From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jiri Pirko <jiri@resnulli.us>
Subject: Re: [patch net-next RFC 2/3] switchdev: allow caller to explicitly
 use deferred attr_set version
Date: Thu, 8 Oct 2015 07:39:33 +0200
Message-ID: <20151008053933.GA2186@nanopsycho.orion>
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Cc: Netdev <netdev@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Ido Schimmel <idosch@mellanox.com>, eladr@mellanox.com,
	Florian Fainelli <f.fainelli@gmail.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
	"andrew@lunn.ch" <andrew@lunn.ch>,
	john fastabend <john.fastabend@gmail.com>,
	David Laight <David.Laight@aculab.com>
To: Scott Feldman <sfeldma@gmail.com>
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Thu, Oct 08, 2015 at 06:27:07AM CEST, sfeldma@gmail.com wrote:
>On Wed, Oct 7, 2015 at 11:30 AM, Jiri Pirko <jiri@resnulli.us> wrote:
>> From: Jiri Pirko <jiri@mellanox.com>
>>
>> Caller should know if he can call attr_set directly (when holding RTNL)
>> or if he has to use deferred version of this function.
>>
>> This also allows drivers to sleep inside attr_set and report operation
>> status back to switchdev core. Switchdev core then warns if status is
>> not ok, instead of silent errors happening in drivers.
>>
>> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
>> ---
>>  include/net/switchdev.h   |   2 +
>>  net/bridge/br_stp.c       |   4 +-
>>  net/switchdev/switchdev.c | 113 +++++++++++++++++++++++++---------------------
>>  3 files changed, 65 insertions(+), 54 deletions(-)
>>
>> diff --git a/include/net/switchdev.h b/include/net/switchdev.h
>> index 89266a3..320be44 100644
>> --- a/include/net/switchdev.h
>> +++ b/include/net/switchdev.h
>> @@ -168,6 +168,8 @@ int switchdev_port_attr_get(struct net_device *dev,
>>                             struct switchdev_attr *attr);
>>  int switchdev_port_attr_set(struct net_device *dev,
>>                             struct switchdev_attr *attr);
>> +int switchdev_port_attr_set_deferred(struct net_device *dev,
>> +                                    struct switchdev_attr *attr);
>
>Rather than adding another op, use attr->flags and define:
>
>#define SWITCHDEV_F_DEFERRED          BIT(x)
>
>So we get:
>
>void br_set_state(struct net_bridge_port *p, unsigned int state)
>{
>        struct switchdev_attr attr = {
>                .id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
>+              .flags = SWITCHDEV_F_DEFERRED,
>                .u.stp_state = state,
>        };
>        int err;
>
>        p->state = state;
>        err = switchdev_port_attr_set(p->dev, &attr);
>        if (err && err != -EOPNOTSUPP)
>                br_warn(p->br, "error setting offload STP state on
>port %u(%s)\n",
>                                (unsigned int) p->port_no,
>p->dev->name);
>}
>
>(And add obj->flags to do the same).

That's what I wanted to avoid. Also because the obj is const and for
call from work, this flag would have to be removed.