From ed8e2c17d62006fb136c30abeb552673727c5eee Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Sat, 14 Apr 2012 17:29:30 +0200 Subject: [PATCH 067/117] um: Implement a custom pte_same() function commit f15b9000eb1d09bbaa4b0a6b2089d7e1f64e84b3 upstream. UML uses the _PAGE_NEWPAGE flag to mark pages which are not jet installed on the host side using mmap(). pte_same() has to ignore this flag, otherwise unuse_pte_range() is unable to unuse the page because two identical page tables entries with different _PAGE_NEWPAGE flags would not match and swapoff() would never return. Analyzed-by: Hugh Dickins Signed-off-by: Richard Weinberger Signed-off-by: Ben Hutchings --- arch/um/include/asm/pgtable.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h index 41474fb..0fea0ec 100644 --- a/arch/um/include/asm/pgtable.h +++ b/arch/um/include/asm/pgtable.h @@ -271,6 +271,12 @@ static inline void set_pte(pte_t *pteptr, pte_t pteval) } #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval) +#define __HAVE_ARCH_PTE_SAME +static inline int pte_same(pte_t pte_a, pte_t pte_b) +{ + return !((pte_val(pte_a) ^ pte_val(pte_b)) & ~_PAGE_NEWPAGE); +} + /* * Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. -- 1.7.9.5