Re: [PATCH 01/17] block: add a bio_add_virt_nofail helper

Damien Le Moal
2025-04-24T05:56:07Z

On 4/22/25 23:26, Christoph Hellwig wrote:
> Add a helper to add a directly mapped kernel virtual address to a
> bio so that callers don't have to convert to pages or folios.
>
> For now only the _nofail variant is provided as that is what all the
> obvious callers want.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> include/linux/bio.h | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index cafc7c215de8..0678b67162ee 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -417,6 +417,23 @@ void __bio_add_page(struct bio *bio, struct page *page,
> unsigned int len, unsigned int off);
> void bio_add_folio_nofail(struct bio *bio, struct folio *folio, size_t len,
> size_t off);
> +
> +/**
> + * bio_add_virt_nofail - add data in the diret kernel mapping to a bio

s/diret/direct

With that, looks good to me.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

> + * @bio: destination bio
> + * @vaddr: data to add
> + * @len: length of the data to add, may cross pages
> + *
> + * Add the data at @vaddr to @bio. The caller must have ensure a segment
> + * is available for the added data. No merging into an existing segment
> + * will be performed.
> + */
> +static inline void bio_add_virt_nofail(struct bio *bio, void *vaddr,
> + unsigned len)
> +{
> + __bio_add_page(bio, virt_to_page(vaddr), len, offset_in_page(vaddr));
> +}
> +
> int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
> void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter);
> void __bio_release_pages(struct bio *bio, bool mark_dirty);

--
Damien Le Moal
Western Digital Research