[PATCH] mips: Re-introduce copy_user_page

[Guenter Roeck <linux@roeck-us.net>]

Commit bcd022801ee5 ("MIPS: Fix COW D-cache aliasing on fork") replaced
the inline function copy_user_page for mips with an external reference,
but neglected to introduce the actual non-inline function. Restore it.

Fixes: bcd022801ee5 ("MIPS: Fix COW D-cache aliasing on fork")
Fixes: 4927b7d77c00 ("dax,ext2: replace the XIP page fault handler with the DAX page fault handler")
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
4927b7d77c00 is in -next.

 arch/mips/include/asm/page.h | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
index 154b70a..69c2f19 100644
--- a/arch/mips/include/asm/page.h
+++ b/arch/mips/include/asm/page.h
@@ -105,8 +105,17 @@ static inline void clear_user_page(void *addr, unsigned long vaddr,
 		flush_data_cache_page((unsigned long)addr);
 }
 
-extern void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
-	struct page *to);
+static inline void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
+				  struct page *to)
+{
+	extern void (*flush_data_cache_page)(unsigned long addr);
+
+	copy_page(vto, vfrom);
+	if (!cpu_has_ic_fills_f_dc || pages_do_alias((unsigned long)vto,
+						     vaddr & PAGE_MASK))
+		flush_data_cache_page((unsigned long)vto);
+}
+
 struct vm_area_struct;
 extern void copy_user_highpage(struct page *to, struct page *from,
 	unsigned long vaddr, struct vm_area_struct *vma);
-- 
2.1.0