[Intel-wired-lan] [PATCH v3 net-next 5/9] ice: respect metadata on XSK Rx to skb

[Alexander Lobakin]

For now, if the XDP prog returns XDP_PASS on XSK, the metadata will
be lost as it doesn't get copied to the skb.
Copy it along with the frame headers. Account its size on skb
allocation, and when copying just treat it as a part of the frame
and do a pull after to "move" it to the "reserved" zone.
net_prefetch() xdp->data_meta and align the copy size to speed-up
memcpy() a little and better match ice_costruct_skb().

Fixes: 2d4238f55697 ("ice: Add support for AF_XDP")
Suggested-by: Jesper Dangaard Brouer <brouer at redhat.com>
Suggested-by: Maciej Fijalkowski <maciej.fijalkowski at intel.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin at intel.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski at linux.intel.com>
---
 drivers/net/ethernet/intel/ice/ice_xsk.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index f0bd8e1953bf..57e49e652439 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -428,18 +428,24 @@ static struct sk_buff *
 ice_construct_skb_zc(struct ice_rx_ring *rx_ring, struct xdp_buff **xdp_arr)
 {
 	struct xdp_buff *xdp = *xdp_arr;
+	unsigned int totalsize = xdp->data_end - xdp->data_meta;
 	unsigned int metasize = xdp->data - xdp->data_meta;
-	unsigned int datasize = xdp->data_end - xdp->data;
 	struct sk_buff *skb;
 
-	skb = __napi_alloc_skb(&rx_ring->q_vector->napi, datasize,
+	net_prefetch(xdp->data_meta);
+
+	skb = __napi_alloc_skb(&rx_ring->q_vector->napi, totalsize,
 			       GFP_ATOMIC | __GFP_NOWARN);
 	if (unlikely(!skb))
 		return NULL;
 
-	memcpy(__skb_put(skb, datasize), xdp->data, datasize);
-	if (metasize)
+	memcpy(__skb_put(skb, totalsize), xdp->data_meta,
+	       ALIGN(totalsize, sizeof(long)));
+
+	if (metasize) {
 		skb_metadata_set(skb, metasize);
+		__skb_pull(skb, metasize);
+	}
 
 	xsk_buff_free(xdp);
 	*xdp_arr = NULL;
-- 
2.33.1