block: move the DISK_MAX_PARTS sanity check into __device_add_disk

Keep this together with the first place that actually looks at
->minors and prepare for not passing a minors argument to
alloc_disk.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -489,6 +489,12 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 	 */
 	if (disk->major) {
 		WARN_ON(!disk->minors);
+
+		if (disk->minors > DISK_MAX_PARTS) {
+			pr_err("block: can't allocate more than %d partitions\n",
+				DISK_MAX_PARTS);
+			disk->minors = DISK_MAX_PARTS;
+		}
 	} else {
 		WARN_ON(disk->minors);
 		WARN_ON(!(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN)));
@@ -1255,13 +1261,6 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 {
 	struct gendisk *disk;
 
-	if (minors > DISK_MAX_PARTS) {
-		printk(KERN_ERR
-			"block: can't allocate more than %d partitions\n",
-			DISK_MAX_PARTS);
-		minors = DISK_MAX_PARTS;
-	}
-
 	disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
 	if (!disk)
 		return NULL;