[PATCH v4 06/21] mm/vma: remove superfluous map->hold_file_rmap_lock

[Lorenzo Stoakes (Oracle)]

We don't need to reference this field, it's confusing as it duplicates
mmap_action->hide_from_rmap_until_complete, so thread the mmap_action
through to __mmap_new_vma() instead and use the same field consistently.

Signed-off-by: Lorenzo Stoakes (Oracle) <ljs at kernel.org>
---
 mm/vma.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/mm/vma.c b/mm/vma.c
index 3fc5fe4f1a7c..6105f54cea61 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -38,8 +38,6 @@ struct mmap_state {
 
 	/* Determine if we can check KSM flags early in mmap() logic. */
 	bool check_ksm_early :1;
-	/* If we map new, hold the file rmap lock on mapping. */
-	bool hold_file_rmap_lock :1;
 	/* If .mmap_prepare changed the file, we don't need to pin. */
 	bool file_doesnt_need_get :1;
 };
@@ -2531,10 +2529,12 @@ static int __mmap_new_file_vma(struct mmap_state *map,
  *
  * @map:  Mapping state.
  * @vmap: Output pointer for the new VMA.
+ * @action: Any mmap_prepare action that is still to complete.
  *
  * Returns: Zero on success, or an error.
  */
-static int __mmap_new_vma(struct mmap_state *map, struct vm_area_struct **vmap)
+static int __mmap_new_vma(struct mmap_state *map, struct vm_area_struct **vmap,
+	struct mmap_action *action)
 {
 	struct vma_iterator *vmi = map->vmi;
 	int error = 0;
@@ -2583,7 +2583,7 @@ static int __mmap_new_vma(struct mmap_state *map, struct vm_area_struct **vmap)
 	vma_start_write(vma);
 	vma_iter_store_new(vmi, vma);
 	map->mm->map_count++;
-	vma_link_file(vma, map->hold_file_rmap_lock);
+	vma_link_file(vma, action->hide_from_rmap_until_complete);
 
 	/*
 	 * vma_merge_new_range() calls khugepaged_enter_vma() too, the below
@@ -2650,8 +2650,6 @@ static int call_action_prepare(struct mmap_state *map,
 	if (err)
 		return err;
 
-	if (desc->action.hide_from_rmap_until_complete)
-		map->hold_file_rmap_lock = true;
 	return 0;
 }
 
@@ -2741,7 +2739,7 @@ static int call_action_complete(struct mmap_state *map,
 	err = mmap_action_complete(vma, action);
 
 	/* If we held the file rmap we need to release it. */
-	if (map->hold_file_rmap_lock) {
+	if (action->hide_from_rmap_until_complete) {
 		struct file *file = vma->vm_file;
 
 		i_mmap_unlock_write(file->f_mapping);
@@ -2795,7 +2793,7 @@ static unsigned long __mmap_region(struct file *file, unsigned long addr,
 
 	/* ...but if we can't, allocate a new VMA. */
 	if (!vma) {
-		error = __mmap_new_vma(&map, &vma);
+		error = __mmap_new_vma(&map, &vma, &desc.action);
 		if (error)
 			goto unacct_error;
 		allocated_new = true;
-- 
2.53.0