This is a note to let you know that I've just added the patch titled i40e: don't reserve excessive XDP_PACKET_HEADROOM 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-don-t-reserve-excessive-xdp_packet_headroom-on-.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 545e835c7db7e375d67f80c07b45b80333621161 Author: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx> Date: Wed Dec 8 15:06:54 2021 +0100 i40e: don't reserve excessive XDP_PACKET_HEADROOM on XSK Rx to skb [ Upstream commit bc97f9c6f988b31b728eb47a94ca825401dbeffe ] {__,}napi_alloc_skb() allocates and reserves additional NET_SKB_PAD + NET_IP_ALIGN for any skb. OTOH, i40e_construct_skb_zc() currently allocates and reserves additional `xdp->data - xdp->data_hard_start`, which is XDP_PACKET_HEADROOM for XSK frames. There's no need for that at all as the frame is post-XDP and will go only to the networking stack core. Pass the size of the actual data only to __napi_alloc_skb() and don't reserve anything. This will give enough headroom for stack processing. Fixes: 0a714186d3c0 ("i40e: add AF_XDP zero-copy Rx support") Signed-off-by: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@xxxxxxxxxxxxxxx> Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> 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 945b1bb9c6f4..a449c84fe357 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c @@ -246,13 +246,11 @@ static struct sk_buff *i40e_construct_skb_zc(struct i40e_ring *rx_ring, struct sk_buff *skb; /* allocate a skb to store the frags */ - skb = __napi_alloc_skb(&rx_ring->q_vector->napi, - xdp->data_end - xdp->data_hard_start, + skb = __napi_alloc_skb(&rx_ring->q_vector->napi, datasize, GFP_ATOMIC | __GFP_NOWARN); if (unlikely(!skb)) goto out; - skb_reserve(skb, xdp->data - xdp->data_hard_start); memcpy(__skb_put(skb, datasize), xdp->data, datasize); if (metasize) skb_metadata_set(skb, metasize);