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

[Mao Zhongyi <maozy.fnst@cn.fujitsu.com>]

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: dmitry@daynix.com
>> Cc: jasowang@redhat.com
>> Cc: alex.williamson@redhat.com
>> Cc: marcel@redhat.com
>> Cc: mst@redhat.com
>> Cc: armbru@redhat.com
>> Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
>> ---
>>   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;
>>       }
>>
>
>
>
>