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dpaa2-eth: add rx copybreak support 

DMA unmapping, allocating a new buffer and DMA mapping it back on the
refill path is really not that efficient. Proper buffer recycling (page
pool, flipping the page and using the other half) cannot be done for
DPAA2 since it's not a ring based controller but it rather deals with
multiple queues which all get their buffers from the same buffer pool on
Rx.

To circumvent these limitations, add support for Rx copybreak. For small
sized packets instead of creating a skb around the buffer in which the
frame was received, allocate a new sk buffer altogether, copy the
contents of the frame and release the initial page back into the buffer
pool.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ioana Ciornei 2021-04-02 12:55:31 +03:00 committed by David S. Miller
parent 28d137cc8c
commit 50f826999a
2 changed files with 36 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
View File

@ -418,6 +418,34 @@ static u32 dpaa2_eth_run_xdp(struct dpaa2_eth_priv *priv,
return xdp_act;
}
static struct sk_buff *dpaa2_eth_copybreak(struct dpaa2_eth_channel *ch,
const struct dpaa2_fd *fd,
void *fd_vaddr)
{
u16 fd_offset = dpaa2_fd_get_offset(fd);
u32 fd_length = dpaa2_fd_get_len(fd);
struct sk_buff *skb = NULL;
unsigned int skb_len;
if (fd_length > DPAA2_ETH_DEFAULT_COPYBREAK)
return NULL;
skb_len = fd_length + dpaa2_eth_needed_headroom(NULL);
skb = napi_alloc_skb(&ch->napi, skb_len);
if (!skb)
return NULL;
skb_reserve(skb, dpaa2_eth_needed_headroom(NULL));
skb_put(skb, fd_length);
memcpy(skb->data, fd_vaddr + fd_offset, fd_length);
dpaa2_eth_recycle_buf(ch->priv, ch, dpaa2_fd_get_addr(fd));
return skb;
}
/* Main Rx frame processing routine */
static void dpaa2_eth_rx(struct dpaa2_eth_priv *priv,
struct dpaa2_eth_channel *ch,
@ -459,9 +487,12 @@ static void dpaa2_eth_rx(struct dpaa2_eth_priv *priv,
return;
}
dma_unmap_page(dev, addr, priv->rx_buf_size,
DMA_BIDIRECTIONAL);
skb = dpaa2_eth_build_linear_skb(ch, fd, vaddr);
skb = dpaa2_eth_copybreak(ch, fd, vaddr);
if (!skb) {
dma_unmap_page(dev, addr, priv->rx_buf_size,
DMA_BIDIRECTIONAL);
skb = dpaa2_eth_build_linear_skb(ch, fd, vaddr);
}
} else if (fd_format == dpaa2_fd_sg) {
WARN_ON(priv->xdp_prog);

2
drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
View File

@ -489,6 +489,8 @@ struct dpaa2_eth_trap_data {
struct dpaa2_eth_priv *priv;
};
#define DPAA2_ETH_DEFAULT_COPYBREAK 512
/* Driver private data */
struct dpaa2_eth_priv {
struct net_device *net_dev;