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

From: Sergei Shtylyov
Date: Sat Feb 13 2016 - 15:08:58 EST


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

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 <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>
---
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...

+
+ 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.


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

Thanks,
-v

MBR, Sergei