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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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24
drivers/s390/char/sclp_con.c
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@@ -16,6 +16,7 @@
#include <linux/bootmem.h>
#include <linux/termios.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include "sclp.h"
#include "sclp_rw.h"
@@ -172,7 +173,7 @@ sclp_console_device(struct console *c, int *index)
* will be flushed to the SCLP.
*/
static void
sclp_console_unblank(void)
sclp_console_flush(void)
{
unsigned long flags;
@@ -188,6 +189,24 @@ sclp_console_unblank(void)
spin_unlock_irqrestore(&sclp_con_lock, flags);
}
static int
sclp_console_notify(struct notifier_block *self,
unsigned long event, void *data)
{
sclp_console_flush();
return NOTIFY_OK;
}
static struct notifier_block on_panic_nb = {
.notifier_call = sclp_console_notify,
.priority = 1,
};
static struct notifier_block on_reboot_nb = {
.notifier_call = sclp_console_notify,
.priority = 1,
};
/*
* used to register the SCLP console to the kernel and to
* give printk necessary information
@@ -197,7 +216,6 @@ static struct console sclp_console =
.name = sclp_console_name,
.write = sclp_console_write,
.device = sclp_console_device,
.unblank = sclp_console_unblank,
.flags = CON_PRINTBUFFER,
.index = 0 /* ttyS0 */
};
@@ -241,6 +259,8 @@ sclp_console_init(void)
sclp_con_width_htab = 8;
/* enable printk-access to this driver */
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
register_reboot_notifier(&on_reboot_nb);
register_console(&sclp_console);
return 0;
}