[RFC PATCH 3/6] mm/vma: Add limits to unmap_region() for vmas

[Liam R. Howlett]

Add a limit to the vma search instead of using the start and end of the
one passed in.

No functional changes intended.

Signed-off-by: Liam R. Howlett <Liam.Howlett at oracle.com>
---
 mm/vma.c | 6 ++++--
 mm/vma.h | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/vma.c b/mm/vma.c
index 3b12c7579831b..fd270345c25d3 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -474,6 +474,7 @@ void remove_vma(struct vm_area_struct *vma)
  * Called with the mm semaphore held.
  */
 void unmap_region(struct ma_state *mas, struct vm_area_struct *vma,
+		unsigned long vma_min, unsigned long vma_max,
 		struct vm_area_struct *prev, struct vm_area_struct *next)
 {
 	struct mm_struct *mm = vma->vm_mm;
@@ -481,7 +482,7 @@ void unmap_region(struct ma_state *mas, struct vm_area_struct *vma,
 
 	tlb_gather_mmu(&tlb, mm);
 	update_hiwater_rss(mm);
-	unmap_vmas(&tlb, mas, vma, vma->vm_start, vma->vm_end, vma->vm_end,
+	unmap_vmas(&tlb, mas, vma, vma_min, vma_max, vma_max,
 		   /* mm_wr_locked = */ true);
 	mas_set(mas, vma->vm_end);
 	free_pgtables(&tlb, mas, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
@@ -2417,7 +2418,8 @@ static int __mmap_new_file_vma(struct mmap_state *map,
 
 		vma_iter_set(vmi, vma->vm_end);
 		/* Undo any partial mapping done by a device driver. */
-		unmap_region(&vmi->mas, vma, map->prev, map->next);
+		unmap_region(&vmi->mas, vma, vma->vm_start, vma->vm_end,
+			     map->prev, map->next);
 
 		return error;
 	}
diff --git a/mm/vma.h b/mm/vma.h
index b123a9cdedb0d..336dae295853e 100644
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -281,6 +281,7 @@ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
 void remove_vma(struct vm_area_struct *vma);
 
 void unmap_region(struct ma_state *mas, struct vm_area_struct *vma,
+		unsigned long min, unsigned long max,
 		struct vm_area_struct *prev, struct vm_area_struct *next);
 
 /* We are about to modify the VMA's flags. */
-- 
2.47.2