Merge branches 'pm-core', 'pm-domains', 'pm-sleep', 'acpi-pm' and 'pm-cpuidle'

Merge changes in the PM core, system-wide PM infrastructure, generic
power domains (genpd) framework, ACPI PM infrastructure and cpuidle
for 4.19.

* pm-core:
  driver core: Add flag to autoremove device link on supplier unbind
  driver core: Rename flag AUTOREMOVE to AUTOREMOVE_CONSUMER

* pm-domains:
  PM / Domains: Introduce dev_pm_domain_attach_by_name()
  PM / Domains: Introduce option to attach a device by name to genpd
  PM / Domains: dt: Add a power-domain-names property

* pm-sleep:
  PM / reboot: Eliminate race between reboot and suspend
  PM / hibernate: Mark expected switch fall-through
  x86/power/hibernate_64: Remove VLA usage
  PM / hibernate: cast PAGE_SIZE to int when comparing with error code

* acpi-pm:
  ACPI / PM: save NVS memory for ASUS 1025C laptop
  ACPI / PM: Default to s2idle in all machines supporting LP S0

* pm-cpuidle:
  ARM: cpuidle: silence error on driver registration failure

Documentation/devicetree/bindings/power/power_domain.txt

@@ -114,18 +114,26 @@ Required properties:
  - power-domains : A list of PM domain specifiers, as defined by bindings of
 		the power controller that is the PM domain provider.
 
+Optional properties:
+ - power-domain-names : A list of power domain name strings sorted in the same
+		order as the power-domains property. Consumers drivers will use
+		power-domain-names to match power domains with power-domains
+		specifiers.
+
 Example:
 
 	leaky-device@12350000 {
 		compatible = "foo,i-leak-current";
 		reg = <0x12350000 0x1000>;
 		power-domains = <&power 0>;
+		power-domain-names = "io";
 	};
 
 	leaky-device@12351000 {
 		compatible = "foo,i-leak-current";
 		reg = <0x12351000 0x1000>;
 		power-domains = <&power 0>, <&power 1> ;
+		power-domain-names = "io", "clk";
 	};
 
 The first example above defines a typical PM domain consumer device, which is

Documentation/driver-api/device_link.rst

@@ -81,10 +81,14 @@ integration is desired.
 Two other flags are specifically targeted at use cases where the device
 link is added from the consumer's ``->probe`` callback:  ``DL_FLAG_RPM_ACTIVE``
 can be specified to runtime resume the supplier upon addition of the
-device link.  ``DL_FLAG_AUTOREMOVE`` causes the device link to be automatically
+device link.  ``DL_FLAG_AUTOREMOVE_CONSUMER`` causes the device link to be
-purged when the consumer fails to probe or later unbinds.  This obviates
+automatically purged when the consumer fails to probe or later unbinds.
-the need to explicitly delete the link in the ``->remove`` callback or in
+This obviates the need to explicitly delete the link in the ``->remove``
-the error path of the ``->probe`` callback.
+callback or in the error path of the ``->probe`` callback.
+
+Similarly, when the device link is added from supplier's ``->probe`` callback,
+``DL_FLAG_AUTOREMOVE_SUPPLIER`` causes the device link to be automatically
+purged when the supplier fails to probe or later unbinds.
 
 Limitations
 ===========

Documentation/power/freezing-of-tasks.txt

@@ -204,26 +204,26 @@ VI. Are there any precautions to be taken to prevent freezing failures?
 
 Yes, there are.
 
-First of all, grabbing the 'pm_mutex' lock to mutually exclude a piece of code
+First of all, grabbing the 'system_transition_mutex' lock to mutually exclude a piece of code
 from system-wide sleep such as suspend/hibernation is not encouraged.
 If possible, that piece of code must instead hook onto the suspend/hibernation
 notifiers to achieve mutual exclusion. Look at the CPU-Hotplug code
 (kernel/cpu.c) for an example.
 
-However, if that is not feasible, and grabbing 'pm_mutex' is deemed necessary,
+However, if that is not feasible, and grabbing 'system_transition_mutex' is deemed necessary,
-it is strongly discouraged to directly call mutex_[un]lock(&pm_mutex) since
+it is strongly discouraged to directly call mutex_[un]lock(&system_transition_mutex) since
 that could lead to freezing failures, because if the suspend/hibernate code
-successfully acquired the 'pm_mutex' lock, and hence that other entity failed
+successfully acquired the 'system_transition_mutex' lock, and hence that other entity failed
 to acquire the lock, then that task would get blocked in TASK_UNINTERRUPTIBLE
 state. As a consequence, the freezer would not be able to freeze that task,
 leading to freezing failure.
 
 However, the [un]lock_system_sleep() APIs are safe to use in this scenario,
 since they ask the freezer to skip freezing this task, since it is anyway
-"frozen enough" as it is blocked on 'pm_mutex', which will be released
+"frozen enough" as it is blocked on 'system_transition_mutex', which will be released
 only after the entire suspend/hibernation sequence is complete.
 So, to summarize, use [un]lock_system_sleep() instead of directly using
-mutex_[un]lock(&pm_mutex). That would prevent freezing failures.
+mutex_[un]lock(&system_transition_mutex). That would prevent freezing failures.
 
 V. Miscellaneous
 /sys/power/pm_freeze_timeout controls how long it will cost at most to freeze

Documentation/power/suspend-and-cpuhotplug.txt

@@ -32,7 +32,7 @@ More details follow:
                                     sysfs file
                                         |
                                         v
-                               Acquire pm_mutex lock
+                               Acquire system_transition_mutex lock
                                         |
                                         v
                              Send PM_SUSPEND_PREPARE
@@ -96,10 +96,10 @@ execution during resume):
 
 * thaw tasks
 * send PM_POST_SUSPEND notifications
-* Release pm_mutex lock.
+* Release system_transition_mutex lock.
 
 
-It is to be noted here that the pm_mutex lock is acquired at the very
+It is to be noted here that the system_transition_mutex lock is acquired at the very
 beginning, when we are just starting out to suspend, and then released only
 after the entire cycle is complete (i.e., suspend + resume).
 

arch/x86/power/hibernate_64.c

@@ -233,29 +233,35 @@ struct restore_data_record {
  */
 static int get_e820_md5(struct e820_table *table, void *buf)
 {
-	struct scatterlist sg;
+	struct crypto_shash *tfm;
-	struct crypto_ahash *tfm;
+	struct shash_desc *desc;
 	int size;
 	int ret = 0;
 
-	tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
+	tfm = crypto_alloc_shash("md5", 0, 0);
 	if (IS_ERR(tfm))
 		return -ENOMEM;
 
-	{
+	desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
-		AHASH_REQUEST_ON_STACK(req, tfm);
+		       GFP_KERNEL);
-		size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries;
+	if (!desc) {
-		ahash_request_set_tfm(req, tfm);
+		ret = -ENOMEM;
-		sg_init_one(&sg, (u8 *)table, size);
+		goto free_tfm;
-		ahash_request_set_callback(req, 0, NULL, NULL);
-		ahash_request_set_crypt(req, &sg, buf, size);
-
-		if (crypto_ahash_digest(req))
-			ret = -EINVAL;
-		ahash_request_zero(req);
 	}
-	crypto_free_ahash(tfm);
 
+	desc->tfm = tfm;
+	desc->flags = 0;
+
+	size = offsetof(struct e820_table, entries) +
+		sizeof(struct e820_entry) * table->nr_entries;
+
+	if (crypto_shash_digest(desc, (u8 *)table, size, buf))
+		ret = -EINVAL;
+
+	kzfree(desc);
+
+free_tfm:
+	crypto_free_shash(tfm);
 	return ret;
 }
 

drivers/acpi/sleep.c

@@ -338,6 +338,14 @@ static const struct dmi_system_id acpisleep_dmi_table[] __initconst = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "K54HR"),
 		},
 	},
+	{
+	.callback = init_nvs_save_s3,
+	.ident = "Asus 1025C",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+		DMI_MATCH(DMI_PRODUCT_NAME, "1025C"),
+		},
+	},
 	/*
 	 * https://bugzilla.kernel.org/show_bug.cgi?id=189431
 	 * Lenovo G50-45 is a platform later than 2012, but needs nvs memory
@@ -718,9 +726,6 @@ static const struct acpi_device_id lps0_device_ids[] = {
 #define ACPI_LPS0_ENTRY		5
 #define ACPI_LPS0_EXIT		6
 
-#define ACPI_LPS0_SCREEN_MASK	((1 << ACPI_LPS0_SCREEN_OFF) | (1 << ACPI_LPS0_SCREEN_ON))
-#define ACPI_LPS0_PLATFORM_MASK	((1 << ACPI_LPS0_ENTRY) | (1 << ACPI_LPS0_EXIT))
-
 static acpi_handle lps0_device_handle;
 static guid_t lps0_dsm_guid;
 static char lps0_dsm_func_mask;
@@ -924,17 +929,14 @@ static int lps0_device_attach(struct acpi_device *adev,
 	if (out_obj && out_obj->type == ACPI_TYPE_BUFFER) {
 		char bitmask = *(char *)out_obj->buffer.pointer;
 
-		if ((bitmask & ACPI_LPS0_PLATFORM_MASK) == ACPI_LPS0_PLATFORM_MASK ||
+		lps0_dsm_func_mask = bitmask;
-		    (bitmask & ACPI_LPS0_SCREEN_MASK) == ACPI_LPS0_SCREEN_MASK) {
+		lps0_device_handle = adev->handle;
-			lps0_dsm_func_mask = bitmask;
+		/*
-			lps0_device_handle = adev->handle;
+		 * Use suspend-to-idle by default if the default
-			/*
+		 * suspend mode was not set from the command line.
-			 * Use suspend-to-idle by default if the default
+		 */
-			 * suspend mode was not set from the command line.
+		if (mem_sleep_default > PM_SUSPEND_MEM)
-			 */
+			mem_sleep_current = PM_SUSPEND_TO_IDLE;
-			if (mem_sleep_default > PM_SUSPEND_MEM)
-				mem_sleep_current = PM_SUSPEND_TO_IDLE;
-		}
 
 		acpi_handle_debug(adev->handle, "_DSM function mask: 0x%x\n",
 				  bitmask);

drivers/base/core.c

@@ -178,10 +178,10 @@ void device_pm_move_to_tail(struct device *dev)
  * of the link.  If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
  * ignored.
  *
- * If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically
+ * If the DL_FLAG_AUTOREMOVE_CONSUMER is set, the link will be removed
- * when the consumer device driver unbinds from it.  The combination of both
+ * automatically when the consumer device driver unbinds from it.
- * DL_FLAG_AUTOREMOVE and DL_FLAG_STATELESS set is invalid and will cause NULL
+ * The combination of both DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_STATELESS
- * to be returned.
+ * set is invalid and will cause NULL to be returned.
  *
  * A side effect of the link creation is re-ordering of dpm_list and the
  * devices_kset list by moving the consumer device and all devices depending
@@ -198,7 +198,8 @@ struct device_link *device_link_add(struct device *consumer,
 	struct device_link *link;
 
 	if (!consumer || !supplier ||
-	    ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE)))
+	    ((flags & DL_FLAG_STATELESS) &&
+	     (flags & DL_FLAG_AUTOREMOVE_CONSUMER)))
 		return NULL;
 
 	device_links_write_lock();
@@ -479,7 +480,7 @@ static void __device_links_no_driver(struct device *dev)
 		if (link->flags & DL_FLAG_STATELESS)
 			continue;
 
-		if (link->flags & DL_FLAG_AUTOREMOVE)
+		if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
 			kref_put(&link->kref, __device_link_del);
 		else if (link->status != DL_STATE_SUPPLIER_UNBIND)
 			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
@@ -515,8 +516,18 @@ void device_links_driver_cleanup(struct device *dev)
 		if (link->flags & DL_FLAG_STATELESS)
 			continue;
 
-		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE);
+		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
 		WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
+
+		/*
+		 * autoremove the links between this @dev and its consumer
+		 * devices that are not active, i.e. where the link state
+		 * has moved to DL_STATE_SUPPLIER_UNBIND.
+		 */
+		if (link->status == DL_STATE_SUPPLIER_UNBIND &&
+		    link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
+			kref_put(&link->kref, __device_link_del);
+
 		WRITE_ONCE(link->status, DL_STATE_DORMANT);
 	}
 

drivers/base/power/common.c

@@ -152,6 +152,23 @@ struct device *dev_pm_domain_attach_by_id(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id);
 
+/**
+ * dev_pm_domain_attach_by_name - Associate a device with one of its PM domains.
+ * @dev: The device used to lookup the PM domain.
+ * @name: The name of the PM domain.
+ *
+ * For a detailed function description, see dev_pm_domain_attach_by_id().
+ */
+struct device *dev_pm_domain_attach_by_name(struct device *dev,
+					    char *name)
+{
+	if (dev->pm_domain)
+		return ERR_PTR(-EEXIST);
+
+	return genpd_dev_pm_attach_by_name(dev, name);
+}
+EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name);
+
 /**
  * dev_pm_domain_detach - Detach a device from its PM domain.
  * @dev: Device to detach.

drivers/base/power/domain.c

@@ -2374,6 +2374,30 @@ struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(genpd_dev_pm_attach_by_id);
 
+/**
+ * genpd_dev_pm_attach_by_name - Associate a device with one of its PM domains.
+ * @dev: The device used to lookup the PM domain.
+ * @name: The name of the PM domain.
+ *
+ * Parse device's OF node to find a PM domain specifier using the
+ * power-domain-names DT property. For further description see
+ * genpd_dev_pm_attach_by_id().
+ */
+struct device *genpd_dev_pm_attach_by_name(struct device *dev, char *name)
+{
+	int index;
+
+	if (!dev->of_node)
+		return NULL;
+
+	index = of_property_match_string(dev->of_node, "power-domain-names",
+					 name);
+	if (index < 0)
+		return NULL;
+
+	return genpd_dev_pm_attach_by_id(dev, index);
+}
+
 static const struct of_device_id idle_state_match[] = {
 	{ .compatible = "domain-idle-state", },
 	{ }

drivers/cpuidle/cpuidle-arm.c

@@ -105,7 +105,8 @@ static int __init arm_idle_init_cpu(int cpu)
 
 	ret = cpuidle_register_driver(drv);
 	if (ret) {
-		pr_err("Failed to register cpuidle driver\n");
+		if (ret != -EBUSY)
+			pr_err("Failed to register cpuidle driver\n");
 		goto out_kfree_drv;
 	}
 

drivers/gpu/drm/tegra/dc.c

@@ -2312,7 +2312,7 @@ static int tegra_dc_couple(struct tegra_dc *dc)
 	 * POWER_CONTROL registers during CRTC enabling.
 	 */
 	if (dc->soc->coupled_pm && dc->pipe == 1) {
-		u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE;
+		u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_CONSUMER;
 		struct device_link *link;
 		struct device *partner;
 

drivers/gpu/ipu-v3/ipu-pre.c

@@ -128,7 +128,8 @@ ipu_pre_lookup_by_phandle(struct device *dev, const char *name, int index)
 	list_for_each_entry(pre, &ipu_pre_list, list) {
 		if (pre_node == pre->dev->of_node) {
 			mutex_unlock(&ipu_pre_list_mutex);
-			device_link_add(dev, pre->dev, DL_FLAG_AUTOREMOVE);
+			device_link_add(dev, pre->dev,
+					DL_FLAG_AUTOREMOVE_CONSUMER);
 			of_node_put(pre_node);
 			return pre;
 		}

drivers/gpu/ipu-v3/ipu-prg.c

@@ -100,7 +100,8 @@ ipu_prg_lookup_by_phandle(struct device *dev, const char *name, int ipu_id)
 	list_for_each_entry(prg, &ipu_prg_list, list) {
 		if (prg_node == prg->dev->of_node) {
 			mutex_unlock(&ipu_prg_list_mutex);
-			device_link_add(dev, prg->dev, DL_FLAG_AUTOREMOVE);
+			device_link_add(dev, prg->dev,
+					DL_FLAG_AUTOREMOVE_CONSUMER);
 			prg->id = ipu_id;
 			of_node_put(prg_node);
 			return prg;

drivers/soc/imx/gpc.c

@@ -209,7 +209,7 @@ static int imx_pgc_power_domain_probe(struct platform_device *pdev)
 			goto genpd_err;
 	}
 
-	device_link_add(dev, dev->parent, DL_FLAG_AUTOREMOVE);
+	device_link_add(dev, dev->parent, DL_FLAG_AUTOREMOVE_CONSUMER);
 
 	return 0;
 

include/linux/device.h

@@ -90,7 +90,7 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
  * @num_vf:	Called to find out how many virtual functions a device on this
  *		bus supports.
  * @dma_configure:	Called to setup DMA configuration on a device on
-			this bus.
+ *			this bus.
  * @pm:		Power management operations of this bus, callback the specific
  *		device driver's pm-ops.
  * @iommu_ops:  IOMMU specific operations for this bus, used to attach IOMMU
@@ -784,14 +784,16 @@ enum device_link_state {
  * Device link flags.
  *
  * STATELESS: The core won't track the presence of supplier/consumer drivers.
- * AUTOREMOVE: Remove this link automatically on consumer driver unbind.
+ * AUTOREMOVE_CONSUMER: Remove the link automatically on consumer driver unbind.
  * PM_RUNTIME: If set, the runtime PM framework will use this link.
  * RPM_ACTIVE: Run pm_runtime_get_sync() on the supplier during link creation.
+ * AUTOREMOVE_SUPPLIER: Remove the link automatically on supplier driver unbind.
  */
-#define DL_FLAG_STATELESS	BIT(0)
+#define DL_FLAG_STATELESS		BIT(0)
-#define DL_FLAG_AUTOREMOVE	BIT(1)
+#define DL_FLAG_AUTOREMOVE_CONSUMER	BIT(1)
-#define DL_FLAG_PM_RUNTIME	BIT(2)
+#define DL_FLAG_PM_RUNTIME		BIT(2)
-#define DL_FLAG_RPM_ACTIVE	BIT(3)
+#define DL_FLAG_RPM_ACTIVE		BIT(3)
+#define DL_FLAG_AUTOREMOVE_SUPPLIER	BIT(4)
 
 /**
  * struct device_link - Device link representation.

include/linux/pm_domain.h

@@ -239,6 +239,8 @@ unsigned int of_genpd_opp_to_performance_state(struct device *dev,
 int genpd_dev_pm_attach(struct device *dev);
 struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 					 unsigned int index);
+struct device *genpd_dev_pm_attach_by_name(struct device *dev,
+					   char *name);
 #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
 static inline int of_genpd_add_provider_simple(struct device_node *np,
 					struct generic_pm_domain *genpd)
@@ -290,6 +292,12 @@ static inline struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 	return NULL;
 }
 
+static inline struct device *genpd_dev_pm_attach_by_name(struct device *dev,
+							 char *name)
+{
+	return NULL;
+}
+
 static inline
 struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)
 {
@@ -301,6 +309,8 @@ struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)
 int dev_pm_domain_attach(struct device *dev, bool power_on);
 struct device *dev_pm_domain_attach_by_id(struct device *dev,
 					  unsigned int index);
+struct device *dev_pm_domain_attach_by_name(struct device *dev,
+					    char *name);
 void dev_pm_domain_detach(struct device *dev, bool power_off);
 void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd);
 #else
@@ -313,6 +323,11 @@ static inline struct device *dev_pm_domain_attach_by_id(struct device *dev,
 {
 	return NULL;
 }
+static inline struct device *dev_pm_domain_attach_by_name(struct device *dev,
+							  char *name)
+{
+	return NULL;
+}
 static inline void dev_pm_domain_detach(struct device *dev, bool power_off) {}
 static inline void dev_pm_domain_set(struct device *dev,
 				     struct dev_pm_domain *pd) {}

include/linux/suspend.h

@@ -414,7 +414,7 @@ static inline bool hibernation_available(void) { return false; }
 #define PM_RESTORE_PREPARE	0x0005 /* Going to restore a saved image */
 #define PM_POST_RESTORE		0x0006 /* Restore failed */
 
-extern struct mutex pm_mutex;
+extern struct mutex system_transition_mutex;
 
 #ifdef CONFIG_PM_SLEEP
 void save_processor_state(void);

kernel/freezer.c

@@ -15,7 +15,9 @@
 atomic_t system_freezing_cnt = ATOMIC_INIT(0);
 EXPORT_SYMBOL(system_freezing_cnt);
 
-/* indicate whether PM freezing is in effect, protected by pm_mutex */
+/* indicate whether PM freezing is in effect, protected by
+ * system_transition_mutex
+ */
 bool pm_freezing;
 bool pm_nosig_freezing;
 

kernel/power/hibernate.c

@@ -338,7 +338,7 @@ static int create_image(int platform_mode)
  * hibernation_snapshot - Quiesce devices and create a hibernation image.
  * @platform_mode: If set, use platform driver to prepare for the transition.
  *
- * This routine must be called with pm_mutex held.
+ * This routine must be called with system_transition_mutex held.
  */
 int hibernation_snapshot(int platform_mode)
 {
@@ -500,8 +500,9 @@ static int resume_target_kernel(bool platform_mode)
  * hibernation_restore - Quiesce devices and restore from a hibernation image.
  * @platform_mode: If set, use platform driver to prepare for the transition.
  *
- * This routine must be called with pm_mutex held.  If it is successful, control
+ * This routine must be called with system_transition_mutex held.  If it is
- * reappears in the restored target kernel in hibernation_snapshot().
+ * successful, control reappears in the restored target kernel in
+ * hibernation_snapshot().
  */
 int hibernation_restore(int platform_mode)
 {
@@ -638,6 +639,7 @@ static void power_down(void)
 		break;
 	case HIBERNATION_PLATFORM:
 		hibernation_platform_enter();
+		/* Fall through */
 	case HIBERNATION_SHUTDOWN:
 		if (pm_power_off)
 			kernel_power_off();
@@ -805,13 +807,13 @@ static int software_resume(void)
 	 * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 	 * is configured into the kernel. Since the regular hibernate
 	 * trigger path is via sysfs which takes a buffer mutex before
-	 * calling hibernate functions (which take pm_mutex) this can
+	 * calling hibernate functions (which take system_transition_mutex)
-	 * cause lockdep to complain about a possible ABBA deadlock
+	 * this can cause lockdep to complain about a possible ABBA deadlock
 	 * which cannot happen since we're in the boot code here and
 	 * sysfs can't be invoked yet. Therefore, we use a subclass
 	 * here to avoid lockdep complaining.
 	 */
-	mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
+	mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 
 	if (swsusp_resume_device)
 		goto Check_image;
@@ -899,7 +901,7 @@ static int software_resume(void)
 	atomic_inc(&snapshot_device_available);
 	/* For success case, the suspend path will release the lock */
  Unlock:
-	mutex_unlock(&pm_mutex);
+	mutex_unlock(&system_transition_mutex);
 	pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 	return error;
  Close_Finish:

kernel/power/main.c

@@ -15,17 +15,16 @@
 #include <linux/workqueue.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
+#include <linux/suspend.h>
 
 #include "power.h"
 
-DEFINE_MUTEX(pm_mutex);
-
 #ifdef CONFIG_PM_SLEEP
 
 void lock_system_sleep(void)
 {
 	current->flags |= PF_FREEZER_SKIP;
-	mutex_lock(&pm_mutex);
+	mutex_lock(&system_transition_mutex);
 }
 EXPORT_SYMBOL_GPL(lock_system_sleep);
 
@@ -37,8 +36,9 @@ void unlock_system_sleep(void)
 	 *
 	 * Reason:
 	 * Fundamentally, we just don't need it, because freezing condition
-	 * doesn't come into effect until we release the pm_mutex lock,
+	 * doesn't come into effect until we release the
-	 * since the freezer always works with pm_mutex held.
+	 * system_transition_mutex lock, since the freezer always works with
+	 * system_transition_mutex held.
 	 *
 	 * More importantly, in the case of hibernation,
 	 * unlock_system_sleep() gets called in snapshot_read() and
@@ -47,7 +47,7 @@ void unlock_system_sleep(void)
 	 * enter the refrigerator, thus causing hibernation to lockup.
 	 */
 	current->flags &= ~PF_FREEZER_SKIP;
-	mutex_unlock(&pm_mutex);
+	mutex_unlock(&system_transition_mutex);
 }
 EXPORT_SYMBOL_GPL(unlock_system_sleep);
 

kernel/power/suspend.c

@@ -556,7 +556,7 @@ static int enter_state(suspend_state_t state)
 	} else if (!valid_state(state)) {
 		return -EINVAL;
 	}
-	if (!mutex_trylock(&pm_mutex))
+	if (!mutex_trylock(&system_transition_mutex))
 		return -EBUSY;
 
 	if (state == PM_SUSPEND_TO_IDLE)
@@ -590,7 +590,7 @@ static int enter_state(suspend_state_t state)
 	pm_pr_dbg("Finishing wakeup.\n");
 	suspend_finish();
  Unlock:
-	mutex_unlock(&pm_mutex);
+	mutex_unlock(&system_transition_mutex);
 	return error;
 }
 

kernel/power/swap.c

@@ -923,7 +923,7 @@ int swsusp_write(unsigned int flags)
 	}
 	memset(&snapshot, 0, sizeof(struct snapshot_handle));
 	error = snapshot_read_next(&snapshot);
-	if (error < PAGE_SIZE) {
+	if (error < (int)PAGE_SIZE) {
 		if (error >= 0)
 			error = -EFAULT;
 
@@ -1483,7 +1483,7 @@ int swsusp_read(unsigned int *flags_p)
 
 	memset(&snapshot, 0, sizeof(struct snapshot_handle));
 	error = snapshot_write_next(&snapshot);
-	if (error < PAGE_SIZE)
+	if (error < (int)PAGE_SIZE)
 		return error < 0 ? error : -EFAULT;
 	header = (struct swsusp_info *)data_of(snapshot);
 	error = get_swap_reader(&handle, flags_p);

kernel/power/user.c

@@ -216,7 +216,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	if (!mutex_trylock(&pm_mutex))
+	if (!mutex_trylock(&system_transition_mutex))
 		return -EBUSY;
 
 	lock_device_hotplug();
@@ -394,7 +394,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 	}
 
 	unlock_device_hotplug();
-	mutex_unlock(&pm_mutex);
+	mutex_unlock(&system_transition_mutex);
 
 	return error;
 }

kernel/reboot.c

@@ -294,7 +294,7 @@ void kernel_power_off(void)
 }
 EXPORT_SYMBOL_GPL(kernel_power_off);
 
-static DEFINE_MUTEX(reboot_mutex);
+DEFINE_MUTEX(system_transition_mutex);
 
 /*
  * Reboot system call: for obvious reasons only root may call it,
@@ -338,7 +338,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 	if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 		cmd = LINUX_REBOOT_CMD_HALT;
 
-	mutex_lock(&reboot_mutex);
+	mutex_lock(&system_transition_mutex);
 	switch (cmd) {
 	case LINUX_REBOOT_CMD_RESTART:
 		kernel_restart(NULL);
@@ -389,7 +389,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 		ret = -EINVAL;
 		break;
 	}
-	mutex_unlock(&reboot_mutex);
+	mutex_unlock(&system_transition_mutex);
 	return ret;
 }
 

mm/page_alloc.c

@@ -155,16 +155,17 @@ static inline void set_pcppage_migratetype(struct page *page, int migratetype)
  * The following functions are used by the suspend/hibernate code to temporarily
  * change gfp_allowed_mask in order to avoid using I/O during memory allocations
  * while devices are suspended.  To avoid races with the suspend/hibernate code,
- * they should always be called with pm_mutex held (gfp_allowed_mask also should
+ * they should always be called with system_transition_mutex held
- * only be modified with pm_mutex held, unless the suspend/hibernate code is
+ * (gfp_allowed_mask also should only be modified with system_transition_mutex
- * guaranteed not to run in parallel with that modification).
+ * held, unless the suspend/hibernate code is guaranteed not to run in parallel
+ * with that modification).
  */
 
 static gfp_t saved_gfp_mask;
 
 void pm_restore_gfp_mask(void)
 {
-	WARN_ON(!mutex_is_locked(&pm_mutex));
+	WARN_ON(!mutex_is_locked(&system_transition_mutex));
 	if (saved_gfp_mask) {
 		gfp_allowed_mask = saved_gfp_mask;
 		saved_gfp_mask = 0;
@@ -173,7 +174,7 @@ void pm_restore_gfp_mask(void)
 
 void pm_restrict_gfp_mask(void)
 {
-	WARN_ON(!mutex_is_locked(&pm_mutex));
+	WARN_ON(!mutex_is_locked(&system_transition_mutex));
 	WARN_ON(saved_gfp_mask);
 	saved_gfp_mask = gfp_allowed_mask;
 	gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);