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net: ena: use build_skb() in RX path

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This patch converts the RX path to use build_skb() for packets larger
than copybreak (set to 256 by default). This function makes the first
descriptor's page to be the linear part of the sk_buff struct buffer.

Also remove the SKB description from the README since most of it no
longer relevant and the parts that are left don't add information.

Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Shay Agroskin 2021-06-08 19:01:12 +03:00 committed by David S. Miller
parent 091d0e85a0
commit 9e5269a915
1 changed files with 41 additions and 25 deletions
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66
drivers/net/ethernet/amazon/ena/ena_netdev.c
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@ -529,7 +529,7 @@ static void ena_xdp_exchange_program_rx_in_range(struct ena_adapter *adapter,
rx_ring->rx_headroom = XDP_PACKET_HEADROOM;
} else {
ena_xdp_unregister_rxq_info(rx_ring);
rx_ring->rx_headroom = 0;
rx_ring->rx_headroom = NET_SKB_PAD;
}
}
}
@ -720,6 +720,7 @@ static void ena_init_io_rings(struct ena_adapter *adapter,
rxr->smoothed_interval =
ena_com_get_nonadaptive_moderation_interval_rx(ena_dev);
rxr->empty_rx_queue = 0;
rxr->rx_headroom = NET_SKB_PAD;
adapter->ena_napi[i].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;
rxr->xdp_ring = &adapter->tx_ring[i + adapter->num_io_queues];
}
@ -982,6 +983,7 @@ static int ena_alloc_rx_page(struct ena_ring *rx_ring,
struct ena_com_buf *ena_buf;
struct page *page;
dma_addr_t dma;
int tailroom;
/* restore page offset value in case it has been changed by device */
rx_info->page_offset = headroom;
@ -1012,10 +1014,12 @@ static int ena_alloc_rx_page(struct ena_ring *rx_ring,
netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
"Allocate page %p, rx_info %p\n", page, rx_info);
tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
rx_info->page = page;
ena_buf = &rx_info->ena_buf;
ena_buf->paddr = dma + headroom;
ena_buf->len = ENA_PAGE_SIZE - headroom;
ena_buf->len = ENA_PAGE_SIZE - headroom - tailroom;
return 0;
}
@ -1381,21 +1385,23 @@ static int ena_clean_tx_irq(struct ena_ring *tx_ring, u32 budget)
return tx_pkts;
}
static struct sk_buff *ena_alloc_skb(struct ena_ring *rx_ring, bool frags)
static struct sk_buff *ena_alloc_skb(struct ena_ring *rx_ring, void *first_frag)
{
struct sk_buff *skb;
if (frags)
skb = napi_get_frags(rx_ring->napi);
else
if (!first_frag)
skb = netdev_alloc_skb_ip_align(rx_ring->netdev,
rx_ring->rx_copybreak);
else
skb = build_skb(first_frag, ENA_PAGE_SIZE);
if (unlikely(!skb)) {
ena_increase_stat(&rx_ring->rx_stats.skb_alloc_fail, 1,
&rx_ring->syncp);
netif_dbg(rx_ring->adapter, rx_err, rx_ring->netdev,
"Failed to allocate skb. frags: %d\n", frags);
"Failed to allocate skb. first_frag %s\n",
first_frag ? "provided" : "not provided");
return NULL;
}
@ -1410,7 +1416,9 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
struct sk_buff *skb;
struct ena_rx_buffer *rx_info;
u16 len, req_id, buf = 0;
void *va;
void *page_addr;
u32 page_offset;
void *data_addr;
len = ena_bufs[buf].len;
req_id = ena_bufs[buf].req_id;
@ -1428,12 +1436,14 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
rx_info, rx_info->page);
/* save virt address of first buffer */
va = page_address(rx_info->page) + rx_info->page_offset;
page_addr = page_address(rx_info->page);
page_offset = rx_info->page_offset;
data_addr = page_addr + page_offset;
prefetch(va);
prefetch(data_addr);
if (len <= rx_ring->rx_copybreak) {
skb = ena_alloc_skb(rx_ring, false);
skb = ena_alloc_skb(rx_ring, NULL);
if (unlikely(!skb))
return NULL;
@ -1446,7 +1456,7 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
dma_unmap_addr(&rx_info->ena_buf, paddr),
len,
DMA_FROM_DEVICE);
skb_copy_to_linear_data(skb, va, len);
skb_copy_to_linear_data(skb, data_addr, len);
dma_sync_single_for_device(rx_ring->dev,
dma_unmap_addr(&rx_info->ena_buf, paddr),
len,
@ -1460,16 +1470,18 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
return skb;
}
skb = ena_alloc_skb(rx_ring, true);
ena_unmap_rx_buff(rx_ring, rx_info);
skb = ena_alloc_skb(rx_ring, page_addr);
if (unlikely(!skb))
return NULL;
/* Populate skb's linear part */
skb_reserve(skb, page_offset);
skb_put(skb, len);
skb->protocol = eth_type_trans(skb, rx_ring->netdev);
do {
ena_unmap_rx_buff(rx_ring, rx_info);
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_info->page,
rx_info->page_offset, len, ENA_PAGE_SIZE);
netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
"RX skb updated. len %d. data_len %d\n",
skb->len, skb->data_len);
@ -1488,6 +1500,12 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
req_id = ena_bufs[buf].req_id;
rx_info = &rx_ring->rx_buffer_info[req_id];
ena_unmap_rx_buff(rx_ring, rx_info);
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_info->page,
rx_info->page_offset, len, ENA_PAGE_SIZE);
} while (1);
return skb;
@ -1700,14 +1718,12 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
skb_record_rx_queue(skb, rx_ring->qid);
if (rx_ring->ena_bufs[0].len <= rx_ring->rx_copybreak) {
total_len += rx_ring->ena_bufs[0].len;
if (rx_ring->ena_bufs[0].len <= rx_ring->rx_copybreak)
rx_copybreak_pkt++;
napi_gro_receive(napi, skb);
} else {
total_len += skb->len;
napi_gro_frags(napi);
}
total_len += skb->len;
napi_gro_receive(napi, skb);
res_budget--;
} while (likely(res_budget));