Add virt_to_head_page and consolidate code in slab and slub

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 14 insertions, 11 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 695b90437bbc..4670ebd1f622 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -286,6 +286,12 @@ static inline void get_page(struct page *page)
         atomic_inc(&page->_count);
 }
 
+static inline struct page *virt_to_head_page(const void *x)
+{
+        struct page *page = virt_to_page(x);
+        return compound_head(page);
+}
+
 /*
  * Setup the page count before being freed into the page allocator for
  * the first time (boot or memory hotplug)
diff --git a/mm/slab.c b/mm/slab.c
index f4b2e22b5c61..3e984afc199c 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -614,20 +614,19 @@ static inline void page_set_slab(struct page *page, struct slab *slab)
 
 static inline struct slab *page_get_slab(struct page *page)
 {
-        page = compound_head(page);
         BUG_ON(!PageSlab(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);
+        struct page *page = virt_to_head_page(obj);
         return page_get_cache(page);
 }
 
 static inline struct slab *virt_to_slab(const void *obj)
 {
-        struct page *page = virt_to_page(obj);
+        struct page *page = virt_to_head_page(obj);
         return page_get_slab(page);
 }
 
@@ -2876,7 +2875,7 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
 
         objp -= obj_offset(cachep);
         kfree_debugcheck(objp);
-        page = virt_to_page(objp);
+        page = virt_to_head_page(objp);
 
         slabp = page_get_slab(page);
 
@@ -3100,7 +3099,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
                 struct slab *slabp;
                 unsigned objnr;
 
-                slabp = page_get_slab(virt_to_page(objp));
+                slabp = page_get_slab(virt_to_head_page(objp));
                 objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;
                 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
         }
diff --git a/mm/slub.c b/mm/slub.c
index 8fa1c6e937f5..347c11e80d8e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1323,9 +1323,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 {
         struct page * page;
 
-        page = virt_to_page(x);
-
-        page = compound_head(page);
+        page = virt_to_head_page(x);
 
         if (unlikely(PageError(page) && (s->flags & SLAB_STORE_USER)))
                 set_tracking(s, x, TRACK_FREE);
@@ -1336,7 +1334,7 @@ EXPORT_SYMBOL(kmem_cache_free);
 /* Figure out on which slab object the object resides */
 static struct page *get_object_page(const void *x)
 {
-        struct page *page = compound_head(virt_to_page(x));
+        struct page *page = virt_to_head_page(x);
 
         if (!PageSlab(page))
                 return NULL;
@@ -2076,7 +2074,7 @@ void kfree(const void *x)
         if (!x)
                 return;
 
-        page = compound_head(virt_to_page(x));
+        page = virt_to_head_page(x);
 
         s = page->slab;
 
@@ -2112,7 +2110,7 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags)
                 return NULL;
         }
 
-        page = compound_head(virt_to_page(p));
+        page = virt_to_head_page(p);
 
         new_cache = get_slab(new_size, flags);