fanotify: Use inode_is_open_for_write

Use the aptly named function rather than opencoding i_writecount check.
No functional changes.

Reviewed-by: Jan Kara <[e-mail]>
Signed-off-by: Nikolay Borisov <[e-mail]>
Signed-off-by: Jan Kara <[e-mail]>

fs/notify/fanotify/fanotify_user.c

···
 	 */
 	if ((flags & FAN_MARK_IGNORED_MASK) &&
 	    !(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
-	    (atomic_read(&inode->i_writecount) > 0))
+	    inode_is_open_for_write(inode))
 		return 0;
 
 	return fanotify_add_mark(group, &inode->i_fsnotify_marks,