diff options
Diffstat (limited to 'drivers/s390/char/con3270.c')
| -rw-r--r-- | drivers/s390/char/con3270.c | 31 |
1 files changed, 16 insertions, 15 deletions
diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c index e4592890f20a..10f6a37fb153 100644 --- a/drivers/s390/char/con3270.c +++ b/drivers/s390/char/con3270.c @@ -535,20 +535,26 @@ con3270_wait_write(struct con3270 *cp) } /* - * panic() calls con3270_flush through a panic_notifier - * before the system enters a disabled, endless loop. + * The below function is called as a panic/reboot notifier before the + * system enters a disabled, endless loop. + * + * Notice we must use the spin_trylock() alternative, to prevent lockups + * in atomic context (panic routine runs with secondary CPUs, local IRQs + * and preemption disabled). */ -static void -con3270_flush(void) +static int con3270_notify(struct notifier_block *self, + unsigned long event, void *data) { struct con3270 *cp; unsigned long flags; cp = condev; if (!cp->view.dev) - return; - raw3270_activate_view(&cp->view); - spin_lock_irqsave(&cp->view.lock, flags); + return NOTIFY_DONE; + if (!raw3270_view_lock_unavailable(&cp->view)) + raw3270_activate_view(&cp->view); + if (!spin_trylock_irqsave(&cp->view.lock, flags)) + return NOTIFY_DONE; con3270_wait_write(cp); cp->nr_up = 0; con3270_rebuild_update(cp); @@ -560,23 +566,18 @@ con3270_flush(void) con3270_wait_write(cp); } 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; + return NOTIFY_DONE; } static struct notifier_block on_panic_nb = { .notifier_call = con3270_notify, - .priority = 0, + .priority = INT_MIN + 1, /* run the callback late */ }; static struct notifier_block on_reboot_nb = { .notifier_call = con3270_notify, - .priority = 0, + .priority = INT_MIN + 1, /* run the callback late */ }; /* |