[PATCH v12 20/69] mm: optimize find_exact_vma() to use vma_lookup()

[Liam Howlett]

From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>

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/20220504011345.662299-5-Liam.Howlett@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20220621204632.3370049-21-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
 include/linux/mm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 051b503c3fdb..8207fbc6ed87 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2864,7 +2864,7 @@ static inline unsigned long vma_pages(struct vm_area_struct *vma)
 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;
-- 
2.35.1