[PATCH v7 04/17] mm: modify vma_iter_store{_gfp} to indicate if it's storing a new vma

[Suren Baghdasaryan <surenb@google.com>]

vma_iter_store() functions can be used both when adding a new vma and
when updating an existing one. However for existing ones we do not need
to mark them attached as they are already marked that way. Add a parameter
to distinguish the usage and skip vma_mark_attached() when not needed.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/mm.h | 12 ++++++++++++
 mm/nommu.c         |  4 ++--
 mm/vma.c           | 16 ++++++++--------
 mm/vma.h           | 13 +++++++++----
 4 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 081178b0eec4..c50edfedd99d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -821,6 +821,16 @@ static inline void vma_assert_locked(struct vm_area_struct *vma)
 		vma_assert_write_locked(vma);
 }
 
+static inline void vma_assert_attached(struct vm_area_struct *vma)
+{
+	VM_BUG_ON_VMA(vma->detached, vma);
+}
+
+static inline void vma_assert_detached(struct vm_area_struct *vma)
+{
+	VM_BUG_ON_VMA(!vma->detached, vma);
+}
+
 static inline void vma_mark_attached(struct vm_area_struct *vma)
 {
 	vma->detached = false;
@@ -866,6 +876,8 @@ static inline void vma_end_read(struct vm_area_struct *vma) {}
 static inline void vma_start_write(struct vm_area_struct *vma) {}
 static inline void vma_assert_write_locked(struct vm_area_struct *vma)
 		{ mmap_assert_write_locked(vma->vm_mm); }
+static inline void vma_assert_attached(struct vm_area_struct *vma) {}
+static inline void vma_assert_detached(struct vm_area_struct *vma) {}
 static inline void vma_mark_attached(struct vm_area_struct *vma) {}
 static inline void vma_mark_detached(struct vm_area_struct *vma) {}
 
diff --git a/mm/nommu.c b/mm/nommu.c
index 9cb6e99215e2..72c8c505836c 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1191,7 +1191,7 @@ unsigned long do_mmap(struct file *file,
 	setup_vma_to_mm(vma, current->mm);
 	current->mm->map_count++;
 	/* add the VMA to the tree */
-	vma_iter_store(&vmi, vma);
+	vma_iter_store(&vmi, vma, true);
 
 	/* we flush the region from the icache only when the first executable
 	 * mapping of it is made  */
@@ -1356,7 +1356,7 @@ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
 
 	setup_vma_to_mm(vma, mm);
 	setup_vma_to_mm(new, mm);
-	vma_iter_store(vmi, new);
+	vma_iter_store(vmi, new, true);
 	mm->map_count++;
 	return 0;
 
diff --git a/mm/vma.c b/mm/vma.c
index 476146c25283..ce113dd8c471 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -306,7 +306,7 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi,
 		 * us to insert it before dropping the locks
 		 * (it may either follow vma or precede it).
 		 */
-		vma_iter_store(vmi, vp->insert);
+		vma_iter_store(vmi, vp->insert, true);
 		mm->map_count++;
 	}
 
@@ -660,14 +660,14 @@ static int commit_merge(struct vma_merge_struct *vmg,
 	vma_set_range(vmg->vma, vmg->start, vmg->end, vmg->pgoff);
 
 	if (expanded)
-		vma_iter_store(vmg->vmi, vmg->vma);
+		vma_iter_store(vmg->vmi, vmg->vma, false);
 
 	if (adj_start) {
 		adjust->vm_start += adj_start;
 		adjust->vm_pgoff += PHYS_PFN(adj_start);
 		if (adj_start < 0) {
 			WARN_ON(expanded);
-			vma_iter_store(vmg->vmi, adjust);
+			vma_iter_store(vmg->vmi, adjust, false);
 		}
 	}
 
@@ -1689,7 +1689,7 @@ int vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
 		return -ENOMEM;
 
 	vma_start_write(vma);
-	vma_iter_store(&vmi, vma);
+	vma_iter_store(&vmi, vma, true);
 	vma_link_file(vma);
 	mm->map_count++;
 	validate_mm(mm);
@@ -2368,7 +2368,7 @@ static int __mmap_new_vma(struct mmap_state *map, struct vm_area_struct **vmap)
 
 	/* Lock the VMA since it is modified after insertion into VMA tree */
 	vma_start_write(vma);
-	vma_iter_store(vmi, vma);
+	vma_iter_store(vmi, vma, true);
 	map->mm->map_count++;
 	vma_link_file(vma);
 
@@ -2542,7 +2542,7 @@ int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
 	vm_flags_init(vma, flags);
 	vma->vm_page_prot = vm_get_page_prot(flags);
 	vma_start_write(vma);
-	if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL))
+	if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL, true))
 		goto mas_store_fail;
 
 	mm->map_count++;
@@ -2785,7 +2785,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 				anon_vma_interval_tree_pre_update_vma(vma);
 				vma->vm_end = address;
 				/* Overwrite old entry in mtree. */
-				vma_iter_store(&vmi, vma);
+				vma_iter_store(&vmi, vma, false);
 				anon_vma_interval_tree_post_update_vma(vma);
 
 				perf_event_mmap(vma);
@@ -2865,7 +2865,7 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address)
 				vma->vm_start = address;
 				vma->vm_pgoff -= grow;
 				/* Overwrite old entry in mtree. */
-				vma_iter_store(&vmi, vma);
+				vma_iter_store(&vmi, vma, false);
 				anon_vma_interval_tree_post_update_vma(vma);
 
 				perf_event_mmap(vma);
diff --git a/mm/vma.h b/mm/vma.h
index 24636a2b0acf..18c9e49b1eae 100644
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -145,7 +145,7 @@ __must_check int vma_shrink(struct vma_iterator *vmi,
 		unsigned long start, unsigned long end, pgoff_t pgoff);
 
 static inline int vma_iter_store_gfp(struct vma_iterator *vmi,
-			struct vm_area_struct *vma, gfp_t gfp)
+			struct vm_area_struct *vma, gfp_t gfp, bool new_vma)
 
 {
 	if (vmi->mas.status != ma_start &&
@@ -157,7 +157,10 @@ static inline int vma_iter_store_gfp(struct vma_iterator *vmi,
 	if (unlikely(mas_is_err(&vmi->mas)))
 		return -ENOMEM;
 
-	vma_mark_attached(vma);
+	if (new_vma)
+		vma_mark_attached(vma);
+	vma_assert_attached(vma);
+
 	return 0;
 }
 
@@ -366,7 +369,7 @@ static inline struct vm_area_struct *vma_iter_load(struct vma_iterator *vmi)
 
 /* Store a VMA with preallocated memory */
 static inline void vma_iter_store(struct vma_iterator *vmi,
-				  struct vm_area_struct *vma)
+				  struct vm_area_struct *vma, bool new_vma)
 {
 
 #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
@@ -390,7 +393,9 @@ static inline void vma_iter_store(struct vma_iterator *vmi,
 
 	__mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1);
 	mas_store_prealloc(&vmi->mas, vma);
-	vma_mark_attached(vma);
+	if (new_vma)
+		vma_mark_attached(vma);
+	vma_assert_attached(vma);
 }
 
 static inline unsigned long vma_iter_addr(struct vma_iterator *vmi)
-- 
2.47.1.613.gc27f4b7a9f-goog