Re: [PATCH v5 09/23] cifs: Convert wdata_alloc_and_fillpages() to use filemap_get_folios_tag()

Vishal Moola
2023-01-12T18:01:00Z

On Wed, Jan 4, 2023 at 1:15 PM Vishal Moola (Oracle)
<vishal.moola@gmail.com> wrote:
>
> This is in preparation for the removal of find_get_pages_range_tag(). Now also
> supports the use of large folios.
>
> Since tofind might be larger than the max number of folios in a
> folio_batch (15), we loop through filling in wdata->pages pulling more
> batches until we either reach tofind pages or run out of folios.
>
> This function may not return all pages in the last found folio before
> tofind pages are reached.
>
> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> ---
> fs/cifs/file.c | 32 +++++++++++++++++++++++++++++---
> 1 file changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 22dfc1f8b4f1..8cdd2f67af24 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2527,14 +2527,40 @@ wdata_alloc_and_fillpages(pgoff_t tofind, struct address_space *mapping,
> unsigned int *found_pages)
> {
> struct cifs_writedata *wdata;
> -
> + struct folio_batch fbatch;
> + unsigned int i, idx, p, nr;
> wdata = cifs_writedata_alloc((unsigned int)tofind,
> cifs_writev_complete);
> if (!wdata)
> return NULL;
>
> - *found_pages = find_get_pages_range_tag(mapping, index, end,
> - PAGECACHE_TAG_DIRTY, tofind, wdata->pages);
> + folio_batch_init(&fbatch);
> + *found_pages = 0;
> +
> +again:
> + nr = filemap_get_folios_tag(mapping, index, end,
> + PAGECACHE_TAG_DIRTY, &fbatch);
> + if (!nr)
> + goto out; /* No dirty pages left in the range */
> +
> + for (i = 0; i < nr; i++) {
> + struct folio *folio = fbatch.folios[i];
> +
> + idx = 0;
> + p = folio_nr_pages(folio);
> +add_more:
> + wdata->pages[*found_pages] = folio_page(folio, idx);
> + folio_get(folio);
> + if (++*found_pages == tofind) {
> + folio_batch_release(&fbatch);
> + goto out;
> + }
> + if (++idx < p)
> + goto add_more;
> + }
> + folio_batch_release(&fbatch);
> + goto again;
> +out:
> return wdata;
> }
>
> --
> 2.38.1
>

Could someone review this cifs patch, please? This is one of the
2 remaining patches that need to be looked at in the series.