4.9-stable patches

[thirdparty/kernel/stable-queue.git] / releases / 4.11.2 / x86-pmem-fix-cache-flushing-for-iovec-write-8-bytes.patch

From 8376efd31d3d7c44bd05be337adde023cc531fa1 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben.hutchings@codethink.co.uk>
Date: Tue, 9 May 2017 18:00:43 +0100
Subject: x86, pmem: Fix cache flushing for iovec write < 8 bytes

From: Ben Hutchings <ben.hutchings@codethink.co.uk>

commit 8376efd31d3d7c44bd05be337adde023cc531fa1 upstream.

Commit 11e63f6d920d added cache flushing for unaligned writes from an
iovec, covering the first and last cache line of a >= 8 byte write and
the first cache line of a < 8 byte write.  But an unaligned write of
2-7 bytes can still cover two cache lines, so make sure we flush both
in that case.

Fixes: 11e63f6d920d ("x86, pmem: fix broken __copy_user_nocache ...")
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/include/asm/pmem.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/include/asm/pmem.h
+++ b/arch/x86/include/asm/pmem.h
@@ -103,7 +103,7 @@ static inline size_t arch_copy_from_iter
 
 		if (bytes < 8) {
 			if (!IS_ALIGNED(dest, 4) || (bytes != 4))
-				arch_wb_cache_pmem(addr, 1);
+				arch_wb_cache_pmem(addr, bytes);
 		} else {
 			if (!IS_ALIGNED(dest, 8)) {
 				dest = ALIGN(dest, boot_cpu_data.x86_clflush_size);