Re: [PATCH] Octeontx2-af: Fix pci_alloc_irq_vectors() return value check

[Harshit Mogalapalli]

Hi Simon,
On 15/10/25 14:06, Simon Horman wrote:
> On Tue, Oct 14, 2025 at 03:50:47PM +0530, Harshit Mogalapalli wrote:
> > Hi,
> >
> > On 14/10/25 15:44, Harshit Mogalapalli wrote:
> > > In cgx_probe() when pci_alloc_irq_vectors() fails the error value will
> > > be negative and that check is sufficient.
> > >
> > > 	err = pci_alloc_irq_vectors(pdev, nvec, nvec, PCI_IRQ_MSIX);
> > >           if (err < 0 || err != nvec) {
> > >           	...
> > > 	}
> > >
> > > Remove the check which compares err with nvec.
> > >
> > > Fixes: 1463f382f58d ("octeontx2-af: Add support for CGX link management")
> > > Suggested-by: Paolo Abeni <pabeni@xxxxxxxxxx>
> > > Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
> > > ---
> > > Only compile tested.
> > > ---
> > >    drivers/net/ethernet/marvell/octeontx2/af/cgx.c | 2 +-
> > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
> > > index d374a4454836..f4d5a3c05fa4 100644
> > > --- a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
> > > +++ b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
> > > @@ -1993,7 +1993,7 @@ static int cgx_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> > >    	nvec = pci_msix_vec_count(cgx->pdev);
> > >    	err = pci_alloc_irq_vectors(pdev, nvec, nvec, PCI_IRQ_MSIX);
> > > -	if (err < 0 || err != nvec) {
> > > +	if (err < 0) {
> > >    		dev_err(dev, "Request for %d msix vectors failed, err %d\n",
> > >    			nvec, err);
> >
> >
> > Now that I think about it more, maybe we want to error out when err != nvec
> > as well ? In that case maybe the right thing to do is leave the check as is
> > and set err = -EXYZ before goto ?
> >
> > Thanks,
> > Harshit>   		goto err_release_regions;
>
> Hi Harshit,
>
> My reading of the documentation of pci_alloc_irq_vectors() is that
> Because nvec is passed as both the min and max desired vectors,
> either nvecs will be allocated, or -ENOSPC will be returned.

Ah thats a nice summary of the correctness of this patch.> Maybe it is 
worth adding a comment about that to patch description
> or the code. But I think the code in this patch is correct.

Definitely will add this and send v2.

Thanks,
Harshit