khugepaged: use helper function range_in_vma() in collapse_pte_mapped_thp()

Patch series "Cleanup for khugepaged".

This series contains cleanups to remove unnecessary out label and
meaningless !pte_present() check.  Also use helper function to simplify
the code.  More details can be found in the respective changelogs.

This patch (of 3):

We could use helper function range_in_vma() to check whether the desired
range is inside the vma to simplify the code.

Link: https://lkml.kernel.org/r/20210325135647.64106-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210325135647.64106-2-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/khugepaged.c

@@ -1446,7 +1446,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
 	int i;
 
 	if (!vma || !vma->vm_file ||
-	    vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE)
+	    !range_in_vma(vma, haddr, haddr + HPAGE_PMD_SIZE))
 		return;
 
 	/*