svcrdma: Use max_sge_rd for destination read depths

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

include/linux/sunrpc/svc_rdma.h

@@ -132,6 +132,7 @@ struct svcxprt_rdma {
 	struct list_head     sc_accept_q;	/* Conn. waiting accept */
 	int		     sc_ord;		/* RDMA read limit */
 	int                  sc_max_sge;
+	int                  sc_max_sge_rd;	/* max sge for read target */
 
 	int                  sc_sq_depth;	/* Depth of SQ */
 	atomic_t             sc_sq_count;	/* Number of SQ WR on queue */

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

@@ -115,15 +115,6 @@ static void rdma_build_arg_xdr(struct svc_rqst *rqstp,
 	rqstp->rq_arg.tail[0].iov_len = 0;
 }
 
-static int rdma_read_max_sge(struct svcxprt_rdma *xprt, int sge_count)
-{
-	if (!rdma_cap_read_multi_sge(xprt->sc_cm_id->device,
-				     xprt->sc_cm_id->port_num))
-		return 1;
-	else
-		return min_t(int, sge_count, xprt->sc_max_sge);
-}
-
 /* Issue an RDMA_READ using the local lkey to map the data sink */
 int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
 			struct svc_rqst *rqstp,
@@ -144,8 +135,7 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
 
 	ctxt->direction = DMA_FROM_DEVICE;
 	ctxt->read_hdr = head;
-	pages_needed =
-		min_t(int, pages_needed, rdma_read_max_sge(xprt, pages_needed));
+	pages_needed = min_t(int, pages_needed, xprt->sc_max_sge_rd);
 	read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
 
 	for (pno = 0; pno < pages_needed; pno++) {

net/sunrpc/xprtrdma/svc_rdma_transport.c

@@ -872,6 +872,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 	 * capabilities of this particular device */
 	newxprt->sc_max_sge = min((size_t)devattr.max_sge,
 				  (size_t)RPCSVC_MAXPAGES);
+	newxprt->sc_max_sge_rd = min_t(size_t, devattr.max_sge_rd,
+				       RPCSVC_MAXPAGES);
 	newxprt->sc_max_requests = min((size_t)devattr.max_qp_wr,
 				   (size_t)svcrdma_max_requests);
 	newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_max_requests;
@@ -1046,6 +1048,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 		"    remote_ip       : %pI4\n"
 		"    remote_port     : %d\n"
 		"    max_sge         : %d\n"
+		"    max_sge_rd      : %d\n"
 		"    sq_depth        : %d\n"
 		"    max_requests    : %d\n"
 		"    ord             : %d\n",
@@ -1059,6 +1062,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
 		       route.addr.dst_addr)->sin_port),
 		newxprt->sc_max_sge,
+		newxprt->sc_max_sge_rd,
 		newxprt->sc_sq_depth,
 		newxprt->sc_max_requests,
 		newxprt->sc_ord);