[RFC PATCH net-next v3 3/4] rocker: Handle IFF_PROTODOWN by doing a PHYS-DOWN on the switch port.

[RFC PATCH net-next v3 3/4] rocker: Handle IFF_PROTODOWN by doing a PHYS-DOWN on the switch port.

[anuradhak]

From: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>

IFF_PROTODOWN can be set by user space applications like MLAG on detecting
errors on a switch port. This patch provides sample switch driver changes
for handling IFF_PROTODOWN. Rocker PHYS disables the port in response to
protodown.

Note: I understand Scott has some rocker changes on hold. I will re-spin
this patch once his changes are in.

Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
---
 drivers/net/ethernet/rocker/rocker.c |   16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
index a87b177..e3084e3 100644
--- a/drivers/net/ethernet/rocker/rocker.c
+++ b/drivers/net/ethernet/rocker/rocker.c
@@ -3838,7 +3838,8 @@ static int rocker_port_open(struct net_device *dev)
 
 	napi_enable(&rocker_port->napi_tx);
 	napi_enable(&rocker_port->napi_rx);
-	rocker_port_set_enable(rocker_port, true);
+	if (!(dev->flags & IFF_PROTO_DOWN))
+		rocker_port_set_enable(rocker_port, true);
 	netif_start_queue(dev);
 	return 0;
 
@@ -4238,6 +4239,18 @@ static int rocker_port_swdev_port_stp_update(struct net_device *dev, u8 state)
 	return rocker_port_stp_update(rocker_port, state);
 }
 
+static int rocker_port_swdev_port_phy_state_set(struct net_device *dev,
+						bool enable)
+{
+	struct rocker_port *rocker_port = netdev_priv(dev);
+
+	if (enable && (dev->flags & IFF_UP) && !(dev->flags & IFF_PROTO_DOWN))
+		rocker_port_set_enable(rocker_port, true);
+	else
+		rocker_port_set_enable(rocker_port, false);
+	return 0;
+}
+
 static int rocker_port_swdev_fib_ipv4_add(struct net_device *dev,
 					  __be32 dst, int dst_len,
 					  struct fib_info *fi,
@@ -4268,6 +4281,7 @@ static const struct swdev_ops rocker_port_swdev_ops = {
 	.swdev_port_stp_update		= rocker_port_swdev_port_stp_update,
 	.swdev_fib_ipv4_add		= rocker_port_swdev_fib_ipv4_add,
 	.swdev_fib_ipv4_del		= rocker_port_swdev_fib_ipv4_del,
+	.swdev_port_phy_state_set	= rocker_port_swdev_port_phy_state_set,
 };
 
 /********************
-- 
1.7.10.4

Re: [RFC PATCH net-next v3 3/4] rocker: Handle IFF_PROTODOWN by doing a PHYS-DOWN on the switch port.

[Scott Feldman]

On Mon, Apr 27, 2015 at 10:38 AM,  <anuradhak@cumulusnetworks.com> wrote:
> From: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>
> IFF_PROTODOWN can be set by user space applications like MLAG on detecting
> errors on a switch port. This patch provides sample switch driver changes
> for handling IFF_PROTODOWN. Rocker PHYS disables the port in response to
> protodown.
>
> Note: I understand Scott has some rocker changes on hold. I will re-spin
> this patch once his changes are in.
>
> Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
> Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
> Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
> ---
>  drivers/net/ethernet/rocker/rocker.c |   16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
> index a87b177..e3084e3 100644
> --- a/drivers/net/ethernet/rocker/rocker.c
> +++ b/drivers/net/ethernet/rocker/rocker.c
> @@ -3838,7 +3838,8 @@ static int rocker_port_open(struct net_device *dev)
>
>         napi_enable(&rocker_port->napi_tx);
>         napi_enable(&rocker_port->napi_rx);
> -       rocker_port_set_enable(rocker_port, true);
> +       if (!(dev->flags & IFF_PROTO_DOWN))
> +               rocker_port_set_enable(rocker_port, true);
>         netif_start_queue(dev);
>         return 0;
>
> @@ -4238,6 +4239,18 @@ static int rocker_port_swdev_port_stp_update(struct net_device *dev, u8 state)
>         return rocker_port_stp_update(rocker_port, state);
>  }
>
> +static int rocker_port_swdev_port_phy_state_set(struct net_device *dev,
> +                                               bool enable)
> +{
> +       struct rocker_port *rocker_port = netdev_priv(dev);
> +
> +       if (enable && (dev->flags & IFF_UP) && !(dev->flags & IFF_PROTO_DOWN))
> +               rocker_port_set_enable(rocker_port, true);
> +       else
> +               rocker_port_set_enable(rocker_port, false);

This isn't working like your expecting.  PHY link is still up on the
rocker port, so the other end of the wire still sees link UP even when
IFF_PROTO_DOWN is set locally.

Re: [RFC PATCH net-next v3 3/4] rocker: Handle IFF_PROTODOWN by doing a PHYS-DOWN on the switch port.

[Anuradha Karuppiah]

On Mon, Apr 27, 2015 at 10:51 PM, Scott Feldman <sfeldma@gmail.com> wrote:
> On Mon, Apr 27, 2015 at 10:38 AM,  <anuradhak@cumulusnetworks.com> wrote:
>> From: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>
>> IFF_PROTODOWN can be set by user space applications like MLAG on detecting
>> errors on a switch port. This patch provides sample switch driver changes
>> for handling IFF_PROTODOWN. Rocker PHYS disables the port in response to
>> protodown.
>>
>> Note: I understand Scott has some rocker changes on hold. I will re-spin
>> this patch once his changes are in.
>>
>> Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>> Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
>> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
>> Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
>> ---
>>  drivers/net/ethernet/rocker/rocker.c |   16 +++++++++++++++-
>>  1 file changed, 15 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
>> index a87b177..e3084e3 100644
>> --- a/drivers/net/ethernet/rocker/rocker.c
>> +++ b/drivers/net/ethernet/rocker/rocker.c
>> @@ -3838,7 +3838,8 @@ static int rocker_port_open(struct net_device *dev)
>>
>>         napi_enable(&rocker_port->napi_tx);
>>         napi_enable(&rocker_port->napi_rx);
>> -       rocker_port_set_enable(rocker_port, true);
>> +       if (!(dev->flags & IFF_PROTO_DOWN))
>> +               rocker_port_set_enable(rocker_port, true);
>>         netif_start_queue(dev);
>>         return 0;
>>
>> @@ -4238,6 +4239,18 @@ static int rocker_port_swdev_port_stp_update(struct net_device *dev, u8 state)
>>         return rocker_port_stp_update(rocker_port, state);
>>  }
>>
>> +static int rocker_port_swdev_port_phy_state_set(struct net_device *dev,
>> +                                               bool enable)
>> +{
>> +       struct rocker_port *rocker_port = netdev_priv(dev);
>> +
>> +       if (enable && (dev->flags & IFF_UP) && !(dev->flags & IFF_PROTO_DOWN))
>> +               rocker_port_set_enable(rocker_port, true);
>> +       else
>> +               rocker_port_set_enable(rocker_port, false);
>
> This isn't working like your expecting.  PHY link is still up on the
> rocker port, so the other end of the wire still sees link UP even when
> IFF_PROTO_DOWN is set locally.

I wanted to check with you first on the rocker handling; that is the main
reason for posting this an RFC (thanks for the review).

I used rocker_port_set_enable/PORT_PHYS_ENABLE for setting the phy state
because I assumed that in the case of an offloaded switch driver it would be
the equivalent of doing "sdk port N en=1|0". Is that not the case? If not,
could you please point me in the right direction?

Re: [RFC PATCH net-next v3 3/4] rocker: Handle IFF_PROTODOWN by doing a PHYS-DOWN on the switch port.

[Scott Feldman]

On Tue, Apr 28, 2015 at 8:49 AM, Anuradha Karuppiah
<anuradhak@cumulusnetworks.com> wrote:
> On Mon, Apr 27, 2015 at 10:51 PM, Scott Feldman <sfeldma@gmail.com> wrote:
>> On Mon, Apr 27, 2015 at 10:38 AM,  <anuradhak@cumulusnetworks.com> wrote:
>>> From: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>>
>>> IFF_PROTODOWN can be set by user space applications like MLAG on detecting
>>> errors on a switch port. This patch provides sample switch driver changes
>>> for handling IFF_PROTODOWN. Rocker PHYS disables the port in response to
>>> protodown.
>>>
>>> Note: I understand Scott has some rocker changes on hold. I will re-spin
>>> this patch once his changes are in.
>>>
>>> Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>> Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
>>> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
>>> Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
>>> ---
>>>  drivers/net/ethernet/rocker/rocker.c |   16 +++++++++++++++-
>>>  1 file changed, 15 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
>>> index a87b177..e3084e3 100644
>>> --- a/drivers/net/ethernet/rocker/rocker.c
>>> +++ b/drivers/net/ethernet/rocker/rocker.c
>>> @@ -3838,7 +3838,8 @@ static int rocker_port_open(struct net_device *dev)
>>>
>>>         napi_enable(&rocker_port->napi_tx);
>>>         napi_enable(&rocker_port->napi_rx);
>>> -       rocker_port_set_enable(rocker_port, true);
>>> +       if (!(dev->flags & IFF_PROTO_DOWN))
>>> +               rocker_port_set_enable(rocker_port, true);
>>>         netif_start_queue(dev);
>>>         return 0;
>>>
>>> @@ -4238,6 +4239,18 @@ static int rocker_port_swdev_port_stp_update(struct net_device *dev, u8 state)
>>>         return rocker_port_stp_update(rocker_port, state);
>>>  }
>>>
>>> +static int rocker_port_swdev_port_phy_state_set(struct net_device *dev,
>>> +                                               bool enable)
>>> +{
>>> +       struct rocker_port *rocker_port = netdev_priv(dev);
>>> +
>>> +       if (enable && (dev->flags & IFF_UP) && !(dev->flags & IFF_PROTO_DOWN))
>>> +               rocker_port_set_enable(rocker_port, true);
>>> +       else
>>> +               rocker_port_set_enable(rocker_port, false);
>>
>> This isn't working like your expecting.  PHY link is still up on the
>> rocker port, so the other end of the wire still sees link UP even when
>> IFF_PROTO_DOWN is set locally.
>
> I wanted to check with you first on the rocker handling; that is the main
> reason for posting this an RFC (thanks for the review).
>
> I used rocker_port_set_enable/PORT_PHYS_ENABLE for setting the phy state
> because I assumed that in the case of an offloaded switch driver it would be
> the equivalent of doing "sdk port N en=1|0". Is that not the case? If not,
> could you please point me in the right direction?

To put PHY link down, on PORT_PHYS_ENABLE true, rocker device (qemu)
would need to down the link state for the port so other end of wire
sees link down.  I think I remember looking into that but didn't
implement it.  In qemu monitor, you can manually set the link up/down
(set_link <dev> [on|off]).  We'd need to call the same from within the
rocker device.

So if we want to be able to test this with rocker, we'll need a device
and driver change.

Re: [RFC PATCH net-next v3 3/4] rocker: Handle IFF_PROTODOWN by doing a PHYS-DOWN on the switch port.

[Anuradha Karuppiah]

On Tue, Apr 28, 2015 at 12:48 PM, Scott Feldman <sfeldma@gmail.com> wrote:
> On Tue, Apr 28, 2015 at 8:49 AM, Anuradha Karuppiah
> <anuradhak@cumulusnetworks.com> wrote:
>> On Mon, Apr 27, 2015 at 10:51 PM, Scott Feldman <sfeldma@gmail.com> wrote:
>>> On Mon, Apr 27, 2015 at 10:38 AM,  <anuradhak@cumulusnetworks.com> wrote:
>>>> From: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>>>
>>>> IFF_PROTODOWN can be set by user space applications like MLAG on detecting
>>>> errors on a switch port. This patch provides sample switch driver changes
>>>> for handling IFF_PROTODOWN. Rocker PHYS disables the port in response to
>>>> protodown.
>>>>
>>>> Note: I understand Scott has some rocker changes on hold. I will re-spin
>>>> this patch once his changes are in.
>>>>
>>>> Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>>> Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
>>>> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
>>>> Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
>>>> ---
>>>>  drivers/net/ethernet/rocker/rocker.c |   16 +++++++++++++++-
>>>>  1 file changed, 15 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
>>>> index a87b177..e3084e3 100644
>>>> --- a/drivers/net/ethernet/rocker/rocker.c
>>>> +++ b/drivers/net/ethernet/rocker/rocker.c
>>>> @@ -3838,7 +3838,8 @@ static int rocker_port_open(struct net_device *dev)
>>>>
>>>>         napi_enable(&rocker_port->napi_tx);
>>>>         napi_enable(&rocker_port->napi_rx);
>>>> -       rocker_port_set_enable(rocker_port, true);
>>>> +       if (!(dev->flags & IFF_PROTO_DOWN))
>>>> +               rocker_port_set_enable(rocker_port, true);
>>>>         netif_start_queue(dev);
>>>>         return 0;
>>>>
>>>> @@ -4238,6 +4239,18 @@ static int rocker_port_swdev_port_stp_update(struct net_device *dev, u8 state)
>>>>         return rocker_port_stp_update(rocker_port, state);
>>>>  }
>>>>
>>>> +static int rocker_port_swdev_port_phy_state_set(struct net_device *dev,
>>>> +                                               bool enable)
>>>> +{
>>>> +       struct rocker_port *rocker_port = netdev_priv(dev);
>>>> +
>>>> +       if (enable && (dev->flags & IFF_UP) && !(dev->flags & IFF_PROTO_DOWN))
>>>> +               rocker_port_set_enable(rocker_port, true);
>>>> +       else
>>>> +               rocker_port_set_enable(rocker_port, false);
>>>
>>> This isn't working like your expecting.  PHY link is still up on the
>>> rocker port, so the other end of the wire still sees link UP even when
>>> IFF_PROTO_DOWN is set locally.
>>
>> I wanted to check with you first on the rocker handling; that is the main
>> reason for posting this an RFC (thanks for the review).
>>
>> I used rocker_port_set_enable/PORT_PHYS_ENABLE for setting the phy state
>> because I assumed that in the case of an offloaded switch driver it would be
>> the equivalent of doing "sdk port N en=1|0". Is that not the case? If not,
>> could you please point me in the right direction?
>
> To put PHY link down, on PORT_PHYS_ENABLE true, rocker device (qemu)
> would need to down the link state for the port so other end of wire
> sees link down.  I think I remember looking into that but didn't
> implement it.  In qemu monitor, you can manually set the link up/down
> (set_link <dev> [on|off]).  We'd need to call the same from within the
> rocker device.
>
> So if we want to be able to test this with rocker, we'll need a device
> and driver change.

Thanks for the details, Scott. We will looking into implementing the necessary
changes to get it working with rocker.

Re: [RFC PATCH net-next v3 3/4] rocker: Handle IFF_PROTODOWN by doing a PHYS-DOWN on the switch port.

[Scott Feldman]

On Tue, Apr 28, 2015 at 1:35 PM, Anuradha Karuppiah
<anuradhak@cumulusnetworks.com> wrote:
> On Tue, Apr 28, 2015 at 12:48 PM, Scott Feldman <sfeldma@gmail.com> wrote:
>> On Tue, Apr 28, 2015 at 8:49 AM, Anuradha Karuppiah
>> <anuradhak@cumulusnetworks.com> wrote:
>>> On Mon, Apr 27, 2015 at 10:51 PM, Scott Feldman <sfeldma@gmail.com> wrote:
>>>> On Mon, Apr 27, 2015 at 10:38 AM,  <anuradhak@cumulusnetworks.com> wrote:
>>>>> From: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>>>>
>>>>> IFF_PROTODOWN can be set by user space applications like MLAG on detecting
>>>>> errors on a switch port. This patch provides sample switch driver changes
>>>>> for handling IFF_PROTODOWN. Rocker PHYS disables the port in response to
>>>>> protodown.
>>>>>
>>>>> Note: I understand Scott has some rocker changes on hold. I will re-spin
>>>>> this patch once his changes are in.
>>>>>
>>>>> Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>>>> Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
>>>>> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
>>>>> Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
>>>>> ---
>>>>>  drivers/net/ethernet/rocker/rocker.c |   16 +++++++++++++++-
>>>>>  1 file changed, 15 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
>>>>> index a87b177..e3084e3 100644
>>>>> --- a/drivers/net/ethernet/rocker/rocker.c
>>>>> +++ b/drivers/net/ethernet/rocker/rocker.c
>>>>> @@ -3838,7 +3838,8 @@ static int rocker_port_open(struct net_device *dev)
>>>>>
>>>>>         napi_enable(&rocker_port->napi_tx);
>>>>>         napi_enable(&rocker_port->napi_rx);
>>>>> -       rocker_port_set_enable(rocker_port, true);
>>>>> +       if (!(dev->flags & IFF_PROTO_DOWN))
>>>>> +               rocker_port_set_enable(rocker_port, true);
>>>>>         netif_start_queue(dev);
>>>>>         return 0;
>>>>>
>>>>> @@ -4238,6 +4239,18 @@ static int rocker_port_swdev_port_stp_update(struct net_device *dev, u8 state)
>>>>>         return rocker_port_stp_update(rocker_port, state);
>>>>>  }
>>>>>
>>>>> +static int rocker_port_swdev_port_phy_state_set(struct net_device *dev,
>>>>> +                                               bool enable)
>>>>> +{
>>>>> +       struct rocker_port *rocker_port = netdev_priv(dev);
>>>>> +
>>>>> +       if (enable && (dev->flags & IFF_UP) && !(dev->flags & IFF_PROTO_DOWN))
>>>>> +               rocker_port_set_enable(rocker_port, true);
>>>>> +       else
>>>>> +               rocker_port_set_enable(rocker_port, false);
>>>>
>>>> This isn't working like your expecting.  PHY link is still up on the
>>>> rocker port, so the other end of the wire still sees link UP even when
>>>> IFF_PROTO_DOWN is set locally.
>>>
>>> I wanted to check with you first on the rocker handling; that is the main
>>> reason for posting this an RFC (thanks for the review).
>>>
>>> I used rocker_port_set_enable/PORT_PHYS_ENABLE for setting the phy state
>>> because I assumed that in the case of an offloaded switch driver it would be
>>> the equivalent of doing "sdk port N en=1|0". Is that not the case? If not,
>>> could you please point me in the right direction?
>>
>> To put PHY link down, on PORT_PHYS_ENABLE true, rocker device (qemu)
>> would need to down the link state for the port so other end of wire
>> sees link down.  I think I remember looking into that but didn't
>> implement it.  In qemu monitor, you can manually set the link up/down
>> (set_link <dev> [on|off]).  We'd need to call the same from within the
>> rocker device.
>>
>> So if we want to be able to test this with rocker, we'll need a device
>> and driver change.
>
> Thanks for the details, Scott. We will looking into implementing the necessary
> changes to get it working with rocker.

Hmmm....looks like we can only go so far using rocker.  The patch
below for rocker device will set link up/down when phy is
enabled/disabled, but that only affects the local link status.  The
remote will not see link down/up when the local changes because there
is no physical signalling between two VM instances (local and remote)
(duh!).  I'll add the device patch to my queue just because it's a
good things to have, but at this point I'm not seeing how you can use
rocker to down the remote link.

diff --git a/hw/net/rocker/rocker_fp.c b/hw/net/rocker/rocker_fp.c
index 42354c3..d8d934c 100644
--- a/hw/net/rocker/rocker_fp.c
+++ b/hw/net/rocker/rocker_fp.c
@@ -188,8 +188,19 @@ bool fp_port_enabled(FpPort *port)
     return port->enabled;
 }

+static void fp_port_set_link(FpPort *port, bool up)
+{
+    NetClientState *nc = qemu_get_queue(port->nic);
+
+    if (up == nc->link_down) {
+        nc->link_down = !up;
+        nc->info->link_status_changed(nc);
+    }
+}
+
 void fp_port_enable(FpPort *port)
 {
+    fp_port_set_link(port, true);
     port->enabled = true;
     DPRINTF("port %d enabled\n", port->index);
 }
@@ -197,6 +208,7 @@ void fp_port_enable(FpPort *port)
 void fp_port_disable(FpPort *port)
 {
     port->enabled = false;
+    fp_port_set_link(port, false);
     DPRINTF("port %d disabled\n", port->index);
 }

Re: [RFC PATCH net-next v3 3/4] rocker: Handle IFF_PROTODOWN by doing a PHYS-DOWN on the switch port.

[Anuradha Karuppiah]

On Tue, Apr 28, 2015 at 10:51 PM, Scott Feldman <sfeldma@gmail.com> wrote:
> On Tue, Apr 28, 2015 at 1:35 PM, Anuradha Karuppiah
> <anuradhak@cumulusnetworks.com> wrote:
>> On Tue, Apr 28, 2015 at 12:48 PM, Scott Feldman <sfeldma@gmail.com> wrote:
>>> On Tue, Apr 28, 2015 at 8:49 AM, Anuradha Karuppiah
>>> <anuradhak@cumulusnetworks.com> wrote:
>>>> On Mon, Apr 27, 2015 at 10:51 PM, Scott Feldman <sfeldma@gmail.com> wrote:
>>>>> On Mon, Apr 27, 2015 at 10:38 AM,  <anuradhak@cumulusnetworks.com> wrote:
>>>>>> From: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>>>>>
>>>>>> IFF_PROTODOWN can be set by user space applications like MLAG on detecting
>>>>>> errors on a switch port. This patch provides sample switch driver changes
>>>>>> for handling IFF_PROTODOWN. Rocker PHYS disables the port in response to
>>>>>> protodown.
>>>>>>
>>>>>> Note: I understand Scott has some rocker changes on hold. I will re-spin
>>>>>> this patch once his changes are in.
>>>>>>
>>>>>> Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
>>>>>> Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
>>>>>> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
>>>>>> Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
>>>>>> ---
>>>>>>  drivers/net/ethernet/rocker/rocker.c |   16 +++++++++++++++-
>>>>>>  1 file changed, 15 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
>>>>>> index a87b177..e3084e3 100644
>>>>>> --- a/drivers/net/ethernet/rocker/rocker.c
>>>>>> +++ b/drivers/net/ethernet/rocker/rocker.c
>>>>>> @@ -3838,7 +3838,8 @@ static int rocker_port_open(struct net_device *dev)
>>>>>>
>>>>>>         napi_enable(&rocker_port->napi_tx);
>>>>>>         napi_enable(&rocker_port->napi_rx);
>>>>>> -       rocker_port_set_enable(rocker_port, true);
>>>>>> +       if (!(dev->flags & IFF_PROTO_DOWN))
>>>>>> +               rocker_port_set_enable(rocker_port, true);
>>>>>>         netif_start_queue(dev);
>>>>>>         return 0;
>>>>>>
>>>>>> @@ -4238,6 +4239,18 @@ static int rocker_port_swdev_port_stp_update(struct net_device *dev, u8 state)
>>>>>>         return rocker_port_stp_update(rocker_port, state);
>>>>>>  }
>>>>>>
>>>>>> +static int rocker_port_swdev_port_phy_state_set(struct net_device *dev,
>>>>>> +                                               bool enable)
>>>>>> +{
>>>>>> +       struct rocker_port *rocker_port = netdev_priv(dev);
>>>>>> +
>>>>>> +       if (enable && (dev->flags & IFF_UP) && !(dev->flags & IFF_PROTO_DOWN))
>>>>>> +               rocker_port_set_enable(rocker_port, true);
>>>>>> +       else
>>>>>> +               rocker_port_set_enable(rocker_port, false);
>>>>>
>>>>> This isn't working like your expecting.  PHY link is still up on the
>>>>> rocker port, so the other end of the wire still sees link UP even when
>>>>> IFF_PROTO_DOWN is set locally.
>>>>
>>>> I wanted to check with you first on the rocker handling; that is the main
>>>> reason for posting this an RFC (thanks for the review).
>>>>
>>>> I used rocker_port_set_enable/PORT_PHYS_ENABLE for setting the phy state
>>>> because I assumed that in the case of an offloaded switch driver it would be
>>>> the equivalent of doing "sdk port N en=1|0". Is that not the case? If not,
>>>> could you please point me in the right direction?
>>>
>>> To put PHY link down, on PORT_PHYS_ENABLE true, rocker device (qemu)
>>> would need to down the link state for the port so other end of wire
>>> sees link down.  I think I remember looking into that but didn't
>>> implement it.  In qemu monitor, you can manually set the link up/down
>>> (set_link <dev> [on|off]).  We'd need to call the same from within the
>>> rocker device.
>>>
>>> So if we want to be able to test this with rocker, we'll need a device
>>> and driver change.
>>
>> Thanks for the details, Scott. We will looking into implementing the necessary
>> changes to get it working with rocker.
>
> Hmmm....looks like we can only go so far using rocker.  The patch
> below for rocker device will set link up/down when phy is
> enabled/disabled, but that only affects the local link status.  The
> remote will not see link down/up when the local changes because there
> is no physical signalling between two VM instances (local and remote)
> (duh!).  I'll add the device patch to my queue just because it's a
> good things to have, but at this point I'm not seeing how you can use
> rocker to down the remote link.
>
> diff --git a/hw/net/rocker/rocker_fp.c b/hw/net/rocker/rocker_fp.c
> index 42354c3..d8d934c 100644
> --- a/hw/net/rocker/rocker_fp.c
> +++ b/hw/net/rocker/rocker_fp.c
> @@ -188,8 +188,19 @@ bool fp_port_enabled(FpPort *port)
>      return port->enabled;
>  }
>
> +static void fp_port_set_link(FpPort *port, bool up)
> +{
> +    NetClientState *nc = qemu_get_queue(port->nic);
> +
> +    if (up == nc->link_down) {
> +        nc->link_down = !up;
> +        nc->info->link_status_changed(nc);
> +    }
> +}
> +
>  void fp_port_enable(FpPort *port)
>  {
> +    fp_port_set_link(port, true);
>      port->enabled = true;
>      DPRINTF("port %d enabled\n", port->index);
>  }
> @@ -197,6 +208,7 @@ void fp_port_enable(FpPort *port)
>  void fp_port_disable(FpPort *port)
>  {
>      port->enabled = false;
> +    fp_port_set_link(port, false);
>      DPRINTF("port %d disabled\n", port->index);
>  }

OK, thanks for the info and for including the changes needed to do the local
phy-to-link setting in rocker.

For the proto_down handling -
1. The local switch port state does need to be down to prevent loops and to
prevent protocols from converging.
2. Remote needs to be signalled (if possible) via a carrier down to stop
sending traffic to this down port. In the case of virtual/emulated switch
ports this is not going to be possible.

I wonder if it still make sense to provide sample usage of this attribute in
rocker along with the documentation that #2 is not possible because of the
emulation restrictions. And that it would be possible in an offloaded switch
driver that did have phy control via the corresponding SDK.