Sv: FAILED: patch "[PATCH] net: dsa: microchip: fix bridging with more than two member" failed to apply to 5.16-stable tree - Linux-stable-mirror

26 Feb 2022

Commit b3612ccdf284 ("net: dsa: microchip: implement multi-bridge support")
plugged a packet leak between ports that were members of different bridges.
Unfortunately, this broke another use case, namely that of more than two
ports that are members of the same bridge.
After that commit, when a port is added to a bridge, hardware bridging
between other member ports of that bridge will be cleared, preventing
packet exchange between them.
Fix by ensuring that the Port VLAN Membership bitmap includes any existing
ports in the bridge, not just the port being added.
Upstream commit 3d00827a90db6f79abc7cdc553887f89a2e0a184, backported to 5.16.
Fixes: b3612ccdf284 ("net: dsa: microchip: implement multi-bridge support")
Signed-off-by: Svenning Sørensen sss@secomea.com
Tested-by: Oleksij Rempel o.rempel@pengutronix.de
Signed-off-by: David S. Miller davem@davemloft.net
---
 drivers/net/dsa/microchip/ksz_common.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 8a04302018dc..7ab9ab58de65 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -26,7 +26,7 @@ void ksz_update_port_member(struct ksz_device *dev, int port)
        struct dsa_switch *ds = dev->ds;
        u8 port_member = 0, cpu_port;
        const struct dsa_port *dp;
-       int i;
+       int i, j;
if (!dsa_is_user_port(ds, port))
                return;
@@ -45,13 +45,33 @@ void ksz_update_port_member(struct ksz_device *dev, int port)
                        continue;
                if (!dp->bridge_dev || dp->bridge_dev != other_dp->bridge_dev)
                        continue;
+               if (other_p->stp_state != BR_STATE_FORWARDING)
+                       continue;
-               if (other_p->stp_state == BR_STATE_FORWARDING &&
-                   p->stp_state == BR_STATE_FORWARDING) {
+               if (p->stp_state == BR_STATE_FORWARDING) {
                        val |= BIT(port);
                        port_member |= BIT(i);
                }
+               /* Retain port [i]'s relationship to other ports than [port] */
+               for (j = 0; j < ds->num_ports; j++) {
+                       const struct dsa_port *third_dp;
+                       struct ksz_port *third_p;
+
+                       if (j == i)
+                               continue;
+                       if (j == port)
+                               continue;
+                       if (!dsa_is_user_port(ds, j))
+                               continue;
+                       third_p = &dev->ports[j];
+                       if (third_p->stp_state != BR_STATE_FORWARDING)
+                               continue;
+                       third_dp = dsa_to_port(ds, j);
+                       if (third_dp->bridge_dev == dp->bridge_dev)
+                               val |= BIT(j);
+               }
+
                dev->dev_ops->cfg_port_member(dev, i, val | cpu_port);
        }
--
2.20.1
Backported upstream commit 3d00827a90db6f79abc7cdc553887f89a2e0a184 to 5.16.
Sorry about the subject; the MS webmail client doesn't seem allow me to change it when
replying to a message :(
Svenning
________________________________________
Fra: Svenning Sørensen sss@secomea.com
Sendt: 26. februar 2022 14:04
Til: gregkh@linuxfoundation.org
Emne: Sv: FAILED: patch "[PATCH] net: dsa: microchip: fix bridging with more than two member" failed to apply to 5.16-stable tree
gregkh@linuxfoundation wrote:
...
...
...
The patch below does not apply to the 5.16-stable tree.
------------------ original commit in Linus's tree ------------------
...
From 3d00827a90db6f79abc7cdc553887f89a2e0a184 Mon Sep 17 00:00:00 2001
...
...
...
That's strange - it applies just fine without errors here:
Try building it :)
Argh, yes, I should have thought of that - Sorry :)
It depended on another patch (implementing dsa_port_bridge_same()) which is
not in the 5.16 tree.
I'll send a properly backported version (which has been both compiled and
runtime tested) in a reply to this message; I hope this is a workable approach,
as I'm not really familiar with your workflow.
Best regards,
Svenning Sørensen
________________________________________
Fra: gregkh@linuxfoundation.org gregkh@linuxfoundation.org
Sendt: 26. februar 2022 08:38
Til: Svenning Sørensen
Cc: davem@davemloft.net; o.rempel@pengutronix.de; stable@vger.kernel.org
Emne: Re: FAILED: patch "[PATCH] net: dsa: microchip: fix bridging with more than two member" failed to apply to 5.16-stable tree
On Fri, Feb 25, 2022 at 05:14:13PM +0000, Svenning Sørensen wrote:
...
gregkh@linuxfoundation wrote:
...
...
The patch below does not apply to the 5.16-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.
...
...
...
------------------ original commit in Linus's tree ------------------
...
From 3d00827a90db6f79abc7cdc553887f89a2e0a184 Mon Sep 17 00:00:00 2001
Hi Greg,
That's strange - it applies just fine without errors here:
--- snip ---
$ git log --oneline -n 1
f40e0f7a433b (HEAD -> linux-5.16.y, tag: v5.16.11, stable/linux-5.16.y) Linux 5.16.11
$ git cherry-pick -x 3d00827a90db6f79abc7cdc553887f89a2e0a184
[linux-5.16.y e1e17aca71a0] net: dsa: microchip: fix bridging with more than two member ports
 Date: Fri Feb 18 11:27:01 2022 +0000
 1 file changed, 23 insertions(+), 3 deletions(-)
--- snip ---
So I'm not sure what's needed for backporting?
Try building it :)

    