The patch titled
Subject: sh: get_user_pages_fast() must flush cache
has been added to the -mm tree. Its filename is
sh-get_user_pages_fast-must-flush-cache-the-way.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/sh-get_user_pages_fast-must-flush-cache-the-way.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/sh-get_user_pages_fast-must-flush-cache-the-way.patch
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------------------------------------------------------
From: Stas Sergeev <stsp@xxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Cc: Kamal Dasu <kdasu.kdev@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/sh/mm/gup.c | 2 ++
1 file changed, 2 insertions(+)
diff -puN arch/sh/mm/gup.c~sh-get_user_pages_fast-must-flush-cache-the-way arch/sh/mm/gup.c
--- a/arch/sh/mm/gup.c~sh-get_user_pages_fast-must-flush-cache-the-way
+++ a/arch/sh/mm/gup.c
@@ -105,6 +105,8 @@ static noinline int gup_pte_range(pmd_t
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)++;
_
Patches currently in -mm which might be from stsp@xxxxxxx are
sh-get_user_pages_fast-must-flush-cache-the-way.patch
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