[PATCH v5 2/5] tracing: Add __print_dynamic_array() helper

From: Avadhut Naik
Date: Tue Oct 01 2024 - 14:17:11 EST


From: Steven Rostedt <rostedt@xxxxxxxxxxx>

When printing a dynamic array in a trace event, the method is rather ugly.
It has the format of:

__print_array(__get_dynamic_array(array),
__get_dynmaic_array_len(array) / el_size, el_size)

Since dynamic arrays are known to the tracing infrastructure, create a
helper macro that does the above for you.

__print_dynamic_array(array, el_size)

Which would expand to the same output.

Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Avadhut Naik <avadhut.naik@xxxxxxx>
---
Changes in v5:
Patch introduced in the series.
---
include/trace/stages/stage3_trace_output.h | 8 ++++++++
include/trace/stages/stage7_class_define.h | 1 +
samples/trace_events/trace-events-sample.h | 7 ++++++-
3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h
index c1fb1355d309..8e3215093e1f 100644
--- a/include/trace/stages/stage3_trace_output.h
+++ b/include/trace/stages/stage3_trace_output.h
@@ -119,6 +119,14 @@
trace_print_array_seq(p, array, count, el_size); \
})

+#undef __print_dynamic_array
+#define __print_dynamic_array(array, el_size) \
+ ({ \
+ __print_array(__get_dynamic_array(array), \
+ __get_dynamic_array_len(array) / el_size, \
+ el_size); \
+ })
+
#undef __print_hex_dump
#define __print_hex_dump(prefix_str, prefix_type, \
rowsize, groupsize, buf, len, ascii) \
diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h
index bcb960d16fc0..fcd564a590f4 100644
--- a/include/trace/stages/stage7_class_define.h
+++ b/include/trace/stages/stage7_class_define.h
@@ -22,6 +22,7 @@
#undef __get_rel_cpumask
#undef __get_rel_sockaddr
#undef __print_array
+#undef __print_dynamic_array
#undef __print_hex_dump
#undef __get_buf

diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 55f9a3da92d5..999f78d380ae 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -319,7 +319,7 @@ TRACE_EVENT(foo_bar,
__assign_cpumask(cpum, cpumask_bits(mask));
),

- TP_printk("foo %s %d %s %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,
+ TP_printk("foo %s %d %s %s %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,

/*
* Notice here the use of some helper functions. This includes:
@@ -363,6 +363,11 @@ TRACE_EVENT(foo_bar,
__print_array(__get_dynamic_array(list),
__get_dynamic_array_len(list) / sizeof(int),
sizeof(int)),
+
+/* A shortcut is to use __print_dynamic_array for dynamic arrays */
+
+ __print_dynamic_array(list, sizeof(int)),
+
__get_str(str), __get_str(lstr),
__get_bitmask(cpus), __get_cpumask(cpum),
__get_str(vstr))
--
2.43.0