PM: hibernate: factor out a helper to find the resume device

Split the logic to find the resume device out software_resume and into
a separate helper to start unwindig the convoluted goto logic.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

kernel/power/hibernate.c

@@ -910,6 +910,41 @@ unlock:
 }
 EXPORT_SYMBOL_GPL(hibernate_quiet_exec);
 
+static int find_resume_device(void)
+{
+	if (!strlen(resume_file))
+		return -ENOENT;
+
+	pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
+
+	if (resume_delay) {
+		pr_info("Waiting %dsec before reading resume device ...\n",
+			resume_delay);
+		ssleep(resume_delay);
+	}
+
+	/* Check if the device is there */
+	swsusp_resume_device = name_to_dev_t(resume_file);
+	if (swsusp_resume_device)
+		return 0;
+
+	/*
+	 * Some device discovery might still be in progress; we need to wait for
+	 * this to finish.
+	 */
+	wait_for_device_probe();
+	if (resume_wait) {
+		while (!(swsusp_resume_device = name_to_dev_t(resume_file)))
+			msleep(10);
+		async_synchronize_full();
+	}
+
+	swsusp_resume_device = name_to_dev_t(resume_file);
+	if (!swsusp_resume_device)
+		return -ENODEV;
+	return 0;
+}
+
 /**
  * software_resume - Resume from a saved hibernation image.
  *
@@ -949,45 +984,12 @@ static int software_resume(void)
 
 	snapshot_test = false;
 
-	if (swsusp_resume_device)
-		goto Check_image;
-
-	if (!strlen(resume_file)) {
-		error = -ENOENT;
-		goto Unlock;
-	}
-
-	pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
-
-	if (resume_delay) {
-		pr_info("Waiting %dsec before reading resume device ...\n",
-			resume_delay);
-		ssleep(resume_delay);
-	}
-
-	/* Check if the device is there */
-	swsusp_resume_device = name_to_dev_t(resume_file);
 	if (!swsusp_resume_device) {
-		/*
-		 * Some device discovery might still be in progress; we need
-		 * to wait for this to finish.
-		 */
-		wait_for_device_probe();
-
-		if (resume_wait) {
-			while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
-				msleep(10);
-			async_synchronize_full();
-		}
-
-		swsusp_resume_device = name_to_dev_t(resume_file);
-		if (!swsusp_resume_device) {
-			error = -ENODEV;
+		error = find_resume_device();
+		if (error)
 			goto Unlock;
-		}
 	}
 
- Check_image:
 	pm_pr_dbg("Hibernation image partition %d:%d present\n",
 		MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));