4.9-stable review patch. If anyone has any objections, please let me know.
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From: Netanel Belgazal netanel@amazon.com
[ Upstream commit ef5b0771d247379c90c8bf1332ff32f7f74bff7f ]
The buffer length field in the ena rx descriptor is 16 bit, and the current driver passes a full page in each ena rx descriptor. When PAGE_SIZE equals 64kB or more, the buffer length field becomes zero. To solve this issue, limit the ena Rx descriptor to use 16kB even when allocating 64kB kernel pages. This change would not impact ena device functionality, as 16kB is still larger than maximum MTU.
Signed-off-by: Netanel Belgazal netanel@amazon.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 10 +++++----- drivers/net/ethernet/amazon/ena/ena_netdev.h | 11 +++++++++++ 2 files changed, 16 insertions(+), 5 deletions(-)
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -422,7 +422,7 @@ static inline int ena_alloc_rx_page(stru return -ENOMEM; }
- dma = dma_map_page(rx_ring->dev, page, 0, PAGE_SIZE, + dma = dma_map_page(rx_ring->dev, page, 0, ENA_PAGE_SIZE, DMA_FROM_DEVICE); if (unlikely(dma_mapping_error(rx_ring->dev, dma))) { u64_stats_update_begin(&rx_ring->syncp); @@ -439,7 +439,7 @@ static inline int ena_alloc_rx_page(stru rx_info->page_offset = 0; ena_buf = &rx_info->ena_buf; ena_buf->paddr = dma; - ena_buf->len = PAGE_SIZE; + ena_buf->len = ENA_PAGE_SIZE;
return 0; } @@ -456,7 +456,7 @@ static void ena_free_rx_page(struct ena_ return; }
- dma_unmap_page(rx_ring->dev, ena_buf->paddr, PAGE_SIZE, + dma_unmap_page(rx_ring->dev, ena_buf->paddr, ENA_PAGE_SIZE, DMA_FROM_DEVICE);
__free_page(page); @@ -849,10 +849,10 @@ static struct sk_buff *ena_rx_skb(struct do { dma_unmap_page(rx_ring->dev, dma_unmap_addr(&rx_info->ena_buf, paddr), - PAGE_SIZE, DMA_FROM_DEVICE); + ENA_PAGE_SIZE, DMA_FROM_DEVICE);
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_info->page, - rx_info->page_offset, len, PAGE_SIZE); + 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", --- a/drivers/net/ethernet/amazon/ena/ena_netdev.h +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h @@ -321,4 +321,15 @@ void ena_dump_stats_to_buf(struct ena_ad
int ena_get_sset_count(struct net_device *netdev, int sset);
+/* The ENA buffer length fields is 16 bit long. So when PAGE_SIZE == 64kB the + * driver passas 0. + * Since the max packet size the ENA handles is ~9kB limit the buffer length to + * 16kB. + */ +#if PAGE_SIZE > SZ_16K +#define ENA_PAGE_SIZE SZ_16K +#else +#define ENA_PAGE_SIZE PAGE_SIZE +#endif + #endif /* !(ENA_H) */