From 88824e3bf29a2fcacfd9ebbfe03063649f0f3254 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Fri, 25 Oct 2019 13:47:24 +1100 Subject: net: ethernet: ftgmac100: Fix DMA coherency issue with SW checksum We are calling the checksum helper after the dma_map_single() call to map the packet. This is incorrect as the checksumming code will touch the packet from the CPU. This means the cache won't be properly flushes (or the bounce buffering will leave us with the unmodified packet to DMA). This moves the calculation of the checksum & vlan tags to before the DMA mapping. This also has the side effect of fixing another bug: If the checksum helper fails, we goto "drop" to drop the packet, which will not unmap the DMA mapping. Signed-off-by: Benjamin Herrenschmidt Fixes: 05690d633f30 ("ftgmac100: Upgrade to NETIF_F_HW_CSUM") Reviewed-by: Vijay Khemka Tested-by: Vijay Khemka Signed-off-by: David S. Miller --- drivers/net/ethernet/faraday/ftgmac100.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c index 9b7af94a40bb..96e9565f1e08 100644 --- a/drivers/net/ethernet/faraday/ftgmac100.c +++ b/drivers/net/ethernet/faraday/ftgmac100.c @@ -727,6 +727,18 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb, */ nfrags = skb_shinfo(skb)->nr_frags; + /* Setup HW checksumming */ + csum_vlan = 0; + if (skb->ip_summed == CHECKSUM_PARTIAL && + !ftgmac100_prep_tx_csum(skb, &csum_vlan)) + goto drop; + + /* Add VLAN tag */ + if (skb_vlan_tag_present(skb)) { + csum_vlan |= FTGMAC100_TXDES1_INS_VLANTAG; + csum_vlan |= skb_vlan_tag_get(skb) & 0xffff; + } + /* Get header len */ len = skb_headlen(skb); @@ -753,19 +765,6 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb, if (nfrags == 0) f_ctl_stat |= FTGMAC100_TXDES0_LTS; txdes->txdes3 = cpu_to_le32(map); - - /* Setup HW checksumming */ - csum_vlan = 0; - if (skb->ip_summed == CHECKSUM_PARTIAL && - !ftgmac100_prep_tx_csum(skb, &csum_vlan)) - goto drop; - - /* Add VLAN tag */ - if (skb_vlan_tag_present(skb)) { - csum_vlan |= FTGMAC100_TXDES1_INS_VLANTAG; - csum_vlan |= skb_vlan_tag_get(skb) & 0xffff; - } - txdes->txdes1 = cpu_to_le32(csum_vlan); /* Next descriptor */ -- cgit v1.2.3-59-g8ed1b