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-rw-r--r--include/linux/huge_mm.h2
-rw-r--r--mm/huge_memory.c10
-rw-r--r--mm/mremap.c30
3 files changed, 18 insertions, 24 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 99c19b06d9a4..fdcb45999b26 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -43,7 +43,7 @@ extern int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 			unsigned char *vec);
 extern bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 			 unsigned long new_addr, unsigned long old_end,
-			 pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush);
+			 pmd_t *old_pmd, pmd_t *new_pmd);
 extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 			unsigned long addr, pgprot_t newprot,
 			int prot_numa);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 58269f8ba7c4..deed97fba979 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1780,7 +1780,7 @@ static pmd_t move_soft_dirty_pmd(pmd_t pmd)
 
 bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 		  unsigned long new_addr, unsigned long old_end,
-		  pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush)
+		  pmd_t *old_pmd, pmd_t *new_pmd)
 {
 	spinlock_t *old_ptl, *new_ptl;
 	pmd_t pmd;
@@ -1811,7 +1811,7 @@ bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 		if (new_ptl != old_ptl)
 			spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
 		pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd);
-		if (pmd_present(pmd) && pmd_dirty(pmd))
+		if (pmd_present(pmd))
 			force_flush = true;
 		VM_BUG_ON(!pmd_none(*new_pmd));
 
@@ -1822,12 +1822,10 @@ bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 		}
 		pmd = move_soft_dirty_pmd(pmd);
 		set_pmd_at(mm, new_addr, new_pmd, pmd);
-		if (new_ptl != old_ptl)
-			spin_unlock(new_ptl);
 		if (force_flush)
 			flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE);
-		else
-			*need_flush = true;
+		if (new_ptl != old_ptl)
+			spin_unlock(new_ptl);
 		spin_unlock(old_ptl);
 		return true;
 	}
diff --git a/mm/mremap.c b/mm/mremap.c
index 5c2e18505f75..a9617e72e6b7 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -115,7 +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;
@@ -163,15 +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);
@@ -179,13 +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);
@@ -198,7 +198,6 @@ 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 */
 
@@ -229,8 +228,7 @@ 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)
@@ -246,10 +244,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 		if (extent > next - new_addr)
 			extent = next - new_addr;
 		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);