch;
 
 	if (atomic_inc_return(&ep->re_receiving) > 1)
 		goto out;
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 8147d2b41494..1051aa612f36 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -216,9 +216,7 @@ struct rpcrdma_rep {
  *
  * Setting this to zero disables Receive post batching.
  */
-enum {
-	RPCRDMA_MAX_RECV_BATCH = 7,
-};
+extern unsigned int rpcrdma_max_recv_batch;
 
 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes
  */
-- 
2.43.7