There are two duplicate code to handle the case when there is no available
swap entry.  To avoid this, we can compare tmp and max first and let the
second guard do its job.

No functional change is expected.
Signed-off-by: NWei Yang <richard.weiyang@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: N"Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200421213824.8099-3-richard.weiyang@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>