[S390] console flush on panic / reboot
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>
diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index d3ec9b5..982cf62 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -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 @@
}
/*
- * 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 @@
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 @@
.name = "ttyS",
.write = con3215_write,
.device = con3215_device,
- .unblank = con3215_unblank,
.flags = CON_PRINTBUFFER,
};
@@ -859,6 +876,8 @@
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;
}