mm/mmap: rework do_mas_munmap() and friends

Pull out alignmnet calculations for functions that have already aligned

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/mm/mmap.c b/mm/mmap.c
index 60aefcc3c4f3ea09d71287aa9b13f1d54cbce7ba..27aa6e9783de688778dae0b1ed4c96c8a90b2548 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2420,34 +2420,23 @@ static inline int unlock_range(struct vm_area_struct *start,
        return count;
 }
 
-/* Munmap is split into 2 main parts -- this part which finds
- * what needs doing, and the areas themselves, which do the
- * work.  This now handles partial unmappings.
- * Jeremy Fitzhardinge <jeremy@goop.org>
+/* do_mas_align_munmap() - munmap the aligned region from @start to @end.
+ *
+ * @mas: The maple_state, ideally set up to alter the correct tree location.
+ * @vma: The starting vm_area_struct
+ * @mm: The mm_struct
+ * @start: The aligned start address to munmap.
+ * @end: The aligned end address to munmap.
+ * @uf: The userfaultfd list_head
+ * @downgrade: Set to true to attempt a downwrite of the mmap_sem
+ *
+ *
  */
-int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
-                 unsigned long start, size_t len, struct list_head *uf,
-                 bool downgrade)
+int do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
+                       struct mm_struct *mm, unsigned long start,
+                       unsigned long end, struct list_head *uf, bool downgrade)
 {
-       unsigned long end;
-       struct vm_area_struct *vma, *prev, *last;
-
-       if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
-               return -EINVAL;
-
-       end = start + PAGE_ALIGN(len);
-       if (end == start)
-               return -EINVAL;
-
-        /* arch_unmap() might do unmaps itself.  */
-       arch_unmap(mm, start, end);
-
-       /* Find the first overlapping VMA */
-       vma = mas_find(mas, end - 1);
-       if (!vma)
-               return 0;
-
-       mas->last = end - 1;
+       struct vm_area_struct *prev, *last;
        /* we have start < vma->vm_end  */
 
        /*
@@ -2553,6 +2542,51 @@ int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
        return downgrade ? 1 : 0;
 }
 
+/*
+ * do_mas_munmap() - munmap a given range.
+ * @mas: The maple state
+ * @mm: The mm_struct
+ * @start: The start address to munmap
+ * @len: The length of the range to munmap
+ * @uf: The userfaultfd list_head
+ * @downgrade: set to true if the user wants to attempt to write_downgrade the
+ * mmap_sem
+ *
+ * This function takes a @mas that is in the correct state to remove the
+ * mapping(s).  The @len will be aligned and any arch_unmap work will be
+ * preformed.
+ */
+int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
+                 unsigned long start, size_t len, struct list_head *uf,
+                 bool downgrade)
+{
+       unsigned long end;
+       struct vm_area_struct *vma;
+
+       if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
+               return -EINVAL;
+
+       end = start + PAGE_ALIGN(len);
+       if (end == start)
+               return -EINVAL;
+
+        /* arch_unmap() might do unmaps itself.  */
+       arch_unmap(mm, start, end);
+
+       /* Find the first overlapping VMA */
+       vma = mas_find(mas, end - 1);
+       if (!vma)
+               return 0;
+
+       mas->last = end - 1;
+       return do_mas_align_munmap(mas, vma, mm, start, end, uf, downgrade);
+}
+/* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls.
+ * @mm: The mm_struct
+ * @start: The start address to munmap
+ * @len: The length to be munmapped.
+ * @uf: The userfaultfd list_head
+ */
 int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
              struct list_head *uf)
 {