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[S390] console flush on panic / reboot

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The s390 console drivers use the unblank callback of the console
structure to flush the console buffer. In case of a panic or a
reboot the CPU doing the callback can block on the console i/o.
The other CPUs in the system continue to work. For panic this is
not a good idea.

Replace the unblank callback with proper panic/reboot notifier.
These get called after all but one CPU have been stopped.

Signed-off-by: Holger Smolinski <Holger.Smolinski@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Holger Smolinski
2008-10-10 21:33:27 +02:00
committed by Martin Schwidefsky
parent 15e86b0c75
commit 2332ce1a97
4 changed files with 86 additions and 18 deletions
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27
drivers/s390/char/con3215.c
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@@ -21,6 +21,7 @@
#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/bootmem.h>
@@ -775,11 +776,11 @@ static struct tty_driver *con3215_device(struct console *c, int *index)
}
/*
* panic() calls console_unblank before the system enters a
* disabled, endless loop.
* panic() calls con3215_flush through a panic_notifier
* before the system enters a disabled, endless loop.
*/
static void
con3215_unblank(void)
con3215_flush(void)
{
struct raw3215_info *raw;
unsigned long flags;
@@ -790,6 +791,23 @@ con3215_unblank(void)
spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}
static int con3215_notify(struct notifier_block *self,
unsigned long event, void *data)
{
con3215_flush();
return NOTIFY_OK;
}
static struct notifier_block on_panic_nb = {
.notifier_call = con3215_notify,
.priority = 0,
};
static struct notifier_block on_reboot_nb = {
.notifier_call = con3215_notify,
.priority = 0,
};
/*
* The console structure for the 3215 console
*/
@@ -797,7 +815,6 @@ static struct console con3215 = {
.name = "ttyS",
.write = con3215_write,
.device = con3215_device,
.unblank = con3215_unblank,
.flags = CON_PRINTBUFFER,
};
@@ -859,6 +876,8 @@ con3215_init(void)
raw3215[0] = NULL;
return -ENODEV;
}
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
register_reboot_notifier(&on_reboot_nb);
register_console(&con3215);
return 0;
}