xprtrdma: Take struct ib_device_attr off the stack

Device attributes are large, and are used in more than one place.
Stash a copy in dynamically allocated memory.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/verbs.c

@@ -588,8 +588,8 @@ int
 rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 {
 	int rc, mem_priv;
-	struct ib_device_attr devattr;
 	struct rpcrdma_ia *ia = &xprt->rx_ia;
+	struct ib_device_attr *devattr = &ia->ri_devattr;
 
 	ia->ri_id = rpcrdma_create_id(xprt, ia, addr);
 	if (IS_ERR(ia->ri_id)) {
@@ -605,26 +605,21 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 		goto out2;
 	}
 
-	/*
-	 * Query the device to determine if the requested memory
-	 * registration strategy is supported. If it isn't, set the
-	 * strategy to a globally supported model.
-	 */
-	rc = ib_query_device(ia->ri_id->device, &devattr);
+	rc = ib_query_device(ia->ri_id->device, devattr);
 	if (rc) {
 		dprintk("RPC:       %s: ib_query_device failed %d\n",
 			__func__, rc);
 		goto out3;
 	}
 
-	if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY) {
+	if (devattr->device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY) {
 		ia->ri_have_dma_lkey = 1;
 		ia->ri_dma_lkey = ia->ri_id->device->local_dma_lkey;
 	}
 
 	if (memreg == RPCRDMA_FRMR) {
 		/* Requires both frmr reg and local dma lkey */
-		if ((devattr.device_cap_flags &
+		if ((devattr->device_cap_flags &
 		     (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) !=
 		    (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) {
 			dprintk("RPC:       %s: FRMR registration "
@@ -634,7 +629,7 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 			/* Mind the ia limit on FRMR page list depth */
 			ia->ri_max_frmr_depth = min_t(unsigned int,
 				RPCRDMA_MAX_DATA_SEGS,
-				devattr.max_fast_reg_page_list_len);
+				devattr->max_fast_reg_page_list_len);
 		}
 	}
 	if (memreg == RPCRDMA_MTHCAFMR) {
@@ -736,20 +731,13 @@ int
 rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 				struct rpcrdma_create_data_internal *cdata)
 {
-	struct ib_device_attr devattr;
+	struct ib_device_attr *devattr = &ia->ri_devattr;
 	struct ib_cq *sendcq, *recvcq;
 	int rc, err;
 
-	rc = ib_query_device(ia->ri_id->device, &devattr);
-	if (rc) {
-		dprintk("RPC:       %s: ib_query_device failed %d\n",
-			__func__, rc);
-		return rc;
-	}
-
 	/* check provider's send/recv wr limits */
-	if (cdata->max_requests > devattr.max_qp_wr)
-		cdata->max_requests = devattr.max_qp_wr;
+	if (cdata->max_requests > devattr->max_qp_wr)
+		cdata->max_requests = devattr->max_qp_wr;
 
 	ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
 	ep->rep_attr.qp_context = ep;
@@ -784,8 +772,8 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 
 		}
 		ep->rep_attr.cap.max_send_wr *= depth;
-		if (ep->rep_attr.cap.max_send_wr > devattr.max_qp_wr) {
-			cdata->max_requests = devattr.max_qp_wr / depth;
+		if (ep->rep_attr.cap.max_send_wr > devattr->max_qp_wr) {
+			cdata->max_requests = devattr->max_qp_wr / depth;
 			if (!cdata->max_requests)
 				return -EINVAL;
 			ep->rep_attr.cap.max_send_wr = cdata->max_requests *
@@ -868,10 +856,11 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 
 	/* Client offers RDMA Read but does not initiate */
 	ep->rep_remote_cma.initiator_depth = 0;
-	if (devattr.max_qp_rd_atom > 32)	/* arbitrary but <= 255 */
+	if (devattr->max_qp_rd_atom > 32)	/* arbitrary but <= 255 */
 		ep->rep_remote_cma.responder_resources = 32;
 	else
-		ep->rep_remote_cma.responder_resources = devattr.max_qp_rd_atom;
+		ep->rep_remote_cma.responder_resources =
+						devattr->max_qp_rd_atom;
 
 	ep->rep_remote_cma.retry_count = 7;
 	ep->rep_remote_cma.flow_control = 0;

net/sunrpc/xprtrdma/xprt_rdma.h

@@ -70,6 +70,7 @@ struct rpcrdma_ia {
 	int			ri_async_rc;
 	enum rpcrdma_memreg	ri_memreg_strategy;
 	unsigned int		ri_max_frmr_depth;
+	struct ib_device_attr	ri_devattr;
 };
 
 /*