tracing: Add __print_dynamic_array() helper

[ Upstream commit e52750f ]

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@goodmis.org>
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20241022194158.110073-3-avadhut.naik@amd.com
Stable-dep-of: ea8d764 ("tracing: Verify event formats that have "%*p.."")
Signed-off-by: Sasha Levin <sashal@kernel.org>

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)		\

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
 

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))