[PATCH 11/62] mm/slub: Convert kfree() to use a struct slab

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

With kfree() using a struct slab, we can also convert slab_free()
and do_slab_free() to use a slab instead of a page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/slub.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 050a0610b3ef..15996ea165ac 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3402,11 +3402,11 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
  * with all sorts of special processing.
  *
  * Bulk free of a freelist with several objects (all pointing to the
- * same page) possible by specifying head and tail ptr, plus objects
+ * same slab) possible by specifying head and tail ptr, plus objects
  * count (cnt). Bulk free indicated by tail pointer being set.
  */
 static __always_inline void do_slab_free(struct kmem_cache *s,
-				struct page *page, void *head, void *tail,
+				struct slab *slab, void *head, void *tail,
 				int cnt, unsigned long addr)
 {
 	void *tail_obj = tail ? : head;
@@ -3427,7 +3427,7 @@ static __always_inline void do_slab_free(struct kmem_cache *s,
 	/* Same with comment on barrier() in slab_alloc_node() */
 	barrier();
 
-	if (likely(page == c->page)) {
+	if (likely(slab_page(slab) == c->page)) {
 #ifndef CONFIG_PREEMPT_RT
 		void **freelist = READ_ONCE(c->freelist);
 
@@ -3453,7 +3453,7 @@ static __always_inline void do_slab_free(struct kmem_cache *s,
 
 		local_lock(&s->cpu_slab->lock);
 		c = this_cpu_ptr(s->cpu_slab);
-		if (unlikely(page != c->page)) {
+		if (unlikely(slab_page(slab) != c->page)) {
 			local_unlock(&s->cpu_slab->lock);
 			goto redo;
 		}
@@ -3468,11 +3468,11 @@ static __always_inline void do_slab_free(struct kmem_cache *s,
 #endif
 		stat(s, FREE_FASTPATH);
 	} else
-		__slab_free(s, page, head, tail_obj, cnt, addr);
+		__slab_free(s, slab_page(slab), head, tail_obj, cnt, addr);
 
 }
 
-static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
+static __always_inline void slab_free(struct kmem_cache *s, struct slab *slab,
 				      void *head, void *tail, int cnt,
 				      unsigned long addr)
 {
@@ -3481,13 +3481,13 @@ static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
 	 * to remove objects, whose reuse must be delayed.
 	 */
 	if (slab_free_freelist_hook(s, &head, &tail))
-		do_slab_free(s, page, head, tail, cnt, addr);
+		do_slab_free(s, slab, head, tail, cnt, addr);
 }
 
 #ifdef CONFIG_KASAN_GENERIC
 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
 {
-	do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
+	do_slab_free(cache, virt_to_slab(x), x, NULL, 1, addr);
 }
 #endif
 
@@ -3496,7 +3496,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 	s = cache_from_obj(s, x);
 	if (!s)
 		return;
-	slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
+	slab_free(s, virt_to_slab(x), x, NULL, 1, _RET_IP_);
 	trace_kmem_cache_free(_RET_IP_, x, s->name);
 }
 EXPORT_SYMBOL(kmem_cache_free);
@@ -3621,7 +3621,7 @@ void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 		if (!df.slab)
 			continue;
 
-		slab_free(df.s, slab_page(df.slab), df.freelist, df.tail, df.cnt, _RET_IP_);
+		slab_free(df.s, df.slab, df.freelist, df.tail, df.cnt, _RET_IP_);
 	} while (likely(size));
 }
 EXPORT_SYMBOL(kmem_cache_free_bulk);
@@ -4527,7 +4527,7 @@ EXPORT_SYMBOL(__ksize);
 
 void kfree(const void *x)
 {
-	struct page *page;
+	struct slab *slab;
 	void *object = (void *)x;
 
 	trace_kfree(_RET_IP_, x);
@@ -4535,12 +4535,12 @@ void kfree(const void *x)
 	if (unlikely(ZERO_OR_NULL_PTR(x)))
 		return;
 
-	page = virt_to_head_page(x);
-	if (unlikely(!PageSlab(page))) {
-		free_nonslab_page(page, object);
+	slab = virt_to_slab(x);
+	if (unlikely(!SlabAllocation(slab))) {
+		free_nonslab_page(slab_page(slab), object);
 		return;
 	}
-	slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
+	slab_free(slab->slab_cache, slab, object, NULL, 1, _RET_IP_);
 }
 EXPORT_SYMBOL(kfree);
 
-- 
2.32.0