[PATCH V2 RFC 1/3] svcrdma: Transport and header file changes

[Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>]

From: Tom Tucker <tom-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>

Change poll logic to grab up to 6 completions at a time.

RDMA write and send completions no longer deal with fastreg objects.

Set SVCRDMA_DEVCAP_FAST_REG and allocate a dma_mr based on the device
capabilities.

Signed-off-by: Tom Tucker <tom-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
Signed-off-by: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
---

 include/linux/sunrpc/svc_rdma.h          |    3 -
 net/sunrpc/xprtrdma/svc_rdma_transport.c |   62 +++++++++++++++++-------------
 2 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 0b8e3e6..5cf99a0 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -115,14 +115,13 @@ struct svc_rdma_fastreg_mr {
 	struct list_head frmr_list;
 };
 struct svc_rdma_req_map {
-	struct svc_rdma_fastreg_mr *frmr;
 	unsigned long count;
 	union {
 		struct kvec sge[RPCSVC_MAXPAGES];
 		struct svc_rdma_chunk_sge ch[RPCSVC_MAXPAGES];
+		unsigned long lkey[RPCSVC_MAXPAGES];
 	};
 };
-#define RDMACTXT_F_FAST_UNREG	1
 #define RDMACTXT_F_LAST_CTXT	2
 
 #define	SVCRDMA_DEVCAP_FAST_REG		1	/* fast mr registration */
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 25688fa..2c5b201 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -1,4 +1,5 @@
 /*
+ * Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved.
  * Copyright (c) 2005-2007 Network Appliance, Inc. All rights reserved.
  *
  * This software is available to you under a choice of one of two
@@ -160,7 +161,6 @@ struct svc_rdma_req_map *svc_rdma_get_req_map(void)
 		schedule_timeout_uninterruptible(msecs_to_jiffies(500));
 	}
 	map->count = 0;
-	map->frmr = NULL;
 	return map;
 }
 
@@ -336,22 +336,21 @@ static void process_context(struct svcxprt_rdma *xprt,
 
 	switch (ctxt->wr_op) {
 	case IB_WR_SEND:
-		if (test_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags))
-			svc_rdma_put_frmr(xprt, ctxt->frmr);
+		BUG_ON(ctxt->frmr);
 		svc_rdma_put_context(ctxt, 1);
 		break;
 
 	case IB_WR_RDMA_WRITE:
+		BUG_ON(ctxt->frmr);
 		svc_rdma_put_context(ctxt, 0);
 		break;
 
 	case IB_WR_RDMA_READ:
 	case IB_WR_RDMA_READ_WITH_INV:
+		svc_rdma_put_frmr(xprt, ctxt->frmr);
 		if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
 			struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
 			BUG_ON(!read_hdr);
-			if (test_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags))
-				svc_rdma_put_frmr(xprt, ctxt->frmr);
 			spin_lock_bh(&xprt->sc_rq_dto_lock);
 			set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
 			list_add_tail(&read_hdr->dto_q,
@@ -363,6 +362,7 @@ static void process_context(struct svcxprt_rdma *xprt,
 		break;
 
 	default:
+		BUG_ON(1);
 		printk(KERN_ERR "svcrdma: unexpected completion type, "
 		       "opcode=%d\n",
 		       ctxt->wr_op);
@@ -378,29 +378,42 @@ static void process_context(struct svcxprt_rdma *xprt,
 static void sq_cq_reap(struct svcxprt_rdma *xprt)
 {
 	struct svc_rdma_op_ctxt *ctxt = NULL;
-	struct ib_wc wc;
+	struct ib_wc wc_a[6];
+	struct ib_wc *wc;
 	struct ib_cq *cq = xprt->sc_sq_cq;
 	int ret;
 
+	memset(wc_a, 0, sizeof(wc_a));
+
 	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) {
-		if (wc.status != IB_WC_SUCCESS)
-			/* Close the transport */
-			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
+	while ((ret = ib_poll_cq(cq, ARRAY_SIZE(wc_a), wc_a)) > 0) {
+		int i;
 
-		/* Decrement used SQ WR count */
-		atomic_dec(&xprt->sc_sq_count);
-		wake_up(&xprt->sc_send_wait);
+		for (i = 0; i < ret; i++) {
+			wc = &wc_a[i];
+			if (wc->status != IB_WC_SUCCESS) {
+				dprintk("svcrdma: sq wc err status %d\n",
+					wc->status);
 
-		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
-		if (ctxt)
-			process_context(xprt, ctxt);
+				/* Close the transport */
+				set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
+			}
 
-		svc_xprt_put(&xprt->sc_xprt);
+			/* Decrement used SQ WR count */
+			atomic_dec(&xprt->sc_sq_count);
+			wake_up(&xprt->sc_send_wait);
+
+			ctxt = (struct svc_rdma_op_ctxt *)
+				(unsigned long)wc->wr_id;
+			if (ctxt)
+				process_context(xprt, ctxt);
+
+			svc_xprt_put(&xprt->sc_xprt);
+		}
 	}
 
 	if (ctxt)
@@ -993,7 +1006,11 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 			need_dma_mr = 0;
 		break;
 	case RDMA_TRANSPORT_IB:
-		if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
+		if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG)) {
+			need_dma_mr = 1;
+			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
+		} else if (!(devattr.device_cap_flags &
+			     IB_DEVICE_LOCAL_DMA_LKEY)) {
 			need_dma_mr = 1;
 			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
 		} else
@@ -1190,14 +1207,7 @@ static int svc_rdma_has_wspace(struct svc_xprt *xprt)
 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
 
 	/*
-	 * If there are fewer SQ WR available than required to send a
-	 * simple response, return false.
-	 */
-	if ((rdma->sc_sq_depth - atomic_read(&rdma->sc_sq_count) < 3))
-		return 0;
-
-	/*
-	 * ...or there are already waiters on the SQ,
+	 * If there are already waiters on the SQ,
 	 * return false.
 	 */
 	if (waitqueue_active(&rdma->sc_send_wait))

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