Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/sc…

…m/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  tracing: Remove comparing of NULL to va_list in trace_array_vprintk()
  tracing: Fix function graph trace_pipe to properly display failed entries
  tracing: Add full state to trace_seq
  tracing: Buffer the output of seq_file in case of filled buffer
  tracing: Only call pipe_close if pipe_close is defined
  tracing: Add pipe_close interface

include/linux/ftrace_event.h

@@ -57,6 +57,7 @@ struct trace_iterator {
 	/* The below is zeroed out in pipe_read */
 	struct trace_seq	seq;
 	struct trace_entry	*ent;
+	int			leftover;
 	int			cpu;
 	u64			ts;
 

include/linux/trace_seq.h

@@ -14,13 +14,15 @@ struct trace_seq {
 	unsigned char		buffer[PAGE_SIZE];
 	unsigned int		len;
 	unsigned int		readpos;
+	int			full;
 };
 
 static inline void
 trace_seq_init(struct trace_seq *s)
 {
 	s->len = 0;
 	s->readpos = 0;
+	s->full = 0;
 }
 
 /*
@@ -33,7 +35,7 @@ extern int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
 	__attribute__ ((format (printf, 2, 0)));
 extern int
 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
-extern void trace_print_seq(struct seq_file *m, struct trace_seq *s);
+extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
 extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 				 size_t cnt);
 extern int trace_seq_puts(struct trace_seq *s, const char *str);
@@ -55,8 +57,9 @@ trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 	return 0;
 }
 
-static inline void trace_print_seq(struct seq_file *m, struct trace_seq *s)
+static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
 {
+	return 0;
 }
 static inline ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 				 size_t cnt)

kernel/trace/trace.c

@@ -1361,11 +1361,7 @@ int trace_array_vprintk(struct trace_array *tr,
 	pause_graph_tracing();
 	raw_local_irq_save(irq_flags);
 	__raw_spin_lock(&trace_buf_lock);
-	if (args == NULL) {
-		strncpy(trace_buf, fmt, TRACE_BUF_SIZE);
-		len = strlen(trace_buf);
-	} else
-		len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+	len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
 
 	size = sizeof(*entry) + len + 1;
 	buffer = tr->buffer;
@@ -1516,6 +1512,8 @@ static void *s_next(struct seq_file *m, void *v, loff_t *pos)
 	int i = (int)*pos;
 	void *ent;
 
+	WARN_ON_ONCE(iter->leftover);
+
 	(*pos)++;
 
 	/* can't go backwards */
@@ -1614,8 +1612,16 @@ static void *s_start(struct seq_file *m, loff_t *pos)
 			;
 
 	} else {
-		l = *pos - 1;
-		p = s_next(m, p, &l);
+		/*
+		 * If we overflowed the seq_file before, then we want
+		 * to just reuse the trace_seq buffer again.
+		 */
+		if (iter->leftover)
+			p = iter;
+		else {
+			l = *pos - 1;
+			p = s_next(m, p, &l);
+		}
 	}
 
 	trace_event_read_lock();
@@ -1923,6 +1929,7 @@ static enum print_line_t print_trace_line(struct trace_iterator *iter)
 static int s_show(struct seq_file *m, void *v)
 {
 	struct trace_iterator *iter = v;
+	int ret;
 
 	if (iter->ent == NULL) {
 		if (iter->tr) {
@@ -1942,9 +1949,27 @@ static int s_show(struct seq_file *m, void *v)
 			if (!(trace_flags & TRACE_ITER_VERBOSE))
 				print_func_help_header(m);
 		}
+	} else if (iter->leftover) {
+		/*
+		 * If we filled the seq_file buffer earlier, we
+		 * want to just show it now.
+		 */
+		ret = trace_print_seq(m, &iter->seq);
+
+		/* ret should this time be zero, but you never know */
+		iter->leftover = ret;
+
 	} else {
 		print_trace_line(iter);
-		trace_print_seq(m, &iter->seq);
+		ret = trace_print_seq(m, &iter->seq);
+		/*
+		 * If we overflow the seq_file buffer, then it will
+		 * ask us for this data again at start up.
+		 * Use that instead.
+		 *  ret is 0 if seq_file write succeeded.
+		 *        -1 otherwise.
+		 */
+		iter->leftover = ret;
 	}
 
 	return 0;
@@ -2898,6 +2923,10 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
 	else
 		cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask);
 
+
+	if (iter->trace->pipe_close)
+		iter->trace->pipe_close(iter);
+
 	mutex_unlock(&trace_types_lock);
 
 	free_cpumask_var(iter->started);
@@ -3320,6 +3349,16 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
 	return cnt;
 }
 
+static int mark_printk(const char *fmt, ...)
+{
+	int ret;
+	va_list args;
+	va_start(args, fmt);
+	ret = trace_vprintk(0, fmt, args);
+	va_end(args);
+	return ret;
+}
+
 static ssize_t
 tracing_mark_write(struct file *filp, const char __user *ubuf,
 					size_t cnt, loff_t *fpos)
@@ -3346,7 +3385,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 	} else
 		buf[cnt] = '\0';
 
-	cnt = trace_vprintk(0, buf, NULL);
+	cnt = mark_printk("%s", buf);
 	kfree(buf);
 	*fpos += cnt;
 

kernel/trace/trace.h

@@ -272,6 +272,7 @@ struct tracer_flags {
  * @pipe_open: called when the trace_pipe file is opened
  * @wait_pipe: override how the user waits for traces on trace_pipe
  * @close: called when the trace file is released
+ * @pipe_close: called when the trace_pipe file is released
  * @read: override the default read callback on trace_pipe
  * @splice_read: override the default splice_read callback on trace_pipe
  * @selftest: selftest to run on boot (see trace_selftest.c)
@@ -290,6 +291,7 @@ struct tracer {
 	void			(*pipe_open)(struct trace_iterator *iter);
 	void			(*wait_pipe)(struct trace_iterator *iter);
 	void			(*close)(struct trace_iterator *iter);
+	void			(*pipe_close)(struct trace_iterator *iter);
 	ssize_t			(*read)(struct trace_iterator *iter,
 					struct file *filp, char __user *ubuf,
 					size_t cnt, loff_t *ppos);