Re: [PATCH V2 1/1] block: avoid to touch unloaded module instance when opening bdev

[Ming Lei <ming.lei@redhat.com>]

On Thu, Nov 11, 2021 at 10:03:43AM +0800, Ming Lei wrote:
> disk->fops->owner is grabbed in blkdev_get_no_open() after the disk
> kobject refcount is increased. This way can't make sure that
> disk->fops->owner is still alive since del_gendisk() still can move
> on if the kobject refcount of disk is grabbed by open() and
> disk->fops->open() isn't called yet.
> 
> Fixes the issue by moving try_module_get() into blkdev_get_by_dev()
> with ->open_mutex() held, then we can drain the in-progress open()
> in del_gendisk(). Meantime new open() won't succeed because disk
> becomes not alive.
> 
> This way is reasonable because blkdev_get_no_open() needn't to touch
> disk->fops or defined callbacks.
> 
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: czhong@redhat.com
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
> V2:
> 	- remove comment as suggested by Christoph
> 	- improve commit log a bit

Hi Jens,

Ping...

Thanks,
Ming