X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fprintk.c;h=19a95561929478ffc99ac1552cf3ab645ec16bc1;hb=92445eaaadc1f03f5a177ecc957bda76bf2ba8d5;hp=13ced0f7828f477d6edc6356dcdfd7e8617cb567;hpb=9d8d5a284e11e45953ad1f12a5bf1ebc18eefb75;p=linux-2.6

diff --git a/kernel/printk.c b/kernel/printk.c
index 13ced0f782..19a9556192 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
@@ -122,44 +123,6 @@ static char *log_buf = __log_buf;
 static int log_buf_len = __LOG_BUF_LEN;
 static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */
 
-/*
- *	Setup a list of consoles. Called from init/main.c
- */
-static int __init console_setup(char *str)
-{
-	char name[sizeof(console_cmdline[0].name)];
-	char *s, *options;
-	int idx;
-
-	/*
-	 *	Decode str into name, index, options.
-	 */
-	if (str[0] >= '0' && str[0] <= '9') {
-		strcpy(name, "ttyS");
-		strncpy(name + 4, str, sizeof(name) - 5);
-	} else
-		strncpy(name, str, sizeof(name) - 1);
-	name[sizeof(name) - 1] = 0;
-	if ((options = strchr(str, ',')) != NULL)
-		*(options++) = 0;
-#ifdef __sparc__
-	if (!strcmp(str, "ttya"))
-		strcpy(name, "ttyS0");
-	if (!strcmp(str, "ttyb"))
-		strcpy(name, "ttyS1");
-#endif
-	for (s = name; *s; s++)
-		if ((*s >= '0' && *s <= '9') || *s == ',')
-			break;
-	idx = simple_strtoul(s, NULL, 10);
-	*s = 0;
-
-	add_preferred_console(name, idx, options);
-	return 1;
-}
-
-__setup("console=", console_setup);
-
 static int __init log_buf_len_setup(char *str)
 {
 	unsigned long size = memparse(str, &str);
@@ -398,8 +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;
@@ -659,6 +621,44 @@ static void call_console_drivers(unsigned long start, unsigned long end)
 
 #endif
 
+/*
+ * Set up a list of consoles.  Called from init/main.c
+ */
+static int __init console_setup(char *str)
+{
+	char name[sizeof(console_cmdline[0].name)];
+	char *s, *options;
+	int idx;
+
+	/*
+	 * Decode str into name, index, options.
+	 */
+	if (str[0] >= '0' && str[0] <= '9') {
+		strcpy(name, "ttyS");
+		strncpy(name + 4, str, sizeof(name) - 5);
+	} else {
+		strncpy(name, str, sizeof(name) - 1);
+	}
+	name[sizeof(name) - 1] = 0;
+	if ((options = strchr(str, ',')) != NULL)
+		*(options++) = 0;
+#ifdef __sparc__
+	if (!strcmp(str, "ttya"))
+		strcpy(name, "ttyS0");
+	if (!strcmp(str, "ttyb"))
+		strcpy(name, "ttyS1");
+#endif
+	for (s = name; *s; s++)
+		if ((*s >= '0' && *s <= '9') || *s == ',')
+			break;
+	idx = simple_strtoul(s, NULL, 10);
+	*s = 0;
+
+	add_preferred_console(name, idx, options);
+	return 1;
+}
+__setup("console=", console_setup);
+
 /**
  * add_preferred_console - add a device to the list of preferred consoles.
  * @name: device name
@@ -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;