mm: remove page_file_index

After using the offset of the swap entry as the key of the swap cache,
the page_index() becomes exactly same as page_file_index(). So the
page_file_index() is removed and the callers are changed to use
page_index() instead.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: "Huang, Ying" <[e-mail]>
Cc: Trond Myklebust <[e-mail]>
Cc: Anna Schumaker <[e-mail]>
Cc: "Kirill A. Shutemov" <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: Dan Williams <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: Ross Zwisler <[e-mail]>
Cc: Eric Dumazet <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/nfs/internal.h

···
 	loff_t i_size = i_size_read(page_file_mapping(page)->host);
 
 	if (i_size > 0) {
-		pgoff_t page_index = page_file_index(page);
+		pgoff_t index = page_index(page);
 		pgoff_t end_index = (i_size - 1) >> PAGE_SHIFT;
-		if (page_index < end_index)
+		if (index < end_index)
 			return PAGE_SIZE;
-		if (page_index == end_index)
+		if (index == end_index)
 			return ((i_size - 1) & ~PAGE_MASK) + 1;
 	}
 	return 0;

fs/nfs/pagelist.c

···
 	 * update_nfs_request below if the region is not locked. */
 	req->wb_page    = page;
 	if (page) {
-		req->wb_index = page_file_index(page);
+		req->wb_index = page_index(page);
 		get_page(page);
 	}
 	req->wb_offset  = offset;

fs/nfs/read.c

···
 	int		error;
 
 	dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
-		page, PAGE_SIZE, page_file_index(page));
+		page, PAGE_SIZE, page_index(page));
 	nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
 	nfs_add_stats(inode, NFSIOS_READPAGES, 1);
 

fs/nfs/write.c

···
 	spin_lock(&inode->i_lock);
 	i_size = i_size_read(inode);
 	end_index = (i_size - 1) >> PAGE_SHIFT;
-	if (i_size > 0 && page_file_index(page) < end_index)
+	if (i_size > 0 && page_index(page) < end_index)
 		goto out;
 	end = page_file_offset(page) + ((loff_t)offset+count);
 	if (i_size >= end)
···
 {
 	int ret;
 
-	nfs_pageio_cond_complete(pgio, page_file_index(page));
+	nfs_pageio_cond_complete(pgio, page_index(page));
 	ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE,
 				   launder);
 	if (ret == -EAGAIN) {

include/linux/mm.h

···
 	return page->index;
 }
 
-/*
- * Return the file index of the page. Regular pagecache pages use ->index
- * whereas swapcache pages use swp_offset(->private)
- */
-static inline pgoff_t page_file_index(struct page *page)
-{
-	if (unlikely(PageSwapCache(page)))
-		return __page_file_index(page);
-
-	return page->index;
-}
-
 bool page_mapped(struct page *page);
 struct address_space *page_mapping(struct page *page);
 

include/linux/pagemap.h

···
 
 static inline loff_t page_file_offset(struct page *page)
 {
-	return ((loff_t)page_file_index(page)) << PAGE_SHIFT;
+	return ((loff_t)page_index(page)) << PAGE_SHIFT;
 }
 
 extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,