There are two locations that have a block of code for munmapping a vma
range. Change those two locations to use a function and add meaningful
comments about what happens to the arguments, which was unclear in the
previous code.
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
mm/mmap.c | 48 +++++++++++++++++++++++++++++++++---------------
1 file changed, 33 insertions(+), 15 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 6026353035966..b59b4e5889b5c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -577,6 +577,33 @@ static inline struct vm_area_struct *vma_next(struct mm_struct *mm,
return vma->vm_next;
}
+
+/*
+ * munmap_vma_range() - munmap VMAs that overlap a range.
+ * @mm: The mm struct
+ * @start: The start of the range.
+ * @len: The length of the range.
+ * @pprev: pointer to the pointer that will be set to previous vm_area_struct
+ * @rb_link: the rb_node
+ * @rb_parent: the parent rb_node
+ *
+ * Find all the vm_area_struct that overlap from @start to
+ * @end and munmap them. Set @pprev to the previous vm_area_struct.
+ *
+ * Returns: -ENOMEM on munmap failure or 0 on success.
+ */
+static inline int
+munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
+ struct vm_area_struct **pprev, struct rb_node ***link,
+ struct rb_node **parent, struct list_head *uf)
+{
+
+ while (find_vma_links(mm, start, start + len, pprev, link, parent))
+ if (do_munmap(mm, start, len, uf))
+ return -ENOMEM;
+
+ return 0;
+}
static unsigned long count_vma_pages_range(struct mm_struct *mm,
unsigned long addr, unsigned long end)
{
@@ -1724,13 +1751,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
return -ENOMEM;
}
- /* Clear old maps */
- while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
- &rb_parent)) {
- if (do_munmap(mm, addr, len, uf))
- return -ENOMEM;
- }
-
+ /* Clear old maps, set up prev, rb_link, rb_parent, and uf */
+ if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
+ return -ENOMEM;
/*
* Private writable mapping: check memory availability
*/
@@ -3056,14 +3079,9 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
if (error)
return error;
- /*
- * Clear old maps. this also does some error checking for us
- */
- while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
- &rb_parent)) {
- if (do_munmap(mm, addr, len, uf))
- return -ENOMEM;
- }
+ /* Clear old maps, set up prev, rb_link, rb_parent, and uf */
+ if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
+ return -ENOMEM;
/* Check against address space limits *after* clearing old maps... */
if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))
--
2.28.0
