1 files changed, 101 insertions, 81 deletions

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 247808333ba4..90b6ab01db59 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -349,7 +349,7 @@ static int console_msg_format = MSG_FORMAT_DEFAULT;
  */
 
 enum log_flags {
-	LOG_NOCONS	= 1,	/* already flushed, do not print to console */
+	LOG_NOCONS	= 1,	/* suppress print, do not print to console */
 	LOG_NEWLINE	= 2,	/* text ended with a newline */
 	LOG_PREFIX	= 4,	/* text started with a prefix */
 	LOG_CONT	= 8,	/* text is a fragment of a continuation line */
@@ -1352,71 +1352,68 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
 {
 	char *text;
 	int len = 0;
+	u64 next_seq;
+	u64 seq;
+	u32 idx;
 
 	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
 	if (!text)
 		return -ENOMEM;
 
 	logbuf_lock_irq();
-	if (buf) {
-		u64 next_seq;
-		u64 seq;
-		u32 idx;
+	/*
+	 * Find first record that fits, including all following records,
+	 * into the user-provided buffer for this dump.
+	 */
+	seq = clear_seq;
+	idx = clear_idx;
+	while (seq < log_next_seq) {
+		struct printk_log *msg = log_from_idx(idx);
 
-		/*
-		 * Find first record that fits, including all following records,
-		 * into the user-provided buffer for this dump.
-		 */
-		seq = clear_seq;
-		idx = clear_idx;
-		while (seq < log_next_seq) {
-			struct printk_log *msg = log_from_idx(idx);
-
-			len += msg_print_text(msg, true, NULL, 0);
-			idx = log_next(idx);
-			seq++;
-		}
+		len += msg_print_text(msg, true, NULL, 0);
+		idx = log_next(idx);
+		seq++;
+	}
 
-		/* move first record forward until length fits into the buffer */
-		seq = clear_seq;
-		idx = clear_idx;
-		while (len > size && seq < log_next_seq) {
-			struct printk_log *msg = log_from_idx(idx);
+	/* move first record forward until length fits into the buffer */
+	seq = clear_seq;
+	idx = clear_idx;
+	while (len > size && seq < log_next_seq) {
+		struct printk_log *msg = log_from_idx(idx);
 
-			len -= msg_print_text(msg, true, NULL, 0);
-			idx = log_next(idx);
-			seq++;
-		}
+		len -= msg_print_text(msg, true, NULL, 0);
+		idx = log_next(idx);
+		seq++;
+	}
 
-		/* last message fitting into this dump */
-		next_seq = log_next_seq;
+	/* last message fitting into this dump */
+	next_seq = log_next_seq;
 
-		len = 0;
-		while (len >= 0 && seq < next_seq) {
-			struct printk_log *msg = log_from_idx(idx);
-			int textlen;
+	len = 0;
+	while (len >= 0 && seq < next_seq) {
+		struct printk_log *msg = log_from_idx(idx);
+		int textlen;
 
-			textlen = msg_print_text(msg, true, text,
-						 LOG_LINE_MAX + PREFIX_MAX);
-			if (textlen < 0) {
-				len = textlen;
-				break;
-			}
-			idx = log_next(idx);
-			seq++;
+		textlen = msg_print_text(msg, true, text,
+					 LOG_LINE_MAX + PREFIX_MAX);
+		if (textlen < 0) {
+			len = textlen;
+			break;
+		}
+		idx = log_next(idx);
+		seq++;
 
-			logbuf_unlock_irq();
-			if (copy_to_user(buf + len, text, textlen))
-				len = -EFAULT;
-			else
-				len += textlen;
-			logbuf_lock_irq();
-
-			if (seq < log_first_seq) {
-				/* messages are gone, move to next one */
-				seq = log_first_seq;
-				idx = log_first_idx;
-			}
+		logbuf_unlock_irq();
+		if (copy_to_user(buf + len, text, textlen))
+			len = -EFAULT;
+		else
+			len += textlen;
+		logbuf_lock_irq();
+
+		if (seq < log_first_seq) {
+			/* messages are gone, move to next one */
+			seq = log_first_seq;
+			idx = log_first_idx;
 		}
 	}
 
@@ -1430,6 +1427,14 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
 	return len;
 }
 
+static void syslog_clear(void)
+{
+	logbuf_lock_irq();
+	clear_seq = log_next_seq;
+	clear_idx = log_next_idx;
+	logbuf_unlock_irq();
+}
+
 int do_syslog(int type, char __user *buf, int len, int source)
 {
 	bool clear = false;
@@ -1474,7 +1479,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
 		break;
 	/* Clear ring buffer */
 	case SYSLOG_ACTION_CLEAR:
-		syslog_print_all(NULL, 0, true);
+		syslog_clear();
 		break;
 	/* Disable logging to console */
 	case SYSLOG_ACTION_CONSOLE_OFF:
@@ -1824,28 +1829,16 @@ static size_t log_output(int facility, int level, enum log_flags lflags, const c
 	return log_store(facility, level, lflags, 0, dict, dictlen, text, text_len);
 }
 
-asmlinkage int vprintk_emit(int facility, int level,
-			    const char *dict, size_t dictlen,
-			    const char *fmt, va_list args)
+/* Must be called under logbuf_lock. */
+int vprintk_store(int facility, int level,
+		  const char *dict, size_t dictlen,
+		  const char *fmt, va_list args)
 {
 	static char textbuf[LOG_LINE_MAX];
 	char *text = textbuf;
 	size_t text_len;
 	enum log_flags lflags = 0;
-	unsigned long flags;
-	int printed_len;
-	bool in_sched = false;
 
-	if (level == LOGLEVEL_SCHED) {
-		level = LOGLEVEL_DEFAULT;
-		in_sched = true;
-	}
-
-	boot_delay_msec(level);
-	printk_delay();
-
-	/* This stops the holder of console_sem just where we want him */
-	logbuf_lock_irqsave(flags);
 	/*
 	 * The printf needs to come first; we need the syslog
 	 * prefix which might be passed-in as a parameter.
@@ -1886,8 +1879,32 @@ asmlinkage int vprintk_emit(int facility, int level,
 	if (dict)
 		lflags |= LOG_PREFIX|LOG_NEWLINE;
 
-	printed_len = log_output(facility, level, lflags, dict, dictlen, text, text_len);
+	if (suppress_message_printing(level))
+		lflags |= LOG_NOCONS;
+
+	return log_output(facility, level, lflags,
+			  dict, dictlen, text, text_len);
+}
+
+asmlinkage int vprintk_emit(int facility, int level,
+			    const char *dict, size_t dictlen,
+			    const char *fmt, va_list args)
+{
+	int printed_len;
+	bool in_sched = false;
+	unsigned long flags;
+
+	if (level == LOGLEVEL_SCHED) {
+		level = LOGLEVEL_DEFAULT;
+		in_sched = true;
+	}
 
+	boot_delay_msec(level);
+	printk_delay();
+
+	/* This stops the holder of console_sem just where we want him */
+	logbuf_lock_irqsave(flags);
+	printed_len = vprintk_store(facility, level, dict, dictlen, fmt, args);
 	logbuf_unlock_irqrestore(flags);
 
 	/* If called from the scheduler, we can not call up(). */
@@ -2013,7 +2030,6 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
 				 const char *text, size_t len) {}
 static size_t msg_print_text(const struct printk_log *msg,
 			     bool syslog, char *buf, size_t size) { return 0; }
-static bool suppress_message_printing(int level) { return false; }
 
 #endif /* CONFIG_PRINTK */
 
@@ -2243,6 +2259,7 @@ int is_console_locked(void)
 {
 	return console_locked;
 }
+EXPORT_SYMBOL(is_console_locked);
 
 /*
  * Check if we have any console that is capable of printing while cpu is
@@ -2349,11 +2366,10 @@ skip:
 			break;
 
 		msg = log_from_idx(console_idx);
-		if (suppress_message_printing(msg->level)) {
+		if (msg->flags & LOG_NOCONS) {
 			/*
-			 * Skip record we have buffered and already printed
-			 * directly to the console when we received it, and
-			 * record that has level above the console loglevel.
+			 * Skip record if !ignore_loglevel, and
+			 * record has level above the console loglevel.
 			 */
 			console_idx = log_next(console_idx);
 			console_seq++;
@@ -2878,16 +2894,20 @@ void wake_up_klogd(void)
 	preempt_enable();
 }
 
-int vprintk_deferred(const char *fmt, va_list args)
+void defer_console_output(void)
 {
-	int r;
-
-	r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
-
 	preempt_disable();
 	__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
 	irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
 	preempt_enable();
+}
+
+int vprintk_deferred(const char *fmt, va_list args)
+{
+	int r;
+
+	r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
+	defer_console_output();
 
 	return r;
 }