From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 15 Dec 2017 18:49:49 +0100
Subject: tracing: Update the "tracing: Inter-event (e.g. latency) support"
 patch
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: 62f92d258e396234f161c632d36743d0d0d0a53c
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension

This commit is an all-in-one update of Tom Zanussi's "tracing: Inter-event
(e.g. latency) support" series from v7 to v8 as posted on 2017-12-21 It
includes the following patches:
 tracing: Move hist trigger Documentation to histogram.txt
 tracing: Add Documentation for log2 modifier
 tracing: Add support to detect and avoid duplicates
 tracing: Remove code which merges duplicates
 ring-buffer: Add interface for setting absolute time stamps
 ring-buffer: Redefine the unimplemented RINGBUF_TYPE_TIME_STAMP
 tracing: Add timestamp_mode trace file
 tracing: Give event triggers access to ring_buffer_event
 tracing: Add ring buffer event param to hist field functions
 tracing: Break out hist trigger assignment parsing
 tracing: Add hist trigger timestamp support
 tracing: Add per-element variable support to tracing_map
 tracing: Add hist_data member to hist_field
 tracing: Add usecs modifier for hist trigger timestamps
 tracing: Add variable support to hist triggers
 tracing: Account for variables in named trigger compatibility
 tracing: Move get_hist_field_flags()
 tracing: Add simple expression support to hist triggers
 tracing: Generalize per-element hist trigger data
 tracing: Pass tracing_map_elt to hist_field accessor functions
 tracing: Add hist_field 'type' field
 tracing: Add variable reference handling to hist triggers
 tracing: Add hist trigger action hook
 tracing: Add support for 'synthetic' events
 tracing: Add support for 'field variables'
 tracing: Add 'onmatch' hist trigger action support
 tracing: Add 'onmax' hist trigger action support
 tracing: Allow whitespace to surround hist trigger filter
 tracing: Add cpu field for hist triggers
 tracing: Add hist trigger support for variable reference aliases
 tracing: Add 'last error' error facility for hist triggers
 tracing: Add inter-event hist trigger Documentation
 tracing: Make tracing_set_clock() non-static
 tracing: Add a clock attribute for hist triggers
 tracing: Increase trace_recursive_lock() limit for synthetic events
 tracing: Add inter-event blurb to HIST_TRIGGERS config option
 selftests: ftrace: Add inter-event hist triggers testcases

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
 kernel/trace/trace_events_hist.c |   34 +++++++++++-----------------------
 1 file changed, 11 insertions(+), 23 deletions(-)

--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -613,7 +613,7 @@ static enum print_line_t print_synth_eve
 		/* parameter values */
 		if (se->fields[i]->is_string) {
 			trace_seq_printf(s, print_fmt, se->fields[i]->name,
-					 (char *)(long)entry->fields[n_u64],
+					 (char *)&entry->fields[n_u64],
 					 i == se->n_fields - 1 ? "" : " ");
 			n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 		} else {
@@ -1500,37 +1500,25 @@ static struct trace_event_file *find_var
 {
 	struct hist_trigger_data *var_hist_data;
 	struct hist_var_data *var_data;
-	struct trace_event_call *call;
 	struct trace_event_file *file, *found = NULL;
-	const char *name;
+
+	if (system)
+		return find_event_file(tr, system, event_name);
 
 	list_for_each_entry(var_data, &tr->hist_vars, list) {
 		var_hist_data = var_data->hist_data;
 		file = var_hist_data->event_file;
 		if (file == found)
 			continue;
-		call = file->event_call;
-		name = trace_event_name(call);
-
-		if (!system || !event_name) {
-			if (find_var(var_hist_data, file, var_name)) {
-				if (found) {
-					hist_err_event("Variable name not unique, need to use fully qualified name (subsys.event.var) for variable: ", system, event_name, var_name);
-					return NULL;
-				}
 
-				found = file;
+		if (find_var_field(var_hist_data, var_name)) {
+			if (found) {
+				hist_err_event("Variable name not unique, need to use fully qualified name (subsys.event.var) for variable: ", system, event_name, var_name);
+				return NULL;
 			}
-			continue;
-		}
-
-		if (strcmp(event_name, name) != 0)
-			continue;
-		if (strcmp(system, call->class->system) != 0)
-			continue;
 
-		found = file;
-		break;
+			found = file;
+		}
 	}
 
 	return found;
@@ -1977,7 +1965,7 @@ static void hist_trigger_elt_data_free(s
 static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
 {
 	struct hist_trigger_data *hist_data = elt->map->private_data;
-	unsigned int size = TASK_COMM_LEN + 1;
+	unsigned int size = TASK_COMM_LEN;
 	struct hist_elt_data *elt_data;
 	struct hist_field *key_field;
 	unsigned int i, n_str;