Return EINVAL for unknown address in change_page_attr

Matches what i386 does and makes more sense.

Signed-off-by: Andi Kleen <ak@suse.de>

---
 arch/x86_64/mm/pageattr.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: linux/arch/x86_64/mm/pageattr.c
===================================================================
--- linux.orig/arch/x86_64/mm/pageattr.c
+++ linux/arch/x86_64/mm/pageattr.c
@@ -154,7 +154,9 @@ __change_page_attr(unsigned long address
 	pgprot_t ref_prot2;
 
 	kpte = lookup_address(address);
-	if (!kpte) return 0;
+	if (!kpte)
+		return -EINVAL;
+
 	kpte_page = virt_to_page(((unsigned long)kpte) & PAGE_MASK);
 	BUG_ON(PageCompound(kpte_page));
 	BUG_ON(PageLRU(kpte_page));