Remove last traces of ->sync_page

Commit 7eaceaccab removed ->sync_page, but a few mentions of it still
existed in documentation and comments,

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Documentation/block/biodoc.txt

@@ -1024,8 +1024,7 @@ could be on demand. For example wait_on_buffer sets the unplugging going
 through sync_buffer() running blk_run_address_space(mapping). Or the caller
 can do it explicity through blk_unplug(bdev). So in the read case,
 the queue gets explicitly unplugged as part of waiting for completion on that
-buffer. For page driven IO, the address space ->sync_page() takes care of
+buffer.
-doing the blk_run_address_space().
 
 Aside:
   This is kind of controversial territory, as it's not clear if plugging is

Documentation/filesystems/Locking

@@ -179,7 +179,6 @@ unlocks and drops the reference.
 prototypes:
 	int (*writepage)(struct page *page, struct writeback_control *wbc);
 	int (*readpage)(struct file *, struct page *);
-	int (*sync_page)(struct page *);
 	int (*writepages)(struct address_space *, struct writeback_control *);
 	int (*set_page_dirty)(struct page *page);
 	int (*readpages)(struct file *filp, struct address_space *mapping,
@@ -208,7 +207,6 @@ locking rules:
 			PageLocked(page)	i_mutex
 writepage:		yes, unlocks (see below)
 readpage:		yes, unlocks
-sync_page:		maybe
 writepages:
 set_page_dirty		no
 readpages:
@@ -226,8 +224,8 @@ error_remove_page:	yes
 swap_activate:		no
 swap_deactivate:	no
 
-	->write_begin(), ->write_end(), ->sync_page() and ->readpage()
+	->write_begin(), ->write_end() and ->readpage() may be called from
-may be called from the request handler (/dev/loop).
+the request handler (/dev/loop).
 
 	->readpage() unlocks the page, either synchronously or via I/O
 completion.
@@ -283,11 +281,6 @@ will leave the page itself marked clean but it will be tagged as dirty in the
 radix tree.  This incoherency can lead to all sorts of hard-to-debug problems
 in the filesystem like having dirty inodes at umount and losing written data.
 
-	->sync_page() locking rules are not well-defined - usually it is called
-with lock on page, but that is not guaranteed. Considering the currently
-existing instances of this method ->sync_page() itself doesn't look
-well-defined...
-
 	->writepages() is used for periodic writeback and for syscall-initiated
 sync operations.  The address_space should start I/O against at least
 *nr_to_write pages.  *nr_to_write must be decremented for each page which is

Documentation/filesystems/vfs.txt

@@ -534,9 +534,7 @@ __sync_single_inode) to check if ->writepages has been successful in
 writing out the whole address_space.
 
 The Writeback tag is used by filemap*wait* and sync_page* functions,
-via filemap_fdatawait_range, to wait for all writeback to
+via filemap_fdatawait_range, to wait for all writeback to complete.
-complete.  While waiting ->sync_page (if defined) will be called on
-each page that is found to require writeback.
 
 An address_space handler may attach extra information to a page,
 typically using the 'private' field in the 'struct page'.  If such
@@ -554,8 +552,8 @@ address_space has finer control of write sizes.
 
 The read process essentially only requires 'readpage'.  The write
 process is more complicated and uses write_begin/write_end or
-set_page_dirty to write data into the address_space, and writepage,
+set_page_dirty to write data into the address_space, and writepage
-sync_page, and writepages to writeback data to storage.
+and writepages to writeback data to storage.
 
 Adding and removing pages to/from an address_space is protected by the
 inode's i_mutex.

fs/isofs/compress.c

@@ -361,7 +361,6 @@ static int zisofs_readpage(struct file *file, struct page *page)
 
 const struct address_space_operations zisofs_aops = {
 	.readpage = zisofs_readpage,
-	/* No sync_page operation supported? */
 	/* No bmap operation supported */
 };
 

fs/ntfs/inode.c

@@ -1854,7 +1854,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 	/* Need this to sanity check attribute list references to $MFT. */
 	vi->i_generation = ni->seq_no = le16_to_cpu(m->sequence_number);
 
-	/* Provides readpage() and sync_page() for map_mft_record(). */
+	/* Provides readpage() for map_mft_record(). */
 	vi->i_mapping->a_ops = &ntfs_mst_aops;
 
 	ctx = ntfs_attr_get_search_ctx(ni, m);