[PATCH net v2] i40e/i40evf: proper update of the page_offset field

[Björn Töpel]

From: Björn Töpel <bjorn.to...@intel.com>

In f8b45b74cc62 ("i40e/i40evf: Use build_skb to build frames")
i40e_build_skb updates the page_offset field with an incorrect offset,
which can lead to data corruption. This patch updates page_offset
correctly, by properly setting truesize.

Note that the bug only appears on architectures where PAGE_SIZE is
8192 or larger.

Fixes: f8b45b74cc62 ("i40e/i40evf: Use build_skb to build frames")
Signed-off-by: Björn Töpel <bjorn.to...@intel.com>
---
 drivers/net/ethernet/intel/i40e/i40e_txrx.c   | 3 ++-
 drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c 
b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 29321a6167a6..cd894f4023b1 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1854,7 +1854,8 @@ static struct sk_buff *i40e_build_skb(struct i40e_ring 
*rx_ring,
 #if (PAGE_SIZE < 8192)
        unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2;
 #else
-       unsigned int truesize = SKB_DATA_ALIGN(size);
+       unsigned int truesize = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) +
+                               SKB_DATA_ALIGN(I40E_SKB_PAD + size);
 #endif
        struct sk_buff *skb;
 
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c 
b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index dfe241a12ad0..12b02e530503 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -1190,7 +1190,8 @@ static struct sk_buff *i40e_build_skb(struct i40e_ring 
*rx_ring,
 #if (PAGE_SIZE < 8192)
        unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2;
 #else
-       unsigned int truesize = SKB_DATA_ALIGN(size);
+       unsigned int truesize = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) +
+                               SKB_DATA_ALIGN(I40E_SKB_PAD + size);
 #endif
        struct sk_buff *skb;
 
-- 
2.11.0