dm: remove dm_get_dev_t

Open code dm_get_dev_t in the only remaining caller, and propagate the
exact error code from lookup_bdev and early_lookup_bdev.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-20-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/dm-table.c

@@ -323,20 +323,6 @@ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 	return 0;
 }
 
-/*
- * Convert the path to a device
- */
-dev_t dm_get_dev_t(const char *path)
-{
-	dev_t dev;
-
-	if (lookup_bdev(path, &dev) &&
-	    early_lookup_bdev(path, &dev))
-		return 0;
-	return dev;
-}
-EXPORT_SYMBOL_GPL(dm_get_dev_t);
-
 /*
  * Add a device to the list, or just increment the usage count if
  * it's already present.
@@ -359,9 +345,11 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 		if (MAJOR(dev) != major || MINOR(dev) != minor)
 			return -EOVERFLOW;
 	} else {
-		dev = dm_get_dev_t(path);
-		if (!dev)
-			return -ENODEV;
+		r = lookup_bdev(path, &dev);
+		if (r)
+			r = early_lookup_bdev(path, &dev);
+		if (r)
+			return r;
 	}
 	if (dev == disk_devt(t->md->disk))
 		return -EINVAL;

include/linux/device-mapper.h

@@ -170,8 +170,6 @@ struct dm_dev {
 	char name[16];
 };
 
-dev_t dm_get_dev_t(const char *path);
-
 /*
  * Constructors should call these functions to ensure destination devices
  * are opened/closed correctly.