[PATCH -next] trace doc: Fix the wrong example of tracepoint

From: Zhang Jianhua
Date: Mon Jul 19 2021 - 22:10:54 EST

The example in tracepoints.rst is out of date, the build error below
will occur if coding according to example in the document.

error: macro "DEFINE_TRACE" requires 3 arguments, but only 1 given
24 | DEFINE_TRACE(test_event);
| ^
In file included from include/trace/events/test.h:8,
from drivers/irqchip/irq-riscv-intc.c:22:
note: macro "DEFINE_TRACE" defined here
368 | #define DEFINE_TRACE(name, proto, args)
warning: data definition has no type or storage class
24 | DEFINE_TRACE(test_event);
| ^~~~~~~~~~~~
error: type defaults to ‘int’ in declaration of ‘DEFINE_TRACE’

There are two reasons for this error. On the one hand, the macro DEFINE_TRACE
has been refactored in commit d25e37d89dd2 ("tracepoint: Optimize using
static_call()") from DEFINE_TRACE(name) to DEFINE_TRACE(name, proto, args),
and the doc is not updated in time. On the other hand, the tracepoint has been
defined in header file, and it does not need to define repeatedly in C file.


Signed-off-by: Zhang Jianhua <chris.zjh@xxxxxxxxxx>
Documentation/trace/tracepoints.rst | 1 -
1 file changed, 1 deletion(-)

diff --git a/Documentation/trace/tracepoints.rst b/Documentation/trace/tracepoints.rst
index 0cb8d9ca3d60..fbb2cb4abd3d 100644
--- a/Documentation/trace/tracepoints.rst
+++ b/Documentation/trace/tracepoints.rst
@@ -66,7 +66,6 @@ In subsys/file.c (where the tracing statement must be added)::
#include <trace/events/subsys.h>

- DEFINE_TRACE(subsys_eventname);

void somefct(void)