mm: introduce node_zonelist() for accessing the zonelist for a GFP mask

Introduce a node_zonelist() helper function.  It is used to lookup the
appropriate zonelist given a node and a GFP mask.  The patch on its own is a
cleanup but it helps clarify parts of the two-zonelist-per-node patchset.  If
necessary, it can be merged with the next patch in this set without problems.

Reviewed-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 3c3601121509..5d20bf44062f 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1183,7 +1183,7 @@ static struct zonelist *zonelist_policy(gfp_t gfp, struct mempolicy *policy)
                 nd = 0;
                 BUG();
         }
-        return NODE_DATA(nd)->node_zonelists + gfp_zone(gfp);
+        return node_zonelist(nd, gfp);
 }
 
 /* Do dynamic interleaving for a process */
@@ -1299,7 +1299,7 @@ struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
                 if (unlikely(pol != &default_policy &&
                                 pol != current->mempolicy))
                         __mpol_free(pol);       /* finished with pol */
-                return NODE_DATA(nid)->node_zonelists + gfp_zone(gfp_flags);
+                return node_zonelist(nid, gfp_flags);
         }
 
         zl = zonelist_policy(GFP_HIGHUSER, pol);
@@ -1321,7 +1321,7 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
         struct zonelist *zl;
         struct page *page;
 
-        zl = NODE_DATA(nid)->node_zonelists + gfp_zone(gfp);
+        zl = node_zonelist(nid, gfp);
         page = __alloc_pages(gfp, order, zl);
         if (page && page_zone(page) == zl->zones[0])
                 inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);