[PATCH] slab: extract virt_to_{cache|slab}

Introduce virt_to_cache() and virt_to_slab() functions to reduce duplicate
code and introduce a proper abstraction should we want to support other kind
of mapping for address to slab and cache (eg.  for vmalloc() or I/O memory).

Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 17 insertions, 5 deletions

diff --git a/mm/slab.c b/mm/slab.c
index ba288b3877d1..c2f9e0a330ff 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -596,6 +596,18 @@ static inline struct slab *page_get_slab(struct page *page)
         return (struct slab *)page->lru.prev;
 }
 
+static inline struct kmem_cache *virt_to_cache(const void *obj)
+{
+        struct page *page = virt_to_page(obj);
+        return page_get_cache(page);
+}
+
+static inline struct slab *virt_to_slab(const void *obj)
+{
+        struct page *page = virt_to_page(obj);
+        return page_get_slab(page);
+}
+
 /* These are the default caches for kmalloc. Custom caches can have other sizes. */
 struct cache_sizes malloc_sizes[] = {
 #define CACHE(x) { .cs_size = (x) },
@@ -1437,7 +1449,7 @@ static void check_poison_obj(kmem_cache_t *cachep, void *objp)
                 /* Print some data about the neighboring objects, if they
                  * exist:
                  */
-                struct slab *slabp = page_get_slab(virt_to_page(objp));
+                struct slab *slabp = virt_to_slab(objp);
                 int objnr;
 
                 objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;
@@ -2767,7 +2779,7 @@ static void free_block(kmem_cache_t *cachep, void **objpp, int nr_objects,
                 void *objp = objpp[i];
                 struct slab *slabp;
 
-                slabp = page_get_slab(virt_to_page(objp));
+                slabp = virt_to_slab(objp);
                 l3 = cachep->nodelists[node];
                 list_del(&slabp->list);
                 check_spinlock_acquired_node(cachep, node);
@@ -2867,7 +2879,7 @@ static inline void __cache_free(kmem_cache_t *cachep, void *objp)
 #ifdef CONFIG_NUMA
         {
                 struct slab *slabp;
-                slabp = page_get_slab(virt_to_page(objp));
+                slabp = virt_to_slab(objp);
                 if (unlikely(slabp->nodeid != numa_node_id())) {
                         struct array_cache *alien = NULL;
                         int nodeid = slabp->nodeid;
@@ -3130,7 +3142,7 @@ void kfree(const void *objp)
                 return;
         local_irq_save(flags);
         kfree_debugcheck(objp);
-        c = page_get_cache(virt_to_page(objp));
+        c = virt_to_cache(objp);
         mutex_debug_check_no_locks_freed(objp, obj_size(c));
         __cache_free(c, (void *)objp);
         local_irq_restore(flags);
@@ -3704,5 +3716,5 @@ unsigned int ksize(const void *objp)
         if (unlikely(objp == NULL))
                 return 0;
 
-        return obj_size(page_get_cache(virt_to_page(objp)));
+        return obj_size(virt_to_cache(objp));
 }