tracing: Constify struct event_trigger_ops

'event_trigger_ops mwifiex_if_ops' are not modified in these drivers.

Constifying these structures moves some data to a read-only section, so
increase overall security, especially when the structure holds some
function pointers.

On a x86_64, with allmodconfig, as an example:
Before:
======
   text	   data	    bss	    dec	    hex	filename
  31368	   9024	   6200	  46592	   b600	kernel/trace/trace_events_trigger.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
  31752	   8608	   6200	  46560	   b5e0	kernel/trace/trace_events_trigger.o

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/66e8f990e649678e4be37d4d1a19158ca0dea2f4.1741521295.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Author: tititiou36

kernel/trace/trace.h

@@ -1714,7 +1714,7 @@ struct event_trigger_data {
 	unsigned long			count;
 	int				ref;
 	int				flags;
-	struct event_trigger_ops	*ops;
+	const struct event_trigger_ops	*ops;
 	struct event_command		*cmd_ops;
 	struct event_filter __rcu	*filter;
 	char				*filter_str;
@@ -1959,7 +1959,7 @@ struct event_command {
 	int			(*set_filter)(char *filter_str,
 					      struct event_trigger_data *data,
 					      struct trace_event_file *file);
-	struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
+	const struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
 };
 
 /**

kernel/trace/trace_eprobe.c

@@ -478,7 +478,7 @@ static void eprobe_trigger_func(struct event_trigger_data *data,
 	__eprobe_trace_func(edata, rec);
 }
 
-static struct event_trigger_ops eprobe_trigger_ops = {
+static const struct event_trigger_ops eprobe_trigger_ops = {
 	.trigger		= eprobe_trigger_func,
 	.print			= eprobe_trigger_print,
 	.init			= eprobe_trigger_init,
@@ -507,8 +507,8 @@ static void eprobe_trigger_unreg_func(char *glob,
 
 }
 
-static struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd,
-							char *param)
+static const struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd,
+							      char *param)
 {
 	return &eprobe_trigger_ops;
 }

kernel/trace/trace_events_hist.c

@@ -6191,7 +6191,7 @@ static void event_hist_trigger_free(struct event_trigger_data *data)
 	}
 }
 
-static struct event_trigger_ops event_hist_trigger_ops = {
+static const struct event_trigger_ops event_hist_trigger_ops = {
 	.trigger		= event_hist_trigger,
 	.print			= event_hist_trigger_print,
 	.init			= event_hist_trigger_init,
@@ -6223,15 +6223,15 @@ static void event_hist_trigger_named_free(struct event_trigger_data *data)
 	}
 }
 
-static struct event_trigger_ops event_hist_trigger_named_ops = {
+static const struct event_trigger_ops event_hist_trigger_named_ops = {
 	.trigger		= event_hist_trigger,
 	.print			= event_hist_trigger_print,
 	.init			= event_hist_trigger_named_init,
 	.free			= event_hist_trigger_named_free,
 };
 
-static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
-							    char *param)
+static const struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
+								  char *param)
 {
 	return &event_hist_trigger_ops;
 }
@@ -6826,38 +6826,38 @@ hist_enable_count_trigger(struct event_trigger_data *data,
 	hist_enable_trigger(data, buffer, rec, event);
 }
 
-static struct event_trigger_ops hist_enable_trigger_ops = {
+static const struct event_trigger_ops hist_enable_trigger_ops = {
 	.trigger		= hist_enable_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops hist_enable_count_trigger_ops = {
+static const struct event_trigger_ops hist_enable_count_trigger_ops = {
 	.trigger		= hist_enable_count_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops hist_disable_trigger_ops = {
+static const struct event_trigger_ops hist_disable_trigger_ops = {
 	.trigger		= hist_enable_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops hist_disable_count_trigger_ops = {
+static const struct event_trigger_ops hist_disable_count_trigger_ops = {
 	.trigger		= hist_enable_count_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 hist_enable_get_trigger_ops(char *cmd, char *param)
 {
-	struct event_trigger_ops *ops;
+	const struct event_trigger_ops *ops;
 	bool enable;
 
 	enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);

kernel/trace/trace_events_trigger.c

@@ -825,7 +825,7 @@ struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
 					       void *private_data)
 {
 	struct event_trigger_data *trigger_data;
-	struct event_trigger_ops *trigger_ops;
+	const struct event_trigger_ops *trigger_ops;
 
 	trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
 
@@ -1367,38 +1367,38 @@ traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
 				   data->filter_str);
 }
 
-static struct event_trigger_ops traceon_trigger_ops = {
+static const struct event_trigger_ops traceon_trigger_ops = {
 	.trigger		= traceon_trigger,
 	.print			= traceon_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops traceon_count_trigger_ops = {
+static const struct event_trigger_ops traceon_count_trigger_ops = {
 	.trigger		= traceon_count_trigger,
 	.print			= traceon_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops traceoff_trigger_ops = {
+static const struct event_trigger_ops traceoff_trigger_ops = {
 	.trigger		= traceoff_trigger,
 	.print			= traceoff_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops traceoff_count_trigger_ops = {
+static const struct event_trigger_ops traceoff_count_trigger_ops = {
 	.trigger		= traceoff_count_trigger,
 	.print			= traceoff_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 onoff_get_trigger_ops(char *cmd, char *param)
 {
-	struct event_trigger_ops *ops;
+	const struct event_trigger_ops *ops;
 
 	/* we register both traceon and traceoff to this callback */
 	if (strcmp(cmd, "traceon") == 0)
@@ -1491,21 +1491,21 @@ snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
 				   data->filter_str);
 }
 
-static struct event_trigger_ops snapshot_trigger_ops = {
+static const struct event_trigger_ops snapshot_trigger_ops = {
 	.trigger		= snapshot_trigger,
 	.print			= snapshot_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops snapshot_count_trigger_ops = {
+static const struct event_trigger_ops snapshot_count_trigger_ops = {
 	.trigger		= snapshot_count_trigger,
 	.print			= snapshot_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 snapshot_get_trigger_ops(char *cmd, char *param)
 {
 	return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
@@ -1586,21 +1586,21 @@ stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
 				   data->filter_str);
 }
 
-static struct event_trigger_ops stacktrace_trigger_ops = {
+static const struct event_trigger_ops stacktrace_trigger_ops = {
 	.trigger		= stacktrace_trigger,
 	.print			= stacktrace_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops stacktrace_count_trigger_ops = {
+static const struct event_trigger_ops stacktrace_count_trigger_ops = {
 	.trigger		= stacktrace_count_trigger,
 	.print			= stacktrace_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_trigger_free,
 };
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 stacktrace_get_trigger_ops(char *cmd, char *param)
 {
 	return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
@@ -1711,28 +1711,28 @@ void event_enable_trigger_free(struct event_trigger_data *data)
 	}
 }
 
-static struct event_trigger_ops event_enable_trigger_ops = {
+static const struct event_trigger_ops event_enable_trigger_ops = {
 	.trigger		= event_enable_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops event_enable_count_trigger_ops = {
+static const struct event_trigger_ops event_enable_count_trigger_ops = {
 	.trigger		= event_enable_count_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops event_disable_trigger_ops = {
+static const struct event_trigger_ops event_disable_trigger_ops = {
 	.trigger		= event_enable_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
 	.free			= event_enable_trigger_free,
 };
 
-static struct event_trigger_ops event_disable_count_trigger_ops = {
+static const struct event_trigger_ops event_disable_count_trigger_ops = {
 	.trigger		= event_enable_count_trigger,
 	.print			= event_enable_trigger_print,
 	.init			= event_trigger_init,
@@ -1916,10 +1916,10 @@ void event_enable_unregister_trigger(char *glob,
 		data->ops->free(data);
 }
 
-static struct event_trigger_ops *
+static const struct event_trigger_ops *
 event_enable_get_trigger_ops(char *cmd, char *param)
 {
-	struct event_trigger_ops *ops;
+	const struct event_trigger_ops *ops;
 	bool enable;
 
 #ifdef CONFIG_HIST_TRIGGERS