--- zzzz-none-000/linux-3.10.107/kernel/power/user.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/kernel/power/user.c	2021-02-04 17:41:59.000000000 +0000
@@ -36,9 +36,10 @@
 	struct snapshot_handle handle;
 	int swap;
 	int mode;
-	char frozen;
-	char ready;
-	char platform_support;
+	bool frozen;
+	bool ready;
+	bool platform_support;
+	bool free_bitmaps;
 } snapshot_state;
 
 atomic_t snapshot_device_available = ATOMIC_INIT(1);
@@ -48,6 +49,9 @@
 	struct snapshot_data *data;
 	int error;
 
+	if (!hibernation_available())
+		return -EPERM;
+
 	lock_system_sleep();
 
 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
@@ -60,11 +64,6 @@
 		error = -ENOSYS;
 		goto Unlock;
 	}
-	if(create_basic_memory_bitmaps()) {
-		atomic_inc(&snapshot_device_available);
-		error = -ENOMEM;
-		goto Unlock;
-	}
 	nonseekable_open(inode, filp);
 	data = &snapshot_state;
 	filp->private_data = data;
@@ -74,6 +73,7 @@
 		data->swap = swsusp_resume_device ?
 			swap_type_of(swsusp_resume_device, 0, NULL) : -1;
 		data->mode = O_RDONLY;
+		data->free_bitmaps = false;
 		error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 		if (error)
 			pm_notifier_call_chain(PM_POST_HIBERNATION);
@@ -87,16 +87,19 @@
 		data->swap = -1;
 		data->mode = O_WRONLY;
 		error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
+		if (!error) {
+			error = create_basic_memory_bitmaps();
+			data->free_bitmaps = !error;
+		}
 		if (error)
 			pm_notifier_call_chain(PM_POST_RESTORE);
 	}
-	if (error) {
-		free_basic_memory_bitmaps();
+	if (error)
 		atomic_inc(&snapshot_device_available);
-	}
-	data->frozen = 0;
-	data->ready = 0;
-	data->platform_support = 0;
+
+	data->frozen = false;
+	data->ready = false;
+	data->platform_support = false;
 
  Unlock:
 	unlock_system_sleep();
@@ -111,12 +114,14 @@
 	lock_system_sleep();
 
 	swsusp_free();
-	free_basic_memory_bitmaps();
 	data = filp->private_data;
 	free_all_swap_pages(data->swap);
 	if (data->frozen) {
 		pm_restore_gfp_mask();
+		free_basic_memory_bitmaps();
 		thaw_processes();
+	} else if (data->free_bitmaps) {
+		free_basic_memory_bitmaps();
 	}
 	pm_notifier_call_chain(data->mode == O_RDONLY ?
 			PM_POST_HIBERNATION : PM_POST_RESTORE);
@@ -207,6 +212,7 @@
 	if (!mutex_trylock(&pm_mutex))
 		return -EBUSY;
 
+	lock_device_hotplug();
 	data = filp->private_data;
 
 	switch (cmd) {
@@ -220,16 +226,25 @@
 		printk("done.\n");
 
 		error = freeze_processes();
-		if (!error)
-			data->frozen = 1;
+		if (error)
+			break;
+
+		error = create_basic_memory_bitmaps();
+		if (error)
+			thaw_processes();
+		else
+			data->frozen = true;
+
 		break;
 
 	case SNAPSHOT_UNFREEZE:
 		if (!data->frozen || data->ready)
 			break;
 		pm_restore_gfp_mask();
+		free_basic_memory_bitmaps();
+		data->free_bitmaps = false;
 		thaw_processes();
-		data->frozen = 0;
+		data->frozen = false;
 		break;
 
 	case SNAPSHOT_CREATE_IMAGE:
@@ -259,7 +274,7 @@
 	case SNAPSHOT_FREE:
 		swsusp_free();
 		memset(&data->handle, 0, sizeof(struct snapshot_handle));
-		data->ready = 0;
+		data->ready = false;
 		/*
 		 * It is necessary to thaw kernel threads here, because
 		 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
@@ -323,7 +338,7 @@
 		 * PM_HIBERNATION_PREPARE
 		 */
 		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
-		data->ready = 0;
+		data->ready = false;
 		break;
 
 	case SNAPSHOT_PLATFORM_SUPPORT:
@@ -371,6 +386,7 @@
 
 	}
 
+	unlock_device_hotplug();
 	mutex_unlock(&pm_mutex);
 
 	return error;