PCI/PM: Remove unused pci_driver.suspend_late() hook

The struct pci_driver.suspend_late() hook is one of the legacy PCI power
management callbacks, and there are no remaining users of it.  Remove it.

Link: https://lore.kernel.org/r/20191101204558.210235-7-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation/power/pci.rst

@@ -692,11 +692,11 @@ controlling the runtime power management of their devices.
 At the time of this writing there are two ways to define power management
 callbacks for a PCI device driver, the recommended one, based on using a
 dev_pm_ops structure described in Documentation/driver-api/pm/devices.rst, and
-the "legacy" one, in which the .suspend(), .suspend_late(), and
+the "legacy" one, in which the .suspend() and .resume() callbacks from struct
-.resume() callbacks from struct pci_driver are used.  The legacy approach,
+pci_driver are used.  The legacy approach, however, doesn't allow one to define
-however, doesn't allow one to define runtime power management callbacks and is
+runtime power management callbacks and is not really suitable for any new
-not really suitable for any new drivers.  Therefore it is not covered by this
+drivers.  Therefore it is not covered by this document (refer to the source code
-document (refer to the source code to learn more about it).
+to learn more about it).
 
 It is recommended that all PCI device drivers define a struct dev_pm_ops object
 containing pointers to power management (PM) callbacks that will be executed by

drivers/pci/pci-driver.c

@@ -599,32 +599,12 @@ static int pci_legacy_suspend(struct device *dev, pm_message_t state)
 static int pci_legacy_suspend_late(struct device *dev, pm_message_t state)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
-	struct pci_driver *drv = pci_dev->driver;
-
-	if (drv && drv->suspend_late) {
-		pci_power_t prev = pci_dev->current_state;
-		int error;
-
-		error = drv->suspend_late(pci_dev, state);
-		suspend_report_result(drv->suspend_late, error);
-		if (error)
-			return error;
-
-		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
-		    && pci_dev->current_state != PCI_UNKNOWN) {
-			pci_WARN_ONCE(pci_dev, pci_dev->current_state != prev,
-				      "PCI PM: Device state not saved by %pS\n",
-				      drv->suspend_late);
-			goto Fixup;
-		}
-	}
 
 	if (!pci_dev->state_saved)
 		pci_save_state(pci_dev);
 
 	pci_pm_set_unknown_state(pci_dev);
 
-Fixup:
 	pci_fixup_device(pci_fixup_suspend_late, pci_dev);
 
 	return 0;
@@ -653,7 +633,7 @@ static void pci_pm_default_suspend(struct pci_dev *pci_dev)
 static bool pci_has_legacy_pm_support(struct pci_dev *pci_dev)
 {
 	struct pci_driver *drv = pci_dev->driver;
-	bool ret = drv && (drv->suspend || drv->suspend_late || drv->resume);
+	bool ret = drv && (drv->suspend || drv->resume);
 
 	/*
 	 * Legacy PM support is used by default, so warn if the new framework is

include/linux/pci.h

@@ -805,7 +805,6 @@ struct module;
  *		The remove function always gets called from process
  *		context, so it can sleep.
  * @suspend:	Put device into low power state.
- * @suspend_late: Put device into low power state.
  * @resume:	Wake device from low power state.
  *		(Please see Documentation/power/pci.rst for descriptions
  *		of PCI Power Management and the related functions.)
@@ -828,7 +827,6 @@ struct pci_driver {
 	int  (*probe)(struct pci_dev *dev, const struct pci_device_id *id);	/* New device inserted */
 	void (*remove)(struct pci_dev *dev);	/* Device removed (NULL if not a hot-plug capable driver) */
 	int  (*suspend)(struct pci_dev *dev, pm_message_t state);	/* Device suspended */
-	int  (*suspend_late)(struct pci_dev *dev, pm_message_t state);
 	int  (*resume)(struct pci_dev *dev);	/* Device woken up */
 	void (*shutdown)(struct pci_dev *dev);
 	int  (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */