Re: [Qemu-devel] [PATCH v2 3/6] pci: Fix the wrong return value judgment condition

[Mao Zhongyi]

Hi, Marcel

On 06/06/2017 12:20 AM, Marcel Apfelbaum wrote:
> On 02/06/2017 10:54, Mao Zhongyi wrote:
> > On success, pci_add_capability2() returns a positive value. On
> > failure, it sets an error and return a negative value. It doesn't
> > always return 0. So the judgment condtion of pci_add_capability2()
> > is wrong if it contains the situation where return value equal to
> > 0. Fix the error checks from its callers.
>
> Hi,
> I would suggest changing the above to a simpler:
>
> pci_add_capability returns a strictly positive value on success,
> correct asserts.
>
> Thanks,
> Marcel

OK, I see.

Thanks a lot.
Mao

> > Cc: address@hidden
> > Cc: address@hidden
> > Cc: address@hidden
> > Cc: address@hidden
> > Cc: address@hidden
> > Cc: address@hidden
> > Signed-off-by: Mao Zhongyi <address@hidden>
> > ---
> >   hw/net/e1000e.c   | 2 +-
> >   hw/net/eepro100.c | 2 +-
> >   hw/vfio/pci.c     | 2 +-
> >   3 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/hw/net/e1000e.c b/hw/net/e1000e.c
> > index 6e23493..8259d67 100644
> > --- a/hw/net/e1000e.c
> > +++ b/hw/net/e1000e.c
> > @@ -374,7 +374,7 @@ e1000e_add_pm_capability(PCIDevice *pdev, uint8_t offset, 
> > uint16_t pmc)
> >   {
> >       int ret = pci_add_capability(pdev, PCI_CAP_ID_PM, offset, PCI_PM_SIZEOF);
> >   -    if (ret >= 0) {
> > +    if (ret > 0) {
> >           pci_set_word(pdev->config + offset + PCI_PM_PMC,
> >                        PCI_PM_CAP_VER_1_1 |
> >                        pmc);
> > diff --git a/hw/net/eepro100.c b/hw/net/eepro100.c
> > index 4bf71f2..da36816 100644
> > --- a/hw/net/eepro100.c
> > +++ b/hw/net/eepro100.c
> > @@ -571,7 +571,7 @@ static void e100_pci_reset(EEPRO100State * s)
> >           int cfg_offset = 0xdc;
> >           int r = pci_add_capability(&s->dev, PCI_CAP_ID_PM,
> >                                      cfg_offset, PCI_PM_SIZEOF);
> > -        assert(r >= 0);
> > +        assert(r > 0);
> >           pci_set_word(pci_conf + cfg_offset + PCI_PM_PMC, 0x7e21);
> >   #if 0 /* TODO: replace dummy code for power management emulation. */
> >           /* TODO: Power Management Control / Status. */
> > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> > index 32aca77..5881968 100644
> > --- a/hw/vfio/pci.c
> > +++ b/hw/vfio/pci.c
> > @@ -1744,7 +1744,7 @@ static int vfio_setup_pcie_cap(VFIOPCIDevice *vdev, int 
> > pos, uint8_t size,
> >       }
> >         pos = pci_add_capability(&vdev->pdev, PCI_CAP_ID_EXP, pos, size);
> > -    if (pos >= 0) {
> > +    if (pos > 0) {
> >           vdev->pdev.exp.exp_cap = pos;
> >       }