From: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
The patch adds supporting for suspending and resuming IUCV HVC terminal
devices from disk. The obligatory Linux device driver interfaces has
been added by registering a device driver on the IUCV bus.
For each IUCV HVC terminal device the driver creates a respective device
on the IUCV bus.
To support suspend and resume, the PM freeze callback severs any established
IUCV communication path and triggers a HVC tty hang-up when the system image
is restored.
IUCV communication path are no longer valid when the z/VM guest is halted.
The device driver initialization has been updated to register devices and
the a new routine has been extracted to facilitate the hang-up of IUCV HVC
terminal devices.
Signed-off-by: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
drivers/char/hvc_iucv.c | 204 +++++++++++++++++++++++++++++++++++++-----------
1 file changed, 161 insertions(+), 43 deletions(-)
Index: linux-2.6/drivers/char/hvc_iucv.c
===================================================================
--- linux-2.6.orig/drivers/char/hvc_iucv.c
+++ linux-2.6/drivers/char/hvc_iucv.c
@@ -4,7 +4,7 @@
* This HVC device driver provides terminal access using
* z/VM IUCV communication paths.
*
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008, 2009
*
* Author(s): Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
*/
@@ -15,6 +15,7 @@
#include <asm/ebcdic.h>
#include <linux/ctype.h>
#include <linux/delay.h>
+#include <linux/device.h>
#include <linux/init.h>
#include <linux/mempool.h>
#include <linux/moduleparam.h>
@@ -74,6 +75,7 @@ struct hvc_iucv_private {
wait_queue_head_t sndbuf_waitq; /* wait for send completion */
struct list_head tty_outqueue; /* outgoing IUCV messages */
struct list_head tty_inqueue; /* incoming IUCV messages */
+ struct device *dev; /* device structure */
};
struct iucv_tty_buffer {
@@ -542,7 +544,68 @@ static void flush_sndbuf_sync(struct hvc
if (sync_wait)
wait_event_timeout(priv->sndbuf_waitq,
- tty_outqueue_empty(priv), HZ);
+ tty_outqueue_empty(priv), HZ/10);
+}
+
+/**
+ * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
+ * @priv: Pointer to hvc_iucv_private structure
+ *
+ * This routine severs an existing IUCV communication path and hangs
+ * up the underlying HVC terminal device.
+ * The hang-up occurs only if an IUCV communication path is established;
+ * otherwise there is no need to hang up the terminal device.
+ *
+ * The IUCV HVC hang-up is separated into two steps:
+ * 1. After the IUCV path has been severed, the iucv_state is set to
+ * IUCV_SEVERED.
+ * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
+ * IUCV_SEVERED state causes the tty hang-up in the HVC layer.
+ *
+ * If the tty has not yet been opened, clean up the hvc_iucv_private
+ * structure to allow re-connects.
+ * If the tty has been opened, let get_chars() return -EPIPE to signal
+ * the HVC layer to hang up the tty and, if so, wake up the HVC thread
+ * to call get_chars()...
+ *
+ * Special notes on hanging up a HVC terminal instantiated as console:
+ * Hang-up: 1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
+ * 2. do_tty_hangup() calls tty->ops->close() for console_filp
+ * => no hangup notifier is called by HVC (default)
+ * 2. hvc_close() returns because of tty_hung_up_p(filp)
+ * => no delete notifier is called!
+ * Finally, the back-end is not being notified, thus, the tty session is
+ * kept active (TTY_OPEN) to be ready for re-connects.
+ *
+ * Locking: spin_lock(&priv->lock) w/o disabling bh
+ */
+static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
+{
+ struct iucv_path *path;
+
+ path = NULL;
+ spin_lock(&priv->lock);
+ if (priv->iucv_state == IUCV_CONNECTED) {
+ path = priv->path;
+ priv->path = NULL;
+ priv->iucv_state = IUCV_SEVERED;
+ if (priv->tty_state == TTY_CLOSED)
+ hvc_iucv_cleanup(priv);
+ else
+ /* console is special (see above) */
+ if (priv->is_console) {
+ hvc_iucv_cleanup(priv);
+ priv->tty_state = TTY_OPENED;
+ } else
+ hvc_kick();
+ }
+ spin_unlock(&priv->lock);
+
+ /* finally sever path (outside of priv->lock due to lock ordering) */
+ if (path) {
+ iucv_path_sever(path, NULL);
+ iucv_path_free(path);
+ }
}
/**
@@ -735,11 +798,8 @@ out_path_handled:
* @ipuser: User specified data for this path
* (AF_IUCV: port/service name and originator port)
*
- * The function also severs the path (as required by the IUCV protocol) and
- * sets the iucv state to IUCV_SEVERED for the associated struct
- * hvc_iucv_private instance. Later, the IUCV_SEVERED state triggers a tty
- * hangup (hvc_iucv_get_chars() / hvc_iucv_write()).
- * If tty portion of the HVC is closed, clean up the outqueue.
+ * This function calls the hvc_iucv_hangup() function for the
+ * respective IUCV HVC terminal.
*
* Locking: struct hvc_iucv_private->lock
*/
@@ -747,33 +807,7 @@ static void hvc_iucv_path_severed(struct
{
struct hvc_iucv_private *priv = path->private;
- spin_lock(&priv->lock);
- priv->iucv_state = IUCV_SEVERED;
-
- /* If the tty has not yet been opened, clean up the hvc_iucv_private
- * structure to allow re-connects.
- * This is also done for our console device because console hangups
- * are handled specially and no notifier is called by HVC.
- * The tty session is active (TTY_OPEN) and ready for re-connects...
- *
- * If it has been opened, let get_chars() return -EPIPE to signal the
- * HVC layer to hang up the tty.
- * If so, we need to wake up the HVC thread to call get_chars()...
- */
- priv->path = NULL;
- if (priv->tty_state == TTY_CLOSED)
- hvc_iucv_cleanup(priv);
- else
- if (priv->is_console) {
- hvc_iucv_cleanup(priv);
- priv->tty_state = TTY_OPENED;
- } else
- hvc_kick();
- spin_unlock(&priv->lock);
-
- /* finally sever path (outside of priv->lock due to lock ordering) */
- iucv_path_sever(path, ipuser);
- iucv_path_free(path);
+ hvc_iucv_hangup(priv);
}
/**
@@ -853,6 +887,37 @@ static void hvc_iucv_msg_complete(struct
destroy_tty_buffer_list(&list_remove);
}
+/**
+ * hvc_iucv_pm_freeze() - Freeze PM callback
+ * @dev: IUVC HVC terminal device
+ *
+ * Sever an established IUCV communication path and
+ * trigger a hang-up of the underlying HVC terminal.
+ */
+static int hvc_iucv_pm_freeze(struct device *dev)
+{
+ struct hvc_iucv_private *priv = dev_get_drvdata(dev);
+
+ local_bh_disable();
+ hvc_iucv_hangup(priv);
+ local_bh_enable();
+
+ return 0;
+}
+
+/**
+ * hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
+ * @dev: IUVC HVC terminal device
+ *
+ * Wake up the HVC thread to trigger hang-up and respective
+ * HVC back-end notifier invocations.
+ */
+static int hvc_iucv_pm_restore_thaw(struct device *dev)
+{
+ hvc_kick();
+ return 0;
+}
+
/* HVC operations */
static struct hv_ops hvc_iucv_ops = {
@@ -863,6 +928,20 @@ static struct hv_ops hvc_iucv_ops = {
.notifier_hangup = hvc_iucv_notifier_hangup,
};
+/* Suspend / resume device operations */
+static struct dev_pm_ops hvc_iucv_pm_ops = {
+ .freeze = hvc_iucv_pm_freeze,
+ .thaw = hvc_iucv_pm_restore_thaw,
+ .restore = hvc_iucv_pm_restore_thaw,
+};
+
+/* IUCV HVC device driver */
+static struct device_driver hvc_iucv_driver = {
+ .name = KMSG_COMPONENT,
+ .bus = &iucv_bus,
+ .pm = &hvc_iucv_pm_ops,
+};
+
/**
* hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
* @id: hvc_iucv_table index
@@ -897,14 +976,12 @@ static int __init hvc_iucv_alloc(int id,
/* set console flag */
priv->is_console = is_console;
- /* finally allocate hvc */
+ /* allocate hvc device */
priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /* PAGE_SIZE */
HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
if (IS_ERR(priv->hvc)) {
rc = PTR_ERR(priv->hvc);
- free_page((unsigned long) priv->sndbuf);
- kfree(priv);
- return rc;
+ goto out_error_hvc;
}
/* notify HVC thread instead of using polling */
@@ -915,8 +992,45 @@ static int __init hvc_iucv_alloc(int id,
memcpy(priv->srv_name, name, 8);
ASCEBC(priv->srv_name, 8);
+ /* create and setup device */
+ priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
+ if (!priv->dev) {
+ rc = -ENOMEM;
+ goto out_error_dev;
+ }
+ dev_set_name(priv->dev, "hvc_iucv%d", id);
+ dev_set_drvdata(priv->dev, priv);
+ priv->dev->bus = &iucv_bus;
+ priv->dev->parent = iucv_root;
+ priv->dev->driver = &hvc_iucv_driver;
+ priv->dev->release = (void (*)(struct device *)) kfree;
+ rc = device_register(priv->dev);
+ if (rc) {
+ kfree(priv->dev);
+ goto out_error_dev;
+ }
+
hvc_iucv_table[id] = priv;
return 0;
+
+out_error_dev:
+ hvc_remove(priv->hvc);
+out_error_hvc:
+ free_page((unsigned long) priv->sndbuf);
+ kfree(priv);
+
+ return rc;
+}
+
+/**
+ * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
+ */
+static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
+{
+ hvc_remove(priv->hvc);
+ device_unregister(priv->dev);
+ free_page((unsigned long) priv->sndbuf);
+ kfree(priv);
}
/**
@@ -1109,6 +1223,11 @@ static int __init hvc_iucv_init(void)
goto out_error;
}
+ /* register IUCV HVC device driver */
+ rc = driver_register(&hvc_iucv_driver);
+ if (rc)
+ goto out_error;
+
/* parse hvc_iucv_allow string and create z/VM user ID filter list */
if (hvc_iucv_filter_string) {
rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
@@ -1183,15 +1302,14 @@ out_error_iucv:
iucv_unregister(&hvc_iucv_handler, 0);
out_error_hvc:
for (i = 0; i < hvc_iucv_devices; i++)
- if (hvc_iucv_table[i]) {
- if (hvc_iucv_table[i]->hvc)
- hvc_remove(hvc_iucv_table[i]->hvc);
- kfree(hvc_iucv_table[i]);
- }
+ if (hvc_iucv_table[i])
+ hvc_iucv_destroy(hvc_iucv_table[i]);
out_error_memory:
mempool_destroy(hvc_iucv_mempool);
kmem_cache_destroy(hvc_iucv_buffer_cache);
out_error:
+ if (hvc_iucv_filter)
+ kfree(hvc_iucv_filter);
hvc_iucv_devices = 0; /* ensure that we do not provide any device */
return rc;
}
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
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