* [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP
@ 2021-01-21 23:43 Rasmus Villemoes
2021-01-22 9:05 ` Horatiu Vultur
2021-01-22 13:42 ` Petr Machata
0 siblings, 2 replies; 5+ messages in thread
From: Rasmus Villemoes @ 2021-01-21 23:43 UTC (permalink / raw)
To: netdev
Cc: Horatiu Vultur, Jiri Pirko, Florian Fainelli, Petr Machata,
Ido Schimmel, David S . Miller, Ivan Vecera, Jakub Kicinski,
Rasmus Villemoes
It's not true that switchdev_port_obj_notify() only inspects the
->handled field of "struct switchdev_notifier_port_obj_info" if
call_switchdev_blocking_notifiers() returns 0 - there's a WARN_ON()
triggering for a non-zero return combined with ->handled not being
true. But the real problem here is that -EOPNOTSUPP is not being
properly handled.
The wrapper functions switchdev_handle_port_obj_add() et al change a
return value of -EOPNOTSUPP to 0, and the treatment of ->handled in
switchdev_port_obj_notify() seems to be designed to change that back
to -EOPNOTSUPP in case nobody actually acted on the notifier (i.e.,
everybody returned -EOPNOTSUPP).
Currently, as soon as some device down the stack passes the check_cb()
check, ->handled gets set to true, which means that
switchdev_port_obj_notify() cannot actually ever return -EOPNOTSUPP.
This, for example, means that the detection of hardware offload
support in the MRP code is broken - br_mrp_set_ring_role() always ends
up setting mrp->ring_role_offloaded to 1, despite not a single
mainline driver implementing any of the SWITCHDEV_OBJ_ID*_MRP. So
since the MRP code thinks the generation of MRP test frames has been
offloaded, no such frames are actually put on the wire.
So, continue to set ->handled true if any callback returns success or
any error distinct from -EOPNOTSUPP. But if all the callbacks return
-EOPNOTSUPP, make sure that ->handled stays false, so the logic in
switchdev_port_obj_notify() can propagate that information.
Fixes: f30f0601eb93 ("switchdev: Add helpers to aid traversal through lower devices")
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas•dk>
---
Resending with more folks on cc and a tentative fixes tag.
net/switchdev/switchdev.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 23d868545362..2c1ffc9ba2eb 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -460,10 +460,11 @@ static int __switchdev_handle_port_obj_add(struct net_device *dev,
extack = switchdev_notifier_info_to_extack(&port_obj_info->info);
if (check_cb(dev)) {
- /* This flag is only checked if the return value is success. */
- port_obj_info->handled = true;
- return add_cb(dev, port_obj_info->obj, port_obj_info->trans,
- extack);
+ err = add_cb(dev, port_obj_info->obj, port_obj_info->trans,
+ extack);
+ if (err != -EOPNOTSUPP)
+ port_obj_info->handled = true;
+ return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
@@ -515,9 +516,10 @@ static int __switchdev_handle_port_obj_del(struct net_device *dev,
int err = -EOPNOTSUPP;
if (check_cb(dev)) {
- /* This flag is only checked if the return value is success. */
- port_obj_info->handled = true;
- return del_cb(dev, port_obj_info->obj);
+ err = del_cb(dev, port_obj_info->obj);
+ if (err != -EOPNOTSUPP)
+ port_obj_info->handled = true;
+ return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
@@ -568,9 +570,10 @@ static int __switchdev_handle_port_attr_set(struct net_device *dev,
int err = -EOPNOTSUPP;
if (check_cb(dev)) {
- port_attr_info->handled = true;
- return set_cb(dev, port_attr_info->attr,
- port_attr_info->trans);
+ err = set_cb(dev, port_attr_info->attr, port_attr_info->trans);
+ if (err != -EOPNOTSUPP)
+ port_attr_info->handled = true;
+ return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
--
2.23.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP
2021-01-21 23:43 [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP Rasmus Villemoes
@ 2021-01-22 9:05 ` Horatiu Vultur
2021-01-22 13:36 ` Rasmus Villemoes
2021-01-22 13:42 ` Petr Machata
1 sibling, 1 reply; 5+ messages in thread
From: Horatiu Vultur @ 2021-01-22 9:05 UTC (permalink / raw)
To: Rasmus Villemoes
Cc: netdev, Jiri Pirko, Florian Fainelli, Petr Machata, Ido Schimmel,
David S . Miller, Ivan Vecera, Jakub Kicinski
The 01/22/2021 00:43, Rasmus Villemoes wrote:
>
> It's not true that switchdev_port_obj_notify() only inspects the
> ->handled field of "struct switchdev_notifier_port_obj_info" if
> call_switchdev_blocking_notifiers() returns 0 - there's a WARN_ON()
> triggering for a non-zero return combined with ->handled not being
> true. But the real problem here is that -EOPNOTSUPP is not being
> properly handled.
>
> The wrapper functions switchdev_handle_port_obj_add() et al change a
> return value of -EOPNOTSUPP to 0, and the treatment of ->handled in
> switchdev_port_obj_notify() seems to be designed to change that back
> to -EOPNOTSUPP in case nobody actually acted on the notifier (i.e.,
> everybody returned -EOPNOTSUPP).
>
> Currently, as soon as some device down the stack passes the check_cb()
> check, ->handled gets set to true, which means that
> switchdev_port_obj_notify() cannot actually ever return -EOPNOTSUPP.
>
> This, for example, means that the detection of hardware offload
> support in the MRP code is broken - br_mrp_set_ring_role() always ends
> up setting mrp->ring_role_offloaded to 1, despite not a single
> mainline driver implementing any of the SWITCHDEV_OBJ_ID*_MRP. So
> since the MRP code thinks the generation of MRP test frames has been
> offloaded, no such frames are actually put on the wire.
Just a small correction to what you have said regarding MRP. Is not the
option mrp->ring_role_offload that determines if the MRP Test frames are
generated by the HW but is the return value of the function
'br_mrp_switchdev_send_ring_test' called from function
'br_mrp_start_test'. But everything else looks good.
I have also started to work on a patch series where I try to improve the
way the return values of switchdev calls are handled in MRP. I should be
able to send these patches by the end of week.
>
> So, continue to set ->handled true if any callback returns success or
> any error distinct from -EOPNOTSUPP. But if all the callbacks return
> -EOPNOTSUPP, make sure that ->handled stays false, so the logic in
> switchdev_port_obj_notify() can propagate that information.
>
> Fixes: f30f0601eb93 ("switchdev: Add helpers to aid traversal through lower devices")
> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas•dk>
> ---
> Resending with more folks on cc and a tentative fixes tag.
>
> net/switchdev/switchdev.c | 23 +++++++++++++----------
> 1 file changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
> index 23d868545362..2c1ffc9ba2eb 100644
> --- a/net/switchdev/switchdev.c
> +++ b/net/switchdev/switchdev.c
> @@ -460,10 +460,11 @@ static int __switchdev_handle_port_obj_add(struct net_device *dev,
> extack = switchdev_notifier_info_to_extack(&port_obj_info->info);
>
> if (check_cb(dev)) {
> - /* This flag is only checked if the return value is success. */
> - port_obj_info->handled = true;
> - return add_cb(dev, port_obj_info->obj, port_obj_info->trans,
> - extack);
> + err = add_cb(dev, port_obj_info->obj, port_obj_info->trans,
> + extack);
> + if (err != -EOPNOTSUPP)
> + port_obj_info->handled = true;
> + return err;
> }
>
> /* Switch ports might be stacked under e.g. a LAG. Ignore the
> @@ -515,9 +516,10 @@ static int __switchdev_handle_port_obj_del(struct net_device *dev,
> int err = -EOPNOTSUPP;
>
> if (check_cb(dev)) {
> - /* This flag is only checked if the return value is success. */
> - port_obj_info->handled = true;
> - return del_cb(dev, port_obj_info->obj);
> + err = del_cb(dev, port_obj_info->obj);
> + if (err != -EOPNOTSUPP)
> + port_obj_info->handled = true;
> + return err;
> }
>
> /* Switch ports might be stacked under e.g. a LAG. Ignore the
> @@ -568,9 +570,10 @@ static int __switchdev_handle_port_attr_set(struct net_device *dev,
> int err = -EOPNOTSUPP;
>
> if (check_cb(dev)) {
> - port_attr_info->handled = true;
> - return set_cb(dev, port_attr_info->attr,
> - port_attr_info->trans);
> + err = set_cb(dev, port_attr_info->attr, port_attr_info->trans);
> + if (err != -EOPNOTSUPP)
> + port_attr_info->handled = true;
> + return err;
> }
>
> /* Switch ports might be stacked under e.g. a LAG. Ignore the
> --
> 2.23.0
>
--
/Horatiu
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP
2021-01-22 9:05 ` Horatiu Vultur
@ 2021-01-22 13:36 ` Rasmus Villemoes
2021-01-23 20:44 ` Jakub Kicinski
0 siblings, 1 reply; 5+ messages in thread
From: Rasmus Villemoes @ 2021-01-22 13:36 UTC (permalink / raw)
To: Horatiu Vultur
Cc: netdev, Jiri Pirko, Florian Fainelli, Petr Machata, Ido Schimmel,
David S . Miller, Ivan Vecera, Jakub Kicinski
On 22/01/2021 10.05, Horatiu Vultur wrote:
> The 01/22/2021 00:43, Rasmus Villemoes wrote:
>>
>> It's not true that switchdev_port_obj_notify() only inspects the
>> ->handled field of "struct switchdev_notifier_port_obj_info" if
>> call_switchdev_blocking_notifiers() returns 0 - there's a WARN_ON()
>> triggering for a non-zero return combined with ->handled not being
>> true. But the real problem here is that -EOPNOTSUPP is not being
>> properly handled.
>>
>> The wrapper functions switchdev_handle_port_obj_add() et al change a
>> return value of -EOPNOTSUPP to 0, and the treatment of ->handled in
>> switchdev_port_obj_notify() seems to be designed to change that back
>> to -EOPNOTSUPP in case nobody actually acted on the notifier (i.e.,
>> everybody returned -EOPNOTSUPP).
>>
>> Currently, as soon as some device down the stack passes the check_cb()
>> check, ->handled gets set to true, which means that
>> switchdev_port_obj_notify() cannot actually ever return -EOPNOTSUPP.
>>
>> This, for example, means that the detection of hardware offload
>> support in the MRP code is broken - br_mrp_set_ring_role() always ends
>> up setting mrp->ring_role_offloaded to 1, despite not a single
>> mainline driver implementing any of the SWITCHDEV_OBJ_ID*_MRP. So
>> since the MRP code thinks the generation of MRP test frames has been
>> offloaded, no such frames are actually put on the wire.
>
> Just a small correction to what you have said regarding MRP. Is not the
> option mrp->ring_role_offload that determines if the MRP Test frames are
> generated by the HW but is the return value of the function
> 'br_mrp_switchdev_send_ring_test' called from function
> 'br_mrp_start_test'.
Hm, you're right, but the underlying problem is the same:
br_mrp_switchdev_set_ring_role() (whose return value is what is used to
determine ->ing_role_offloaded) and br_mrp_switchdev_send_ring_test()
both make use of switchdev_port_obj_add(SWITCHDEV_OBJ_ID_*MRP), and that
function is currently unable to return -EOPNOTSUPP, which it must in
order for the MRP logic to work.
Rasmus
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP
2021-01-22 13:36 ` Rasmus Villemoes
@ 2021-01-23 20:44 ` Jakub Kicinski
0 siblings, 0 replies; 5+ messages in thread
From: Jakub Kicinski @ 2021-01-23 20:44 UTC (permalink / raw)
To: Rasmus Villemoes
Cc: Horatiu Vultur, netdev, Jiri Pirko, Florian Fainelli,
Petr Machata, Ido Schimmel, David S . Miller, Ivan Vecera
On Fri, 22 Jan 2021 14:36:08 +0100 Rasmus Villemoes wrote:
> On 22/01/2021 10.05, Horatiu Vultur wrote:
> > The 01/22/2021 00:43, Rasmus Villemoes wrote:
> >>
> >> It's not true that switchdev_port_obj_notify() only inspects the
> >> ->handled field of "struct switchdev_notifier_port_obj_info" if
> >> call_switchdev_blocking_notifiers() returns 0 - there's a WARN_ON()
> >> triggering for a non-zero return combined with ->handled not being
> >> true. But the real problem here is that -EOPNOTSUPP is not being
> >> properly handled.
> >>
> >> The wrapper functions switchdev_handle_port_obj_add() et al change a
> >> return value of -EOPNOTSUPP to 0, and the treatment of ->handled in
> >> switchdev_port_obj_notify() seems to be designed to change that back
> >> to -EOPNOTSUPP in case nobody actually acted on the notifier (i.e.,
> >> everybody returned -EOPNOTSUPP).
> >>
> >> Currently, as soon as some device down the stack passes the check_cb()
> >> check, ->handled gets set to true, which means that
> >> switchdev_port_obj_notify() cannot actually ever return -EOPNOTSUPP.
> >>
> >> This, for example, means that the detection of hardware offload
> >> support in the MRP code is broken - br_mrp_set_ring_role() always ends
> >> up setting mrp->ring_role_offloaded to 1, despite not a single
> >> mainline driver implementing any of the SWITCHDEV_OBJ_ID*_MRP. So
> >> since the MRP code thinks the generation of MRP test frames has been
> >> offloaded, no such frames are actually put on the wire.
> >
> > Just a small correction to what you have said regarding MRP. Is not the
> > option mrp->ring_role_offload that determines if the MRP Test frames are
> > generated by the HW but is the return value of the function
> > 'br_mrp_switchdev_send_ring_test' called from function
> > 'br_mrp_start_test'.
>
> Hm, you're right, but the underlying problem is the same:
> br_mrp_switchdev_set_ring_role() (whose return value is what is used to
> determine ->ing_role_offloaded) and br_mrp_switchdev_send_ring_test()
> both make use of switchdev_port_obj_add(SWITCHDEV_OBJ_ID_*MRP), and that
> function is currently unable to return -EOPNOTSUPP, which it must in
> order for the MRP logic to work.
Could you reword the commit message to avoid confusion for folks
reading git history and repost? You can keep Petr's tag.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP
2021-01-21 23:43 [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP Rasmus Villemoes
2021-01-22 9:05 ` Horatiu Vultur
@ 2021-01-22 13:42 ` Petr Machata
1 sibling, 0 replies; 5+ messages in thread
From: Petr Machata @ 2021-01-22 13:42 UTC (permalink / raw)
To: Rasmus Villemoes
Cc: netdev, Horatiu Vultur, Jiri Pirko, Florian Fainelli,
Petr Machata, Ido Schimmel, David S . Miller, Ivan Vecera,
Jakub Kicinski
Rasmus Villemoes <rasmus.villemoes@prevas•dk> writes:
> It's not true that switchdev_port_obj_notify() only inspects the
> ->handled field of "struct switchdev_notifier_port_obj_info" if
> call_switchdev_blocking_notifiers() returns 0 - there's a WARN_ON()
> triggering for a non-zero return combined with ->handled not being
> true. But the real problem here is that -EOPNOTSUPP is not being
> properly handled.
>
> The wrapper functions switchdev_handle_port_obj_add() et al change a
> return value of -EOPNOTSUPP to 0, and the treatment of ->handled in
> switchdev_port_obj_notify() seems to be designed to change that back
> to -EOPNOTSUPP in case nobody actually acted on the notifier (i.e.,
> everybody returned -EOPNOTSUPP).
>
> Currently, as soon as some device down the stack passes the check_cb()
> check, ->handled gets set to true, which means that
> switchdev_port_obj_notify() cannot actually ever return -EOPNOTSUPP.
>
> This, for example, means that the detection of hardware offload
> support in the MRP code is broken - br_mrp_set_ring_role() always ends
> up setting mrp->ring_role_offloaded to 1, despite not a single
> mainline driver implementing any of the SWITCHDEV_OBJ_ID*_MRP. So
> since the MRP code thinks the generation of MRP test frames has been
> offloaded, no such frames are actually put on the wire.
>
> So, continue to set ->handled true if any callback returns success or
> any error distinct from -EOPNOTSUPP. But if all the callbacks return
> -EOPNOTSUPP, make sure that ->handled stays false, so the logic in
> switchdev_port_obj_notify() can propagate that information.
>
> Fixes: f30f0601eb93 ("switchdev: Add helpers to aid traversal through lower devices")
> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas•dk>
Looks good.
Reviewed-by: Petr Machata <petrm@nvidia•com>
Thanks!
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-01-21 23:43 [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP Rasmus Villemoes
2021-01-22 9:05 ` Horatiu Vultur
2021-01-22 13:36 ` Rasmus Villemoes
2021-01-23 20:44 ` Jakub Kicinski
2021-01-22 13:42 ` Petr Machata
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