mm/slab: move kfree() from slab_common.c to slub.c

This should result in better code. Currently kfree() makes a function
call between compilation units to __kmem_cache_free() which does its own
virt_to_slab(), throwing away the struct slab pointer we already had in
kfree(). Now it can be reused. Additionally kfree() can now inline the
whole SLUB freeing fastpath.

Also move over free_large_kmalloc() as the only callsites are now in
slub.c, and make it static.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

1 files changed, 46 insertions, 5 deletions

diff --git a/mm/slub.c b/mm/slub.c
index cc801f8258fe..2baa9e94d9df 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4197,11 +4197,6 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 	return cachep;
 }
 
-void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller)
-{
-	slab_free(s, virt_to_slab(x), x, NULL, &x, 1, caller);
-}
-
 /**
  * kmem_cache_free - Deallocate an object
  * @s: The cache the allocation was from.
@@ -4220,6 +4215,52 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 }
 EXPORT_SYMBOL(kmem_cache_free);
 
+static void free_large_kmalloc(struct folio *folio, void *object)
+{
+	unsigned int order = folio_order(folio);
+
+	if (WARN_ON_ONCE(order == 0))
+		pr_warn_once("object pointer: 0x%p\n", object);
+
+	kmemleak_free(object);
+	kasan_kfree_large(object);
+	kmsan_kfree_large(object);
+
+	mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B,
+			      -(PAGE_SIZE << order));
+	__free_pages(folio_page(folio, 0), order);
+}
+
+/**
+ * kfree - free previously allocated memory
+ * @object: pointer returned by kmalloc() or kmem_cache_alloc()
+ *
+ * If @object is NULL, no operation is performed.
+ */
+void kfree(const void *object)
+{
+	struct folio *folio;
+	struct slab *slab;
+	struct kmem_cache *s;
+	void *x = (void *)object;
+
+	trace_kfree(_RET_IP_, object);
+
+	if (unlikely(ZERO_OR_NULL_PTR(object)))
+		return;
+
+	folio = virt_to_folio(object);
+	if (unlikely(!folio_test_slab(folio))) {
+		free_large_kmalloc(folio, (void *)object);
+		return;
+	}
+
+	slab = folio_slab(folio);
+	s = slab->slab_cache;
+	slab_free(s, slab, x, NULL, &x, 1, _RET_IP_);
+}
+EXPORT_SYMBOL(kfree);
+
 struct detached_freelist {
 	struct slab *slab;
 	void *tail;