vm/vm_page: provide accessors to private data

Make per-page private data generic, provide accessors, and make the
slab allocator use them.

2 files changed, 19 insertions, 4 deletions

diff --git a/kern/kmem.c b/kern/kmem.c
index bda5dcbf..0f3b4962 100644
--- a/kern/kmem.c
+++ b/kern/kmem.c
@@ -667,8 +667,8 @@ kmem_cache_register(struct kmem_cache *cache, struct kmem_slab *slab)
         assert(page != NULL);
         assert((virtual && vm_page_type(page) == VM_PAGE_KERNEL)
                || (!virtual && vm_page_type(page) == VM_PAGE_KMEM));
-        assert(page->slab_priv == NULL);
-        page->slab_priv = slab;
+        assert(vm_page_get_priv(page) == NULL);
+        vm_page_set_priv(page, slab);
     }
 }
 
@@ -708,7 +708,7 @@ kmem_cache_lookup(struct kmem_cache *cache, void *buf)
         return NULL;
     }
 
-    slab = page->slab_priv;
+    slab = vm_page_get_priv(page);
     assert((unsigned long)buf >= kmem_slab_buf(slab));
     assert((unsigned long)buf < (kmem_slab_buf(slab) + cache->slab_size));
     return slab;
diff --git a/vm/vm_page.h b/vm/vm_page.h
index 097bcc6b..1ce172f2 100644
--- a/vm/vm_page.h
+++ b/vm/vm_page.h
@@ -76,7 +76,7 @@ struct vm_page {
     unsigned short seg_index;
     unsigned short order;
     phys_addr_t phys_addr;
-    void *slab_priv;
+    void *priv;
 };
 
 static inline unsigned short
@@ -122,6 +122,21 @@ vm_page_direct_ptr(const struct vm_page *page)
 }
 
 /*
+ * Associate private data with a page.
+ */
+static inline void
+vm_page_set_priv(struct vm_page *page, void *priv)
+{
+    page->priv = priv;
+}
+
+static inline void *
+vm_page_get_priv(const struct vm_page *page)
+{
+    return page->priv;
+}
+
+/*
  * Load physical memory into the vm_page module at boot time.
  *
  * All addresses must be page-aligned. Segments can be loaded in any order.