files: Hide pslist selection logic into file desc handlers

Don't do explicit switch by file type in files.c and don't export
intimate knowledge of pty being master/slave. Use a file desc op
for that.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

eventpoll.c

@@ -158,10 +158,16 @@ static int eventpoll_post_open(struct file_desc *d, int fd)
 	return 0;
 }
 
+static struct list_head *eventpoll_select_list(struct file_desc *d, struct rst_info *ri)
+{
+	return &ri->eventpoll;
+}
+
 static struct file_desc_ops desc_ops = {
 	.type = FD_TYPES__EVENTPOLL,
 	.open = eventpoll_open,
 	.post_open = eventpoll_post_open,
+	.select_ps_list = eventpoll_select_list,
 };
 
 static int collect_one_epoll_tfd(void *o, ProtobufCMessage *msg)

files.c

@@ -148,18 +148,12 @@ int rst_file_params(int fd, FownEntry *fown, int flags)
 	return 0;
 }
 
-static struct list_head *select_ps_list(int type, struct fdinfo_list_entry *le, struct rst_info *ri)
+static struct list_head *select_ps_list(struct file_desc *desc, struct rst_info *ri)
 {
-	switch (type) {
-	case FD_TYPES__EVENTPOLL:
-		return &ri->eventpoll;
-	case FD_TYPES__TTY:
-		if (!tty_is_master(le))
-			return &ri->tty_slaves;
-		/* Fall through */
-	default:
+	if (desc->ops->select_ps_list)
+		return desc->ops->select_ps_list(desc, ri);
+	else
 		return &ri->fds;
-	}
 }
 
 static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
@@ -191,7 +185,7 @@ static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
 
 	list_add_tail(&new_le->desc_list, &le->desc_list);
 	new_le->desc = fdesc;
-	list_add_tail(&new_le->ps_list, select_ps_list(e->type, new_le, rst_info));
+	list_add_tail(&new_le->ps_list, select_ps_list(fdesc, rst_info));
 
 	return 0;
 }

include/files.h

@@ -48,6 +48,7 @@ struct file_desc_ops {
 	int			(*open)(struct file_desc *d);
 	int			(*post_open)(struct file_desc *d, int fd);
 	int			(*want_transport)(FdinfoEntry *fe, struct file_desc *d);
+	struct list_head *	(*select_ps_list)(struct file_desc *, struct rst_info *);
 };
 
 struct file_desc {

include/tty.h

@@ -15,7 +15,6 @@
 
 extern int dump_tty(struct fd_parms *p, int lfd, const struct cr_fdset *set);
 extern int collect_tty(void);
-extern int tty_is_master(struct fdinfo_list_entry *le);
 extern int prepare_shared_tty(void);
 extern void tty_setup_slavery(void);
 

tty.c

@@ -438,16 +438,6 @@ err:
 		return -1;
 }
 
-/*
- * Unix98 pty slave peers requires the master peers being
- * opened early, this function test if it's master pty.
- */
-int tty_is_master(struct fdinfo_list_entry *le)
-{
-	struct tty_info *info = container_of(le->desc, struct tty_info, d);
-	return pty_is_master(info);
-}
-
 static int pty_open_slaves(struct tty_info *info)
 {
 	int sock = -1, fd = -1, ret = -1;
@@ -616,11 +606,25 @@ static int tty_transport(FdinfoEntry *fe, struct file_desc *d)
 	return !info->create;
 }
 
+static struct list_head *tty_select_pslist(struct file_desc *d, struct rst_info *ri)
+{
+	/*
+	 * Unix98 pty slave peers requires the master peers being
+	 * opened before them
+	 */
+
+	if (pty_is_master(container_of(d, struct tty_info, d)))
+		return &ri->fds;
+	else
+		return &ri->tty_slaves;
+}
+
 static struct file_desc_ops tty_desc_ops = {
 	.type		= FD_TYPES__TTY,
 	.open		= tty_open,
 	.post_open	= tty_restore_ctl_terminal,
 	.want_transport = tty_transport,
+	.select_ps_list	= tty_select_pslist,
 };
 
 static int tty_find_restoring_task(struct tty_info *info)