svcrdma: Add a service to register a Fast Reg MR with the device

Fast Reg MR introduces a new WR type. Add a service to register the
region with the adapter and update the completion handling to support
completions with a NULL WR context.
Signed-off-by: NTom Tucker <tom@opengridcomputing.com>

include/linux/sunrpc/svc_rdma.h

@@ -214,6 +214,7 @@ extern struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *);
 extern void svc_rdma_put_context(struct svc_rdma_op_ctxt *, int);
 extern struct svc_rdma_req_map *svc_rdma_get_req_map(void);
 extern void svc_rdma_put_req_map(struct svc_rdma_req_map *);
+extern int svc_rdma_fastreg(struct svcxprt_rdma *, struct svc_rdma_fastreg_mr *);
 extern struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *);
 extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
 			      struct svc_rdma_fastreg_mr *);

net/sunrpc/xprtrdma/svc_rdma_transport.c

@@ -325,6 +325,45 @@ static void rq_cq_reap(struct svcxprt_rdma *xprt)
 		svc_xprt_enqueue(&xprt->sc_xprt);
 }
 
+/*
+ * Processs a completion context
+ */
+static void process_context(struct svcxprt_rdma *xprt,
+			    struct svc_rdma_op_ctxt *ctxt)
+{
+	svc_rdma_unmap_dma(ctxt);
+
+	switch (ctxt->wr_op) {
+	case IB_WR_SEND:
+		svc_rdma_put_context(ctxt, 1);
+		break;
+
+	case IB_WR_RDMA_WRITE:
+		svc_rdma_put_context(ctxt, 0);
+		break;
+
+	case IB_WR_RDMA_READ:
+		if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
+			struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
+			BUG_ON(!read_hdr);
+			spin_lock_bh(&xprt->sc_rq_dto_lock);
+			set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
+			list_add_tail(&read_hdr->dto_q,
+				      &xprt->sc_read_complete_q);
+			spin_unlock_bh(&xprt->sc_rq_dto_lock);
+			svc_xprt_enqueue(&xprt->sc_xprt);
+		}
+		svc_rdma_put_context(ctxt, 0);
+		break;
+
+	default:
+		printk(KERN_ERR "svcrdma: unexpected completion type, "
+		       "opcode=%d\n",
+		       ctxt->wr_op);
+		break;
+	}
+}
+
 /*
  * Send Queue Completion Handler - potentially called on interrupt context.
  *
@@ -337,17 +376,12 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
 	struct ib_cq *cq = xprt->sc_sq_cq;
 	int ret;
 
-
 	if (!test_and_clear_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags))
 		return;
 
 	ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
 	atomic_inc(&rdma_stat_sq_poll);
 	while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
-		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
-		xprt = ctxt->xprt;
-
-		svc_rdma_unmap_dma(ctxt);
 		if (wc.status != IB_WC_SUCCESS)
 			/* Close the transport */
 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
@@ -356,35 +390,10 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
 		atomic_dec(&xprt->sc_sq_count);
 		wake_up(&xprt->sc_send_wait);
 
-		switch (ctxt->wr_op) {
-		case IB_WR_SEND:
-			svc_rdma_put_context(ctxt, 1);
-			break;
-
-		case IB_WR_RDMA_WRITE:
-			svc_rdma_put_context(ctxt, 0);
-			break;
-
-		case IB_WR_RDMA_READ:
-			if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
-				struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
-				BUG_ON(!read_hdr);
-				spin_lock_bh(&xprt->sc_rq_dto_lock);
-				set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
-				list_add_tail(&read_hdr->dto_q,
-					      &xprt->sc_read_complete_q);
-				spin_unlock_bh(&xprt->sc_rq_dto_lock);
-				svc_xprt_enqueue(&xprt->sc_xprt);
-			}
-			svc_rdma_put_context(ctxt, 0);
-			break;
+		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
+		if (ctxt)
+			process_context(xprt, ctxt);
 
-		default:
-			printk(KERN_ERR "svcrdma: unexpected completion type, "
-			       "opcode=%d, status=%d\n",
-			       wc.opcode, wc.status);
-			break;
-		}
 		svc_xprt_put(&xprt->sc_xprt);
 	}
 
@@ -1184,6 +1193,40 @@ static int svc_rdma_has_wspace(struct svc_xprt *xprt)
 	return 1;
 }
 
+/*
+ * Attempt to register the kvec representing the RPC memory with the
+ * device.
+ *
+ * Returns:
+ *  NULL : The device does not support fastreg or there were no more
+ *         fastreg mr.
+ *  frmr : The kvec register request was successfully posted.
+ *    <0 : An error was encountered attempting to register the kvec.
+ */
+int svc_rdma_fastreg(struct svcxprt_rdma *xprt,
+		     struct svc_rdma_fastreg_mr *frmr)
+{
+	struct ib_send_wr fastreg_wr;
+	u8 key;
+
+	/* Bump the key */
+	key = (u8)(frmr->mr->lkey & 0x000000FF);
+	ib_update_fast_reg_key(frmr->mr, ++key);
+
+	/* Prepare FASTREG WR */
+	memset(&fastreg_wr, 0, sizeof fastreg_wr);
+	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
+	fastreg_wr.send_flags = IB_SEND_SIGNALED;
+	fastreg_wr.wr.fast_reg.iova_start = (unsigned long)frmr->kva;
+	fastreg_wr.wr.fast_reg.page_list = frmr->page_list;
+	fastreg_wr.wr.fast_reg.page_list_len = frmr->page_list_len;
+	fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
+	fastreg_wr.wr.fast_reg.length = frmr->map_len;
+	fastreg_wr.wr.fast_reg.access_flags = frmr->access_flags;
+	fastreg_wr.wr.fast_reg.rkey = frmr->mr->lkey;
+	return svc_rdma_send(xprt, &fastreg_wr);
+}
+
 int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
 {
 	struct ib_send_wr *bad_wr;
@@ -1193,8 +1236,6 @@ int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
 		return -ENOTCONN;
 
 	BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
-	BUG_ON(((struct svc_rdma_op_ctxt *)(unsigned long)wr->wr_id)->wr_op !=
-		wr->opcode);
 	/* If the SQ is full, wait until an SQ entry is available */
 	while (1) {
 		spin_lock_bh(&xprt->sc_lock);