[PATCH] drivers/pci/hotplug: Handle presence detection change properly

[Gavin Shan]

On Tue, Dec 20, 2016 at 05:49:33PM +1100, Gavin Shan wrote:
>The surprise hotplug is driven by interrupt in PowerNV PCI hotplug
>driver. In the interrupt handler, pnv_php_interrupt(), we bail when
>pnv_pci_get_presence_state() returns zero wrongly. It causes the
>presence change event is always ignored incorrectly.
>
>This fixes the issue by bailing on error (non-zero value) returned
>from pnv_pci_get_presence_state().
>
>Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
>Cc: stable at vger.kernel.org #v4.9+
>Reported-by: Hank Chang <hankmax0000 at gmail.com>
>Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
>Tested-by: Willie Liauw <williel at supermicro.com.tw>
>---

Please ignore this one for now. I will post a revised series to fix
more issues found in recent testing. Also, the warning message will
be modified accordingly.

Thanks,
Gavin

> drivers/pci/hotplug/pnv_php.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
>index 56efaf7..38a2309 100644
>--- a/drivers/pci/hotplug/pnv_php.c
>+++ b/drivers/pci/hotplug/pnv_php.c
>@@ -707,8 +707,12 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data)
> 		added = !!(lsts & PCI_EXP_LNKSTA_DLLLA);
> 	} else if (sts & PCI_EXP_SLTSTA_PDC) {
> 		ret = pnv_pci_get_presence_state(php_slot->id, &presence);
>-		if (!ret)
>+		if (ret) {
>+			dev_warn(&pdev->dev, "PCI slot [%s] error %d handling PDC event (0x%04x)\n",
>+				php_slot->name, ret, sts);
> 			return IRQ_HANDLED;
>+		}
>+
> 		added = !!(presence == OPAL_PCI_SLOT_PRESENT);
> 	} else {
> 		return IRQ_NONE;
>-- 
>2.7.4
>