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:
https://kernel.googlesource.com/pub/scm/linux/kernel/git/ralf/linux/+/linux-3.4.50%5E!/#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 <stsp@users.sourceforge.net>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 @@
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = pte_page(pte);
get_page(page);
+ __flush_anon_page(page, addr);
+ flush_dcache_page(page);
pages[*nr] = page;
(*nr)++;
