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net: ena: fix packet's addresses for rx_offset feature
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[ Upstream commit 1396d31 ]

This patch fixes two lines in which the rx_offset received by the device
wasn't taken into account:

- prefetch function:
	In our driver the copied data would reside in
	rx_info->page + rx_headroom + rx_offset

	so the prefetch function is changed accordingly.

- setting page_offset to zero for descriptors > 1:
	for every descriptor but the first, the rx_offset is zero. Hence
	the page_offset value should be set to rx_headroom.

	The previous implementation changed the value of rx_info after
	the descriptor was added to the SKB (essentially providing wrong
	page offset).

Fixes: 68f236d ("net: ena: add support for the rx offset feature")
Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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ShayAgros authored and gregkh committed Dec 2, 2020
1 parent 9b58e35 commit aafcf7a
Showing 1 changed file with 11 additions and 9 deletions.
20 changes: 11 additions & 9 deletions drivers/net/ethernet/amazon/ena/ena_netdev.c
Original file line number Diff line number Diff line change
Expand Up @@ -920,10 +920,14 @@ static void ena_free_all_io_rx_resources(struct ena_adapter *adapter)
static int ena_alloc_rx_page(struct ena_ring *rx_ring,
struct ena_rx_buffer *rx_info, gfp_t gfp)
{
int headroom = rx_ring->rx_headroom;
struct ena_com_buf *ena_buf;
struct page *page;
dma_addr_t dma;

/* restore page offset value in case it has been changed by device */
rx_info->page_offset = headroom;

/* if previous allocated page is not used */
if (unlikely(rx_info->page))
return 0;
Expand Down Expand Up @@ -953,10 +957,9 @@ static int ena_alloc_rx_page(struct ena_ring *rx_ring,
"alloc page %p, rx_info %p\n", page, rx_info);

rx_info->page = page;
rx_info->page_offset = 0;
ena_buf = &rx_info->ena_buf;
ena_buf->paddr = dma + rx_ring->rx_headroom;
ena_buf->len = ENA_PAGE_SIZE - rx_ring->rx_headroom;
ena_buf->paddr = dma + headroom;
ena_buf->len = ENA_PAGE_SIZE - headroom;

return 0;
}
Expand Down Expand Up @@ -1368,7 +1371,8 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,

/* save virt address of first buffer */
va = page_address(rx_info->page) + rx_info->page_offset;
prefetch(va + NET_IP_ALIGN);

prefetch(va);

if (len <= rx_ring->rx_copybreak) {
skb = ena_alloc_skb(rx_ring, false);
Expand Down Expand Up @@ -1409,8 +1413,6 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,

skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_info->page,
rx_info->page_offset, len, ENA_PAGE_SIZE);
/* The offset is non zero only for the first buffer */
rx_info->page_offset = 0;

netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
"rx skb updated. len %d. data_len %d\n",
Expand Down Expand Up @@ -1529,8 +1531,7 @@ static int ena_xdp_handle_buff(struct ena_ring *rx_ring, struct xdp_buff *xdp)
int ret;

rx_info = &rx_ring->rx_buffer_info[rx_ring->ena_bufs[0].req_id];
xdp->data = page_address(rx_info->page) +
rx_info->page_offset + rx_ring->rx_headroom;
xdp->data = page_address(rx_info->page) + rx_info->page_offset;
xdp_set_data_meta_invalid(xdp);
xdp->data_hard_start = page_address(rx_info->page);
xdp->data_end = xdp->data + rx_ring->ena_bufs[0].len;
Expand Down Expand Up @@ -1597,8 +1598,9 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
if (unlikely(ena_rx_ctx.descs == 0))
break;

/* First descriptor might have an offset set by the device */
rx_info = &rx_ring->rx_buffer_info[rx_ring->ena_bufs[0].req_id];
rx_info->page_offset = ena_rx_ctx.pkt_offset;
rx_info->page_offset += ena_rx_ctx.pkt_offset;

netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
"rx_poll: q %d got packet from ena. descs #: %d l3 proto %d l4 proto %d hash: %x\n",
Expand Down

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