Using vma_lookup() verifies the start address is contained in the found
vma.  This results in easier to read the code.

Link: https://lkml.kernel.org/r/20221007030345.5029-1-wangdeming@inspur.comSigned-off-by: NDeming Wang <wangdeming@inspur.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>