block: automatically enable GENHD_FL_EXT_DEVT

Automatically set the GENHD_FL_EXT_DEVT flag for all disks allocated
without an explicit number of minors.  This is what all new block
drivers should do, so make sure it is the default without boilerplate
code.
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/20210521055116.1053587-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -497,7 +497,6 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 		}
 	} else {
 		WARN_ON(disk->minors);
-		WARN_ON(!(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN)));
 
 		ret = blk_alloc_ext_minor();
 		if (ret < 0) {
@@ -506,6 +505,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 		}
 		disk->major = BLOCK_EXT_MAJOR;
 		disk->first_minor = MINOR(ret);
+		disk->flags |= GENHD_FL_EXT_DEVT;
 	}
 
 	disk->flags |= GENHD_FL_UP;

block/partitions/core.c

@@ -326,10 +326,6 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
 	const char *dname;
 	int err;
 
-	/*
-	 * disk_max_parts() won't be zero, either GENHD_FL_EXT_DEVT is set
-	 * or 'minors' is passed to alloc_disk().
-	 */
 	if (partno >= disk_max_parts(disk))
 		return ERR_PTR(-EINVAL);
 

drivers/block/n64cart.c

@@ -141,7 +141,7 @@ static int __init n64cart_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	disk->first_minor = 0;
-	disk->flags = GENHD_FL_NO_PART_SCAN | GENHD_FL_EXT_DEVT;
+	disk->flags = GENHD_FL_NO_PART_SCAN;
 	disk->fops = &n64cart_fops;
 	disk->private_data = &pdev->dev;
 	strcpy(disk->disk_name, "n64cart");

drivers/lightnvm/core.c

@@ -383,7 +383,6 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
 	}
 
 	strlcpy(tdisk->disk_name, create->tgtname, sizeof(tdisk->disk_name));
-	tdisk->flags = GENHD_FL_EXT_DEVT;
 	tdisk->major = 0;
 	tdisk->first_minor = 0;
 	tdisk->fops = tt->bops;

drivers/memstick/core/ms_block.c

@@ -2136,7 +2136,6 @@ static int msb_init_disk(struct memstick_dev *card)
 	msb->disk->fops = &msb_bdops;
 	msb->disk->private_data = msb;
 	msb->disk->queue = msb->queue;
-	msb->disk->flags |= GENHD_FL_EXT_DEVT;
 
 	capacity = msb->pages_in_block * msb->logical_block_count;
 	capacity *= (msb->page_size / 512);

drivers/nvdimm/blk.c

@@ -267,7 +267,6 @@ static int nsblk_attach_disk(struct nd_namespace_blk *nsblk)
 	disk->first_minor	= 0;
 	disk->fops		= &nd_blk_fops;
 	disk->queue		= q;
-	disk->flags		= GENHD_FL_EXT_DEVT;
 	disk->private_data	= nsblk;
 	nvdimm_namespace_disk_name(&nsblk->common, disk->disk_name);
 

drivers/nvdimm/btt.c

@@ -1537,7 +1537,6 @@ static int btt_blk_init(struct btt *btt)
 	btt->btt_disk->fops = &btt_fops;
 	btt->btt_disk->private_data = btt;
 	btt->btt_disk->queue = btt->btt_queue;
-	btt->btt_disk->flags = GENHD_FL_EXT_DEVT;
 
 	blk_queue_logical_block_size(btt->btt_queue, btt->sector_size);
 	blk_queue_max_hw_sectors(btt->btt_queue, UINT_MAX);

drivers/nvdimm/pmem.c

@@ -477,7 +477,6 @@ static int pmem_attach_disk(struct device *dev,
 
 	disk->fops		= &pmem_fops;
 	disk->queue		= q;
-	disk->flags		= GENHD_FL_EXT_DEVT;
 	disk->private_data	= pmem;
 	nvdimm_namespace_disk_name(ndns, disk->disk_name);
 	set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)

drivers/nvme/host/core.c

@@ -3699,7 +3699,6 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
 	disk->fops = &nvme_bdev_ops;
 	disk->private_data = ns;
 	disk->queue = ns->queue;
-	disk->flags = GENHD_FL_EXT_DEVT;
 	/*
 	 * Without the multipath code enabled, multiple controller per
 	 * subsystems are visible as devices and thus we cannot use the

drivers/nvme/host/multipath.c

@@ -462,7 +462,6 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 	head->disk->fops = &nvme_ns_head_ops;
 	head->disk->private_data = head;
 	head->disk->queue = q;
-	head->disk->flags = GENHD_FL_EXT_DEVT;
 	sprintf(head->disk->disk_name, "nvme%dn%d",
 			ctrl->subsys->instance, head->instance);
 	return 0;