s390/3270: asynchronous size sensing

Convert the synchronous size sense code to an interrupt driven
approach. This allows to set the device online even if the
terminal is not connected. With the new code views can be
registered without a connected terminal, the tty can be opened
as soon as the device is online. After the terminal has been
connected and the size has been determined the tty is resized
to match the device characteristics..
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/raw3270.h

@@ -141,6 +141,7 @@ struct raw3270_fn {
 		     struct raw3270_request *, struct irb *);
 	void (*release)(struct raw3270_view *);
 	void (*free)(struct raw3270_view *);
+	void (*resize)(struct raw3270_view *, int, int, int);
 };
 
 /*

drivers/s390/char/tty3270.c

@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/console.h>
 #include <linux/interrupt.h>
+#include <linux/workqueue.h>
 
 #include <linux/slab.h>
 #include <linux/bootmem.h>
@@ -80,6 +81,8 @@ struct tty3270 {
 	unsigned int highlight;		/* Blink/reverse/underscore */
 	unsigned int f_color;		/* Foreground color */
 	struct tty3270_line *screen;
+	unsigned int n_model, n_cols, n_rows;	/* New model & size */
+	struct work_struct resize_work;
 
 	/* Input stuff. */
 	struct string *prompt;		/* Output string for input area. */
@@ -115,6 +118,7 @@ struct tty3270 {
 #define TTY_UPDATE_ALL		16	/* Recreate screen. */
 
 static void tty3270_update(struct tty3270 *);
+static void tty3270_resize_work(struct work_struct *work);
 
 /*
  * Setup timeout for a device. On timeout trigger an update.
@@ -711,6 +715,7 @@ tty3270_alloc_view(void)
 	tasklet_init(&tp->readlet,
 		     (void (*)(unsigned long)) tty3270_read_tasklet,
 		     (unsigned long) tp->read);
+	INIT_WORK(&tp->resize_work, tty3270_resize_work);
 
 	return tp;
 
@@ -754,42 +759,96 @@ tty3270_free_view(struct tty3270 *tp)
 /*
  * Allocate tty3270 screen.
  */
-static int
-tty3270_alloc_screen(struct tty3270 *tp)
+static struct tty3270_line *
+tty3270_alloc_screen(unsigned int rows, unsigned int cols)
 {
+	struct tty3270_line *screen;
 	unsigned long size;
 	int lines;
 
-	size = sizeof(struct tty3270_line) * (tp->view.rows - 2);
-	tp->screen = kzalloc(size, GFP_KERNEL);
-	if (!tp->screen)
+	size = sizeof(struct tty3270_line) * (rows - 2);
+	screen = kzalloc(size, GFP_KERNEL);
+	if (!screen)
 		goto out_err;
-	for (lines = 0; lines < tp->view.rows - 2; lines++) {
-		size = sizeof(struct tty3270_cell) * tp->view.cols;
-		tp->screen[lines].cells = kzalloc(size, GFP_KERNEL);
-		if (!tp->screen[lines].cells)
+	for (lines = 0; lines < rows - 2; lines++) {
+		size = sizeof(struct tty3270_cell) * cols;
+		screen[lines].cells = kzalloc(size, GFP_KERNEL);
+		if (!screen[lines].cells)
 			goto out_screen;
 	}
-	return 0;
+	return screen;
 out_screen:
 	while (lines--)
-		kfree(tp->screen[lines].cells);
-	kfree(tp->screen);
+		kfree(screen[lines].cells);
+	kfree(screen);
 out_err:
-	return -ENOMEM;
+	return ERR_PTR(-ENOMEM);
 }
 
 /*
  * Free tty3270 screen.
  */
 static void
-tty3270_free_screen(struct tty3270 *tp)
+tty3270_free_screen(struct tty3270_line *screen, unsigned int rows)
 {
 	int lines;
 
-	for (lines = 0; lines < tp->view.rows - 2; lines++)
-		kfree(tp->screen[lines].cells);
-	kfree(tp->screen);
+	for (lines = 0; lines < rows - 2; lines++)
+		kfree(screen[lines].cells);
+	kfree(screen);
+}
+
+/*
+ * Resize tty3270 screen
+ */
+static void tty3270_resize_work(struct work_struct *work)
+{
+	struct tty3270 *tp = container_of(work, struct tty3270, resize_work);
+	struct tty3270_line *screen, *oscreen;
+	struct tty_struct *tty;
+	unsigned int orows;
+	struct winsize ws;
+
+	screen = tty3270_alloc_screen(tp->n_rows, tp->n_cols);
+	if (!screen)
+		return;
+	/* Switch to new output size */
+	spin_lock_bh(&tp->view.lock);
+	oscreen = tp->screen;
+	orows = tp->view.rows;
+	tp->view.model = tp->n_model;
+	tp->view.rows = tp->n_rows;
+	tp->view.cols = tp->n_cols;
+	tp->screen = screen;
+	free_string(&tp->freemem, tp->prompt);
+	free_string(&tp->freemem, tp->status);
+	tty3270_create_prompt(tp);
+	tty3270_create_status(tp);
+	tp->nr_up = 0;
+	while (tp->nr_lines < tp->view.rows - 2)
+		tty3270_blank_line(tp);
+	tp->update_flags = TTY_UPDATE_ALL;
+	spin_unlock_bh(&tp->view.lock);
+	tty3270_free_screen(oscreen, orows);
+	tty3270_set_timer(tp, 1);
+	/* Informat tty layer about new size */
+	tty = tty_port_tty_get(&tp->port);
+	if (!tty)
+		return;
+	ws.ws_row = tp->view.rows - 2;
+	ws.ws_col = tp->view.cols;
+	tty_do_resize(tty, &ws);
+}
+
+static void
+tty3270_resize(struct raw3270_view *view, int model, int rows, int cols)
+{
+	struct tty3270 *tp = container_of(view, struct tty3270, view);
+
+	tp->n_model = model;
+	tp->n_rows = rows;
+	tp->n_cols = cols;
+	schedule_work(&tp->resize_work);
 }
 
 /*
@@ -817,7 +876,8 @@ static void
 tty3270_free(struct raw3270_view *view)
 {
 	struct tty3270 *tp = container_of(view, struct tty3270, view);
-	tty3270_free_screen(tp);
+
+	tty3270_free_screen(tp->screen, tp->view.rows);
 	tty3270_free_view(tp);
 }
 
@@ -841,7 +901,8 @@ static struct raw3270_fn tty3270_fn = {
 	.deactivate = tty3270_deactivate,
 	.intv = (void *) tty3270_irq,
 	.release = tty3270_release,
-	.free = tty3270_free
+	.free = tty3270_free,
+	.resize = tty3270_resize
 };
 
 /*
@@ -869,10 +930,6 @@ static int tty3270_install(struct tty_driver *driver, struct tty_struct *tty)
 	if (tty3270_max_index < tty->index)
 		tty3270_max_index = tty->index;
 
-	/* Quick exit if there is no device for tty->index. */
-	if (PTR_ERR(view) == -ENODEV)
-		return -ENODEV;
-
 	/* Allocate tty3270 structure on first open. */
 	tp = tty3270_alloc_view();
 	if (IS_ERR(tp))
@@ -884,10 +941,12 @@ static int tty3270_install(struct tty_driver *driver, struct tty_struct *tty)
 		return rc;
 	}
 
-	rc = tty3270_alloc_screen(tp);
-	if (rc) {
+	tp->screen = tty3270_alloc_screen(tp->view.cols, tp->view.rows);
+	if (IS_ERR(tp->screen)) {
+		rc = PTR_ERR(tp->screen);
 		raw3270_put_view(&tp->view);
 		raw3270_del_view(&tp->view);
+		tty3270_free_view(tp);
 		return rc;
 	}
 

drivers/tty/tty_io.c

@@ -2203,6 +2203,7 @@ int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
 	mutex_unlock(&tty->termios_mutex);
 	return 0;
 }
+EXPORT_SYMBOL(tty_do_resize);
 
 /**
  *	tiocswinsz		-	implement window size set ioctl