[PATCH net-next v3 2/2] enic: use netdev_dma_alloc

[Govindarajulu Varadarajan <_govind@gmx.com>]

This patches uses dma cache skb allocator fot rx buffers.

netdev_dma_head is initialized per rq. All calls to netdev_dma_alloc_skb() and
netdev_dma_frag_unmap() happens in napi_poll and they are serialized.

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
---
 drivers/net/ethernet/cisco/enic/enic_main.c | 31 +++++++++--------------------
 drivers/net/ethernet/cisco/enic/vnic_rq.c   |  3 +++
 drivers/net/ethernet/cisco/enic/vnic_rq.h   |  3 +++
 3 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
index 204bd182..3be5bc12 100644
--- a/drivers/net/ethernet/cisco/enic/enic_main.c
+++ b/drivers/net/ethernet/cisco/enic/enic_main.c
@@ -952,13 +952,9 @@ nla_put_failure:
 
 static void enic_free_rq_buf(struct vnic_rq *rq, struct vnic_rq_buf *buf)
 {
-	struct enic *enic = vnic_dev_priv(rq->vdev);
-
 	if (!buf->os_buf)
 		return;
-
-	pci_unmap_single(enic->pdev, buf->dma_addr,
-		buf->len, PCI_DMA_FROMDEVICE);
+	netdev_dma_frag_unmap(&rq->nc_head, buf->nc);
 	dev_kfree_skb_any(buf->os_buf);
 	buf->os_buf = NULL;
 }
@@ -979,17 +975,10 @@ static int enic_rq_alloc_buf(struct vnic_rq *rq)
 
 		return 0;
 	}
-	skb = netdev_alloc_skb_ip_align(netdev, len);
+	skb = netdev_dma_alloc_skb(&rq->nc_head, &buf->nc, &dma_addr, len);
 	if (!skb)
 		return -ENOMEM;
 
-	dma_addr = pci_map_single(enic->pdev, skb->data, len,
-				  PCI_DMA_FROMDEVICE);
-	if (unlikely(enic_dma_map_check(enic, dma_addr))) {
-		dev_kfree_skb(skb);
-		return -ENOMEM;
-	}
-
 	enic_queue_rq_desc(rq, skb, os_buf_index,
 		dma_addr, len);
 
@@ -1016,8 +1005,6 @@ static bool enic_rxcopybreak(struct net_device *netdev, struct sk_buff **skb,
 	new_skb = netdev_alloc_skb_ip_align(netdev, len);
 	if (!new_skb)
 		return false;
-	pci_dma_sync_single_for_cpu(enic->pdev, buf->dma_addr, len,
-				    DMA_FROM_DEVICE);
 	memcpy(new_skb->data, (*skb)->data, len);
 	*skb = new_skb;
 
@@ -1065,8 +1052,7 @@ static void enic_rq_indicate_buf(struct vnic_rq *rq,
 				enic->rq_truncated_pkts++;
 		}
 
-		pci_unmap_single(enic->pdev, buf->dma_addr, buf->len,
-				 PCI_DMA_FROMDEVICE);
+		netdev_dma_frag_unmap(&rq->nc_head, buf->nc);
 		dev_kfree_skb_any(skb);
 		buf->os_buf = NULL;
 
@@ -1078,10 +1064,11 @@ static void enic_rq_indicate_buf(struct vnic_rq *rq,
 		/* Good receive
 		 */
 
+		pci_dma_sync_single_for_cpu(enic->pdev, buf->dma_addr,
+					    bytes_written, DMA_FROM_DEVICE);
 		if (!enic_rxcopybreak(netdev, &skb, buf, bytes_written)) {
 			buf->os_buf = NULL;
-			pci_unmap_single(enic->pdev, buf->dma_addr, buf->len,
-					 PCI_DMA_FROMDEVICE);
+			netdev_dma_frag_unmap(&rq->nc_head, buf->nc);
 		}
 		prefetch(skb->data - NET_IP_ALIGN);
 
@@ -1122,9 +1109,7 @@ static void enic_rq_indicate_buf(struct vnic_rq *rq,
 
 		/* Buffer overflow
 		 */
-
-		pci_unmap_single(enic->pdev, buf->dma_addr, buf->len,
-				 PCI_DMA_FROMDEVICE);
+		netdev_dma_frag_unmap(&rq->nc_head, buf->nc);
 		dev_kfree_skb_any(skb);
 		buf->os_buf = NULL;
 	}
@@ -1648,6 +1633,8 @@ static int enic_open(struct net_device *netdev)
 	}
 
 	for (i = 0; i < enic->rq_count; i++) {
+		netdev_dma_init(&enic->rq[i].nc_head, &enic->pdev->dev,
+				GFP_ATOMIC);
 		vnic_rq_fill(&enic->rq[i], enic_rq_alloc_buf);
 		/* Need at least one buffer on ring to get going */
 		if (vnic_rq_desc_used(&enic->rq[i]) == 0) {
diff --git a/drivers/net/ethernet/cisco/enic/vnic_rq.c b/drivers/net/ethernet/cisco/enic/vnic_rq.c
index 36a2ed6..afa1d71 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_rq.c
+++ b/drivers/net/ethernet/cisco/enic/vnic_rq.c
@@ -23,6 +23,7 @@
 #include <linux/pci.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
+#include <linux/skbuff.h>
 
 #include "vnic_dev.h"
 #include "vnic_rq.h"
@@ -199,6 +200,8 @@ void vnic_rq_clean(struct vnic_rq *rq,
 		rq->ring.desc_avail++;
 	}
 
+	netdev_dma_destroy(&rq->nc_head);
+
 	/* Use current fetch_index as the ring starting point */
 	fetch_index = ioread32(&rq->ctrl->fetch_index);
 
diff --git a/drivers/net/ethernet/cisco/enic/vnic_rq.h b/drivers/net/ethernet/cisco/enic/vnic_rq.h
index 8111d52..d4ee963 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_rq.h
+++ b/drivers/net/ethernet/cisco/enic/vnic_rq.h
@@ -21,6 +21,7 @@
 #define _VNIC_RQ_H_
 
 #include <linux/pci.h>
+#include <linux/skbuff.h>
 
 #include "vnic_dev.h"
 #include "vnic_cq.h"
@@ -73,6 +74,7 @@ struct vnic_rq_buf {
 	unsigned int index;
 	void *desc;
 	uint64_t wr_id;
+	struct netdev_dma_node *nc;
 };
 
 struct vnic_rq {
@@ -100,6 +102,7 @@ struct vnic_rq {
 	unsigned int bpoll_state;
 	spinlock_t bpoll_lock;
 #endif /* CONFIG_NET_RX_BUSY_POLL */
+	struct netdev_dma_head nc_head;
 };
 
 static inline unsigned int vnic_rq_desc_avail(struct vnic_rq *rq)
-- 
2.3.2