net: dsa: Initialize ds->cpu_port_mask earlier

The mt7530 driver has its dsa_switch_ops::get_tag_protocol function
check ds->cpu_port_mask to issue a warning in case the configured CPU
port is not capable of supporting tags.

After commit 14be36c2c96c ("net: dsa: Initialize all CPU and enabled
ports masks in dsa_ds_parse()") we slightly re-arranged the
initialization such that this was no longer working. Just make sure that
ds->cpu_port_mask is set prior to the first call to get_tag_protocol,
thus restoring the expected contract. In case of error, the CPU port bit
is cleared.

Fixes: 14be36c2c96c ("net: dsa: Initialize all CPU and enabled ports masks in dsa_ds_parse()")
Reported-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 56e46090526bb3baf26b5e06478cdd66ccc94280..c442051d5a55732d37ddc18187389d66d8d08bd9 100644 (file)
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -509,21 +509,22 @@ static int dsa_cpu_parse(struct dsa_port *port, u32 index,
                dst->cpu_dp->netdev = ethernet_dev;
        }
 
+       /* Initialize cpu_port_mask now for drv->setup()
+        * to have access to a correct value, just like what
+        * net/dsa/dsa.c::dsa_switch_setup_one does.
+        */
+       ds->cpu_port_mask |= BIT(index);
+
        tag_protocol = ds->ops->get_tag_protocol(ds);
        dst->tag_ops = dsa_resolve_tag_protocol(tag_protocol);
        if (IS_ERR(dst->tag_ops)) {
                dev_warn(ds->dev, "No tagger for this switch\n");
+               ds->cpu_port_mask &= ~BIT(index);
                return PTR_ERR(dst->tag_ops);
        }
 
        dst->rcv = dst->tag_ops->rcv;
 
-       /* Initialize cpu_port_mask now for drv->setup()
-        * to have access to a correct value, just like what
-        * net/dsa/dsa.c::dsa_switch_setup_one does.
-        */
-       ds->cpu_port_mask |= BIT(index);
-
        return 0;
 }