Re: [PATCH v2] PCI/MSI: Correct use of can_mask in msi_add_msi_desc()

[Jason Gunthorpe <jgg@xxxxxxxxxx>]

On Fri, Aug 05, 2022 at 12:03:15PM +0200, Josef Johansson wrote:
> On 2/14/22 11:07, Josef Johansson wrote:
> > From: Josef Johansson <josef@xxxxxxxxxxx>
> > 
> > PCI/MSI: Correct use of can_mask in msi_add_msi_desc()
> > Commit 71020a3c0dff4 ("PCI/MSI: Use msi_add_msi_desc()") modifies
> > the logic of checking msi_attrib.can_mask, without any reason.
> > This commits restores that logic.
> >
> > Fixes: 71020a3c0dff4 ("PCI/MSI: Use msi_add_msi_desc()")
> > Signed-off-by: Josef Johansson <josef@xxxxxxxxxxx>
> > 
> > ---
> > v2: Changing subject line to fit earlier commits.
> > 
> > Trying to fix a NULL BUG in the NVMe MSIX implementation I stumbled upon 
> > this code,
> > which ironically was what my last MSI patch resulted into.
> > 
> > I don't see any reason why this logic was change, and it did not break 
> > anything
> > correcting the logic.
> > 
> > CC xen-devel since it very much relates to Xen kernel (via 
> > pci_msi_ignore_mask).
> > ---
> > 
> > diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
> > index c19c7ca58186..146e7b9a01cc 100644
> > --- a/drivers/pci/msi/msi.c
> > +++ b/drivers/pci/msi/msi.c
> > @@ -526,7 +526,7 @@ static int msix_setup_msi_descs(struct pci_dev *dev, 
> > void __iomem *base,
> >             desc.pci.msi_attrib.can_mask = !pci_msi_ignore_mask &&
> >                                            !desc.pci.msi_attrib.is_virtual;
> > -           if (!desc.pci.msi_attrib.can_mask) {
> > +           if (desc.pci.msi_attrib.can_mask) {
> >                     addr = pci_msix_desc_addr(&desc);
> >                     desc.pci.msix_ctrl = readl(addr + 
> > PCI_MSIX_ENTRY_VECTOR_CTRL);
> >             }
> > 

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

Bjorn, please take it?

Jason