FAILED: patch "[PATCH] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e0068620e5e1779b3d5bb5649cd196e1cbf277a9 Mon Sep 17 00:00:00 2001
From: Tobias Waldekranz <tobias@waldekranz.com>
Date: Thu, 9 Dec 2021 23:24:24 +0100
Subject: [PATCH] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate
 devices

In a typical mv88e6xxx switch tree like this:

  CPU
   |    .----.
.--0--. | .--0--.
| sw0 | | | sw1 |
'-1-2-' | '-1-2-'
    '---'

If sw1p{1,2} are added to a bridge that sw0p1 is not a part of, sw0
still needs to add a crosschip PVT entry for the virtual DSA device
assigned to represent the bridge.

Fixes: ce5df6894a57 ("net: dsa: mv88e6xxx: map virtual bridges with forwarding offload in the PVT")
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 45aaa7333fb8..dced1505e6bf 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2531,6 +2531,7 @@ static int mv88e6xxx_crosschip_bridge_join(struct dsa_switch *ds,
 
 	mv88e6xxx_reg_lock(chip);
 	err = mv88e6xxx_pvt_map(chip, sw_index, port);
+	err = err ? : mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num);
 	mv88e6xxx_reg_unlock(chip);
 
 	return err;
@@ -2546,7 +2547,8 @@ static void mv88e6xxx_crosschip_bridge_leave(struct dsa_switch *ds,
 		return;
 
 	mv88e6xxx_reg_lock(chip);
-	if (mv88e6xxx_pvt_map(chip, sw_index, port))
+	if (mv88e6xxx_pvt_map(chip, sw_index, port) ||
+	    mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num))
 		dev_err(ds->dev, "failed to remap cross-chip Port VLAN\n");
 	mv88e6xxx_reg_unlock(chip);
 }