Patch "i40e: respect metadata on XSK Rx to skb" has been added to the 5.17-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    i40e: respect metadata on XSK Rx to skb

to the 5.17-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i40e-respect-metadata-on-xsk-rx-to-skb.patch
and it can be found in the queue-5.17 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit f911ec9e3877c5b39eea12c3618094f4f2460cde
Author: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
Date:   Wed Dec 8 15:06:55 2021 +0100

    i40e: respect metadata on XSK Rx to skb
    
    [ Upstream commit 6dba29537c0f639b482bd8f8bbd50ab4ae74b48d ]
    
    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 i40e_construct_skb().
    
    Fixes: 0a714186d3c0 ("i40e: add AF_XDP zero-copy Rx support")
    Suggested-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
    Suggested-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
    Signed-off-by: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
    Reviewed-by: Michal Swiatkowski <michal.swiatkowski@xxxxxxxxxxxxxxx>
    Tested-by: Kiran Bhandare <kiranx.bhandare@xxxxxxxxx>
    Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index a449c84fe357..67e9844e2076 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -241,19 +241,25 @@ bool i40e_alloc_rx_buffers_zc(struct i40e_ring *rx_ring, u16 count)
 static struct sk_buff *i40e_construct_skb_zc(struct i40e_ring *rx_ring,
 					     struct xdp_buff *xdp)
 {
+	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;
 
+	net_prefetch(xdp->data_meta);
+
 	/* allocate a skb to store the frags */
-	skb = __napi_alloc_skb(&rx_ring->q_vector->napi, datasize,
+	skb = __napi_alloc_skb(&rx_ring->q_vector->napi, totalsize,
 			       GFP_ATOMIC | __GFP_NOWARN);
 	if (unlikely(!skb))
 		goto out;
 
-	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);
+	}
 
 out:
 	xsk_buff_free(xdp);