Re: [PATCH] xen/events: fix error codes in xen_bind_pirq_msi_to_irq()

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

On Mon, Nov 27, 2023 at 02:17:05PM +0100, Juergen Gross wrote:
> On 27.11.23 13:57, Dan Carpenter wrote:
> > The error code needs to be set on these error paths.
> > 
> > Fixes: 5dd9ad32d775 ("xen/events: drop xen_allocate_irqs_dynamic()")
> > Fixes: d2ba3166f23b ("xen/events: move drivers/xen/events.c into 
> > drivers/xen/events/")
> 
> Please drop the last Fixes: tag. Said patch didn't introduce any new problem.

Yup.

> 
> > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > ---
> > Are we going to backport these to stable?  Should I split this into two
> > patches?
> > 
> >   drivers/xen/events/events_base.c | 8 ++++++--
> >   1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/xen/events/events_base.c 
> > b/drivers/xen/events/events_base.c
> > index f5edb9e27e3c..aae62603b461 100644
> > --- a/drivers/xen/events/events_base.c
> > +++ b/drivers/xen/events/events_base.c
> > @@ -1105,13 +1105,17 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, 
> > struct msi_desc *msidesc,
> >     mutex_lock(&irq_mapping_update_lock);
> >     irq = irq_alloc_descs(-1, 0, nvec, -1);
> > -   if (irq < 0)
> > +   if (irq < 0) {
> > +           ret = irq;
> >             goto out;
> > +   }
> 
> Why? The return value for the out: label is in irq.
> 

This patch is full of embarrassment.  I misread this code.  I thought
the out label was in the error handling block.

> >     for (i = 0; i < nvec; i++) {
> >             info = xen_irq_init(irq + i);
> > -           if (!info)
> > +           if (!info) {
> > +                   ret = -ENOMEM;
> >                     goto error_irq;
> > +           }
> 
> It would be easier to just preset ret with -ENOMEM when defining it.
> 

That only works if it fails on the first iteration.

I'll fix this up and resend.

regards,
dan carpenter