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Commit d6f8bb13 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

i386 mm: use pte_update() in ptep_test_and_clear_dirty() 



It is not safe to use pte_update_defer() in ptep_test_and_clear_young():
its only user, /proc/<pid>/clear_refs, drops pte lock before flushing TLB.
Use the safe though less efficient pte_update() paravirtop in its place.
Likewise in ptep_test_and_clear_dirty(), though that has no current use.

These are macros (header file dependency stops them from becoming inline
functions), so be more liberal with the underscores and parentheses.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 30475cc1

include/asm-i386/pgtable.h

+14 −12
Original line number Diff line number Diff line
@@ -295,22 +295,24 @@ do { \ 


#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY

#define ptep_test_and_clear_dirty(vma, addr, ptep) ({			\

	int ret = 0;							\

	if (pte_dirty(*ptep))						\

		ret = test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low); \

	if (ret)							\

		pte_update_defer(vma->vm_mm, addr, ptep);		\

	ret;								\

	int __ret = 0;							\

	if (pte_dirty(*(ptep)))						\

		__ret = test_and_clear_bit(_PAGE_BIT_DIRTY,		\

						&(ptep)->pte_low);	\

	if (__ret)							\

		pte_update((vma)->vm_mm, addr, ptep);			\

	__ret;								\

})



#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG

#define ptep_test_and_clear_young(vma, addr, ptep) ({			\

	int ret = 0;							\

	if (pte_young(*ptep))						\

		ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low); \

	if (ret)							\

		pte_update_defer(vma->vm_mm, addr, ptep);		\

	ret;								\

	int __ret = 0;							\

	if (pte_young(*(ptep)))						\

		__ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,		\

						&(ptep)->pte_low);	\

	if (__ret)							\

		pte_update((vma)->vm_mm, addr, ptep);			\

	__ret;								\

})



/*