Jakub Kicinski [k...@kernel.org] wrote:
> On Thu, 7 Jan 2021 23:12:34 -0800 Sukadev Bhattiprolu wrote:
> > Use a separate lock to serialze ibmvnic_reset() and ibmvnic_remove()
> > functions. ibmvnic_reset() schedules work for the worker thread and
> > ibmvnic_remove() flushes the work before removing the adapter. We
> > don't want any work to be scheduled once we start removing the
> > adapter (i.e after we have already flushed the work).
>
> Locking based on functions, not on data being accessed is questionable
> IMO. If you don't want work to be scheduled isn't it enough to have a
> bit / flag that you set to let other flows know not to schedule reset?
Maybe I could improve the description, but the "data" being protected
is the work queue. Basically don't add to the work queue while/after
it is (being) flushed.
Existing code is checking for the VNIC_REMOVING state before scheduling
the work but without a lock. If state goes to REMOVING after we check,
we could schedule work after the flush?
>
> > @@ -5459,6 +5464,7 @@ static int ibmvnic_remove(struct vio_dev *dev)
> > {
> > struct net_device *netdev = dev_get_drvdata(&dev->dev);
> > struct ibmvnic_adapter *adapter = netdev_priv(netdev);
> > + unsigned long rmflags;
> > unsigned long flags;
> >
> > spin_lock_irqsave(&adapter->state_lock, flags);
> > @@ -5467,7 +5473,15 @@ static int ibmvnic_remove(struct vio_dev *dev)
> > return -EBUSY;
> > }
>
> > + spin_lock_irqsave(&adapter->remove_lock, rmflags);
>
> You can just use flags again, no need for separate variables.
Ok.
>
> > adapter->state = VNIC_REMOVING;
> > + spin_unlock_irqrestore(&adapter->remove_lock, rmflags);
