PM: hibernate: remove the global snapshot_test variable

Passing call dependent variable in global variables is a huge
antipattern.  Fix it up.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

kernel/power/hibernate.c

@@ -64,7 +64,6 @@ enum {
 static int hibernation_mode = HIBERNATION_SHUTDOWN;
 
 bool freezer_test_done;
-bool snapshot_test;
 
 static const struct platform_hibernation_ops *hibernation_ops;
 
@@ -684,7 +683,7 @@ static void power_down(void)
 		cpu_relax();
 }
 
-static int load_image_and_restore(void)
+static int load_image_and_restore(bool snapshot_test)
 {
 	int error;
 	unsigned int flags;
@@ -721,6 +720,7 @@ static int load_image_and_restore(void)
  */
 int hibernate(void)
 {
+	bool snapshot_test = false;
 	unsigned int sleep_flags;
 	int error;
 
@@ -748,9 +748,6 @@ int hibernate(void)
 	if (error)
 		goto Exit;
 
-	/* protected by system_transition_mutex */
-	snapshot_test = false;
-
 	lock_device_hotplug();
 	/* Allocate memory management structures */
 	error = create_basic_memory_bitmaps();
@@ -792,9 +789,9 @@ int hibernate(void)
 	unlock_device_hotplug();
 	if (snapshot_test) {
 		pm_pr_dbg("Checking hibernation image\n");
-		error = swsusp_check();
+		error = swsusp_check(snapshot_test);
 		if (!error)
-			error = load_image_and_restore();
+			error = load_image_and_restore(snapshot_test);
 	}
 	thaw_processes();
 
@@ -982,8 +979,6 @@ static int software_resume(void)
 	 */
 	mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 
-	snapshot_test = false;
-
 	if (!swsusp_resume_device) {
 		error = find_resume_device();
 		if (error)
@@ -994,7 +989,7 @@ static int software_resume(void)
 		MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 
 	pm_pr_dbg("Looking for hibernation image.\n");
-	error = swsusp_check();
+	error = swsusp_check(false);
 	if (error)
 		goto Unlock;
 
@@ -1022,7 +1017,7 @@ static int software_resume(void)
 		goto Close_Finish;
 	}
 
-	error = load_image_and_restore();
+	error = load_image_and_restore(false);
 	thaw_processes();
  Finish:
 	pm_notifier_call_chain(PM_POST_RESTORE);

kernel/power/power.h

@@ -59,7 +59,6 @@ asmlinkage int swsusp_save(void);
 
 /* kernel/power/hibernate.c */
 extern bool freezer_test_done;
-extern bool snapshot_test;
 
 extern int hibernation_snapshot(int platform_mode);
 extern int hibernation_restore(int platform_mode);
@@ -174,7 +173,7 @@ extern int swsusp_swap_in_use(void);
 #define SF_HW_SIG		8
 
 /* kernel/power/hibernate.c */
-extern int swsusp_check(void);
+int swsusp_check(bool snapshot_test);
 extern void swsusp_free(void);
 extern int swsusp_read(unsigned int *flags_p);
 extern int swsusp_write(unsigned int flags);

kernel/power/swap.c

@@ -1514,7 +1514,7 @@ int swsusp_read(unsigned int *flags_p)
  *      swsusp_check - Check for swsusp signature in the resume device
  */
 
-int swsusp_check(void)
+int swsusp_check(bool snapshot_test)
 {
 	int error;
 	void *holder;