Commit f15b9000 authored Apr 14, 2012 by Richard Weinberger

um: Implement a custom pte_same() function



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.

CC: stable@kernel.org
Analyzed-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

parent 62179d47

arch/um/include/asm/pgtable.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -273,6 +273,12 @@ 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.