diff --git a/include/linux/hash.h b/include/linux/hash.h
index 06d25c1..b80506b 100644
--- a/include/linux/hash.h
+++ b/include/linux/hash.h
@@ -63,7 +63,7 @@
 	return hash >> (32 - bits);
 }
 
-static inline unsigned long hash_ptr(void *ptr, unsigned int bits)
+static inline unsigned long hash_ptr(const void *ptr, unsigned int bits)
 {
 	return hash_long((unsigned long)ptr, bits);
 }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fd599f4..c06454d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -737,7 +737,7 @@
 #endif
 
 #if defined(HASHED_PAGE_VIRTUAL)
-void *page_address(struct page *page);
+void *page_address(const struct page *page);
 void set_page_address(struct page *page, void *virtual);
 void page_address_init(void);
 #endif
diff --git a/mm/highmem.c b/mm/highmem.c
index 693394da..5ef672c 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -326,7 +326,7 @@
 	spinlock_t lock;			/* Protect this bucket's list */
 } ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER];
 
-static struct page_address_slot *page_slot(struct page *page)
+static struct page_address_slot *page_slot(const struct page *page)
 {
 	return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)];
 }
@@ -337,7 +337,7 @@
  *
  * Returns the page's virtual address.
  */
-void *page_address(struct page *page)
+void *page_address(const struct page *page)
 {
 	unsigned long flags;
 	void *ret;