mm: move readahead prototypes from mm.h

[linux-2.6-microblaze.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5a32342..92704fd 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -782,6 +782,11 @@ static inline void *kvcalloc(size_t n, size_t size, gfp_t flags)
 
 extern void kvfree(const void *addr);
 
+/*
+ * Mapcount of compound page as a whole, does not include mapped sub-pages.
+ *
+ * Must be called only for compound pages or any their tail sub-pages.
+ */
 static inline int compound_mapcount(struct page *page)
 {
        VM_BUG_ON_PAGE(!PageCompound(page), page);
@@ -801,10 +806,16 @@ static inline void page_mapcount_reset(struct page *page)
 
 int __page_mapcount(struct page *page);
 
+/*
+ * Mapcount of 0-order page; when compound sub-page, includes
+ * compound_mapcount().
+ *
+ * Result is undefined for pages which cannot be mapped into userspace.
+ * For example SLAB or special types of pages. See function page_has_type().
+ * They use this place in struct page differently.
+ */
 static inline int page_mapcount(struct page *page)
 {
-       VM_BUG_ON_PAGE(PageSlab(page), page);
-
        if (unlikely(PageCompound(page)))
                return __page_mapcount(page);
        return atomic_read(&page->_mapcount) + 1;
@@ -2601,25 +2612,6 @@ extern vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf);
 int __must_check write_one_page(struct page *page);
 void task_dirty_inc(struct task_struct *tsk);
 
-/* readahead.c */
-#define VM_READAHEAD_PAGES     (SZ_128K / PAGE_SIZE)
-
-int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
-                       pgoff_t offset, unsigned long nr_to_read);
-
-void page_cache_sync_readahead(struct address_space *mapping,
-                              struct file_ra_state *ra,
-                              struct file *filp,
-                              pgoff_t offset,
-                              unsigned long size);
-
-void page_cache_async_readahead(struct address_space *mapping,
-                               struct file_ra_state *ra,
-                               struct file *filp,
-                               struct page *pg,
-                               pgoff_t offset,
-                               unsigned long size);
-
 extern unsigned long stack_guard_gap;
 /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);