RE: [RFC 1/4] bus/pci: fix check on interrupt FD for FreeBSD

[Marat Khalili <marat.khalili@huawei.com>]

> > > --- a/drivers/bus/pci/bsd/pci.c
> > > +++ b/drivers/bus/pci/bsd/pci.c
> > > @@ -93,7 +93,7 @@ pci_uio_free_resource(struct rte_pci_device *dev,
> > >  {
> > >       rte_free(uio_res);
> > >
> > > -     if (rte_intr_fd_get(dev->intr_handle)) {
> > > +     if (rte_intr_fd_get(dev->intr_handle) >= 0) {
> > >               close(rte_intr_fd_get(dev->intr_handle));
> > >               rte_intr_fd_set(dev->intr_handle, -1);
> > >               rte_intr_type_set(dev->intr_handle, RTE_INTR_HANDLE_UNKNOWN);
> >
> > Unlikely that we actually have fd as 0 for this call, but change is
> > technically correct.
> 
> Yes, this is why I did not Cc: stable.
> Thanks.

Just trying to understand what's going on here out of curiosity.

Zero fd is valid and negative (typically -1) indicating error is a standard
logic in Linux, but here intr_handle->fd is zero-filled by
rte_intr_instance_alloc, so its initial state is 0 instead of -1. Do we have
reasons to believe that something always sets fd to non-zero value before
pci_uio_free_resource is called? Should rte_intr_instance_alloc set it to -1?