tracing: Add __string_len() example

There's no example code that uses __string_len(), and since the sample
code is used for testing the event logic, add a use case.

Link: https://lore.kernel.org/linux-trace-kernel/20240223152827.5f9f78e2@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Google) 2024-02-23 15:28:27 -05:00
parent c759e60903
commit dd6ae6d90a

View File

@ -303,6 +303,7 @@ TRACE_EVENT(foo_bar,
__bitmask( cpus, num_possible_cpus() )
__cpumask( cpum )
__vstring( vstr, fmt, va )
__string_len( lstr, foo, bar / 2 < strlen(foo) ? bar / 2 : strlen(foo) )
),
TP_fast_assign(
@ -311,12 +312,13 @@ TRACE_EVENT(foo_bar,
memcpy(__get_dynamic_array(list), lst,
__length_of(lst) * sizeof(int));
__assign_str(str, string);
__assign_str(lstr, foo);
__assign_vstr(vstr, fmt, va);
__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
__assign_cpumask(cpum, cpumask_bits(mask));
),
TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,
TP_printk("foo %s %d %s %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,
/*
* Notice here the use of some helper functions. This includes:
@ -360,7 +362,8 @@ TRACE_EVENT(foo_bar,
__print_array(__get_dynamic_array(list),
__get_dynamic_array_len(list) / sizeof(int),
sizeof(int)),
__get_str(str), __get_bitmask(cpus), __get_cpumask(cpum),
__get_str(str), __get_str(lstr),
__get_bitmask(cpus), __get_cpumask(cpum),
__get_str(vstr))
);