slub: Remove static kmem_cache_cpu array for boot

The percpu allocator can now handle allocations during early boot.
So drop the static kmem_cache_cpu array.

Cc: Tejun Heo <tj@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

mm/slub.c

@@ -2062,23 +2062,14 @@ init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
 #endif
 }
 
-static DEFINE_PER_CPU(struct kmem_cache_cpu, kmalloc_percpu[KMALLOC_CACHES]);
-
 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
 {
-	if (s < kmalloc_caches + KMALLOC_CACHES && s >= kmalloc_caches)
-		/*
-		 * Boot time creation of the kmalloc array. Use static per cpu data
-		 * since the per cpu allocator is not available yet.
-		 */
-		s->cpu_slab = kmalloc_percpu + (s - kmalloc_caches);
-	else
-		s->cpu_slab =  alloc_percpu(struct kmem_cache_cpu);
+	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
+			SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
 
-	if (!s->cpu_slab)
-		return 0;
+	s->cpu_slab = alloc_percpu(struct kmem_cache_cpu);
 
-	return 1;
+	return s->cpu_slab != NULL;
 }
 
 #ifdef CONFIG_NUMA