1 files changed, 55 insertions, 38 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index 2d607f4d179..0b31715f335 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -42,6 +42,7 @@
 #include <linux/notifier.h>
 #include <linux/rculist.h>
 #include <linux/poll.h>
+#include <linux/irq_work.h>
 
 #include <asm/uaccess.h>
 
@@ -87,6 +88,12 @@ static DEFINE_SEMAPHORE(console_sem);
 struct console *console_drivers;
 EXPORT_SYMBOL_GPL(console_drivers);
 
+#ifdef CONFIG_LOCKDEP
+static struct lockdep_map console_lock_dep_map = {
+	.name = "console_lock"
+};
+#endif
+
 /*
  * This is used for debugging the mess that is the VT code by
  * keeping track if we have the console semaphore held. It's
@@ -741,6 +748,21 @@ void __init setup_log_buf(int early)
 		free, (free * 100) / __LOG_BUF_LEN);
 }
 
+static bool __read_mostly ignore_loglevel;
+
+static int __init ignore_loglevel_setup(char *str)
+{
+	ignore_loglevel = 1;
+	printk(KERN_INFO "debug: ignoring loglevel setting.\n");
+
+	return 0;
+}
+
+early_param("ignore_loglevel", ignore_loglevel_setup);
+module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
+	"print all kernel messages to the console.");
+
 #ifdef CONFIG_BOOT_PRINTK_DELAY
 
 static int boot_delay; /* msecs delay after each printk during bootup */
@@ -764,13 +786,15 @@ static int __init boot_delay_setup(char *str)
 }
 __setup("boot_delay=", boot_delay_setup);
 
-static void boot_delay_msec(void)
+static void boot_delay_msec(int level)
 {
 	unsigned long long k;
 	unsigned long timeout;
 
-	if (boot_delay == 0 || system_state != SYSTEM_BOOTING)
+	if ((boot_delay == 0 || system_state != SYSTEM_BOOTING)
+		|| (level >= console_loglevel && !ignore_loglevel)) {
 		return;
+	}
 
 	k = (unsigned long long)loops_per_msec * boot_delay;
 
@@ -789,7 +813,7 @@ static void boot_delay_msec(void)
 	}
 }
 #else
-static inline void boot_delay_msec(void)
+static inline void boot_delay_msec(int level)
 {
 }
 #endif
@@ -847,10 +871,11 @@ static size_t print_time(u64 ts, char *buf)
 	if (!printk_time)
 		return 0;
 
+	rem_nsec = do_div(ts, 1000000000);
+
 	if (!buf)
-		return 15;
+		return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts);
 
-	rem_nsec = do_div(ts, 1000000000);
 	return sprintf(buf, "[%5lu.%06lu] ",
 		       (unsigned long)ts, rem_nsec / 1000);
 }
@@ -1232,21 +1257,6 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
 	return do_syslog(type, buf, len, SYSLOG_FROM_CALL);
 }
 
-static bool __read_mostly ignore_loglevel;
-
-static int __init ignore_loglevel_setup(char *str)
-{
-	ignore_loglevel = 1;
-	printk(KERN_INFO "debug: ignoring loglevel setting.\n");
-
-	return 0;
-}
-
-early_param("ignore_loglevel", ignore_loglevel_setup);
-module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
-	"print all kernel messages to the console.");
-
 /*
  * Call the console drivers, asking them to write out
  * log_buf[start] to log_buf[end - 1].
@@ -1492,7 +1502,7 @@ asmlinkage int vprintk_emit(int facility, int level,
 	int this_cpu;
 	int printed_len = 0;
 
-	boot_delay_msec();
+	boot_delay_msec(level);
 	printk_delay();
 
 	/* This stops the holder of console_sem just where we want him */
@@ -1908,12 +1918,14 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self,
  */
 void console_lock(void)
 {
-	BUG_ON(in_interrupt());
+	might_sleep();
+
 	down(&console_sem);
 	if (console_suspended)
 		return;
 	console_locked = 1;
 	console_may_schedule = 1;
+	mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);
 }
 EXPORT_SYMBOL(console_lock);
 
@@ -1935,6 +1947,7 @@ int console_trylock(void)
 	}
 	console_locked = 1;
 	console_may_schedule = 0;
+	mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_);
 	return 1;
 }
 EXPORT_SYMBOL(console_trylock);
@@ -1955,30 +1968,32 @@ int is_console_locked(void)
 static DEFINE_PER_CPU(int, printk_pending);
 static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
 
-void printk_tick(void)
+static void wake_up_klogd_work_func(struct irq_work *irq_work)
 {
-	if (__this_cpu_read(printk_pending)) {
-		int pending = __this_cpu_xchg(printk_pending, 0);
-		if (pending & PRINTK_PENDING_SCHED) {
-			char *buf = __get_cpu_var(printk_sched_buf);
-			printk(KERN_WARNING "[sched_delayed] %s", buf);
-		}
-		if (pending & PRINTK_PENDING_WAKEUP)
-			wake_up_interruptible(&log_wait);
+	int pending = __this_cpu_xchg(printk_pending, 0);
+
+	if (pending & PRINTK_PENDING_SCHED) {
+		char *buf = __get_cpu_var(printk_sched_buf);
+		printk(KERN_WARNING "[sched_delayed] %s", buf);
 	}
-}
 
-int printk_needs_cpu(int cpu)
-{
-	if (cpu_is_offline(cpu))
-		printk_tick();
-	return __this_cpu_read(printk_pending);
+	if (pending & PRINTK_PENDING_WAKEUP)
+		wake_up_interruptible(&log_wait);
 }
 
+static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
+	.func = wake_up_klogd_work_func,
+	.flags = IRQ_WORK_LAZY,
+};
+
 void wake_up_klogd(void)
 {
-	if (waitqueue_active(&log_wait))
+	preempt_disable();
+	if (waitqueue_active(&log_wait)) {
 		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
+		irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
+	}
+	preempt_enable();
 }
 
 static void console_cont_flush(char *text, size_t size)
@@ -2095,6 +2110,7 @@ skip:
 		local_irq_restore(flags);
 	}
 	console_locked = 0;
+	mutex_release(&console_lock_dep_map, 1, _RET_IP_);
 
 	/* Release the exclusive_console once it is used */
 	if (unlikely(exclusive_console))
@@ -2458,6 +2474,7 @@ int printk_sched(const char *fmt, ...)
 	va_end(args);
 
 	__this_cpu_or(printk_pending, PRINTK_PENDING_SCHED);
+	irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
 	local_irq_restore(flags);
 
 	return r;