svc_rdma: use local_dma_lkey

We now alwasy have a per-PD local_dma_lkey available. Make use of that
fact in svc_rdma and stop registering our own MR.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Sagi Grimberg <[e-mail]>
Reviewed-by: Jason Gunthorpe <[e-mail]>
Reviewed-by: Chuck Lever <[e-mail]>
Reviewed-by: Steve Wise <[e-mail]>
Acked-by: J. Bruce Fields <[e-mail]>
Signed-off-by: Doug Ledford <[e-mail]>

include/linux/sunrpc/svc_rdma.h

···
 	struct ib_qp         *sc_qp;
 	struct ib_cq         *sc_rq_cq;
 	struct ib_cq         *sc_sq_cq;
-	struct ib_mr         *sc_phys_mr;	/* MR for server memory */
 	int		     (*sc_reader)(struct svcxprt_rdma *,
 					  struct svc_rqst *,
 					  struct svc_rdma_op_ctxt *,
 					  int *, u32 *, u32, u32, u64, bool);
 	u32		     sc_dev_caps;	/* distilled device caps */
-	u32		     sc_dma_lkey;	/* local dma key */
 	unsigned int	     sc_frmr_pg_list_len;
 	struct list_head     sc_frmr_q;
 	spinlock_t	     sc_frmr_q_lock;

net/sunrpc/xprtrdma/svc_rdma_backchannel.c

···
 
 	ctxt->wr_op = IB_WR_SEND;
 	ctxt->direction = DMA_TO_DEVICE;
-	ctxt->sge[0].lkey = rdma->sc_dma_lkey;
+	ctxt->sge[0].lkey = rdma->sc_pd->local_dma_lkey;
 	ctxt->sge[0].length = sndbuf->len;
 	ctxt->sge[0].addr =
 	    ib_dma_map_page(rdma->sc_cm_id->device, ctxt->pages[0], 0,

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

···
 
 		head->arg.pages[pg_no] = rqstp->rq_arg.pages[pg_no];
 		head->arg.page_len += len;
+
 		head->arg.len += len;
 		if (!pg_off)
 			head->count++;
···
 			goto err;
 		atomic_inc(&xprt->sc_dma_used);
 
-		/* The lkey here is either a local dma lkey or a dma_mr lkey */
-		ctxt->sge[pno].lkey = xprt->sc_dma_lkey;
+		ctxt->sge[pno].lkey = xprt->sc_pd->local_dma_lkey;
 		ctxt->sge[pno].length = len;
 		ctxt->count++;
 

net/sunrpc/xprtrdma/svc_rdma_sendto.c

···
 					 sge[sge_no].addr))
 			goto err;
 		atomic_inc(&xprt->sc_dma_used);
-		sge[sge_no].lkey = xprt->sc_dma_lkey;
+		sge[sge_no].lkey = xprt->sc_pd->local_dma_lkey;
 		ctxt->count++;
 		sge_off = 0;
 		sge_no++;
···
 	ctxt->count = 1;
 
 	/* Prepare the SGE for the RPCRDMA Header */
-	ctxt->sge[0].lkey = rdma->sc_dma_lkey;
+	ctxt->sge[0].lkey = rdma->sc_pd->local_dma_lkey;
 	ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
 	ctxt->sge[0].addr =
 	    ib_dma_map_page(rdma->sc_cm_id->device, page, 0,
···
 					 ctxt->sge[sge_no].addr))
 			goto err;
 		atomic_inc(&rdma->sc_dma_used);
-		ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey;
+		ctxt->sge[sge_no].lkey = rdma->sc_pd->local_dma_lkey;
 		ctxt->sge[sge_no].length = sge_bytes;
 	}
 	if (byte_count != 0) {

net/sunrpc/xprtrdma/svc_rdma_transport.c

···
 	for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
 		/*
 		 * Unmap the DMA addr in the SGE if the lkey matches
-		 * the sc_dma_lkey, otherwise, ignore it since it is
+		 * the local_dma_lkey, otherwise, ignore it since it is
 		 * an FRMR lkey and will be unmapped later when the
 		 * last WR that uses it completes.
 		 */
-		if (ctxt->sge[i].lkey == xprt->sc_dma_lkey) {
+		if (ctxt->sge[i].lkey == xprt->sc_pd->local_dma_lkey) {
 			atomic_dec(&xprt->sc_dma_used);
 			ib_dma_unmap_page(xprt->sc_cm_id->device,
 					    ctxt->sge[i].addr,
···
 		atomic_inc(&xprt->sc_dma_used);
 		ctxt->sge[sge_no].addr = pa;
 		ctxt->sge[sge_no].length = PAGE_SIZE;
-		ctxt->sge[sge_no].lkey = xprt->sc_dma_lkey;
+		ctxt->sge[sge_no].lkey = xprt->sc_pd->local_dma_lkey;
 		ctxt->count = sge_no + 1;
 		buflen += PAGE_SIZE;
 	}
···
 	struct ib_cq_init_attr cq_attr = {};
 	struct ib_qp_init_attr qp_attr;
 	struct ib_device *dev;
-	int uninitialized_var(dma_mr_acc);
-	int need_dma_mr = 0;
 	unsigned int i;
 	int ret = 0;
 
···
 	    !rdma_ib_or_roce(dev, newxprt->sc_cm_id->port_num))
 		goto errout;
 
-	if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG) ||
-	    !(dev->attrs.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
-		need_dma_mr = 1;
-		dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
-		if (rdma_protocol_iwarp(dev, newxprt->sc_cm_id->port_num) &&
-		    !(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG))
-			dma_mr_acc |= IB_ACCESS_REMOTE_WRITE;
-	}
-
 	if (rdma_protocol_iwarp(dev, newxprt->sc_cm_id->port_num))
 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
-
-	/* Create the DMA MR if needed, otherwise, use the DMA LKEY */
-	if (need_dma_mr) {
-		/* Register all of physical memory */
-		newxprt->sc_phys_mr =
-			ib_get_dma_mr(newxprt->sc_pd, dma_mr_acc);
-		if (IS_ERR(newxprt->sc_phys_mr)) {
-			dprintk("svcrdma: Failed to create DMA MR ret=%d\n",
-				ret);
-			goto errout;
-		}
-		newxprt->sc_dma_lkey = newxprt->sc_phys_mr->lkey;
-	} else
-		newxprt->sc_dma_lkey = dev->local_dma_lkey;
 
 	/* Post receive buffers */
 	for (i = 0; i < newxprt->sc_rq_depth; i++) {
···
 	if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
 		ib_destroy_cq(rdma->sc_rq_cq);
 
-	if (rdma->sc_phys_mr && !IS_ERR(rdma->sc_phys_mr))
-		ib_dereg_mr(rdma->sc_phys_mr);
-
 	if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
 		ib_dealloc_pd(rdma->sc_pd);
 
···
 		return;
 	}
 	atomic_inc(&xprt->sc_dma_used);
-	ctxt->sge[0].lkey = xprt->sc_dma_lkey;
+	ctxt->sge[0].lkey = xprt->sc_pd->local_dma_lkey;
 	ctxt->sge[0].length = length;
 
 	/* Prepare SEND WR */