init: refactor devt_from_partuuid

The code in devt_from_partuuid is very convoluted.  Refactor a bit by
sanitizing the goto and variable name usage.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

init/do_mounts.c

@@ -105,13 +105,10 @@ static int match_dev_by_uuid(struct device *dev, const void *data)
  */
 static dev_t devt_from_partuuid(const char *uuid_str)
 {
-	dev_t res = 0;
 	struct uuidcmp cmp;
 	struct device *dev = NULL;
-	struct gendisk *disk;
-	struct hd_struct *part;
+	dev_t devt = 0;
 	int offset = 0;
-	bool clear_root_wait = false;
 	char *slash;
 
 	cmp.uuid = uuid_str;
@@ -120,52 +117,49 @@ static dev_t devt_from_partuuid(const char *uuid_str)
 	/* Check for optional partition number offset attributes. */
 	if (slash) {
 		char c = 0;
+
 		/* Explicitly fail on poor PARTUUID syntax. */
-		if (sscanf(slash + 1,
-			   "PARTNROFF=%d%c", &offset, &c) != 1) {
-			clear_root_wait = true;
-			goto done;
-		}
+		if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1)
+			goto clear_root_wait;
 		cmp.len = slash - uuid_str;
 	} else {
 		cmp.len = strlen(uuid_str);
 	}
 
-	if (!cmp.len) {
-		clear_root_wait = true;
-		goto done;
-	}
+	if (!cmp.len)
+		goto clear_root_wait;
 
-	dev = class_find_device(&block_class, NULL, &cmp,
-				&match_dev_by_uuid);
+	dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid);
 	if (!dev)
-		goto done;
-
-	res = dev->devt;
+		return 0;
 
-	/* Attempt to find the partition by offset. */
-	if (!offset)
-		goto no_offset;
+	if (offset) {
+		/*
+		 * Attempt to find the requested partition by adding an offset
+		 * to the partition number found by UUID.
+		 */
+		struct hd_struct *part;
 
-	res = 0;
-	disk = part_to_disk(dev_to_part(dev));
-	part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
-	if (part) {
-		res = part_devt(part);
-		put_device(part_to_dev(part));
+		part = disk_get_part(dev_to_disk(dev),
+				     dev_to_part(dev)->partno + offset);
+		if (part) {
+			devt = part_devt(part);
+			put_device(part_to_dev(part));
+		}
+	} else {
+		devt = dev->devt;
 	}
 
-no_offset:
 	put_device(dev);
-done:
-	if (clear_root_wait) {
-		pr_err("VFS: PARTUUID= is invalid.\n"
-		       "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
-		if (root_wait)
-			pr_err("Disabling rootwait; root= is invalid.\n");
-		root_wait = 0;
-	}
-	return res;
+	return devt;
+
+clear_root_wait:
+	pr_err("VFS: PARTUUID= is invalid.\n"
+	       "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
+	if (root_wait)
+		pr_err("Disabling rootwait; root= is invalid.\n");
+	root_wait = 0;
+	return 0;
 }
 
 /**