From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
Subject: mm: optimize find_exact_vma() to use vma_lookup()

Use vma_lookup() to walk the tree to the start value requested.  If the
vma at the start does not match, then the answer is NULL and there is no
need to look at the next vma the way that find_vma() would.

Link: https://lkml.kernel.org/r/20220426150616.3937571-22-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mm.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/mm.h~mm-optimize-find_exact_vma-to-use-vma_lookup
+++ a/include/linux/mm.h
@@ -2854,7 +2854,7 @@ static inline unsigned long vma_pages(st
 static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
 				unsigned long vm_start, unsigned long vm_end)
 {
-	struct vm_area_struct *vma = find_vma(mm, vm_start);
+	struct vm_area_struct *vma = vma_lookup(mm, vm_start);
 
 	if (vma && (vma->vm_start != vm_start || vma->vm_end != vm_end))
 		vma = NULL;
_