On Thu, Jul 11, 2024 at 10:37:46AM +0530, Kundan Kumar wrote:
> -bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,
> - struct page *page, unsigned len, unsigned offset,
> +bool bvec_try_merge_hw_folio(struct request_queue *q, struct bio_vec *bv,
> + struct folio *folio, size_t len, size_t offset,
> bool *same_page)
> {
> + struct page *page = folio_page(folio, 0);
> unsigned long mask = queue_segment_boundary(q);
> phys_addr_t addr1 = bvec_phys(bv);
> phys_addr_t addr2 = page_to_phys(page) + offset + len - 1;
[...]
> +bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,
> + struct page *page, unsigned int len, unsigned int offset,
> + bool *same_page)
> +{
> + struct folio *folio = page_folio(page);
> +
> + return bvec_try_merge_hw_folio(q, bv, folio, len,
> + ((size_t)folio_page_idx(folio, page) << PAGE_SHIFT) +
> + offset, same_page);
> +}
This is the wrong way to do it. bio_add_folio() does it correctly
by being a wrapper around bio_add_page().
The reason is that in the future, not all pages will belong to folios.
For those pages, page_folio() will return NULL, and this will crash.
