[PATCH] add MAP_POPULATE/sys_remap_file_pages support to XFS

filemap_populate needs to be exported so that filesystems with their own
vm_operations (like XFS) can use it.

Cc: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/xfs/linux-2.6/xfs_file.c

@@ -531,6 +531,7 @@ struct file_operations linvfs_dir_operations = {
 
 static struct vm_operations_struct linvfs_file_vm_ops = {
 	.nopage		= filemap_nopage,
+	.populate	= filemap_populate,
 #ifdef HAVE_VMOP_MPROTECT
 	.mprotect	= linvfs_mprotect,
 #endif

include/linux/mm.h

@@ -756,7 +756,9 @@ extern unsigned long page_unuse(struct page *);
 extern void truncate_inode_pages(struct address_space *, loff_t);
 
 /* generic vm_area_ops exported for stackable file systems */
-struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int *);
+extern struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int *);
+extern int filemap_populate(struct vm_area_struct *, unsigned long,
+		unsigned long, pgprot_t, unsigned long, int);
 
 /* mm/page-writeback.c */
 int write_one_page(struct page *page, int wait);

mm/filemap.c

@@ -1458,11 +1458,8 @@ static struct page * filemap_getpage(struct file *file, unsigned long pgoff,
 	return NULL;
 }
 
-static int filemap_populate(struct vm_area_struct *vma,
-			unsigned long addr,
-			unsigned long len,
-			pgprot_t prot,
-			unsigned long pgoff,
+int filemap_populate(struct vm_area_struct *vma, unsigned long addr,
+		unsigned long len, pgprot_t prot, unsigned long pgoff,
 		int nonblock)
 {
 	struct file *file = vma->vm_file;
@@ -1523,6 +1520,7 @@ int generic_file_mmap(struct file * file, struct vm_area_struct * vma)
 	vma->vm_ops = &generic_file_vm_ops;
 	return 0;
 }
+EXPORT_SYMBOL(filemap_populate);
 
 /*
  * This is for filesystems which do not implement ->writepage.