From: Wen Yang wenyang.linux@foxmail.com

This reverts commit 0daa75bf750c400af0a0127fae37cd959d36dee7.

These problems such as: https://lore.kernel.org/all/CACPK8XfUWoOHr-0RwRoYoskia4fbAbZ7DYf5wWBnv6qUnGq... It was introduced by introduced by commit b1a811633f73 ("block: nbd: add sanity check for first_minor") and has been have been fixed by commit e4c4871a7394 ("nbd: fix max value for 'first_minor'").

Cc: Joel Stanley joel@jms.id.au Cc: Christoph Hellwig hch@lst.de Cc: Pavel Skripkin paskripkin@gmail.com Cc: Jens Axboe axboe@kernel.dk Cc: Sasha Levin sashal@kernel.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Wen Yang wenyang.linux@foxmail.com --- drivers/block/nbd.c | 10 ++++++++++ 1 file changed, 10 insertions(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index b0d3dadeb964..bf8148ebd858 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1771,7 +1771,17 @@ static int nbd_dev_add(int index) refcount_set(&nbd->refs, 1); INIT_LIST_HEAD(&nbd->list); disk->major = NBD_MAJOR; + + /* Too big first_minor can cause duplicate creation of + * sysfs files/links, since first_minor will be truncated to + * byte in __device_add_disk(). + */ disk->first_minor = index << part_shift; + if (disk->first_minor > 0xff) { + err = -EINVAL; + goto out_free_idr; + } + disk->fops = &nbd_fops; disk->private_data = nbd; sprintf(disk->disk_name, "nbd%d", index);