Re: [PATCH 1/6] net: ethernet: ti: netcp: add support of cpts

From: Grygorii Strashko
Date: Wed Nov 30 2016 - 12:32:10 EST




On 11/30/2016 03:44 AM, Richard Cochran wrote:
> On Mon, Nov 28, 2016 at 05:04:23PM -0600, Grygorii Strashko wrote:
>> @@ -678,6 +744,9 @@ struct gbe_priv {
>> int num_et_stats;
>> /* Lock for updating the hwstats */
>> spinlock_t hw_stats_lock;
>> +
>> + int cpts_registered;
>
> The usage of this counter is racy.
>
>> + struct cpts *cpts;
>> };
>
> This ++ and -- business ...
>
>> +static void gbe_register_cpts(struct gbe_priv *gbe_dev)
>> +{
>> + if (!gbe_dev->cpts)
>> + return;
>> +
>> + if (gbe_dev->cpts_registered > 0)
>> + goto done;
>> +
>> + if (cpts_register(gbe_dev->cpts)) {
>> + dev_err(gbe_dev->dev, "error registering cpts device\n");
>> + return;
>> + }
>> +
>> +done:
>> + ++gbe_dev->cpts_registered;
>> +}
>> +
>> +static void gbe_unregister_cpts(struct gbe_priv *gbe_dev)
>> +{
>> + if (!gbe_dev->cpts || (gbe_dev->cpts_registered <= 0))
>> + return;
>> +
>> + if (--gbe_dev->cpts_registered)
>> + return;
>> +
>> + cpts_unregister(gbe_dev->cpts);
>> +}
>
> is invoked from your open() and close() methods, but those methods
> are not serialized among multiple ports.
>

ok. Seems my assumption that ndo_open/ndo_close serialized by rtnl_lock is incorrect. Right?
net_device_ops.ndo_open ->
netcp_ndo_open
gbe_open
gbe_register_cpts

--
regards,
-grygorii