patches for a network-based hvc backend (s390)

@@ -416,8 +416,8 @@ static void hvc_hangup(struct tty_struct
 	hp->n_outbuf = 0;
 	hp->tty = NULL;
 
-	if (hp->ops->notifier_del)
-			hp->ops->notifier_del(hp, hp->data);
+	if (hp->ops->notifier_hangup)
+			hp->ops->notifier_hangup(hp, hp->data);
 
 	spin_unlock_irqrestore(&hp->lock, flags);
 

@@ -65,9 +65,10 @@ struct hv_ops {
 	int (*get_chars)(uint32_t vtermno, char *buf, int count);
 	int (*put_chars)(uint32_t vtermno, const char *buf, int count);
 
-	/* Callbacks for notification. Called in open and close */
+	/* Callbacks for notification. Called in open, close and hangup */
 	int (*notifier_add)(struct hvc_struct *hp, int irq);
 	void (*notifier_del)(struct hvc_struct *hp, int irq);
+	void (*notifier_hangup)(struct hvc_struct *hp, int irq);
 };
 
 /* Register a vterm and a slot index for use as a console (console_init) */

@@ -86,6 +87,7 @@ void hvc_kick(void);
 /* default notifier for irq based notification */
 extern int notifier_add_irq(struct hvc_struct *hp, int data);
 extern void notifier_del_irq(struct hvc_struct *hp, int data);
+extern void notifier_hangup_irq(struct hvc_struct *hp, int data);
 
 
 #if defined(CONFIG_XMON) && defined(CONFIG_SMP)

@@ -42,3 +42,8 @@ void notifier_del_irq(struct hvc_struct 
 	free_irq(irq, hp);
 	hp->irq_requested = 0;
 }
+
+void notifier_hangup_irq(struct hvc_struct *hp, int irq)
+{
+	notifier_del_irq(hp, irq);
+}

@@ -202,6 +202,7 @@ static struct hv_ops hvc_get_put_ops = {
 	.put_chars = put_chars,
 	.notifier_add = notifier_add_irq,
 	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
 };
 
 static int __devinit hvc_vio_probe(struct vio_dev *vdev,

@@ -102,6 +102,7 @@ static struct hv_ops hvc_ops = {
 	.put_chars = write_console,
 	.notifier_add = notifier_add_irq,
 	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
 };
 
 static int __init xen_init(void)

@@ -82,6 +82,7 @@ static struct hv_ops hvc_get_put_ops = {
 	.put_chars = hvc_put_chars,
 	.notifier_add = notifier_add_irq,
 	.notifier_del = notifier_del_irq,
+	.notifier_hangup = notifier_hangup_irq,
 };
 
 static int __devinit hvc_vio_probe(struct vio_dev *vdev,

@@ -198,6 +198,7 @@ static int __devinit virtcons_probe(stru
 	virtio_cons.put_chars = put_chars;
 	virtio_cons.notifier_add = notifier_add_vio;
 	virtio_cons.notifier_del = notifier_del_vio;
+	virtio_cons.notifier_hangup = notifier_del_vio;
 
 	/* The first argument of hvc_alloc() is the virtual console number, so
 	 * we use zero.  The second argument is the parameter for the

@@ -796,7 +796,7 @@ static int hvc_init(void)
 	drv->minor_start = HVC_MINOR;
 	drv->type = TTY_DRIVER_TYPE_SYSTEM;
 	drv->init_termios = tty_std_termios;
-	drv->flags = TTY_DRIVER_REAL_RAW;
+	drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
 	tty_set_operations(drv, &hvc_ops);
 
 	/* Always start the kthread because there can be hotplug vty adapters

@@ -1243,10 +1243,9 @@ int tty_init_termios(struct tty_struct *
 		tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 		if (tp == NULL)
 			return -ENOMEM;
-		memcpy(tp, &tty->driver->init_termios,
-						sizeof(struct ktermios));
 		tty->driver->termios[idx] = tp;
 	}
+	memcpy(tp, &tty->driver->init_termios, sizeof(struct ktermios));
 	tty->termios = tp;
 	tty->termios_locked = tp + 1;
 

@@ -161,7 +161,7 @@ static void hvc_console_print(struct con
 			}
 		} else {
 			r = cons_ops[index]->put_chars(vtermnos[index], c, i);
-			if (r < 0) {
+			if (r <= 0) {
 				/* throw away chars on error */
 				i = 0;
 			} else if (r > 0) {

@@ -431,7 +431,7 @@ static void hvc_hangup(struct tty_struct
  * Push buffered characters whether they were just recently buffered or waiting
  * on a blocked hypervisor.  Call this function with hp->lock held.
  */
-static void hvc_push(struct hvc_struct *hp)
+static int hvc_push(struct hvc_struct *hp)
 {
 	int n;
 

@@ -439,7 +439,7 @@ static void hvc_push(struct hvc_struct *
 	if (n <= 0) {
 		if (n == 0) {
 			hp->do_wakeup = 1;
-			return;
+			return 0;
 		}
 		/* throw away output on error; this happens when
 		   there is no session connected to the vterm. */

@@ -450,6 +450,8 @@ static void hvc_push(struct hvc_struct *
 		memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
 	else
 		hp->do_wakeup = 1;
+
+	return n;
 }
 
 static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)

@@ -538,16 +540,20 @@ int hvc_poll(struct hvc_struct *hp)
 	char buf[N_INBUF] __ALIGNED__;
 	unsigned long flags;
 	int read_total = 0;
+	int written_total = 0;
 
 	spin_lock_irqsave(&hp->lock, flags);
 
 	/* Push pending writes */
 	if (hp->n_outbuf > 0)
-		hvc_push(hp);
+		written_total = hvc_push(hp);
 
 	/* Reschedule us if still some write pending */
-	if (hp->n_outbuf > 0)
+	if (hp->n_outbuf > 0) {
 		poll_mask |= HVC_POLL_WRITE;
+		/* If hvc_push() was not able to write, sleep a few msecs */
+		timeout = (written_total) ? 0 : MIN_TIMEOUT;
+	}
 
 	/* No tty attached, just skip */
 	tty = hp->tty;

@@ -659,10 +665,6 @@ static int khvcd(void *unused)
 			poll_mask |= HVC_POLL_READ;
 		if (hvc_kicked)
 			continue;
-		if (poll_mask & HVC_POLL_WRITE) {
-			yield();
-			continue;
-		}
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (!hvc_kicked) {
 			if (poll_mask == 0)

@@ -494,6 +494,48 @@ static int hvc_write(struct tty_struct *
 	return written;
 }
 
+/**
+ * hvc_set_winsz() - Resize the hvc tty terminal window.
+ * @work:	work structure.
+ *
+ * The routine shall not be called within an atomic context because it
+ * acquires the tty termios mutex and might sleep.
+ *
+ * Locking:	hp->lock, tty->termios_mutex and tty->ctrl_lock
+ */
+static void hvc_set_winsz(struct work_struct *work)
+{
+	struct hvc_struct *hp;
+	struct pid *pgrp;
+	unsigned long hvc_flags;
+	unsigned long ctrl_flags;
+
+	hp = container_of(work, struct hvc_struct, tty_resize);
+	if (!hp || !hp->tty)
+		return;
+
+	mutex_lock(&hp->tty->termios_mutex);
+	spin_lock_irqsave(&hp->lock, hvc_flags);
+
+	if ((hp->ws.ws_row == hp->tty->winsize.ws_row) &&
+	    (hp->ws.ws_col == hp->tty->winsize.ws_col))
+		goto out_mutex_unlock;
+
+	spin_lock_irqsave(&hp->tty->ctrl_lock, ctrl_flags);
+	pgrp = get_pid(hp->tty->pgrp);
+	spin_unlock_irqrestore(&hp->tty->ctrl_lock, ctrl_flags);
+
+	if (pgrp)
+		kill_pgrp(pgrp, SIGWINCH, 1);
+	put_pid(pgrp);
+
+	hp->tty->winsize = hp->ws;
+
+out_mutex_unlock:
+	spin_unlock_irqrestore(&hp->lock, hvc_flags);
+	mutex_unlock(&hp->tty->termios_mutex);
+}
+
 /*
  * This is actually a contract between the driver and the tty layer outlining
  * how much write room the driver can guarantee will be sent OR BUFFERED.  This

@@ -638,6 +680,24 @@ int hvc_poll(struct hvc_struct *hp)
 }
 EXPORT_SYMBOL_GPL(hvc_poll);
 
+/**
+ * hvc_resize() - Update terminal window size information.
+ * @hp:		HVC console pointer
+ * @ws:		Terminal window size structure
+ *
+ * Stores the specified window size information in the hvc structure of @hp.
+ * The function schedule the tty resize update.
+ *
+ * Locking:	Locking free; the function MUST be called holding hp->lock
+ */
+void hvc_resize(struct hvc_struct *hp, struct winsize ws)
+{
+	if ((hp->ws.ws_row != ws.ws_row) || (hp->ws.ws_col != ws.ws_col)) {
+		hp->ws = ws;
+		schedule_work(&hp->tty_resize);
+	}
+}
+
 /*
  * This kthread is either polling or interrupt driven.  This is determined by
  * calling hvc_poll() who determines whether a console adapter support

@@ -720,6 +780,7 @@ struct hvc_struct __devinit *hvc_alloc(u
 
 	kref_init(&hp->kref);
 
+	INIT_WORK(&hp->tty_resize, hvc_set_winsz);
 	spin_lock_init(&hp->lock);
 	spin_lock(&hvc_structs_lock);
 

@@ -27,6 +27,7 @@
 #ifndef HVC_CONSOLE_H
 #define HVC_CONSOLE_H
 #include <linux/kref.h>
+#include <linux/tty.h>
 
 /*
  * This is the max number of console adapters that can/will be found as

@@ -56,6 +57,8 @@ struct hvc_struct {
 	struct hv_ops *ops;
 	int irq_requested;
 	int data;
+	struct winsize ws;
+	struct work_struct tty_resize;
 	struct list_head next;
 	struct kref kref; /* ref count & hvc_struct lifetime */
 };

@@ -84,6 +87,9 @@ extern int __devexit hvc_remove(struct h
 int hvc_poll(struct hvc_struct *hp);
 void hvc_kick(void);
 
+/* Resize hvc tty terminal window */
+extern void hvc_resize(struct hvc_struct *hp, struct winsize ws);
+
 /* default notifier for irq based notification */
 extern int notifier_add_irq(struct hvc_struct *hp, int data);
 extern void notifier_del_irq(struct hvc_struct *hp, int data);

@@ -374,6 +374,9 @@ static void hvc_close(struct tty_struct 
 		hp->tty = NULL;
 		spin_unlock_irqrestore(&hp->lock, flags);
 
+		/* cancel pending tty resize work */
+		cancel_work_sync(&hp->tty_resize);
+
 		/*
 		 * Chain calls chars_in_buffer() and returns immediately if
 		 * there is no buffered data otherwise sleeps on a wait queue

@@ -399,6 +402,9 @@ static void hvc_hangup(struct tty_struct
 	if (!hp)
 		return;
 
+	/* cancel pending tty resize work */
+	cancel_work_sync(&hp->tty_resize);
+
 	spin_lock_irqsave(&hp->lock, flags);
 
 	/*

@@ -494,6 +500,39 @@ static int hvc_write(struct tty_struct *
 	return written;
 }
 
+/**
+ * hvc_set_winsz() - Resize the hvc tty terminal window.
+ * @work:	work structure.
+ *
+ * The routine shall not be called within an atomic context because it
+ * might sleep.
+ *
+ * Locking:	hp->lock
+ */
+static void hvc_set_winsz(struct work_struct *work)
+{
+	struct hvc_struct *hp;
+	unsigned long hvc_flags;
+	struct tty_struct *tty;
+	struct winsize ws;
+
+	hp = container_of(work, struct hvc_struct, tty_resize);
+	if (!hp)
+		return;
+
+	spin_lock_irqsave(&hp->lock, hvc_flags);
+	if (!hp->tty) {
+		spin_unlock_irqrestore(&hp->lock, hvc_flags);
+		return;
+	}
+	ws  = hp->ws;
+	tty = tty_kref_get(hp->tty);
+	spin_unlock_irqrestore(&hp->lock, hvc_flags);
+
+	tty_do_resize(tty, tty, &ws);
+	tty_kref_put(tty);
+}
+
 /*
  * This is actually a contract between the driver and the tty layer outlining
  * how much write room the driver can guarantee will be sent OR BUFFERED.  This

@@ -638,6 +677,24 @@ int hvc_poll(struct hvc_struct *hp)
 }
 EXPORT_SYMBOL_GPL(hvc_poll);
 
+/**
+ * hvc_resize() - Update terminal window size information.
+ * @hp:		HVC console pointer
+ * @ws:		Terminal window size structure
+ *
+ * Stores the specified window size information in the hvc structure of @hp.
+ * The function schedule the tty resize update.
+ *
+ * Locking:	Locking free; the function MUST be called holding hp->lock
+ */
+void hvc_resize(struct hvc_struct *hp, struct winsize ws)
+{
+	if ((hp->ws.ws_row != ws.ws_row) || (hp->ws.ws_col != ws.ws_col)) {
+		hp->ws = ws;
+		schedule_work(&hp->tty_resize);
+	}
+}
+
 /*
  * This kthread is either polling or interrupt driven.  This is determined by
  * calling hvc_poll() who determines whether a console adapter support

@@ -720,6 +777,7 @@ struct hvc_struct __devinit *hvc_alloc(u
 
 	kref_init(&hp->kref);
 
+	INIT_WORK(&hp->tty_resize, hvc_set_winsz);
 	spin_lock_init(&hp->lock);
 	spin_lock(&hvc_structs_lock);
 

@@ -27,6 +27,7 @@
 #ifndef HVC_CONSOLE_H
 #define HVC_CONSOLE_H
 #include <linux/kref.h>
+#include <linux/tty.h>
 
 /*
  * This is the max number of console adapters that can/will be found as

@@ -56,6 +57,8 @@ struct hvc_struct {
 	struct hv_ops *ops;
 	int irq_requested;
 	int data;
+	struct winsize ws;
+	struct work_struct tty_resize;
 	struct list_head next;
 	struct kref kref; /* ref count & hvc_struct lifetime */
 };

@@ -84,6 +87,9 @@ extern int __devexit hvc_remove(struct h
 int hvc_poll(struct hvc_struct *hp);
 void hvc_kick(void);
 
+/* Resize hvc tty terminal window */
+extern void hvc_resize(struct hvc_struct *hp, struct winsize ws);
+
 /* default notifier for irq based notification */
 extern int notifier_add_irq(struct hvc_struct *hp, int data);
 extern void notifier_del_irq(struct hvc_struct *hp, int data);

@@ -806,7 +806,7 @@ struct hvc_struct __devinit *hvc_alloc(u
 }
 EXPORT_SYMBOL_GPL(hvc_alloc);
 
-int __devexit hvc_remove(struct hvc_struct *hp)
+int hvc_remove(struct hvc_struct *hp)
 {
 	unsigned long flags;
 	struct tty_struct *tty;

@@ -81,7 +81,7 @@ extern int hvc_instantiate(uint32_t vter
 extern struct hvc_struct * __devinit hvc_alloc(uint32_t vtermno, int data,
 				struct hv_ops *ops, int outbuf_size);
 /* remove a vterm from hvc tty operation (module_exit or hotplug remove) */
-extern int __devexit hvc_remove(struct hvc_struct *hp);
+extern int hvc_remove(struct hvc_struct *hp);
 
 /* data available */
 int hvc_poll(struct hvc_struct *hp);