mm/filemap: Add filemap_get_folio

filemap_get_folio() is a replacement for find_get_page().
Turn pagecache_get_page() into a wrapper around __filemap_get_folio().
Remove find_lock_head() as this use case is now covered by
filemap_get_folio().

Reduces overall kernel size by 209 bytes.  __filemap_get_folio() is
316 bytes shorter than pagecache_get_page() was, but the new
pagecache_get_page() wrapper is 99 bytes.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

1 files changed, 12 insertions, 0 deletions

diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 6b19bc4ed6b0..e833e680e944 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -115,3 +115,15 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
 	return filemap_add_folio(mapping, page_folio(page), index, gfp);
 }
 EXPORT_SYMBOL(add_to_page_cache_lru);
+
+struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
+		int fgp_flags, gfp_t gfp)
+{
+	struct folio *folio;
+
+	folio = __filemap_get_folio(mapping, index, fgp_flags, gfp);
+	if ((fgp_flags & FGP_HEAD) || !folio || xa_is_value(folio))
+		return &folio->page;
+	return folio_file_page(folio, index);
+}
+EXPORT_SYMBOL(pagecache_get_page);