[PATCH net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices

[PATCH net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices

[Tobias Waldekranz]

In a typical mv88e6xxx switch tree like this:

  CPU
   |    .----.
.--0--. | .--0--.
| sw0 | | | sw1 |
'-1-2-' | '-1-2-'
    '---'

If sw1p{1,2} are added to a bridge that sw0p1 is not a part of, sw0
still needs to add a crosschip PVT entry for the virtual DSA device
assigned to represent the bridge.

Fixes: ce5df6894a57 ("net: dsa: mv88e6xxx: map virtual bridges with forwarding offload in the PVT")
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---

Though this is a bugfix, it still targets net-next as it depends on
the recent work done by Vladimir here:

https://lore.kernel.org/netdev/20211206165758.1553882-1-vladimir.oltean@nxp.com/

 drivers/net/dsa/mv88e6xxx/chip.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 7fadbf987b23..85f5a35340d7 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2522,6 +2522,7 @@ static int mv88e6xxx_crosschip_bridge_join(struct dsa_switch *ds,
 
 	mv88e6xxx_reg_lock(chip);
 	err = mv88e6xxx_pvt_map(chip, sw_index, port);
+	err = err ? : mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num);
 	mv88e6xxx_reg_unlock(chip);
 
 	return err;
@@ -2537,7 +2538,8 @@ static void mv88e6xxx_crosschip_bridge_leave(struct dsa_switch *ds,
 		return;
 
 	mv88e6xxx_reg_lock(chip);
-	if (mv88e6xxx_pvt_map(chip, sw_index, port))
+	if (mv88e6xxx_pvt_map(chip, sw_index, port) ||
+	    mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num))
 		dev_err(ds->dev, "failed to remap cross-chip Port VLAN\n");
 	mv88e6xxx_reg_unlock(chip);
 }
-- 
2.25.1

Re: [PATCH net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices

[Vladimir Oltean]

On Thu, Dec 09, 2021 at 11:24:24PM +0100, Tobias Waldekranz wrote:
> In a typical mv88e6xxx switch tree like this:
> 
>   CPU
>    |    .----.
> .--0--. | .--0--.
> | sw0 | | | sw1 |
> '-1-2-' | '-1-2-'
>     '---'
> 
> If sw1p{1,2} are added to a bridge that sw0p1 is not a part of, sw0
> still needs to add a crosschip PVT entry for the virtual DSA device
> assigned to represent the bridge.
> 
> Fixes: ce5df6894a57 ("net: dsa: mv88e6xxx: map virtual bridges with forwarding offload in the PVT")
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
> ---

This makes sense. Sorry, my Turris MOX has 3 cascaded switches but I
only test it using a single bridge that spans all of the ports.
So this is why in my case the DSA and CPU ports could receive packets
using the virtual bridge device, because mv88e6xxx_port_vlan() had been
called on them through the direct mv88e6xxx_port_bridge_join(), not
through mv88e6xxx_crosschip_bridge_join(). I guess you have a use case
where some leaf ports are in a bridge but some upstream ports aren't,
and this is how you caught this?

Thanks!

Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>

> 
> Though this is a bugfix, it still targets net-next as it depends on
> the recent work done by Vladimir here:
> 
> https://lore.kernel.org/netdev/20211206165758.1553882-1-vladimir.oltean@nxp.com/
> 
>  drivers/net/dsa/mv88e6xxx/chip.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index 7fadbf987b23..85f5a35340d7 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -2522,6 +2522,7 @@ static int mv88e6xxx_crosschip_bridge_join(struct dsa_switch *ds,
>  
>  	mv88e6xxx_reg_lock(chip);
>  	err = mv88e6xxx_pvt_map(chip, sw_index, port);
> +	err = err ? : mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num);
>  	mv88e6xxx_reg_unlock(chip);
>  
>  	return err;
> @@ -2537,7 +2538,8 @@ static void mv88e6xxx_crosschip_bridge_leave(struct dsa_switch *ds,
>  		return;
>  
>  	mv88e6xxx_reg_lock(chip);
> -	if (mv88e6xxx_pvt_map(chip, sw_index, port))
> +	if (mv88e6xxx_pvt_map(chip, sw_index, port) ||
> +	    mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num))
>  		dev_err(ds->dev, "failed to remap cross-chip Port VLAN\n");
>  	mv88e6xxx_reg_unlock(chip);
>  }
> -- 
> 2.25.1
> 

Re: [PATCH net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices

[Tobias Waldekranz]

On Fri, Dec 10, 2021 at 00:41, Vladimir Oltean <olteanv@gmail.com> wrote:
> On Thu, Dec 09, 2021 at 11:24:24PM +0100, Tobias Waldekranz wrote:
>> In a typical mv88e6xxx switch tree like this:
>> 
>>   CPU
>>    |    .----.
>> .--0--. | .--0--.
>> | sw0 | | | sw1 |
>> '-1-2-' | '-1-2-'
>>     '---'
>> 
>> If sw1p{1,2} are added to a bridge that sw0p1 is not a part of, sw0
>> still needs to add a crosschip PVT entry for the virtual DSA device
>> assigned to represent the bridge.
>> 
>> Fixes: ce5df6894a57 ("net: dsa: mv88e6xxx: map virtual bridges with forwarding offload in the PVT")
>> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
>> ---
>
> This makes sense. Sorry, my Turris MOX has 3 cascaded switches but I
> only test it using a single bridge that spans all of the ports.
> So this is why in my case the DSA and CPU ports could receive packets
> using the virtual bridge device, because mv88e6xxx_port_vlan() had been
> called on them through the direct mv88e6xxx_port_bridge_join(), not
> through mv88e6xxx_crosschip_bridge_join().

Yeah this is by far the most common setup, that's why I missed it as
well.

> I guess you have a use case
> where some leaf ports are in a bridge but some upstream ports aren't,
> and this is how you caught this?

I've been doing some work on running kselftest-like tests on a multichip
mv88e6xxx system. In that process, I discovered this issue along with a
whole slew of other nasty things related to isolation of standalone
ports.

I am finalizing a series to tackle that which (while not exactly
elegant) should get the job done. Stay tuned :)

Re: [PATCH net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices

[Jakub Kicinski]

On Thu,  9 Dec 2021 23:24:24 +0100 Tobias Waldekranz wrote:
> In a typical mv88e6xxx switch tree like this:
> 
>   CPU
>    |    .----.
> .--0--. | .--0--.
> | sw0 | | | sw1 |
> '-1-2-' | '-1-2-'
>     '---'
> 
> If sw1p{1,2} are added to a bridge that sw0p1 is not a part of, sw0
> still needs to add a crosschip PVT entry for the virtual DSA device
> assigned to represent the bridge.
> 
> Fixes: ce5df6894a57 ("net: dsa: mv88e6xxx: map virtual bridges with forwarding offload in the PVT")

Hm, should this go to net? The commit above is in 5.15 it seems.

Re: [PATCH net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices

[Tobias Waldekranz]

On Fri, Dec 10, 2021 at 21:18, Jakub Kicinski <kuba@kernel.org> wrote:
> On Thu,  9 Dec 2021 23:24:24 +0100 Tobias Waldekranz wrote:
>> In a typical mv88e6xxx switch tree like this:
>> 
>>   CPU
>>    |    .----.
>> .--0--. | .--0--.
>> | sw0 | | | sw1 |
>> '-1-2-' | '-1-2-'
>>     '---'
>> 
>> If sw1p{1,2} are added to a bridge that sw0p1 is not a part of, sw0
>> still needs to add a crosschip PVT entry for the virtual DSA device
>> assigned to represent the bridge.
>> 
>> Fixes: ce5df6894a57 ("net: dsa: mv88e6xxx: map virtual bridges with forwarding offload in the PVT")
>
> Hm, should this go to net? The commit above is in 5.15 it seems.

Since there was no cover letter for this patch I put that motivation
after the commit message cutoff:

    Though this is a bugfix, it still targets net-next as it depends on
    the recent work done by Vladimir here:

    https://lore.kernel.org/netdev/20211206165758.1553882-1-vladimir.oltean@nxp.com/

I have patches for 5.15 but the implementation is completely
different. Given that (1) multichip devices are pretty uncommon to begin
with and (2) that this configuration is also rare, I thought it might be
more trouble than it was worth.

Let me know if you want me to send that too - but independent of that, I
think this should go in on net-next.

Re: [PATCH net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices

[Jakub Kicinski]

On Sat, 11 Dec 2021 22:20:28 +0100 Tobias Waldekranz wrote:
> Since there was no cover letter for this patch I put that motivation
> after the commit message cutoff:
> 
>     Though this is a bugfix, it still targets net-next as it depends on
>     the recent work done by Vladimir here:
> 
>     https://lore.kernel.org/netdev/20211206165758.1553882-1-vladimir.oltean@nxp.com/


Sigh, I should read the stuff under ---, sorry.

Re: [PATCH net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Thu,  9 Dec 2021 23:24:24 +0100 you wrote:
> In a typical mv88e6xxx switch tree like this:
> 
>   CPU
>    |    .----.
> .--0--. | .--0--.
> | sw0 | | | sw1 |
> '-1-2-' | '-1-2-'
>     '---'
> 
> [...]

Here is the summary with links:
  - [net-next] net: dsa: mv88e6xxx: Add tx fwd offload PVT on intermediate devices
    https://git.kernel.org/netdev/net-next/c/e0068620e5e1

You are awesome, thank you!
-- 
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