[PATCH v8 04/16] mm: introduce vma_iter_store_attached() to use with attached vmas

[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. Introduce
vma_iter_store_attached() to be used with already attached vmas.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/mm.h | 12 ++++++++++++
 mm/vma.c           |  8 ++++----
 mm/vma.h           | 11 +++++++++--
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index a9d8dd5745f7..e0d403c1ff63 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/vma.c b/mm/vma.c
index d603494e69d7..b9cf552e120c 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -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_attached(vmg->vmi, vmg->vma);
 
 	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_attached(vmg->vmi, adjust);
 		}
 	}
 
@@ -2845,7 +2845,7 @@ 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_attached(&vmi, vma);
 				anon_vma_interval_tree_post_update_vma(vma);
 
 				perf_event_mmap(vma);
@@ -2925,7 +2925,7 @@ 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_attached(&vmi, vma);
 				anon_vma_interval_tree_post_update_vma(vma);
 
 				perf_event_mmap(vma);
diff --git a/mm/vma.h b/mm/vma.h
index 2a2668de8d2c..63dd38d5230c 100644
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -365,9 +365,10 @@ 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)
+static inline void vma_iter_store_attached(struct vma_iterator *vmi,
+					   struct vm_area_struct *vma)
 {
+	vma_assert_attached(vma);
 
 #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
 	if (MAS_WARN_ON(&vmi->mas, vmi->mas.status != ma_start &&
@@ -390,7 +391,13 @@ 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);
+}
+
+static inline void vma_iter_store(struct vma_iterator *vmi,
+				  struct vm_area_struct *vma)
+{
 	vma_mark_attached(vma);
+	vma_iter_store_attached(vmi, vma);
 }
 
 static inline unsigned long vma_iter_addr(struct vma_iterator *vmi)
-- 
2.47.1.613.gc27f4b7a9f-goog