Re: [PATCH v1 3/7] dmaengine: tegra-apb: Prevent race conditions on channel's freeing

[Michał Mirosław]

On Mon, Dec 30, 2019 at 09:45:55PM +0100, Michał Mirosław wrote:
> On Sat, Dec 28, 2019 at 11:46:36PM +0300, Dmitry Osipenko wrote:
> > It's unsafe to check the channel's "busy" state without taking a lock,
> > it is also unsafe to assume that tasklet isn't in-fly.
> 
> 'in-flight'. Also, the patch seems to have two independent bug-fixes
> in it. Second one doesn't look right, at least not without an explanation.
> 
> First:
> 
> > -	if (tdc->busy)
> > -		tegra_dma_terminate_all(dc);
> > +	tegra_dma_terminate_all(dc);
> 
> Second:
> 
> > +	tasklet_kill(&tdc->tasklet);

BTW, maybe you can convert the code to threaded interrupt handler and
just get rid of the tasklet instead of fixing it?

Best Regards,
Michał Mirosław