X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=mm%2Fmremap.c;h=88ceeb4ef817e7c92286c3aab2b37e045a1f8022;hb=fd317818ce72043e86ccd4a0fa6d7da0fb18b36e;hp=cfec004c4ff9a95511940039d6975d270bf37996;hpb=dff4d1f6fe85627b7ce8e4c5291d8621a1995605;p=platform%2Fkernel%2Flinux-exynos.git

diff --git a/mm/mremap.c b/mm/mremap.c
index cfec004..88ceeb4 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *	mm/mremap.c
  *
@@ -114,7 +115,7 @@ static pte_t move_soft_dirty_pte(pte_t pte)
 static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
 		unsigned long old_addr, unsigned long old_end,
 		struct vm_area_struct *new_vma, pmd_t *new_pmd,
-		unsigned long new_addr, bool need_rmap_locks, bool *need_flush)
+		unsigned long new_addr, bool need_rmap_locks)
 {
 	struct mm_struct *mm = vma->vm_mm;
 	pte_t *old_pte, *new_pte, pte;
@@ -162,15 +163,17 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
 
 		pte = ptep_get_and_clear(mm, old_addr, old_pte);
 		/*
-		 * If we are remapping a dirty PTE, make sure
+		 * If we are remapping a valid PTE, make sure
 		 * to flush TLB before we drop the PTL for the
-		 * old PTE or we may race with page_mkclean().
+		 * PTE.
 		 *
-		 * This check has to be done after we removed the
-		 * old PTE from page tables or another thread may
-		 * dirty it after the check and before the removal.
+		 * NOTE! Both old and new PTL matter: the old one
+		 * for racing with page_mkclean(), the new one to
+		 * make sure the physical page stays valid until
+		 * the TLB entry for the old mapping has been
+		 * flushed.
 		 */
-		if (pte_present(pte) && pte_dirty(pte))
+		if (pte_present(pte))
 			force_flush = true;
 		pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr);
 		pte = move_soft_dirty_pte(pte);
@@ -178,13 +181,11 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
 	}
 
 	arch_leave_lazy_mmu_mode();
+	if (force_flush)
+		flush_tlb_range(vma, old_end - len, old_end);
 	if (new_ptl != old_ptl)
 		spin_unlock(new_ptl);
 	pte_unmap(new_pte - 1);
-	if (force_flush)
-		flush_tlb_range(vma, old_end - len, old_end);
-	else
-		*need_flush = true;
 	pte_unmap_unlock(old_pte - 1, old_ptl);
 	if (need_rmap_locks)
 		drop_rmap_locks(vma);
@@ -199,7 +200,6 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 {
 	unsigned long extent, next, old_end;
 	pmd_t *old_pmd, *new_pmd;
-	bool need_flush = false;
 	unsigned long mmun_start;	/* For mmu_notifiers */
 	unsigned long mmun_end;		/* For mmu_notifiers */
 
@@ -230,8 +230,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 				if (need_rmap_locks)
 					take_rmap_locks(vma);
 				moved = move_huge_pmd(vma, old_addr, new_addr,
-						    old_end, old_pmd, new_pmd,
-						    &need_flush);
+						    old_end, old_pmd, new_pmd);
 				if (need_rmap_locks)
 					drop_rmap_locks(vma);
 				if (moved)
@@ -249,10 +248,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 		if (extent > LATENCY_LIMIT)
 			extent = LATENCY_LIMIT;
 		move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma,
-			  new_pmd, new_addr, need_rmap_locks, &need_flush);
+			  new_pmd, new_addr, need_rmap_locks);
 	}
-	if (need_flush)
-		flush_tlb_range(vma, old_end-len, old_addr);
 
 	mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);