| Date | Sun, 27 May 2012 09:25:34 +0900 | From | Greg KH <> | Subject | [ 28/91] um: Implement a custom pte_same() function |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Richard Weinberger <richard@nod.at>
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 <hughd@google.com> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/um/include/asm/pgtable.h | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/arch/um/include/asm/pgtable.h +++ b/arch/um/include/asm/pgtable.h @@ -273,6 +273,12 @@ static inline void set_pte(pte_t *pteptr } #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.
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