Merge tag 'driver-core-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the big driver core update for 4.13-rc1.

  The large majority of this is a lot of cleanup of old fields in the
  driver core structures and their remaining usages in random drivers.
  All of those fixes have been reviewed by the various subsystem
  maintainers. There's also some small firmware updates in here, a new
  kobject uevent api interface that makes userspace interaction easier,
  and a few other minor things.

  All of these have been in linux-next for a long while with no reported
  issues"

* tag 'driver-core-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (56 commits)
  arm: mach-rpc: ecard: fix build error
  zram: convert remaining CLASS_ATTR() to CLASS_ATTR_RO()
  driver-core: remove struct bus_type.dev_attrs
  powerpc: vio_cmo: use dev_groups and not dev_attrs for bus_type
  powerpc: vio: use dev_groups and not dev_attrs for bus_type
  USB: usbip: convert to use DRIVER_ATTR_RW
  s390: drivers: convert to use DRIVER_ATTR_RO/WO
  platform: thinkpad_acpi: convert to use DRIVER_ATTR_RO/RW
  pcmcia: ds: convert to use DRIVER_ATTR_RO
  wireless: ipw2x00: convert to use DRIVER_ATTR_RW
  net: ehea: convert to use DRIVER_ATTR_RO
  net: caif: convert to use DRIVER_ATTR_RO
  TTY: hvc: convert to use DRIVER_ATTR_RW
  PCI: pci-driver: convert to use DRIVER_ATTR_WO
  IB: nes: convert to use DRIVER_ATTR_RW
  HID: hid-core: convert to use DRIVER_ATTR_RO and drv_groups
  arm: ecard: fix dev_groups patch typo
  tty: serdev: use dev_groups and not dev_attrs for bus_type
  sparc: vio: use dev_groups and not dev_attrs for bus_type
  hid: intel-ish-hid: use dev_groups and not dev_attrs for bus_type
  ...

1 files changed, 201 insertions, 101 deletions

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index ac350c5..b9f907e 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -260,6 +260,38 @@ static int fw_cache_piggyback_on_request(const char *name);
  * guarding for corner cases a global lock should be OK */
 static DEFINE_MUTEX(fw_lock);
 
+static bool __enable_firmware = false;
+
+static void enable_firmware(void)
+{
+	mutex_lock(&fw_lock);
+	__enable_firmware = true;
+	mutex_unlock(&fw_lock);
+}
+
+static void disable_firmware(void)
+{
+	mutex_lock(&fw_lock);
+	__enable_firmware = false;
+	mutex_unlock(&fw_lock);
+}
+
+/*
+ * When disabled only the built-in firmware and the firmware cache will be
+ * used to look for firmware.
+ */
+static bool firmware_enabled(void)
+{
+	bool enabled = false;
+
+	mutex_lock(&fw_lock);
+	if (__enable_firmware)
+		enabled = true;
+	mutex_unlock(&fw_lock);
+
+	return enabled;
+}
+
 static struct firmware_cache fw_cache;
 
 static struct firmware_buf *__allocate_fw_buf(const char *fw_name,
@@ -523,6 +555,44 @@ static int fw_add_devm_name(struct device *dev, const char *name)
 }
 #endif
 
+static int assign_firmware_buf(struct firmware *fw, struct device *device,
+			       unsigned int opt_flags)
+{
+	struct firmware_buf *buf = fw->priv;
+
+	mutex_lock(&fw_lock);
+	if (!buf->size || fw_state_is_aborted(&buf->fw_st)) {
+		mutex_unlock(&fw_lock);
+		return -ENOENT;
+	}
+
+	/*
+	 * add firmware name into devres list so that we can auto cache
+	 * and uncache firmware for device.
+	 *
+	 * device may has been deleted already, but the problem
+	 * should be fixed in devres or driver core.
+	 */
+	/* don't cache firmware handled without uevent */
+	if (device && (opt_flags & FW_OPT_UEVENT) &&
+	    !(opt_flags & FW_OPT_NOCACHE))
+		fw_add_devm_name(device, buf->fw_id);
+
+	/*
+	 * After caching firmware image is started, let it piggyback
+	 * on request firmware.
+	 */
+	if (!(opt_flags & FW_OPT_NOCACHE) &&
+	    buf->fwc->state == FW_LOADER_START_CACHE) {
+		if (fw_cache_piggyback_on_request(buf->fw_id))
+			kref_get(&buf->ref);
+	}
+
+	/* pass the pages buffer to driver at the last minute */
+	fw_set_page_data(buf, fw);
+	mutex_unlock(&fw_lock);
+	return 0;
+}
 
 /*
  * user-mode helper code
@@ -562,23 +632,19 @@ static void fw_load_abort(struct firmware_priv *fw_priv)
 
 static LIST_HEAD(pending_fw_head);
 
-/* reboot notifier for avoid deadlock with usermode_lock */
-static int fw_shutdown_notify(struct notifier_block *unused1,
-			      unsigned long unused2, void *unused3)
+static void kill_pending_fw_fallback_reqs(bool only_kill_custom)
 {
+	struct firmware_buf *buf;
+	struct firmware_buf *next;
+
 	mutex_lock(&fw_lock);
-	while (!list_empty(&pending_fw_head))
-		__fw_load_abort(list_first_entry(&pending_fw_head,
-					       struct firmware_buf,
-					       pending_list));
+	list_for_each_entry_safe(buf, next, &pending_fw_head, pending_list) {
+		if (!buf->need_uevent || !only_kill_custom)
+			 __fw_load_abort(buf);
+	}
 	mutex_unlock(&fw_lock);
-	return NOTIFY_DONE;
 }
 
-static struct notifier_block fw_shutdown_nb = {
-	.notifier_call = fw_shutdown_notify,
-};
-
 static ssize_t timeout_show(struct class *class, struct class_attribute *attr,
 			    char *buf)
 {
@@ -1036,46 +1102,56 @@ err_put_dev:
 
 static int fw_load_from_user_helper(struct firmware *firmware,
 				    const char *name, struct device *device,
-				    unsigned int opt_flags, long timeout)
+				    unsigned int opt_flags)
 {
 	struct firmware_priv *fw_priv;
+	long timeout;
+	int ret;
+
+	timeout = firmware_loading_timeout();
+	if (opt_flags & FW_OPT_NOWAIT) {
+		timeout = usermodehelper_read_lock_wait(timeout);
+		if (!timeout) {
+			dev_dbg(device, "firmware: %s loading timed out\n",
+				name);
+			return -EBUSY;
+		}
+	} else {
+		ret = usermodehelper_read_trylock();
+		if (WARN_ON(ret)) {
+			dev_err(device, "firmware: %s will not be loaded\n",
+				name);
+			return ret;
+		}
+	}
 
 	fw_priv = fw_create_instance(firmware, name, device, opt_flags);
-	if (IS_ERR(fw_priv))
-		return PTR_ERR(fw_priv);
+	if (IS_ERR(fw_priv)) {
+		ret = PTR_ERR(fw_priv);
+		goto out_unlock;
+	}
 
 	fw_priv->buf = firmware->priv;
-	return _request_firmware_load(fw_priv, opt_flags, timeout);
-}
+	ret = _request_firmware_load(fw_priv, opt_flags, timeout);
 
-#ifdef CONFIG_PM_SLEEP
-/* kill pending requests without uevent to avoid blocking suspend */
-static void kill_requests_without_uevent(void)
-{
-	struct firmware_buf *buf;
-	struct firmware_buf *next;
+	if (!ret)
+		ret = assign_firmware_buf(firmware, device, opt_flags);
 
-	mutex_lock(&fw_lock);
-	list_for_each_entry_safe(buf, next, &pending_fw_head, pending_list) {
-		if (!buf->need_uevent)
-			 __fw_load_abort(buf);
-	}
-	mutex_unlock(&fw_lock);
+out_unlock:
+	usermodehelper_read_unlock();
+
+	return ret;
 }
-#endif
 
 #else /* CONFIG_FW_LOADER_USER_HELPER */
 static inline int
 fw_load_from_user_helper(struct firmware *firmware, const char *name,
-			 struct device *device, unsigned int opt_flags,
-			 long timeout)
+			 struct device *device, unsigned int opt_flags)
 {
 	return -ENOENT;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static inline void kill_requests_without_uevent(void) { }
-#endif
+static inline void kill_pending_fw_fallback_reqs(bool only_kill_custom) { }
 
 #endif /* CONFIG_FW_LOADER_USER_HELPER */
 
@@ -1124,45 +1200,6 @@ _request_firmware_prepare(struct firmware **firmware_p, const char *name,
 	return 1; /* need to load */
 }
 
-static int assign_firmware_buf(struct firmware *fw, struct device *device,
-			       unsigned int opt_flags)
-{
-	struct firmware_buf *buf = fw->priv;
-
-	mutex_lock(&fw_lock);
-	if (!buf->size || fw_state_is_aborted(&buf->fw_st)) {
-		mutex_unlock(&fw_lock);
-		return -ENOENT;
-	}
-
-	/*
-	 * add firmware name into devres list so that we can auto cache
-	 * and uncache firmware for device.
-	 *
-	 * device may has been deleted already, but the problem
-	 * should be fixed in devres or driver core.
-	 */
-	/* don't cache firmware handled without uevent */
-	if (device && (opt_flags & FW_OPT_UEVENT) &&
-	    !(opt_flags & FW_OPT_NOCACHE))
-		fw_add_devm_name(device, buf->fw_id);
-
-	/*
-	 * After caching firmware image is started, let it piggyback
-	 * on request firmware.
-	 */
-	if (!(opt_flags & FW_OPT_NOCACHE) &&
-	    buf->fwc->state == FW_LOADER_START_CACHE) {
-		if (fw_cache_piggyback_on_request(buf->fw_id))
-			kref_get(&buf->ref);
-	}
-
-	/* pass the pages buffer to driver at the last minute */
-	fw_set_page_data(buf, fw);
-	mutex_unlock(&fw_lock);
-	return 0;
-}
-
 /* called from request_firmware() and request_firmware_work_func() */
 static int
 _request_firmware(const struct firmware **firmware_p, const char *name,
@@ -1170,7 +1207,6 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 		  unsigned int opt_flags)
 {
 	struct firmware *fw = NULL;
-	long timeout;
 	int ret;
 
 	if (!firmware_p)
@@ -1185,23 +1221,10 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 	if (ret <= 0) /* error or already assigned */
 		goto out;
 
-	ret = 0;
-	timeout = firmware_loading_timeout();
-	if (opt_flags & FW_OPT_NOWAIT) {
-		timeout = usermodehelper_read_lock_wait(timeout);
-		if (!timeout) {
-			dev_dbg(device, "firmware: %s loading timed out\n",
-				name);
-			ret = -EBUSY;
-			goto out;
-		}
-	} else {
-		ret = usermodehelper_read_trylock();
-		if (WARN_ON(ret)) {
-			dev_err(device, "firmware: %s will not be loaded\n",
-				name);
-			goto out;
-		}
+	if (!firmware_enabled()) {
+		WARN(1, "firmware request while host is not available\n");
+		ret = -EHOSTDOWN;
+		goto out;
 	}
 
 	ret = fw_get_filesystem_firmware(device, fw->priv);
@@ -1213,15 +1236,11 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 		if (opt_flags & FW_OPT_USERHELPER) {
 			dev_warn(device, "Falling back to user helper\n");
 			ret = fw_load_from_user_helper(fw, name, device,
-						       opt_flags, timeout);
+						       opt_flags);
 		}
-	}
-
-	if (!ret)
+	} else
 		ret = assign_firmware_buf(fw, device, opt_flags);
 
-	usermodehelper_read_unlock();
-
  out:
 	if (ret < 0) {
 		release_firmware(fw);
@@ -1717,6 +1736,62 @@ static void device_uncache_fw_images_delay(unsigned long delay)
 			   msecs_to_jiffies(delay));
 }
 
+/**
+ * fw_pm_notify - notifier for suspend/resume
+ * @notify_block: unused
+ * @mode: mode we are switching to
+ * @unused: unused
+ *
+ * Used to modify the firmware_class state as we move in between states.
+ * The firmware_class implements a firmware cache to enable device driver
+ * to fetch firmware upon resume before the root filesystem is ready. We
+ * disable API calls which do not use the built-in firmware or the firmware
+ * cache when we know these calls will not work.
+ *
+ * The inner logic behind all this is a bit complex so it is worth summarizing
+ * the kernel's own suspend/resume process with context and focus on how this
+ * can impact the firmware API.
+ *
+ * First a review on how we go to suspend::
+ *
+ *	pm_suspend() --> enter_state() -->
+ *	sys_sync()
+ *	suspend_prepare() -->
+ *		__pm_notifier_call_chain(PM_SUSPEND_PREPARE, ...);
+ *		suspend_freeze_processes() -->
+ *			freeze_processes() -->
+ *				__usermodehelper_set_disable_depth(UMH_DISABLED);
+ *				freeze all tasks ...
+ *			freeze_kernel_threads()
+ *	suspend_devices_and_enter() -->
+ *		dpm_suspend_start() -->
+ *				dpm_prepare()
+ *				dpm_suspend()
+ *		suspend_enter()  -->
+ *			platform_suspend_prepare()
+ *			dpm_suspend_late()
+ *			freeze_enter()
+ *			syscore_suspend()
+ *
+ * When we resume we bail out of a loop from suspend_devices_and_enter() and
+ * unwind back out to the caller enter_state() where we were before as follows::
+ *
+ * 	enter_state() -->
+ *	suspend_devices_and_enter() --> (bail from loop)
+ *		dpm_resume_end() -->
+ *			dpm_resume()
+ *			dpm_complete()
+ *	suspend_finish() -->
+ *		suspend_thaw_processes() -->
+ *			thaw_processes() -->
+ *				__usermodehelper_set_disable_depth(UMH_FREEZING);
+ *				thaw_workqueues();
+ *				thaw all processes ...
+ *				usermodehelper_enable();
+ *		pm_notifier_call_chain(PM_POST_SUSPEND);
+ *
+ * fw_pm_notify() works through pm_notifier_call_chain().
+ */
 static int fw_pm_notify(struct notifier_block *notify_block,
 			unsigned long mode, void *unused)
 {
@@ -1724,8 +1799,13 @@ static int fw_pm_notify(struct notifier_block *notify_block,
 	case PM_HIBERNATION_PREPARE:
 	case PM_SUSPEND_PREPARE:
 	case PM_RESTORE_PREPARE:
-		kill_requests_without_uevent();
+		/*
+		 * kill pending fallback requests with a custom fallback
+		 * to avoid stalling suspend.
+		 */
+		kill_pending_fw_fallback_reqs(true);
 		device_cache_fw_images();
+		disable_firmware();
 		break;
 
 	case PM_POST_SUSPEND:
@@ -1738,6 +1818,7 @@ static int fw_pm_notify(struct notifier_block *notify_block,
 		mutex_lock(&fw_lock);
 		fw_cache.state = FW_LOADER_NO_CACHE;
 		mutex_unlock(&fw_lock);
+		enable_firmware();
 
 		device_uncache_fw_images_delay(10 * MSEC_PER_SEC);
 		break;
@@ -1783,11 +1864,29 @@ static void __init fw_cache_init(void)
 #endif
 }
 
+static int fw_shutdown_notify(struct notifier_block *unused1,
+			      unsigned long unused2, void *unused3)
+{
+	disable_firmware();
+	/*
+	 * Kill all pending fallback requests to avoid both stalling shutdown,
+	 * and avoid a deadlock with the usermode_lock.
+	 */
+	kill_pending_fw_fallback_reqs(false);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block fw_shutdown_nb = {
+	.notifier_call = fw_shutdown_notify,
+};
+
 static int __init firmware_class_init(void)
 {
+	enable_firmware();
 	fw_cache_init();
-#ifdef CONFIG_FW_LOADER_USER_HELPER
 	register_reboot_notifier(&fw_shutdown_nb);
+#ifdef CONFIG_FW_LOADER_USER_HELPER
 	return class_register(&firmware_class);
 #else
 	return 0;
@@ -1796,12 +1895,13 @@ static int __init firmware_class_init(void)
 
 static void __exit firmware_class_exit(void)
 {
+	disable_firmware();
 #ifdef CONFIG_PM_SLEEP
 	unregister_syscore_ops(&fw_syscore_ops);
 	unregister_pm_notifier(&fw_cache.pm_notify);
 #endif
-#ifdef CONFIG_FW_LOADER_USER_HELPER
 	unregister_reboot_notifier(&fw_shutdown_nb);
+#ifdef CONFIG_FW_LOADER_USER_HELPER
 	class_unregister(&firmware_class);
 #endif
 }