misc: pci_endpoint_test: Fix BUG_ON error during pci_disable_msi()

pci_disable_msi() throws a Kernel BUG if the driver has successfully
requested an IRQ and not released it. Fix it here by freeing IRQs before
invoking pci_disable_msi().

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/misc/pci_endpoint_test.c

@@ -92,6 +92,7 @@ struct pci_endpoint_test {
 	void __iomem	*bar[6];
 	struct completion irq_raised;
 	int		last_irq;
+	int		num_irqs;
 	/* mutex to protect the ioctls */
 	struct mutex	mutex;
 	struct miscdevice miscdev;
@@ -513,6 +514,7 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev,
 		irq = pci_alloc_irq_vectors(pdev, 1, 32, PCI_IRQ_MSI);
 		if (irq < 0)
 			dev_err(dev, "failed to get MSI interrupts\n");
+		test->num_irqs = irq;
 	}
 
 	err = devm_request_irq(dev, pdev->irq, pci_endpoint_test_irqhandler,
@@ -587,6 +589,9 @@ err_iounmap:
 			pci_iounmap(pdev, test->bar[bar]);
 	}
 
+	for (i = 0; i < irq; i++)
+		devm_free_irq(dev, pdev->irq + i, test);
+
 err_disable_msi:
 	pci_disable_msi(pdev);
 	pci_release_regions(pdev);
@@ -600,6 +605,7 @@ err_disable_pdev:
 static void pci_endpoint_test_remove(struct pci_dev *pdev)
 {
 	int id;
+	int i;
 	enum pci_barno bar;
 	struct pci_endpoint_test *test = pci_get_drvdata(pdev);
 	struct miscdevice *misc_device = &test->miscdev;
@@ -616,6 +622,8 @@ static void pci_endpoint_test_remove(struct pci_dev *pdev)
 		if (test->bar[bar])
 			pci_iounmap(pdev, test->bar[bar]);
 	}
+	for (i = 0; i < test->num_irqs; i++)
+		devm_free_irq(&pdev->dev, pdev->irq + i, test);
 	pci_disable_msi(pdev);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);