[PATCH 4.9 083/153] pci/hotplug/pnv-php: Disable MSI and PCI device properly

Greg Kroah-Hartman
2017-03-10T11:10:53Z

From: Gavin Shan <gwshan@linux.vnet.ibm.com>

commit 49f4b08e61547a5ccd2db551d994c4503efe5666 upstream.

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.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/pci/hotplug/pnv_php.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

--- a/drivers/pci/hotplug/pnv_php.c
+++ b/drivers/pci/hotplug/pnv_php.c
@@ -35,9 +35,11 @@ static void pnv_php_register(struct devi
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 p
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 kre
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);
}
@@ -759,7 +765,7 @@ static void pnv_php_init_irq(struct pnv_
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;
}

@@ -772,7 +778,7 @@ static void pnv_php_init_irq(struct pnv_
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;
}