mm: introduce page_size()

Patch series "Make working with compound pages easier", v2.

These three patches add three helpers and convert the appropriate
places to use them.

This patch (of 3):

It's unnecessarily hard to find out the size of a potentially huge page.
Replace 'PAGE_SIZE << compound_order(page)' with page_size(page).

Link: http://lkml.kernel.org/r/20190721104612.19120-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 9 deletions

diff --git a/mm/slub.c b/mm/slub.c
index 17fe1cac11fb..42c1b3af3c98 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -829,7 +829,7 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
                 return 1;
 
         start = page_address(page);
-        length = PAGE_SIZE << compound_order(page);
+        length = page_size(page);
         end = start + length;
         remainder = length % s->size;
         if (!remainder)
@@ -1074,13 +1074,14 @@ static void setup_object_debug(struct kmem_cache *s, struct page *page,
         init_tracking(s, object);
 }
 
-static void setup_page_debug(struct kmem_cache *s, void *addr, int order)
+static
+void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr)
 {
         if (!(s->flags & SLAB_POISON))
                 return;
 
         metadata_access_enable();
-        memset(addr, POISON_INUSE, PAGE_SIZE << order);
+        memset(addr, POISON_INUSE, page_size(page));
         metadata_access_disable();
 }
 
@@ -1340,8 +1341,8 @@ slab_flags_t kmem_cache_flags(unsigned int object_size,
 #else /* !CONFIG_SLUB_DEBUG */
 static inline void setup_object_debug(struct kmem_cache *s,
                         struct page *page, void *object) {}
-static inline void setup_page_debug(struct kmem_cache *s,
-                        void *addr, int order) {}
+static inline
+void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr) {}
 
 static inline int alloc_debug_processing(struct kmem_cache *s,
         struct page *page, void *object, unsigned long addr) { return 0; }
@@ -1639,7 +1640,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
         struct kmem_cache_order_objects oo = s->oo;
         gfp_t alloc_gfp;
         void *start, *p, *next;
-        int idx, order;
+        int idx;
         bool shuffle;
 
         flags &= gfp_allowed_mask;
@@ -1673,7 +1674,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
         page->objects = oo_objects(oo);
 
-        order = compound_order(page);
         page->slab_cache = s;
         __SetPageSlab(page);
         if (page_is_pfmemalloc(page))
@@ -1683,7 +1683,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
         start = page_address(page);
 
-        setup_page_debug(s, start, order);
+        setup_page_debug(s, page, start);
 
         shuffle = shuffle_freelist(s, page);
 
@@ -3932,7 +3932,7 @@ size_t __ksize(const void *object)
 
         if (unlikely(!PageSlab(page))) {
                 WARN_ON(!PageCompound(page));
-                return PAGE_SIZE << compound_order(page);
+                return page_size(page);
         }
 
         return slab_ksize(page->slab_cache);