[merged mm-stable] mm-mmap-use-the-maple-tree-for-find_vma_prev-instead-of-the-rbtree.patch removed from -mm tree

[merged mm-stable] mm-mmap-use-the-maple-tree-for-find_vma_prev-instead-of-the-rbtree.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/mmap: use the maple tree for find_vma_prev() instead of the rbtree
has been removed from the -mm tree.  Its filename was
     mm-mmap-use-the-maple-tree-for-find_vma_prev-instead-of-the-rbtree.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
Subject: mm/mmap: use the maple tree for find_vma_prev() instead of the rbtree
Date: Tue, 6 Sep 2022 19:48:47 +0000

Use the maple tree's advanced API and a maple state to walk the tree for
the entry at the address of the next vma, then use the maple state to walk
back one entry to find the previous entry.

Add kernel documentation comments for this API.

Link: https://lkml.kernel.org/r/20220906194824.2110408-13-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mmap.c |   27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

--- a/mm/mmap.c~mm-mmap-use-the-maple-tree-for-find_vma_prev-instead-of-the-rbtree
+++ a/mm/mmap.c
@@ -2475,23 +2475,30 @@ struct vm_area_struct *find_vma(struct m
 }
 EXPORT_SYMBOL(find_vma);
 
-/*
- * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
+/**
+ * find_vma_prev() - Find the VMA for a given address, or the next vma and
+ * set %pprev to the previous VMA, if any.
+ * @mm: The mm_struct to check
+ * @addr: The address
+ * @pprev: The pointer to set to the previous VMA
+ *
+ * Note that RCU lock is missing here since the external mmap_lock() is used
+ * instead.
+ *
+ * Returns: The VMA associated with @addr, or the next vma.
+ * May return %NULL in the case of no vma at addr or above.
  */
 struct vm_area_struct *
 find_vma_prev(struct mm_struct *mm, unsigned long addr,
 			struct vm_area_struct **pprev)
 {
 	struct vm_area_struct *vma;
+	MA_STATE(mas, &mm->mm_mt, addr, addr);
 
-	vma = find_vma(mm, addr);
-	if (vma) {
-		*pprev = vma->vm_prev;
-	} else {
-		struct rb_node *rb_node = rb_last(&mm->mm_rb);
-
-		*pprev = rb_node ? rb_entry(rb_node, struct vm_area_struct, vm_rb) : NULL;
-	}
+	vma = mas_walk(&mas);
+	*pprev = mas_prev(&mas, 0);
+	if (!vma)
+		vma = mas_next(&mas, ULONG_MAX);
 	return vma;
 }
 
_

Patches currently in -mm which might be from Liam.Howlett@Oracle.com are