* [PATCH net v3] gve: Fixes DMA synchronization.
@ 2019-11-01 17:09 Yangchun Fu
2019-11-01 22:00 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Yangchun Fu @ 2019-11-01 17:09 UTC (permalink / raw)
To: netdev; +Cc: davem, simon.horman, Yangchun Fu, Catherine Sullivan
Synces the DMA buffer properly in order for CPU and device to see
the most up-to-data data.
Signed-off-by: Yangchun Fu <yangchun@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
---
Changes in v3:
- Places local variables in reverse christmas tree ordering.
drivers/net/ethernet/google/gve/gve_rx.c | 2 ++
drivers/net/ethernet/google/gve/gve_tx.c | 24 ++++++++++++++++++++++--
2 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c
index 59564ac99d2a..edec61dfc868 100644
--- a/drivers/net/ethernet/google/gve/gve_rx.c
+++ b/drivers/net/ethernet/google/gve/gve_rx.c
@@ -289,6 +289,8 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc,
len = be16_to_cpu(rx_desc->len) - GVE_RX_PAD;
page_info = &rx->data.page_info[idx];
+ dma_sync_single_for_cpu(&priv->pdev->dev, rx->data.qpl->page_buses[idx],
+ PAGE_SIZE, DMA_FROM_DEVICE);
/* gvnic can only receive into registered segments. If the buffer
* can't be recycled, our only choice is to copy the data out of
diff --git a/drivers/net/ethernet/google/gve/gve_tx.c b/drivers/net/ethernet/google/gve/gve_tx.c
index 778b87b5a06c..0a9a7ee2a866 100644
--- a/drivers/net/ethernet/google/gve/gve_tx.c
+++ b/drivers/net/ethernet/google/gve/gve_tx.c
@@ -390,7 +390,21 @@ static void gve_tx_fill_seg_desc(union gve_tx_desc *seg_desc,
seg_desc->seg.seg_addr = cpu_to_be64(addr);
}
-static int gve_tx_add_skb(struct gve_tx_ring *tx, struct sk_buff *skb)
+static void gve_dma_sync_for_device(struct device *dev, dma_addr_t *page_buses,
+ u64 iov_offset, u64 iov_len)
+{
+ dma_addr_t dma;
+ u64 addr;
+
+ for (addr = iov_offset; addr < iov_offset + iov_len;
+ addr += PAGE_SIZE) {
+ dma = page_buses[addr / PAGE_SIZE];
+ dma_sync_single_for_device(dev, dma, PAGE_SIZE, DMA_TO_DEVICE);
+ }
+}
+
+static int gve_tx_add_skb(struct gve_tx_ring *tx, struct sk_buff *skb,
+ struct device *dev)
{
int pad_bytes, hlen, hdr_nfrags, payload_nfrags, l4_hdr_offset;
union gve_tx_desc *pkt_desc, *seg_desc;
@@ -432,6 +446,9 @@ static int gve_tx_add_skb(struct gve_tx_ring *tx, struct sk_buff *skb)
skb_copy_bits(skb, 0,
tx->tx_fifo.base + info->iov[hdr_nfrags - 1].iov_offset,
hlen);
+ gve_dma_sync_for_device(dev, tx->tx_fifo.qpl->page_buses,
+ info->iov[hdr_nfrags - 1].iov_offset,
+ info->iov[hdr_nfrags - 1].iov_len);
copy_offset = hlen;
for (i = payload_iov; i < payload_nfrags + payload_iov; i++) {
@@ -445,6 +462,9 @@ static int gve_tx_add_skb(struct gve_tx_ring *tx, struct sk_buff *skb)
skb_copy_bits(skb, copy_offset,
tx->tx_fifo.base + info->iov[i].iov_offset,
info->iov[i].iov_len);
+ gve_dma_sync_for_device(dev, tx->tx_fifo.qpl->page_buses,
+ info->iov[i].iov_offset,
+ info->iov[i].iov_len);
copy_offset += info->iov[i].iov_len;
}
@@ -473,7 +493,7 @@ netdev_tx_t gve_tx(struct sk_buff *skb, struct net_device *dev)
gve_tx_put_doorbell(priv, tx->q_resources, tx->req);
return NETDEV_TX_BUSY;
}
- nsegs = gve_tx_add_skb(tx, skb);
+ nsegs = gve_tx_add_skb(tx, skb, &priv->pdev->dev);
netdev_tx_sent_queue(tx->netdev_txq, skb->len);
skb_tx_timestamp(skb);
--
2.24.0.rc1.363.gb1bccd3e3d-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net v3] gve: Fixes DMA synchronization.
2019-11-01 17:09 [PATCH net v3] gve: Fixes DMA synchronization Yangchun Fu
@ 2019-11-01 22:00 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2019-11-01 22:00 UTC (permalink / raw)
To: yangchun; +Cc: netdev, simon.horman, csully
From: Yangchun Fu <yangchun@google.com>
Date: Fri, 1 Nov 2019 10:09:56 -0700
> Synces the DMA buffer properly in order for CPU and device to see
> the most up-to-data data.
>
> Signed-off-by: Yangchun Fu <yangchun@google.com>
> Reviewed-by: Catherine Sullivan <csully@google.com>
Applied, thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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