PCI: Unify device inaccessible

task #29600094

commit a6bd101b8f84f9b98768e9ab1e418c239e2e669f upstream.
Backport summary: for 4.19 kernel ICX PCIe Gen4 support.

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: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NSinan Kaya <okaya@kernel.org>
(cherry picked from commit a6bd101b8f84f9b98768e9ab1e418c239e2e669f)
Signed-off-by: NEthan Zhao <haifeng.zhao@intel.com>
Signed-off-by: NArtie Ding <artie.ding@linux.alibaba.com>
Acked-by: NCaspar Zhang <caspar@linux.alibaba.com>

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;