sh: get_user_pages_fast() must flush cache

This patch avoids fuse hangs on sh4 by flushing the cache on
get_user_pages_fast().  This is not necessary a good thing to do, but
get_user_pages() does this, so get_user_pages_fast() should too.

Please note the patch for mips arch that addresses the similar problem:!/#F0

They basically simply disable get_user_pages_fast() at all, using a
fall-back to get_user_pages().  But my fix is different, it adds an
explicit cache flushes.

Signed-off-by: Stas Sergeev <>
Cc: Geert Uytterhoeven <>
Cc: Kamal Dasu <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
diff --git a/arch/sh/mm/gup.c b/arch/sh/mm/gup.c
index bf8daf9..37458f3 100644
--- a/arch/sh/mm/gup.c
+++ b/arch/sh/mm/gup.c
@@ -105,6 +105,8 @@
 		page = pte_page(pte);
+		__flush_anon_page(page, addr);
+		flush_dcache_page(page);
 		pages[*nr] = page;