diff options
| author | Sven Van Asbroeck <thesven73@gmail.com> | 2021-02-15 20:08:03 -0500 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-02-16 15:15:21 -0800 |
| commit | 966df6ded24d537834402a421d46ef31b3647a78 (patch) | |
| tree | 8d6c6e8c966f88e0e892eb394b47e6e0ba33e062 /drivers/net | |
| parent | a8db76d40e4d568a9e9cc9fb8d81352b5ff530ee (diff) | |
lan743x: sync only the received area of an rx ring buffer
On cpu architectures w/o dma cache snooping, dma_unmap() is a
is a very expensive operation, because its resulting sync
needs to invalidate cpu caches.
Increase efficiency/performance by syncing only those sections
of the lan743x's rx ring buffers that are actually in use.
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Reviewed-by: Bryan Whitehead <Bryan.Whitehead@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/ethernet/microchip/lan743x_main.c | 35 |
1 files changed, 26 insertions, 9 deletions
diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c index 475b00e9c7bc..dbdfabff3b00 100644 --- a/drivers/net/ethernet/microchip/lan743x_main.c +++ b/drivers/net/ethernet/microchip/lan743x_main.c @@ -1939,35 +1939,52 @@ static int lan743x_rx_init_ring_element(struct lan743x_rx *rx, int index) struct net_device *netdev = rx->adapter->netdev; struct device *dev = &rx->adapter->pdev->dev; struct lan743x_rx_buffer_info *buffer_info; + unsigned int buffer_length, used_length; struct lan743x_rx_descriptor *descriptor; struct sk_buff *skb; dma_addr_t dma_ptr; - int length; - length = netdev->mtu + ETH_HLEN + 4 + RX_HEAD_PADDING; + buffer_length = netdev->mtu + ETH_HLEN + 4 + RX_HEAD_PADDING; descriptor = &rx->ring_cpu_ptr[index]; buffer_info = &rx->buffer_info[index]; - skb = __netdev_alloc_skb(netdev, length, GFP_ATOMIC | GFP_DMA); + skb = __netdev_alloc_skb(netdev, buffer_length, GFP_ATOMIC | GFP_DMA); if (!skb) return -ENOMEM; - dma_ptr = dma_map_single(dev, skb->data, length, DMA_FROM_DEVICE); + dma_ptr = dma_map_single(dev, skb->data, buffer_length, DMA_FROM_DEVICE); if (dma_mapping_error(dev, dma_ptr)) { dev_kfree_skb_any(skb); return -ENOMEM; } - if (buffer_info->dma_ptr) - dma_unmap_single(dev, buffer_info->dma_ptr, - buffer_info->buffer_length, DMA_FROM_DEVICE); + if (buffer_info->dma_ptr) { + /* sync used area of buffer only */ + if (le32_to_cpu(descriptor->data0) & RX_DESC_DATA0_LS_) + /* frame length is valid only if LS bit is set. + * it's a safe upper bound for the used area in this + * buffer. + */ + used_length = min(RX_DESC_DATA0_FRAME_LENGTH_GET_ + (le32_to_cpu(descriptor->data0)), + buffer_info->buffer_length); + else + used_length = buffer_info->buffer_length; + dma_sync_single_for_cpu(dev, buffer_info->dma_ptr, + used_length, + DMA_FROM_DEVICE); + dma_unmap_single_attrs(dev, buffer_info->dma_ptr, + buffer_info->buffer_length, + DMA_FROM_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); + } buffer_info->skb = skb; buffer_info->dma_ptr = dma_ptr; - buffer_info->buffer_length = length; + buffer_info->buffer_length = buffer_length; descriptor->data1 = cpu_to_le32(DMA_ADDR_LOW32(buffer_info->dma_ptr)); descriptor->data2 = cpu_to_le32(DMA_ADDR_HIGH32(buffer_info->dma_ptr)); descriptor->data3 = 0; descriptor->data0 = cpu_to_le32((RX_DESC_DATA0_OWN_ | - (length & RX_DESC_DATA0_BUF_LENGTH_MASK_))); + (buffer_length & RX_DESC_DATA0_BUF_LENGTH_MASK_))); lan743x_rx_update_tail(rx, index); return 0; |