[PATCH 13/20] dpaa_eth: use a page to store the SGT

From: Madalin Bucur
Date: Tue Oct 08 2019 - 08:12:16 EST


Use a page to store the scatter gather table on the transmit path.

Signed-off-by: Madalin Bucur <madalin.bucur@xxxxxxx>
---
drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 43 +++++++++++++-------------
1 file changed, 21 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index 20f0062afdec..e2385c2fa81a 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -1592,9 +1592,9 @@ static struct sk_buff *dpaa_cleanup_tx_fd(const struct dpaa_priv *priv,
int i;

if (unlikely(qm_fd_get_format(fd) == qm_fd_sg)) {
- dma_unmap_single(priv->tx_dma_dev, addr,
- qm_fd_get_offset(fd) + DPAA_SGT_SIZE,
- dma_dir);
+ dma_unmap_page(priv->tx_dma_dev, addr,
+ qm_fd_get_offset(fd) + DPAA_SGT_SIZE,
+ dma_dir);

/* The sgt buffer has been allocated with netdev_alloc_frag(),
* it's from lowmem.
@@ -1636,8 +1636,8 @@ static struct sk_buff *dpaa_cleanup_tx_fd(const struct dpaa_priv *priv,
}

if (qm_fd_get_format(fd) == qm_fd_sg)
- /* Free the page frag that we allocated on Tx */
- skb_free_frag(vaddr);
+ /* Free the page that we allocated on Tx for the SGT */
+ free_pages((unsigned long)vaddr, 0);

return skb;
}
@@ -1885,21 +1885,20 @@ static int skb_to_sg_fd(struct dpaa_priv *priv,
struct net_device *net_dev = priv->net_dev;
struct qm_sg_entry *sgt;
struct sk_buff **skbh;
- int i, j, err, sz;
- void *buffer_start;
+ void *buff_start;
skb_frag_t *frag;
dma_addr_t addr;
size_t frag_len;
- void *sgt_buf;
-
- /* get a page frag to store the SGTable */
- sz = SKB_DATA_ALIGN(priv->tx_headroom + DPAA_SGT_SIZE);
- sgt_buf = netdev_alloc_frag(sz);
- if (unlikely(!sgt_buf)) {
- netdev_err(net_dev, "netdev_alloc_frag() failed for size %d\n",
- sz);
+ struct page *p;
+ int i, j, err;
+
+ /* get a page to store the SGTable */
+ p = dev_alloc_pages(0);
+ if (unlikely(!p)) {
+ netdev_err(net_dev, "dev_alloc_pages() failed\n");
return -ENOMEM;
}
+ buff_start = page_address(p);

/* Enable L3/L4 hardware checksum computation.
*
@@ -1907,7 +1906,7 @@ static int skb_to_sg_fd(struct dpaa_priv *priv,
* need to write into the skb.
*/
err = dpaa_enable_tx_csum(priv, skb, fd,
- sgt_buf + DPAA_TX_PRIV_DATA_SIZE);
+ buff_start + DPAA_TX_PRIV_DATA_SIZE);
if (unlikely(err < 0)) {
if (net_ratelimit())
netif_err(priv, tx_err, net_dev, "HW csum error: %d\n",
@@ -1916,7 +1915,7 @@ static int skb_to_sg_fd(struct dpaa_priv *priv,
}

/* SGT[0] is used by the linear part */
- sgt = (struct qm_sg_entry *)(sgt_buf + priv->tx_headroom);
+ sgt = (struct qm_sg_entry *)(buff_start + priv->tx_headroom);
frag_len = skb_headlen(skb);
qm_sg_entry_set_len(&sgt[0], frag_len);
sgt[0].bpid = FSL_DPAA_BPID_INV;
@@ -1954,15 +1953,15 @@ static int skb_to_sg_fd(struct dpaa_priv *priv,
/* Set the final bit in the last used entry of the SGT */
qm_sg_entry_set_f(&sgt[nr_frags], frag_len);

+ /* set fd offset to priv->tx_headroom */
qm_fd_set_sg(fd, priv->tx_headroom, skb->len);

/* DMA map the SGT page */
- buffer_start = (void *)sgt - priv->tx_headroom;
- skbh = (struct sk_buff **)buffer_start;
+ skbh = (struct sk_buff **)buff_start;
*skbh = skb;

- addr = dma_map_single(priv->tx_dma_dev, buffer_start,
- priv->tx_headroom + DPAA_SGT_SIZE, dma_dir);
+ addr = dma_map_page(priv->tx_dma_dev, p, 0,
+ priv->tx_headroom + DPAA_SGT_SIZE, dma_dir);
if (unlikely(dma_mapping_error(priv->tx_dma_dev, addr))) {
netdev_err(priv->net_dev, "DMA mapping failed");
err = -EINVAL;
@@ -1982,7 +1981,7 @@ static int skb_to_sg_fd(struct dpaa_priv *priv,
qm_sg_entry_get_len(&sgt[j]), dma_dir);
sg0_map_failed:
csum_failed:
- skb_free_frag(sgt_buf);
+ free_pages((unsigned long)buff_start, 0);

return err;
}
--
2.1.0