diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 4eb60cf5ff8ba618da8c0588e7950bc060c23cb0..267dfde43b91366e392014d448594bfe8483b7ba 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -427,10 +427,11 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
 	/* Set required slab fields. */
 	slab = virt_to_slab((void *)meta->addr);
 	slab->slab_cache = cache;
-	if (IS_ENABLED(CONFIG_SLUB))
-		slab->objects = 1;
-	if (IS_ENABLED(CONFIG_SLAB))
-		slab->s_mem = addr;
+#if defined(CONFIG_SLUB)
+	slab->objects = 1;
+#elif defined(CONFIG_SLAB)
+	slab->s_mem = addr;
+#endif
 
 	/* Memory initialization. */
 	for_each_canary(meta, set_canary_byte);
diff --git a/mm/slab.h b/mm/slab.h
index b8d7ed42cca894256cd1bdd39dc88e5a3728e95a..ad15f624a6b5bcd871c2420b7a63a1265322d44b 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -8,9 +8,24 @@
 /* Reuses the bits in struct page */
 struct slab {
 	unsigned long __page_flags;
+
+#if defined(CONFIG_SLAB)
+
 	union {
 		struct list_head slab_list;
-		struct {	/* Partial pages */
+		struct rcu_head rcu_head;
+	};
+	struct kmem_cache *slab_cache;
+	void *freelist;	/* array of free object indexes */
+	void *s_mem;	/* first object */
+	unsigned int active;
+
+#elif defined(CONFIG_SLUB)
+
+	union {
+		struct list_head slab_list;
+		struct rcu_head rcu_head;
+		struct {
 			struct slab *next;
 #ifdef CONFIG_64BIT
 			int slabs;	/* Nr of slabs left */
@@ -18,25 +33,32 @@ struct slab {
 			short int slabs;
 #endif
 		};
-		struct rcu_head rcu_head;
 	};
-	struct kmem_cache *slab_cache; /* not slob */
+	struct kmem_cache *slab_cache;
 	/* Double-word boundary */
 	void *freelist;		/* first free object */
 	union {
-		void *s_mem;	/* slab: first object */
-		unsigned long counters;		/* SLUB */
-		struct {			/* SLUB */
+		unsigned long counters;
+		struct {
 			unsigned inuse:16;
 			unsigned objects:15;
 			unsigned frozen:1;
 		};
 	};
+	unsigned int __unused;
+
+#elif defined(CONFIG_SLOB)
+
+	struct list_head slab_list;
+	void *__unused_1;
+	void *freelist;		/* first free block */
+	void *__unused_2;
+	int units;
+
+#else
+#error "Unexpected slab allocator configured"
+#endif
 
-	union {
-		unsigned int active;		/* SLAB */
-		int units;			/* SLOB */
-	};
 	atomic_t __page_refcount;
 #ifdef CONFIG_MEMCG
 	unsigned long memcg_data;
@@ -48,10 +70,14 @@ struct slab {
 SLAB_MATCH(flags, __page_flags);
 SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
 SLAB_MATCH(slab_list, slab_list);
+#ifndef CONFIG_SLOB
 SLAB_MATCH(rcu_head, rcu_head);
 SLAB_MATCH(slab_cache, slab_cache);
+#endif
+#ifdef CONFIG_SLAB
 SLAB_MATCH(s_mem, s_mem);
 SLAB_MATCH(active, active);
+#endif
 SLAB_MATCH(_refcount, __page_refcount);
 #ifdef CONFIG_MEMCG
 SLAB_MATCH(memcg_data, memcg_data);
@@ -599,6 +625,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s,
 }
 #endif /* CONFIG_MEMCG_KMEM */
 
+#ifndef CONFIG_SLOB
 static inline struct kmem_cache *virt_to_cache(const void *obj)
 {
 	struct slab *slab;
@@ -645,6 +672,7 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 		print_tracking(cachep, x);
 	return cachep;
 }
+#endif /* CONFIG_SLOB */
 
 static inline size_t slab_ksize(const struct kmem_cache *s)
 {