It makes more sense to allocate new (empty) skb and pass it to the
hardware. That way we avoid copying whole packet into new skb which
should result in better performance.
---
drivers/net/ethernet/broadcom/bgmac.c | 74 ++++++++++++++++++++++++---------
1 file changed, 54 insertions(+), 20 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/bgmac.c
b/drivers/net/ethernet/broadcom/bgmac.c
index e70ee43..425fe81 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -304,9 +304,9 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct
bgmac_dma_ring *ring,
struct device *dma_dev = bgmac->core->dma_dev;
struct bgmac_slot_info *slot = &ring->slots[ring->start];
struct sk_buff *skb = slot->skb;
- struct sk_buff *new_skb;
struct bgmac_rx_header *rx;
u16 len, flags;
+ bool resync_skb = true;
/* Unmap buffer to make it accessible to the CPU */
dma_sync_single_for_cpu(dma_dev, slot->dma_addr,
@@ -317,36 +317,70 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct
bgmac_dma_ring *ring,
len = le16_to_cpu(rx->len);
flags = le16_to_cpu(rx->flags);
- /* Check for poison and drop or pass the packet */
- if (len == 0xdead && flags == 0xbeef) {
- bgmac_err(bgmac, "Found poisoned packet at slot %d, DMA
issue!\n",
- ring->start);
- } else {
+ do {
+ /* Check for poisoned packet */
+ if (len == 0xdead && flags == 0xbeef) {
+ bgmac_err(bgmac, "Found poisoned packet at slot
%d, DMA issue!\n",
+ ring->start);
+ break;
+ }
+
/* Omit CRC. */
len -= ETH_FCS_LEN;
- new_skb = netdev_alloc_skb_ip_align(bgmac->net_dev,
len);
- if (new_skb) {
+ /* Use skb_copy for small packets only */
+ if (len > 1) {
+ dma_addr_t old_dma_addr = slot->dma_addr;
+ int err;
+
+ /* Prepare new skb for further packets */
+ err = bgmac_dma_rx_skb_for_slot(bgmac, slot);
+ if (err) {
+ bgmac_err(bgmac, "Couldn't allocate new
skb for slot %d!\n",
+ ring->start);
+ bgmac->net_dev->stats.rx_dropped++;
+ break;
+ }
+ bgmac_dma_rx_setup_desc(bgmac, ring,
+ ring->start);
+
+ /* Unmap old skb, we'll pass it to the netfif */
+ dma_unmap_single(dma_dev, old_dma_addr,
+ BGMAC_RX_BUF_SIZE,
+ DMA_FROM_DEVICE);
+ resync_skb = false;
+
+ skb_put(skb, BGMAC_RX_FRAME_OFFSET + len);
+ skb_pull(skb, BGMAC_RX_FRAME_OFFSET);
+ } else {
+ struct sk_buff *new_skb;
+
+ /* Poison the old skb */
+ rx->len = cpu_to_le16(0xdead);
+ rx->flags = cpu_to_le16(0xbeef);
+
+ new_skb =
netdev_alloc_skb_ip_align(bgmac->net_dev, len);
+ if (!new_skb) {
+ bgmac_err(bgmac, "Allocation of skb for
copying packet failed!\n");
+ bgmac->net_dev->stats.rx_dropped++;
+ break;
+ }
+
skb_put(new_skb, len);
skb_copy_from_linear_data_offset(skb,
BGMAC_RX_FRAME_OFFSET,
new_skb->data,
len);
- skb_checksum_none_assert(skb);
- new_skb->protocol =
- eth_type_trans(new_skb, bgmac->net_dev);
- netif_receive_skb(new_skb);
- handled++;
- } else {
- bgmac->net_dev->stats.rx_dropped++;
- bgmac_err(bgmac, "Allocation of skb for copying
packet failed!\n");
+ skb = new_skb;
}
- /* Poison the old skb */
- rx->len = cpu_to_le16(0xdead);
- rx->flags = cpu_to_le16(0xbeef);
- }
+ skb_checksum_none_assert(skb);
+ skb->protocol = eth_type_trans(skb, bgmac->net_dev);
+ netif_receive_skb(skb);
+ handled++;
+ } while (0);
/* Make it back accessible to the hardware */
+ if (resync_skb)
dma_sync_single_for_device(dma_dev, slot->dma_addr,
BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
--
1.7.10.4
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