Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm

[sfrench/cifs-2.6.git] / kernel / printk.c

diff --git a/kernel/printk.c b/kernel/printk.c
index 8cc19431e74ba1d5c52095e7c0f97c56f6018734..19a95561929478ffc99ac1552cf3ab645ec16bc1 100644 (file)
--- 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
@@ -360,8 +361,7 @@ static void call_console_drivers(unsigned long start, unsigned long end)
        unsigned long cur_index, start_print;
        static int msg_level = -1;
 
-       if (((long)(start - end)) > 0)
-               BUG();
+       BUG_ON(((long)(start - end)) > 0);
 
        cur_index = start;
        start_print = start;
@@ -698,6 +698,23 @@ int __init add_preferred_console(char *name, int idx, char *options)
        return 0;
 }
 
+/**
+ * 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.
  *
@@ -708,8 +725,11 @@ int __init add_preferred_console(char *name, int idx, char *options)
  */
 void acquire_console_sem(void)
 {
-       if (in_interrupt())
-               BUG();
+       BUG_ON(in_interrupt());
+       if (console_suspended) {
+               down(&secondary_console_sem);
+               return;
+       }
        down(&console_sem);
        console_locked = 1;
        console_may_schedule = 1;
@@ -752,6 +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;