[PATCH AUTOSEL 4.9 05/14] net: hns: fix skb->truesize underestimation

From: Sasha Levin
Date: Wed Sep 19 2018 - 22:54:18 EST

From: Huazhong Tan <tanhuazhong@xxxxxxxxxx>

[ Upstream commit b1ccd4c0ab6ef499f47dd84ed4920502a7147bba ]

skb->truesize is not meant to be tracking amount of used bytes in a skb,
but amount of reserved/consumed bytes in memory.

For instance, if we use a single byte in last page fragment, we have to
account the full size of the fragment.

So skb_add_rx_frag needs to calculate the length of the entire buffer into

Fixes: 9cbe9fd5214e ("net: hns: optimize XGE capability by reducing cpu usage")
Signed-off-by: Huazhong tan <tanhuazhong@xxxxxxxxxx>
Signed-off-by: Salil Mehta <salil.mehta@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
drivers/net/ethernet/hisilicon/hns/hns_enet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
index 111e1aab7d83..8a2a07e21324 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
@@ -529,7 +529,7 @@ static void hns_nic_reuse_page(struct sk_buff *skb, int i,

skb_add_rx_frag(skb, i, desc_cb->priv, desc_cb->page_offset + pull_len,
- size - pull_len, truesize - pull_len);
+ size - pull_len, truesize);

/* avoid re-using remote pages,flag default unreuse */
if (unlikely(page_to_nid(desc_cb->priv) != numa_node_id()))