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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/con3270.c
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@ -15,6 +15,7 @@
#include <linux/list.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
@ -528,11 +529,11 @@ con3270_wait_write(struct con3270 *cp)
}
/*
* panic() calls console_unblank before the system enters a
* disabled, endless loop.
* panic() calls con3270_flush through a panic_notifier
* before the system enters a disabled, endless loop.
*/
static void
con3270_unblank(void)
con3270_flush(void)
{
struct con3270 *cp;
unsigned long flags;
@ -554,6 +555,23 @@ con3270_unblank(void)
spin_unlock_irqrestore(&cp->view.lock, flags);
}
static int con3270_notify(struct notifier_block *self,
unsigned long event, void *data)
{
con3270_flush();
return NOTIFY_OK;
}
static struct notifier_block on_panic_nb = {
.notifier_call = con3270_notify,
.priority = 0,
};
static struct notifier_block on_reboot_nb = {
.notifier_call = con3270_notify,
.priority = 0,
};
/*
* The console structure for the 3270 console
*/
@ -561,7 +579,6 @@ static struct console con3270 = {
.name = "tty3270",
.write = con3270_write,
.device = con3270_device,
.unblank = con3270_unblank,
.flags = CON_PRINTBUFFER,
};
@ -623,6 +640,8 @@ con3270_init(void)
condev->cline->len = 0;
con3270_create_status(condev);
condev->input = alloc_string(&condev->freemem, 80);
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
register_reboot_notifier(&on_reboot_nb);
register_console(&con3270);
return 0;
}