Patch "net: fec: correct queue selection" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    net: fec: correct queue selection

to the 5.15-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:
     net-fec-correct-queue-selection.patch
and it can be found in the queue-5.15 subdirectory.

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



commit 959b4f30427b49794f411a48408a559c1eadf50a
Author: Radu Bulie <radu-andrei.bulie@xxxxxxx>
Date:   Thu Dec 7 16:38:01 2023 +0800

    net: fec: correct queue selection
    
    [ Upstream commit 9fc95fe95c3e2a63ced8eeca4b256518ab204b63 ]
    
    The old implementation extracted VLAN TCI info from the payload
    before the VLAN tag has been pushed in the payload.
    
    Another problem was that the VLAN TCI was extracted even if the
    packet did not have VLAN protocol header.
    
    This resulted in invalid VLAN TCI and as a consequence a random
    queue was computed.
    
    This patch fixes the above issues and use the VLAN TCI from the
    skb if it is present or VLAN TCI from payload if present. If no
    VLAN header is present queue 0 is selected.
    
    Fixes: 52c4a1a85f4b ("net: fec: add ndo_select_queue to fix TX bandwidth fluctuations")
    Signed-off-by: Radu Bulie <radu-andrei.bulie@xxxxxxx>
    Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index c0c96de7a9de4..717d4bc5bac63 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -3436,31 +3436,26 @@ static int fec_set_features(struct net_device *netdev,
 	return 0;
 }
 
-static u16 fec_enet_get_raw_vlan_tci(struct sk_buff *skb)
-{
-	struct vlan_ethhdr *vhdr;
-	unsigned short vlan_TCI = 0;
-
-	if (skb->protocol == htons(ETH_P_ALL)) {
-		vhdr = (struct vlan_ethhdr *)(skb->data);
-		vlan_TCI = ntohs(vhdr->h_vlan_TCI);
-	}
-
-	return vlan_TCI;
-}
-
 static u16 fec_enet_select_queue(struct net_device *ndev, struct sk_buff *skb,
 				 struct net_device *sb_dev)
 {
 	struct fec_enet_private *fep = netdev_priv(ndev);
-	u16 vlan_tag;
+	u16 vlan_tag = 0;
 
 	if (!(fep->quirks & FEC_QUIRK_HAS_AVB))
 		return netdev_pick_tx(ndev, skb, NULL);
 
-	vlan_tag = fec_enet_get_raw_vlan_tci(skb);
-	if (!vlan_tag)
+	/* VLAN is present in the payload.*/
+	if (eth_type_vlan(skb->protocol)) {
+		struct vlan_ethhdr *vhdr = skb_vlan_eth_hdr(skb);
+
+		vlan_tag = ntohs(vhdr->h_vlan_TCI);
+	/*  VLAN is present in the skb but not yet pushed in the payload.*/
+	} else if (skb_vlan_tag_present(skb)) {
+		vlan_tag = skb->vlan_tci;
+	} else {
 		return vlan_tag;
+	}
 
 	return fec_enet_vlan_pri_to_queue[vlan_tag >> 13];
 }