Re: [PATCH 1/2] [PATCH] bcache: cached_dev_free needs to put the sb page

[Christoph Hellwig]

On Fri, Dec 06, 2019 at 04:55:42PM +0800, Liang Chen wrote:
> Same as cache device, the buffer page needs to be put while
> freeing cached_dev.  Otherwise a page would be leaked every
> time a cached_dev is stopped.
> 
> Signed-off-by: Liang Chen <liangchen.linux@xxxxxxxxx>
> ---
>  drivers/md/bcache/super.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 77e9869345e7..a573ce1d85aa 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -1275,6 +1275,9 @@ static void cached_dev_free(struct closure *cl)
>  
>  	mutex_unlock(&bch_register_lock);
>  
> +	if (dc->sb_bio.bi_inline_vecs[0].bv_page)
> +		put_page(bio_first_page_all(&dc->sb_bio));

Using bio_first_page_all in the put_page call, but open coding it
for the check looks rather strange.

The cleanest thing here would be to just add a page pointer to the
cached device structure and use that instead of all the indirections.