Re: [patch net-next v5 3/8] switchdev: allow caller to explicitly request attr_set as deferred

[Jiri Pirko <jiri@resnulli.us>]

Thu, Oct 15, 2015 at 06:34:01AM CEST, sfeldma@gmail.com wrote:
>On Wed, Oct 14, 2015 at 10:40 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 defer the att_set processing for later.
>>
>> 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.
>>
>> Benefit from newly introduced switchdev deferred ops infrastructure.
>>
>> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
>> ---
>>  include/net/switchdev.h   |   1 +
>>  net/bridge/br_stp.c       |   3 +-
>>  net/switchdev/switchdev.c | 108 ++++++++++++++++++----------------------------
>>  3 files changed, 46 insertions(+), 66 deletions(-)
>>
>> diff --git a/include/net/switchdev.h b/include/net/switchdev.h
>> index d1c7f90..f7de6f8 100644
>> --- a/include/net/switchdev.h
>> +++ b/include/net/switchdev.h
>> @@ -17,6 +17,7 @@
>>
>>  #define SWITCHDEV_F_NO_RECURSE         BIT(0)
>>  #define SWITCHDEV_F_SKIP_EOPNOTSUPP    BIT(1)
>> +#define SWITCHDEV_F_DEFER              BIT(2)
>>
>>  struct switchdev_trans_item {
>>         struct list_head list;
>> diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
>> index db6d243de..80c34d7 100644
>> --- a/net/bridge/br_stp.c
>> +++ b/net/bridge/br_stp.c
>> @@ -41,13 +41,14 @@ 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_DEFER,
>>                 .u.stp_state = state,
>>         };
>>         int err;
>>
>>         p->state = state;
>>         err = switchdev_port_attr_set(p->dev, &attr);
>> -       if (err && err != -EOPNOTSUPP)
>> +       if (err)
>>                 br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
>>                                 (unsigned int) p->port_no, p->dev->name);
>>  }
>
>Should this part of the patch be moved to patch 6/8 where
>switchdev_deferred_process() is called from del_nbp()?

No, this part relates to the fact that attr_set now does not defer
automagically. So caller must say when to defer. So having this here is
correct.