pci/hotplug/pnv-php: Disable MSI and PCI device properly

pnv_php_disable_irq() can be called in two paths: Bailing path in
pnv_php_enable_irq() or releasing slot. The MSI (or MSIx) interrupts
is disabled unconditionally in pnv_php_disable_irq(). It's wrong
because that might be enabled by drivers other than pnv-php.

This disables MSI (or MSIx) interrupts and the PCI device only if
it was enabled by pnv-php. In the error path of pnv_php_enable_irq(),
we rely on the newly added parameter @disable_device. In the path
of releasing slot, @pnv_php->irq is checked.

Cc: <stable@vger.kernel.org> # v4.9+
Fixes: 360aebd85a4c ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
index 6d36b76..335a556 100644 (file)
--- a/drivers/pci/hotplug/pnv_php.c
+++ b/drivers/pci/hotplug/pnv_php.c
@@ -35,9 +35,11 @@ static void pnv_php_register(struct device_node *dn);
 static void pnv_php_unregister_one(struct device_node *dn);
 static void pnv_php_unregister(struct device_node *dn);
 
-static void pnv_php_disable_irq(struct pnv_php_slot *php_slot)
+static void pnv_php_disable_irq(struct pnv_php_slot *php_slot,
+                               bool disable_device)
 {
        struct pci_dev *pdev = php_slot->pdev;
+       int irq = php_slot->irq;
        u16 ctrl;
 
        if (php_slot->irq > 0) {
@@ -56,10 +58,14 @@ static void pnv_php_disable_irq(struct pnv_php_slot *php_slot)
                php_slot->wq = NULL;
        }
 
-       if (pdev->msix_enabled)
-               pci_disable_msix(pdev);
-       else if (pdev->msi_enabled)
-               pci_disable_msi(pdev);
+       if (disable_device || irq > 0) {
+               if (pdev->msix_enabled)
+                       pci_disable_msix(pdev);
+               else if (pdev->msi_enabled)
+                       pci_disable_msi(pdev);
+
+               pci_disable_device(pdev);
+       }
 }
 
 static void pnv_php_free_slot(struct kref *kref)
@@ -68,7 +74,7 @@ static void pnv_php_free_slot(struct kref *kref)
                                        struct pnv_php_slot, kref);
 
        WARN_ON(!list_empty(&php_slot->children));
-       pnv_php_disable_irq(php_slot);
+       pnv_php_disable_irq(php_slot, false);
        kfree(php_slot->name);
        kfree(php_slot);
 }
@@ -777,7 +783,7 @@ static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq)
        php_slot->wq = alloc_workqueue("pciehp-%s", 0, 0, php_slot->name);
        if (!php_slot->wq) {
                dev_warn(&pdev->dev, "Cannot alloc workqueue\n");
-               pnv_php_disable_irq(php_slot);
+               pnv_php_disable_irq(php_slot, true);
                return;
        }
 
@@ -799,7 +805,7 @@ static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq)
        ret = request_irq(irq, pnv_php_interrupt, IRQF_SHARED,
                          php_slot->name, php_slot);
        if (ret) {
-               pnv_php_disable_irq(php_slot);
+               pnv_php_disable_irq(php_slot, true);
                dev_warn(&pdev->dev, "Error %d enabling IRQ %d\n", ret, irq);
                return;
        }