Re: [PATCH] PCI: endpoint: functions/pci-epf-test: Avoid DMA release when DMA is unsupported

[Kunihiko Hayashi]

Hi Kishon,

On 2020/04/22 14:45, Kishon Vijay Abraham I wrote:
> Hi Kunihiko,
>
> On 3/23/2020 3:15 PM, Kunihiko Hayashi wrote:
> > When unbinding pci_epf_test, pci_epf_test_clean_dma_chan() is called in
> > pci_epf_test_unbind() even though epf_test->dma_supported is false.
> > As a result, dma_release_channel() will occur null pointer access because
> > dma_chan isn't set.
> >
> > This avoids calling dma_release_channel() if epf_test->dma_supported
> > is false.
> >
> > Fixes: a1d105d4ab8e ("PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data")
> > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
> > ---
> >   drivers/pci/endpoint/functions/pci-epf-test.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > index 3b4cf7e..8b4f136 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -609,7 +609,8 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
> >   	int bar;
> >   
> >   	cancel_delayed_work(&epf_test->cmd_handler);
> > -	pci_epf_test_clean_dma_chan(epf_test);
> > +	if (epf_test->dma_supported)
> > +		pci_epf_test_clean_dma_chan(epf_test);
>
> Can you add this check inside the pci_epf_test_clean_dma_chan()?
Okay, I'll move this check to the pci_epf_test_clean_dma_chan().

Thank you,

---
Best Regards
Kunihiko Hayashi