sh: use folio_mapped() instead of page_mapped() in sh4_flush_cache_page()

Patch series "mm: remove page_mapped()".

While preparing my slides for an LSF/MM talk, I realized that I did not
yet remove page_mapped().

So let's do that.  In the BPF arena code it's unclear which memdesc we
would want to allocate in the future: certainly something with a refcount,
but likely none with a mapcount.  So let's just rely on the page refcount
instead to decide whether we want to try zapping the page from user page
tables.


This patch (of 3):

We already have the folio in our hands, so let's just use folio_mapped().

Link: https://lore.kernel.org/20260427-page_mapped-v1-0-e89c3592c74c@kernel.org
Link: https://lore.kernel.org/20260427-page_mapped-v1-1-e89c3592c74c@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Harry Yoo <harry@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <song@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/sh/mm/cache-sh4.c

@@ -248,7 +248,7 @@ static void sh4_flush_cache_page(void *args)
 		 */
 		map_coherent = (current_cpu_data.dcache.n_aliases &&
 			test_bit(PG_dcache_clean, folio_flags(folio, 0)) &&
-			page_mapped(page));
+			folio_mapped(folio));
 		if (map_coherent)
 			vaddr = kmap_coherent(page, address);
 		else