mm/sl[aou]b: Move duping of slab name to slab_common.c

Duping of the slabname has to be done by each slab. Moving this code to
slab_common avoids duplicate implementations.

With this patch we have common string handling for all slab allocators.
Strings passed to kmem_cache_create() are copied internally. Subsystems
can create temporary strings to create slab caches.

Slabs allocated in early states of bootstrap will never be freed (and
those can never be freed since they are essential to slab allocator
operations).  During bootstrap we therefore do not have to worry about
duping names.

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

1 files changed, 21 insertions, 9 deletions

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 7df814e8fbea..f18c06fd97c7 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -100,6 +100,7 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align
 {
         struct kmem_cache *s = NULL;
         int err = 0;
+        char *n;
 
         get_online_cpus();
         mutex_lock(&slab_mutex);
@@ -108,16 +109,26 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align
                 goto out_locked;
 
 
-        s = __kmem_cache_create(name, size, align, flags, ctor);
-        if (!s)
-                err = -ENOSYS; /* Until __kmem_cache_create returns code */
+        n = kstrdup(name, GFP_KERNEL);
+        if (!n) {
+                err = -ENOMEM;
+                goto out_locked;
+        }
+
+        s = __kmem_cache_create(n, size, align, flags, ctor);
+
+        if (s) {
+                /*
+                 * Check if the slab has actually been created and if it was a
+                 * real instatiation. Aliases do not belong on the list
+                 */
+                if (s->refcount == 1)
+                        list_add(&s->list, &slab_caches);
 
-        /*
-         * Check if the slab has actually been created and if it was a
-         * real instatiation. Aliases do not belong on the list
-         */
-        if (s && s->refcount == 1)
-                list_add(&s->list, &slab_caches);
+        } else {
+                kfree(n);
+                err = -ENOSYS; /* Until __kmem_cache_create returns code */
+        }
 
 out_locked:
         mutex_unlock(&slab_mutex);
@@ -153,6 +164,7 @@ void kmem_cache_destroy(struct kmem_cache *s)
                         if (s->flags & SLAB_DESTROY_BY_RCU)
                                 rcu_barrier();
 
+                        kfree(s->name);
                         kmem_cache_free(kmem_cache, s);
                 } else {
                         list_add(&s->list, &slab_caches);