From 659200e3e4c9d393d1a3d005752c588eb18d5044 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 11 Nov 2019 20:47:32 +0800 Subject: [PATCH] net: ethernet: ftgmac100: Fix DMA coherency issue with SW checksum [ Upstream commit 88824e3bf29a2fcacfd9ebbfe03063649f0f3254 ] 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 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yang Yingliang --- drivers/net/ethernet/faraday/ftgmac100.c | 25 ++++++++++++------------ 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c index ed6c76d20b45..f6ed889bc36a 100644 --- a/drivers/net/ethernet/faraday/ftgmac100.c +++ b/drivers/net/ethernet/faraday/ftgmac100.c @@ -739,6 +739,18 @@ static int 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); @@ -765,19 +777,6 @@ static int 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 */ -- GitLab