There are three places that the next vma is required which uses the same
block of code.  Replace the block with a function and add comments on what
happens in the case where NULL is encountered.
Signed-off-by: NLiam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200818154707.2515169-1-Liam.Howlett@Oracle.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>