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>

2 files changed, 59 insertions, 11 deletions

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9b279805489f..eb3125decffe 100644
--- a/drivers/pci/pci.h
+++ b/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);
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 31e8a4314384..4da2a62b4f77 100644
--- a/drivers/pci/pcie/err.c
+++ b/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;