diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 284153d3e0fc..678b2882faaa 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3855,6 +3855,60 @@ got_pg:
 	return page;
 }
 
+static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
+		struct zonelist *zonelist, nodemask_t *nodemask,
+		struct alloc_context *ac, gfp_t *alloc_mask,
+		unsigned int *alloc_flags)
+{
+	ac->high_zoneidx = gfp_zone(gfp_mask);
+	ac->zonelist = zonelist;
+	ac->nodemask = nodemask;
+	ac->migratetype = gfpflags_to_migratetype(gfp_mask);
+
+	if (cpusets_enabled()) {
+		*alloc_mask |= __GFP_HARDWALL;
+		*alloc_flags |= ALLOC_CPUSET;
+		if (!ac->nodemask)
+			ac->nodemask = &cpuset_current_mems_allowed;
+	}
+
+	lockdep_trace_alloc(gfp_mask);
+
+	might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
+
+	if (should_fail_alloc_page(gfp_mask, order))
+		return false;
+
+	/*
+	 * Check the zones suitable for the gfp_mask contain at least one
+	 * valid zone. It's possible to have an empty zonelist as a result
+	 * of __GFP_THISNODE and a memoryless node
+	 */
+	if (unlikely(!ac->zonelist->_zonerefs->zone))
+		return false;
+
+	if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE)
+		*alloc_flags |= ALLOC_CMA;
+
+	return true;
+}
+
+/* Determine whether to spread dirty pages and what the first usable zone */
+static inline void finalise_ac(gfp_t gfp_mask,
+		unsigned int order, struct alloc_context *ac)
+{
+	/* Dirty zone balancing only done in the fast path */
+	ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
+
+	/*
+	 * The preferred zone is used for statistics but crucially it is
+	 * also used as the starting point for the zonelist iterator. It
+	 * may get reset for allocations that ignore memory policies.
+	 */
+	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
+					ac->high_zoneidx, ac->nodemask);
+}
+
 /*
  * This is the 'heart' of the zoned buddy allocator.
  */
@@ -3865,50 +3919,13 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 	struct page *page;
 	unsigned int alloc_flags = ALLOC_WMARK_LOW;
 	gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */
-	struct alloc_context ac = {
-		.high_zoneidx = gfp_zone(gfp_mask),
-		.zonelist = zonelist,
-		.nodemask = nodemask,
-		.migratetype = gfpflags_to_migratetype(gfp_mask),
-	};
-
-	if (cpusets_enabled()) {
-		alloc_mask |= __GFP_HARDWALL;
-		alloc_flags |= ALLOC_CPUSET;
-		if (!ac.nodemask)
-			ac.nodemask = &cpuset_current_mems_allowed;
-	}
+	struct alloc_context ac = { };
 
 	gfp_mask &= gfp_allowed_mask;
-
-	lockdep_trace_alloc(gfp_mask);
-
-	might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
-
-	if (should_fail_alloc_page(gfp_mask, order))
+	if (!prepare_alloc_pages(gfp_mask, order, zonelist, nodemask, &ac, &alloc_mask, &alloc_flags))
 		return NULL;
 
-	/*
-	 * Check the zones suitable for the gfp_mask contain at least one
-	 * valid zone. It's possible to have an empty zonelist as a result
-	 * of __GFP_THISNODE and a memoryless node
-	 */
-	if (unlikely(!zonelist->_zonerefs->zone))
-		return NULL;
-
-	if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE)
-		alloc_flags |= ALLOC_CMA;
-
-	/* Dirty zone balancing only done in the fast path */
-	ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE);
-
-	/*
-	 * The preferred zone is used for statistics but crucially it is
-	 * also used as the starting point for the zonelist iterator. It
-	 * may get reset for allocations that ignore memory policies.
-	 */
-	ac.preferred_zoneref = first_zones_zonelist(ac.zonelist,
-					ac.high_zoneidx, ac.nodemask);
+	finalise_ac(gfp_mask, order, &ac);
 	if (!ac.preferred_zoneref->zone) {
 		page = NULL;
 		/*