diff options
Diffstat (limited to 'kernel/printk.c')
| -rw-r--r-- | kernel/printk.c | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/kernel/printk.c b/kernel/printk.c index c056f3324432..19a955619294 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -67,6 +67,7 @@ EXPORT_SYMBOL(oops_in_progress); * driver system. */ static DECLARE_MUTEX(console_sem); +static DECLARE_MUTEX(secondary_console_sem); struct console *console_drivers; /* * This is used for debugging the mess that is the VT code by @@ -76,7 +77,7 @@ struct console *console_drivers; * path in the console code where we end up in places I want * locked without the console sempahore held */ -static int console_locked; +static int console_locked, console_suspended; /* * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars @@ -698,6 +699,23 @@ int __init add_preferred_console(char *name, int idx, char *options) } /** + * suspend_console - suspend the console subsystem + * + * This disables printk() while we go into suspend states + */ +void suspend_console(void) +{ + acquire_console_sem(); + console_suspended = 1; +} + +void resume_console(void) +{ + console_suspended = 0; + release_console_sem(); +} + +/** * acquire_console_sem - lock the console system for exclusive use. * * Acquires a semaphore which guarantees that the caller has @@ -708,6 +726,10 @@ int __init add_preferred_console(char *name, int idx, char *options) void acquire_console_sem(void) { BUG_ON(in_interrupt()); + if (console_suspended) { + down(&secondary_console_sem); + return; + } down(&console_sem); console_locked = 1; console_may_schedule = 1; @@ -750,6 +772,10 @@ void release_console_sem(void) unsigned long _con_start, _log_end; unsigned long wake_klogd = 0; + if (console_suspended) { + up(&secondary_console_sem); + return; + } for ( ; ; ) { spin_lock_irqsave(&logbuf_lock, flags); wake_klogd |= log_start - log_end; |