Re: [PATCH net-next RFC v1 3/4] devlink: Add hierarchy between traps in device level and port level

[Aya Levin]

On 9/6/2020 6:58 PM, Ido Schimmel wrote:
> On Wed, Sep 02, 2020 at 06:32:13PM +0300, Aya Levin wrote:
> > Managing large scale port's traps may be complicated. This patch
> > introduces a shortcut: when setting a trap on a device and this trap is
> > not registered on this device, the action will take place on all related
> > ports that did register this trap.
>
> I'm not really a fan of this and I'm not sure there is precedent for
> something similar. Also, it's an optimization, so I wouldn't put it as
> part of the first submission before you gather some operational
> experience with the initial interface.

I thought it was a nice idea but I agree that this is an optimization 
and can be dropped from preliminary submission
> In addition, I find it very unintuitive for users. When I do 'devlink
> trap show' I will not see anything. I will only see the traps when I
> issue 'devlink port trap show', yet 'devlink trap set ...' is expected
> to work.
>
> Lets assume that this is a valid change, it would be better implemented
> with my suggestion from the previous patch: When devlink sees that a
> trap is registered on all the ports it can auto-register a new
> per-device trap and user space gets the appropriate notification.
>
> > Signed-off-by: Aya Levin <ayal@xxxxxxxxxxxx>
> > ---
> >   net/core/devlink.c | 43 +++++++++++++++++++++++++++++++++----------
> >   1 file changed, 33 insertions(+), 10 deletions(-)
> >
> > diff --git a/net/core/devlink.c b/net/core/devlink.c
> > index b13e1b40bf1c..dea5482b2517 100644
> > --- a/net/core/devlink.c
> > +++ b/net/core/devlink.c
> > @@ -6501,23 +6501,46 @@ static int devlink_nl_cmd_trap_set_doit(struct sk_buff *skb,
> >   	struct devlink *devlink = info->user_ptr[0];
> >   	struct devlink_trap_mngr *trap_mngr;
> >   	struct devlink_trap_item *trap_item;
> > +	struct devlink_port *devlink_port;
> >   	int err;
> >   
> > -	trap_mngr = devlink_trap_get_trap_mngr_from_info(devlink, info);
> > -	if (list_empty(&trap_mngr->trap_list))
> > -		return -EOPNOTSUPP;
> > +	devlink_port = devlink_port_get_from_attrs(devlink, info->attrs);
> > +	if (IS_ERR(devlink_port)) {
> > +		trap_mngr =  &devlink->trap_mngr;
> > +		if (list_empty(&trap_mngr->trap_list))
> > +			goto loop_over_ports;
> >   
> > -	trap_item = devlink_trap_item_get_from_info(trap_mngr, info);
> > -	if (!trap_item) {
> > -		NL_SET_ERR_MSG_MOD(extack, "Device did not register this trap");
> > -		return -ENOENT;
> > +		trap_item = devlink_trap_item_get_from_info(trap_mngr, info);
> > +		if (!trap_item)
> > +			goto loop_over_ports;
> > +	} else {
> > +		trap_mngr = &devlink_port->trap_mngr;
> > +		if (list_empty(&trap_mngr->trap_list))
> > +			return -EOPNOTSUPP;
> > +
> > +		trap_item = devlink_trap_item_get_from_info(trap_mngr, info);
> > +		if (!trap_item) {
> > +			NL_SET_ERR_MSG_MOD(extack, "Port did not register this trap");
> > +			return -ENOENT;
> > +		}
> >   	}
> >   	return devlink_trap_action_set(devlink, trap_mngr, trap_item, info);
> >   
> > -	err = devlink_trap_action_set(devlink, trap_mngr, trap_item, info);
> > -	if (err)
> > -		return err;
> > +loop_over_ports:
> > +	if (list_empty(&devlink->port_list))
> > +		return -EOPNOTSUPP;
> > +	list_for_each_entry(devlink_port, &devlink->port_list, list) {
> > +		trap_mngr = &devlink_port->trap_mngr;
> > +		if (list_empty(&trap_mngr->trap_list))
> > +			continue;
> >   
> > +		trap_item = devlink_trap_item_get_from_info(trap_mngr, info);
> > +		if (!trap_item)
> > +			continue;
> > +		err = devlink_trap_action_set(devlink, trap_mngr, trap_item, info);
> > +		if (err)
> > +			return err;
> > +	}
> >   	return 0;
> >   }
> >   
> > --
> > 2.14.1