lkml.org 
[lkml]   [2019]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH net-next 06/17] net: dsa: Call driver's setup callback after setting up its switchdev notifier
From
Date
On 4/3/19 12:03 AM, Andrew Lunn wrote:
> On Sun, Mar 31, 2019 at 08:42:21PM +0300, Vladimir Oltean wrote:
>> This allows the driver to perform some manipulations of its own during
>> setup, using generic code.
>> One current usage scenario is for the driver to request DSA to set up
>> 802.1Q based switch tagging for its ports.
>>
>> Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
>> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
>> ---
>> net/dsa/dsa2.c | 8 ++++----
>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
>> index c00ee464afc7..5beceb18b7e2 100644
>> --- a/net/dsa/dsa2.c
>> +++ b/net/dsa/dsa2.c
>> @@ -360,14 +360,14 @@ static int dsa_switch_setup(struct dsa_switch *ds)
>> if (err)
>> return err;
>>
>> - err = ds->ops->setup(ds);
>> - if (err < 0)
>> - return err;
>> -
>> err = dsa_switch_register_notifier(ds);
>> if (err)
>> return err;
>
> It seems that notifiers are the important thing here? Maybe state that
> in the commit message?
>
> I'm also wondering how safe this is in general. If we have not yet
> called the driver setup, the switch is potentially not yet ready to
> actually handle an requests that come via the notifier. If such
> notifiers can only come from the driver itself, it should be
> safe. However, if they could come from the rest of the stack, i could
> see bad things happening.
>
> Andrew
>

Hi Andrew,

Correct me if I'm wrong, but the switchdev notifiers coming from the
stack are coming through a net device, and the slave net devices are
only created in dsa_port_setup, which is later than the code I'm
modifying anyway? Do you have an example of potentially racy situation
caused by this change?

Thanks,
-Vladimir

\
 
 \ /
  Last update: 2019-04-03 11:59    [W:0.059 / U:0.652 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site