Re: [PATCH 2/3] dmaengine: xilinx: xdma: Fix synchronization issue

[Lizhi Hou]

On 3/27/24 17:23, Miquel Raynal wrote:
> Hi Lizhi,
>
> > > @@ -376,6 +378,8 @@ static int xdma_xfer_start(struct xdma_chan *xchan)
> > >    		return ret;
> > >    >   	xchan->busy = true;
> > > +	xchan->stop_requested = false;
> > > +	reinit_completion(&xchan->last_interrupt);
> > If stop_requested is true, it should not start another transfer. So I would suggest to add
> >
> >        if (xchan->stop_requested)
> >
> >                   return -ENODEV;
> Maybe -EBUSY in this case?
>
> I thought synchronize() was mandatory in-between. If that's not the
> case then indeed we need to block or error-out if a new transfer
> gets started.

Okay. It looks issue_pending is not expected between terminate_all() and 
synchronize().

This check is not needed.


Thanks,

Lizhi

> > at the beginning of xdma_xfer_start().
> >
> > xdma_xfer_start() is protected by chan lock.
> >
> > >    >   	return 0;
> > >    }
> Thanks,
> Miquèl