From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Tue, 1 Dec 2020 02:28:44 +0000 (-0500)
Subject: mm/mmap: rework do_mas_munmap() and friends
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0c52c044d10ae3b2442aa35aeebe5f7f12abe404;p=users%2Fjedix%2Flinux-maple.git

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 60aefcc3c4f3..27aa6e9783de 100644
--- 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)
 {