mm/khugepaged: optimize collapse_pte_mapped_thp() by using vma_lookup()

vma_lookup() will walk the vma tree once and not continue to look for the
next vma.  Since the exact vma is checked below, this is a more optimal
way of searching.

Link: https://lkml.kernel.org/r/20220906194824.2110408-22-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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/khugepaged.c

@@ -1389,7 +1389,7 @@ static void collapse_and_free_pmd(struct mm_struct *mm, struct vm_area_struct *v
 void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
 {
 	unsigned long haddr = addr & HPAGE_PMD_MASK;
-	struct vm_area_struct *vma = find_vma(mm, haddr);
+	struct vm_area_struct *vma = vma_lookup(mm, haddr);
 	struct page *hpage;
 	pte_t *start_pte, *pte;
 	pmd_t *pmd;