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    Subject[PATCH 11/25] mm: Convert mapping_get_entry to return a folio
    Date
    The pagecache only contains folios, so this is the right thing to do.

    Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
    ---
    mm/filemap.c | 24 ++++++++++++------------
    1 file changed, 12 insertions(+), 12 deletions(-)

    diff --git a/mm/filemap.c b/mm/filemap.c
    index 654bba53442a..b9f25a2d8312 100644
    --- a/mm/filemap.c
    +++ b/mm/filemap.c
    @@ -1673,33 +1673,33 @@ EXPORT_SYMBOL(page_cache_prev_miss);
    * @index: The page cache index.
    *
    * Looks up the page cache slot at @mapping & @offset. If there is a
    - * page cache page, the head page is returned with an increased refcount.
    + * page cache page, the folio is returned with an increased refcount.
    *
    * If the slot holds a shadow entry of a previously evicted page, or a
    * swap entry from shmem/tmpfs, it is returned.
    *
    - * Return: The head page or shadow entry, %NULL if nothing is found.
    + * Return: The folio or shadow entry, %NULL if nothing is found.
    */
    -static struct page *mapping_get_entry(struct address_space *mapping,
    +static struct folio *mapping_get_entry(struct address_space *mapping,
    pgoff_t index)
    {
    XA_STATE(xas, &mapping->i_pages, index);
    - struct page *page;
    + struct folio *folio;

    rcu_read_lock();
    repeat:
    xas_reset(&xas);
    - page = xas_load(&xas);
    - if (xas_retry(&xas, page))
    + folio = xas_load(&xas);
    + if (xas_retry(&xas, folio))
    goto repeat;
    /*
    * A shadow entry of a recently evicted page, or a swap entry from
    * shmem/tmpfs. Return it without attempting to raise page count.
    */
    - if (!page || xa_is_value(page))
    + if (!folio || xa_is_value(folio))
    goto out;

    - if (!page_cache_get_speculative(page))
    + if (!page_cache_get_speculative(&folio->page))
    goto repeat;

    /*
    @@ -1707,14 +1707,14 @@ static struct page *mapping_get_entry(struct address_space *mapping,
    * This is part of the lockless pagecache protocol. See
    * include/linux/pagemap.h for details.
    */
    - if (unlikely(page != xas_reload(&xas))) {
    - put_page(page);
    + if (unlikely(folio != xas_reload(&xas))) {
    + put_folio(folio);
    goto repeat;
    }
    out:
    rcu_read_unlock();

    - return page;
    + return folio;
    }

    /**
    @@ -1757,7 +1757,7 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
    struct page *page;

    repeat:
    - page = mapping_get_entry(mapping, index);
    + page = &mapping_get_entry(mapping, index)->page;
    if (xa_is_value(page)) {
    if (fgp_flags & FGP_ENTRY)
    return page;
    --
    2.29.2
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