Re: [PATCH net-next 3/4] net: dsa: mv88e6xxx: check hardware VLAN in use

On 02/13/2016 10:53 PM, Vivien Didelot wrote:

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The DSA drivers now have access to the VLAN prepare phase and the bridge
net_device. It is easier to check for overlapping bridges from within
the driver. Thus add such check in mv88e6xxx_port_vlan_prepare.

Signed-off-by: Vivien Didelot <redacted>
---
   drivers/net/dsa/mv88e6xxx.c | 64 +++++++++++++++++++++++++++++++++++++++++++++
   1 file changed, 64 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index 2e515e8..685dcb0 100644
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c

@@ -1471,14 +1471,78 @@ static int _mv88e6xxx_vlan_init(struct dsa_switch *ds, u16 vid,
   	return 0;
   }

+static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
+					u16 vid_begin, u16 vid_end)
+{
+	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
+	struct mv88e6xxx_vtu_stu_entry vlan;
+	int i, err;
+
+	if (!vid_begin)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&ps->smi_mutex);
+
+	err = _mv88e6xxx_vtu_vid_write(ds, vid_begin - 1);
+	if (err)
+		goto unlock;
+
+	do {
+		err = _mv88e6xxx_vtu_getnext(ds, &vlan);
+		if (err)
+			goto unlock;

     Why are you not using *break*?

I use goto for explicit error handling, and break for expected flow.

    Thought you'd say so. :-)
    I still think *break* is preferable...

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+
+		if (!vlan.valid)
+			break;
+
+		if (vlan.vid > vid_end)
+			break;
+
+		for (i = 0; i < ps->num_ports; ++i) {
+			if (dsa_is_dsa_port(ds, i) || dsa_is_cpu_port(ds, i))
+				continue;
+
+			if (vlan.data[i] ==
+			    GLOBAL_VTU_DATA_MEMBER_TAG_NON_MEMBER)
+				continue;
+
+			if (ps->ports[i].bridge_dev ==
+			    ps->ports[port].bridge_dev)
+				break; /* same bridge, check next VLAN */
+
+			netdev_warn(ds->ports[port],
+				    "hardware VLAN %d already used by %s\n",
+				    vlan.vid,
+				    netdev_name(ps->ports[i].bridge_dev));
+			err = -EOPNOTSUPP;
+			goto unlock;
+		}

     Why not *break*?

Because here it would only break the for loop, and not the while loop.

    Oops, I overlooked the *for* loop. Sorry about that.

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+	} while (vlan.vid < vid_end);
+
+unlock:
+	mutex_unlock(&ps->smi_mutex);
+
+	return err;
+}
+

[...]

Thanks,
-v

MBR, Sergei