mm/sl[aou]b: Extract a common function for kmem_cache_destroy

kmem_cache_destroy does basically the same in all allocators.

Extract common code which is easy since we already have common mutex
handling.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

5 files changed, 49 insertions, 75 deletions

diff --git a/mm/slab.c b/mm/slab.c
index a69903168497..49a74b349e39 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2206,7 +2206,7 @@ static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
         }
 }
 
-static void __kmem_cache_destroy(struct kmem_cache *cachep)
+void __kmem_cache_destroy(struct kmem_cache *cachep)
 {
         int i;
         struct kmem_list3 *l3;
@@ -2763,49 +2763,10 @@ int kmem_cache_shrink(struct kmem_cache *cachep)
 }
 EXPORT_SYMBOL(kmem_cache_shrink);
 
-/**
- * kmem_cache_destroy - delete a cache
- * @cachep: the cache to destroy
- *
- * Remove a &struct kmem_cache object from the slab cache.
- *
- * It is expected this function will be called by a module when it is
- * unloaded.  This will remove the cache completely, and avoid a duplicate
- * cache being allocated each time a module is loaded and unloaded, if the
- * module doesn't have persistent in-kernel storage across loads and unloads.
- *
- * The cache must be empty before calling this function.
- *
- * The caller must guarantee that no one will allocate memory from the cache
- * during the kmem_cache_destroy().
- */
-void kmem_cache_destroy(struct kmem_cache *cachep)
+int __kmem_cache_shutdown(struct kmem_cache *cachep)
 {
-        BUG_ON(!cachep || in_interrupt());
-
-        /* Find the cache in the chain of caches. */
-        get_online_cpus();
-        mutex_lock(&slab_mutex);
-        /*
-         * the chain is never empty, cache_cache is never destroyed
-         */
-        list_del(&cachep->list);
-        if (__cache_shrink(cachep)) {
-                slab_error(cachep, "Can't free all objects");
-                list_add(&cachep->list, &slab_caches);
-                mutex_unlock(&slab_mutex);
-                put_online_cpus();
-                return;
-        }
-
-        if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
-                rcu_barrier();
-
-        __kmem_cache_destroy(cachep);
-        mutex_unlock(&slab_mutex);
-        put_online_cpus();
+        return __cache_shrink(cachep);
 }
-EXPORT_SYMBOL(kmem_cache_destroy);
 
 /*
  * Get the memory for a slab management obj.
diff --git a/mm/slab.h b/mm/slab.h
index db7848caaa25..07a537ed5da3 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -30,4 +30,7 @@ extern struct list_head slab_caches;
 struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
         size_t align, unsigned long flags, void (*ctor)(void *));
 
+int __kmem_cache_shutdown(struct kmem_cache *);
+void __kmem_cache_destroy(struct kmem_cache *);
+
 #endif
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 5190a7cd02bd..a1c4f0b5aaed 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -140,6 +140,31 @@ out_locked:
 }
 EXPORT_SYMBOL(kmem_cache_create);
 
+void kmem_cache_destroy(struct kmem_cache *s)
+{
+        get_online_cpus();
+        mutex_lock(&slab_mutex);
+        s->refcount--;
+        if (!s->refcount) {
+                list_del(&s->list);
+
+                if (!__kmem_cache_shutdown(s)) {
+                        if (s->flags & SLAB_DESTROY_BY_RCU)
+                                rcu_barrier();
+
+                        __kmem_cache_destroy(s);
+                } else {
+                        list_add(&s->list, &slab_caches);
+                        printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",
+                                s->name);
+                        dump_stack();
+                }
+        }
+        mutex_unlock(&slab_mutex);
+        put_online_cpus();
+}
+EXPORT_SYMBOL(kmem_cache_destroy);
+
 int slab_is_available(void)
 {
         return slab_state >= UP;
diff --git a/mm/slob.c b/mm/slob.c
index 5225d28f2694..289be4f4681a 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -538,18 +538,11 @@ struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
         return c;
 }
 
-void kmem_cache_destroy(struct kmem_cache *c)
+void __kmem_cache_destroy(struct kmem_cache *c)
 {
-        mutex_lock(&slab_mutex);
-        list_del(&c->list);
-        mutex_unlock(&slab_mutex);
-
         kmemleak_free(c);
-        if (c->flags & SLAB_DESTROY_BY_RCU)
-                rcu_barrier();
         slob_free(c, sizeof(struct kmem_cache));
 }
-EXPORT_SYMBOL(kmem_cache_destroy);
 
 void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
 {
@@ -617,6 +610,12 @@ unsigned int kmem_cache_size(struct kmem_cache *c)
 }
 EXPORT_SYMBOL(kmem_cache_size);
 
+int __kmem_cache_shutdown(struct kmem_cache *c)
+{
+        /* No way to check for remaining objects */
+        return 0;
+}
+
 int kmem_cache_shrink(struct kmem_cache *d)
 {
         return 0;
diff --git a/mm/slub.c b/mm/slub.c
index 24aa362edef7..724adea34384 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -624,7 +624,7 @@ static void object_err(struct kmem_cache *s, struct page *page,
         print_trailer(s, page, object);
 }
 
-static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
+static void slab_err(struct kmem_cache *s, struct page *page, const char *fmt, ...)
 {
         va_list args;
         char buf[100];
@@ -3146,7 +3146,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
                                      sizeof(long), GFP_ATOMIC);
         if (!map)
                 return;
-        slab_err(s, page, "%s", text);
+        slab_err(s, page, text, s->name);
         slab_lock(page);
 
         get_map(s, page, map);
@@ -3178,7 +3178,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
                         discard_slab(s, page);
                 } else {
                         list_slab_objects(s, page,
-                                "Objects remaining on kmem_cache_close()");
+                        "Objects remaining in %s on kmem_cache_close()");
                 }
         }
 }
@@ -3191,7 +3191,6 @@ static inline int kmem_cache_close(struct kmem_cache *s)
         int node;
 
         flush_all(s);
-        free_percpu(s->cpu_slab);
         /* Attempt to free all objects */
         for_each_node_state(node, N_NORMAL_MEMORY) {
                 struct kmem_cache_node *n = get_node(s, node);
@@ -3200,33 +3199,20 @@ static inline int kmem_cache_close(struct kmem_cache *s)
                 if (n->nr_partial || slabs_node(s, node))
                         return 1;
         }
+        free_percpu(s->cpu_slab);
         free_kmem_cache_nodes(s);
         return 0;
 }
 
-/*
- * Close a cache and release the kmem_cache structure
- * (must be used for caches created using kmem_cache_create)
- */
-void kmem_cache_destroy(struct kmem_cache *s)
+int __kmem_cache_shutdown(struct kmem_cache *s)
 {
-        mutex_lock(&slab_mutex);
-        s->refcount--;
-        if (!s->refcount) {
-                list_del(&s->list);
-                mutex_unlock(&slab_mutex);
-                if (kmem_cache_close(s)) {
-                        printk(KERN_ERR "SLUB %s: %s called for cache that "
-                                "still has objects.\n", s->name, __func__);
-                        dump_stack();
-                }
-                if (s->flags & SLAB_DESTROY_BY_RCU)
-                        rcu_barrier();
-                sysfs_slab_remove(s);
-        } else
-                mutex_unlock(&slab_mutex);
+        return kmem_cache_close(s);
+}
+
+void __kmem_cache_destroy(struct kmem_cache *s)
+{
+        sysfs_slab_remove(s);
 }
-EXPORT_SYMBOL(kmem_cache_destroy);
 
 /********************************************************************
  *              Kmalloc subsystem