mm: unify checks in alloc_pages_node() and __alloc_pages_node()

mm: unify checks in alloc_pages_node() and __alloc_pages_node()

Perform the same debug checks in alloc_pages_node() as are done in
__alloc_pages_node(), by making the former function a wrapper of the
latter one.

In addition to better diagnostics in DEBUG_VM builds for situations
which have been already fatal (e.g.  out-of-bounds node id), there are
two visible changes for potential existing buggy callers of
alloc_pages_node():

- calling alloc_pages_node() with any negative nid (e.g. due to arithmetic
  overflow) was treated as passing NUMA_NO_NODE and fallback to local node was
  applied. This will now be fatal.
- calling alloc_pages_node() with an offline node will now be checked for
  DEBUG_VM builds. Since it's not fatal if the node has been previously online,
  and this patch may expose some existing buggy callers, change the VM_BUG_ON
  in __alloc_pages_node() to VM_WARN_ON.

Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: David Rientjes <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Christoph Lameter <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>