Re: [PATCH] PCI: endpoint: pci-epf-test: Roll back BAR mapping when subrange setup fails

[Koichiro Den]

On Mon, Mar 16, 2026 at 05:19:26PM +0100, Niklas Cassel wrote:
> On Mon, Mar 16, 2026 at 11:02:25PM +0900, Koichiro Den wrote:
> > When the BAR subrange mapping test on DWC-based platforms fails due to
> > insufficient free inbound iATU regions,
> > pci_epf_test_bar_subrange_setup() returns an error (-ENOSPC) but does
> > not restore the original BAR mapping. This causes subsequent test runs
> > to become confusing, since the failure may leave room for the next
> > subrange mapping test to pass.
> > 
> > Fix this by restoring the original BAR mapping when preparation of the
> > subrange mapping fails, so that no side effect remains regardless of the
> > test success or failure.
> > 
> > Fixes: 6c5e6101423b ("PCI: endpoint: pci-epf-test: Add BAR subrange mapping test support")
> > Reported-by: Christian Bruel <christian.bruel@xxxxxxxxxxx>
> > Closes: https://lore.kernel.org/linux-pci/b2b03ebe-9482-4a13-b22f-7b44da096eed@xxxxxxxxxxx/
> > Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
> > ---
> >  drivers/pci/endpoint/functions/pci-epf-test.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > index 14e61ebe1f11..f44c36f5cac5 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -898,16 +898,22 @@ static void pci_epf_test_bar_subrange_setup(struct pci_epf_test *epf_test,
> >  	bar->submap = submap;
> >  	bar->num_submap = nsub;
> >  
> >  	ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, bar);
> >  	if (ret) {
> >  		dev_err(&epf->dev, "pci_epc_set_bar() failed: %d\n", ret);
> >  		bar->submap = old_submap;
> >  		bar->num_submap = old_nsub;
> > +		ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, bar);
> > +		if (ret)
> > +			dev_warn(&epf->dev,
> > +				 "failed to restore the original BAR mapping: %d\n",
> 
> Nit:
> I would use a capitalized F:
> "Failed to restore ..."
> 
> in order to match most other prints in this file.

Agree. Bjorn or Mani, please feel free to fix this up (i.e. s/failed/Failed/)
when applying, to avoid a respin for such a minor change.

> 
> Reviewed-by: Niklas Cassel <cassel@xxxxxxxxxx>

Thanks again for reviewing, Niklas.

Christian, if possible, it would be very helpful if you could take a look or
test this slightly polished version and add a Tested-by or Reviewed-by.

Best regards,
Koichiro