mm/slub: Convert slab_lock() and slab_unlock() to struct slab

Improve type safety to the point where we can get rid of the assertions
that this is not a tail page.  Remove a lot of calls to slab_page().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

diff --git a/mm/slub.c b/mm/slub.c
index 86d06f6aa743746717ec62512d7a7763dd492480..5cf305b2b8dad4fddd2b88b64a54afb3967610d3 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -48,7 +48,7 @@
  *   1. slab_mutex (Global Mutex)
  *   2. node->list_lock (Spinlock)
  *   3. kmem_cache->cpu_slab->lock (Local lock)
- *   4. slab_lock(page) (Only on some arches or for debugging)
+ *   4. slab_lock() (Only on some arches or for debugging)
  *   5. object_map_lock (Only for debugging)
  *
  *   slab_mutex
@@ -64,10 +64,10 @@
  *
  *   The slab_lock is only used for debugging and on arches that do not
  *   have the ability to do a cmpxchg_double. It only protects:
- *     A. page->freelist       -> List of object free in a page
- *     B. page->inuse          -> Number of objects in use
- *     C. page->objects        -> Number of objects in page
- *     D. page->frozen         -> frozen state
+ *     A. slab->freelist       -> List of object free in a page
+ *     B. slab->inuse          -> Number of objects in use
+ *     C. slab->objects        -> Number of objects in page
+ *     D. slab->frozen         -> frozen state
  *
  *   Frozen slabs
  *
@@ -417,28 +417,26 @@ static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
 /*
  * Per slab locking using the pagelock
  */
-static __always_inline void __slab_lock(struct page *page)
+static __always_inline void __slab_lock(struct slab *slab)
 {
-       VM_BUG_ON_PAGE(PageTail(page), page);
-       bit_spin_lock(PG_locked, &page->flags);
+       bit_spin_lock(PG_locked, &slab->flags);
 }
 
-static __always_inline void __slab_unlock(struct page *page)
+static __always_inline void __slab_unlock(struct slab *slab)
 {
-       VM_BUG_ON_PAGE(PageTail(page), page);
-       __bit_spin_unlock(PG_locked, &page->flags);
+       __bit_spin_unlock(PG_locked, &slab->flags);
 }
 
-static __always_inline void slab_lock(struct page *page, unsigned long *flags)
+static __always_inline void slab_lock(struct slab *slab, unsigned long *flags)
 {
        if (IS_ENABLED(CONFIG_PREEMPT_RT))
                local_irq_save(*flags);
-       __slab_lock(page);
+       __slab_lock(slab);
 }
 
-static __always_inline void slab_unlock(struct page *page, unsigned long *flags)
+static __always_inline void slab_unlock(struct slab *slab, unsigned long *flags)
 {
-       __slab_unlock(page);
+       __slab_unlock(slab);
        if (IS_ENABLED(CONFIG_PREEMPT_RT))
                local_irq_restore(*flags);
 }
@@ -468,15 +466,15 @@ static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab
                /* init to 0 to prevent spurious warnings */
                unsigned long flags = 0;
 
-               slab_lock(slab_page(slab), &flags);
+               slab_lock(slab, &flags);
                if (slab->freelist == freelist_old &&
                                        slab->counters == counters_old) {
                        slab->freelist = freelist_new;
                        slab->counters = counters_new;
-                       slab_unlock(slab_page(slab), &flags);
+                       slab_unlock(slab, &flags);
                        return true;
                }
-               slab_unlock(slab_page(slab), &flags);
+               slab_unlock(slab, &flags);
        }
 
        cpu_relax();
@@ -507,16 +505,16 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
                unsigned long flags;
 
                local_irq_save(flags);
-               __slab_lock(slab_page(slab));
+               __slab_lock(slab);
                if (slab->freelist == freelist_old &&
                                        slab->counters == counters_old) {
                        slab->freelist = freelist_new;
                        slab->counters = counters_new;
-                       __slab_unlock(slab_page(slab));
+                       __slab_unlock(slab);
                        local_irq_restore(flags);
                        return true;
                }
-               __slab_unlock(slab_page(slab));
+               __slab_unlock(slab);
                local_irq_restore(flags);
        }
 
@@ -1353,7 +1351,7 @@ static noinline int free_debug_processing(
        int ret = 0;
 
        spin_lock_irqsave(&n->list_lock, flags);
-       slab_lock(slab_page(slab), &flags2);
+       slab_lock(slab, &flags2);
 
        if (s->flags & SLAB_CONSISTENCY_CHECKS) {
                if (!check_slab(s, slab))
@@ -1386,7 +1384,7 @@ out:
                slab_err(s, slab, "Bulk freelist count(%d) invalid(%d)\n",
                         bulk_cnt, cnt);
 
-       slab_unlock(slab_page(slab), &flags2);
+       slab_unlock(slab, &flags2);
        spin_unlock_irqrestore(&n->list_lock, flags);
        if (!ret)
                slab_fix(s, "Object at 0x%p not freed", object);
@@ -4214,7 +4212,7 @@ static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
        void *p;
 
        slab_err(s, slab, text, s->name);
-       slab_lock(slab_page(slab), &flags);
+       slab_lock(slab, &flags);
 
        map = get_map(s, slab);
        for_each_object(p, s, addr, slab->objects) {
@@ -4225,7 +4223,7 @@ static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
                }
        }
        put_map(map);
-       slab_unlock(slab_page(slab), &flags);
+       slab_unlock(slab, &flags);
 #endif
 }
 
@@ -4958,7 +4956,7 @@ static void validate_slab(struct kmem_cache *s, struct slab *slab,
        void *addr = slab_address(slab);
        unsigned long flags;
 
-       slab_lock(slab_page(slab), &flags);
+       slab_lock(slab, &flags);
 
        if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
                goto unlock;
@@ -4973,7 +4971,7 @@ static void validate_slab(struct kmem_cache *s, struct slab *slab,
                        break;
        }
 unlock:
-       slab_unlock(slab_page(slab), &flags);
+       slab_unlock(slab, &flags);
 }
 
 static int validate_slab_node(struct kmem_cache *s,