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tracing: Remove logic for registering multiple event triggers at a time

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Code for registering triggers assumes it's possible to register more
than one trigger at a time.  In fact, it's unimplemented and there
doesn't seem to be a reason to do that.

Remove the n_registered param from event_trigger_register() and fix up
callers.

Doing so simplifies the logic in event_trigger_register to the point
that it just becomes a wrapper calling event_command.reg().

It also removes the problematic call to event_command.unreg() in case
of failure.  A new function, event_trigger_unregister() is also added
for callers to call themselves.

The changes to trace_events_hist.c simply allow compilation; a
separate patch follows which updates the hist triggers to work
correctly with the new changes.

Link: https://lkml.kernel.org/r/6149fec7a139d93e84fa4535672fb5bef88006b0.1644010575.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Tom Zanussi
2022-02-04 16:12:04 -06:00
committed by Steven Rostedt (Google)
parent 217d8c05ec
commit b8cc44a4d3
3 changed files with 45 additions and 77 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/trace/trace_events_hist.c
+6 -11
View File
@@ -6287,7 +6287,7 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
goto out_free;
}
cmd_ops->unreg(glob+1, trigger_data, file);
event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
se_name = trace_event_name(file->event_call);
se = find_synth_event(se_name);
if (se)
@@ -6296,13 +6296,10 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
goto out_free;
}
ret = cmd_ops->reg(glob, trigger_data, file);
/*
* The above returns on success the # of triggers registered,
* but if it didn't register any it returns zero. Consider no
* triggers registered a failure too.
*/
if (!ret) {
ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
if (ret)
goto out_free;
if (ret == 0) {
if (!(attrs->pause || attrs->cont || attrs->clear))
ret = -ENOENT;
goto out_free;
@@ -6331,15 +6328,13 @@ enable:
se = find_synth_event(se_name);
if (se)
se->ref++;
/* Just return zero, not the number of registered triggers */
ret = 0;
out:
if (ret == 0)
hist_err_clear();
return ret;
out_unreg:
cmd_ops->unreg(glob+1, trigger_data, file);
event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
out_free:
if (cmd_ops->set_filter)
cmd_ops->set_filter(NULL, trigger_data, NULL);