PCI: Unify device inaccessible

Bring surprise removals and permanent failures together so we no longer
need separate flags.  The implementation enforces that error handling will
not be able to override a surprise removal's permanent channel failure.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>

drivers/pci/pci.h

@@ -295,21 +295,71 @@ struct pci_sriov {
 	bool		drivers_autoprobe; /* Auto probing of VFs by driver */
 };
 
-/* pci_dev priv_flags */
-#define PCI_DEV_DISCONNECTED 0
-#define PCI_DEV_ADDED 1
+/**
+ * pci_dev_set_io_state - Set the new error state if possible.
+ *
+ * @dev - pci device to set new error_state
+ * @new - the state we want dev to be in
+ *
+ * Must be called with device_lock held.
+ *
+ * Returns true if state has been changed to the requested state.
+ */
+static inline bool pci_dev_set_io_state(struct pci_dev *dev,
+					pci_channel_state_t new)
+{
+	bool changed = false;
+
+	device_lock_assert(&dev->dev);
+	switch (new) {
+	case pci_channel_io_perm_failure:
+		switch (dev->error_state) {
+		case pci_channel_io_frozen:
+		case pci_channel_io_normal:
+		case pci_channel_io_perm_failure:
+			changed = true;
+			break;
+		}
+		break;
+	case pci_channel_io_frozen:
+		switch (dev->error_state) {
+		case pci_channel_io_frozen:
+		case pci_channel_io_normal:
+			changed = true;
+			break;
+		}
+		break;
+	case pci_channel_io_normal:
+		switch (dev->error_state) {
+		case pci_channel_io_frozen:
+		case pci_channel_io_normal:
+			changed = true;
+			break;
+		}
+		break;
+	}
+	if (changed)
+		dev->error_state = new;
+	return changed;
+}
 
 static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)
 {
-	set_bit(PCI_DEV_DISCONNECTED, &dev->priv_flags);
+	device_lock(&dev->dev);
+	pci_dev_set_io_state(dev, pci_channel_io_perm_failure);
+	device_unlock(&dev->dev);
+
 	return 0;
 }
 
 static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
 {
-	return test_bit(PCI_DEV_DISCONNECTED, &dev->priv_flags);
+	return dev->error_state == pci_channel_io_perm_failure;
 }
 
+/* pci_dev priv_flags */
+#define PCI_DEV_ADDED 0
+
 static inline void pci_dev_assign_added(struct pci_dev *dev, bool added)
 {
 	assign_bit(PCI_DEV_ADDED, &dev->priv_flags, added);

drivers/pci/pcie/err.c

@@ -52,9 +52,8 @@ static int report_error_detected(struct pci_dev *dev,
 	const struct pci_error_handlers *err_handler;
 
 	device_lock(&dev->dev);
-	dev->error_state = state;
-
-	if (!dev->driver ||
+	if (!pci_dev_set_io_state(dev, state) ||
+		!dev->driver ||
 		!dev->driver->err_handler ||
 		!dev->driver->err_handler->error_detected) {
 		/*
@@ -130,9 +129,8 @@ static int report_resume(struct pci_dev *dev, void *data)
 	const struct pci_error_handlers *err_handler;
 
 	device_lock(&dev->dev);
-	dev->error_state = pci_channel_io_normal;
-
-	if (!dev->driver ||
+	if (!pci_dev_set_io_state(dev, pci_channel_io_normal) ||
+		!dev->driver ||
 		!dev->driver->err_handler ||
 		!dev->driver->err_handler->resume)
 		goto out;