Re: [PATCH v5 09/20] gfs2: use __bio_add_page for adding single page to bio

Bob Peterson
2023-05-02T15:20:28Z

On 5/2/23 6:19 AM, Johannes Thumshirn wrote:
> The GFS2 superblock reading code uses bio_add_page() to add a page to a
> newly created bio. bio_add_page() can fail, but the return value is never
> checked.
>
> Use __bio_add_page() as adding a single page to a newly created bio is
> guaranteed to succeed.
>
> This brings us a step closer to marking bio_add_page() as __must_check.
>
> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
> fs/gfs2/ops_fstype.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
> index 9af9ddb61ca0..cd962985b058 100644
> --- a/fs/gfs2/ops_fstype.c
> +++ b/fs/gfs2/ops_fstype.c
> @@ -254,7 +254,7 @@ static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector, int silent)
>
> bio = bio_alloc(sb->s_bdev, 1, REQ_OP_READ | REQ_META, GFP_NOFS);
> bio->bi_iter.bi_sector = sector * (sb->s_blocksize >> 9);
> - bio_add_page(bio, page, PAGE_SIZE, 0);
> + __bio_add_page(bio, page, PAGE_SIZE, 0);
>
> bio->bi_end_io = end_bio_io_page;
> bio->bi_private = page;
Hi Johannes,

So...I see 6 different calls to bio_add_page() in gfs2.
Why change this particular bio_add_page() to __bio_add_page() and not
the other five?

Regards,

Bob Peterson