perf session: Add host_env argument to perf_session__new

When creating a perf_session the host perf_env may or may not want to
be used. For example, `perf top` uses a host perf_env while `perf
inject` does not. Add a host_env argument to perf_session__new so that
sessions requiring a host perf_env can pass it in. Currently if none
is specified the global perf_env variable is used, but this will
change in later patches.

Signed-off-by: Ian Rogers <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/builtin-inject.c

···
 	inject.tool.bpf_metadata	= perf_event__repipe_op2_synth;
 	inject.tool.dont_split_sample_group = true;
 	inject.session = __perf_session__new(&data, &inject.tool,
-					     /*trace_event_repipe=*/inject.output.is_pipe);
+					     /*trace_event_repipe=*/inject.output.is_pipe,
+					     /*host_env=*/NULL);
 
 	if (IS_ERR(inject.session)) {
 		ret = PTR_ERR(inject.session);

tools/perf/util/session.c

···
 
 struct perf_session *__perf_session__new(struct perf_data *data,
 					 struct perf_tool *tool,
-					 bool trace_event_repipe)
+					 bool trace_event_repipe,
+					 struct perf_env *host_env)
 {
 	int ret = -ENOMEM;
 	struct perf_session *session = zalloc(sizeof(*session));
···
 				symbol_conf.kallsyms_name = perf_data__kallsyms_name(data);
 		}
 	} else  {
-		session->machines.host.env = &perf_env;
+		session->machines.host.env = host_env ?: &perf_env;
 	}
 	if (session->evlist)
 		session->evlist->session = session;

tools/perf/util/session.h

···
 
 struct perf_session *__perf_session__new(struct perf_data *data,
 					 struct perf_tool *tool,
-					 bool trace_event_repipe);
+					 bool trace_event_repipe,
+					 struct perf_env *host_env);
 
 static inline struct perf_session *perf_session__new(struct perf_data *data,
 						     struct perf_tool *tool)
 {
-	return __perf_session__new(data, tool, /*trace_event_repipe=*/false);
+	return __perf_session__new(data, tool, /*trace_event_repipe=*/false, /*host_env=*/NULL);
 }
 
 void perf_session__delete(struct perf_session *session);