tracing: Add 'traceon' and 'traceoff' event trigger commands
Add 'traceon' and 'traceoff' event_command commands. traceon and
traceoff event triggers are added by the user via these commands in a
similar way and using practically the same syntax as the analagous
'traceon' and 'traceoff' ftrace function commands, but instead of
writing to the set_ftrace_filter file, the traceon and traceoff
triggers are written to the per-event 'trigger' files:
echo 'traceon' > .../tracing/events/somesys/someevent/trigger
echo 'traceoff' > .../tracing/events/somesys/someevent/trigger
The above command will turn tracing on or off whenever someevent is
hit.
This also adds a 'count' version that limits the number of times the
command will be invoked:
echo 'traceon:N' > .../tracing/events/somesys/someevent/trigger
echo 'traceoff:N' > .../tracing/events/somesys/someevent/trigger
Where N is the number of times the command will be invoked.
The above commands will will turn tracing on or off whenever someevent
is hit, but only N times.
Some common register/unregister_trigger() implementations of the
event_command reg()/unreg() callbacks are also provided, which add and
remove trigger instances to the per-event list of triggers, and
arm/disarm them as appropriate. event_trigger_callback() is a
general-purpose event_command func() implementation that orchestrates
command parsing and registration for most normal commands.
Most event commands will use these, but some will override and
possibly reuse them.
The event_trigger_init(), event_trigger_free(), and
event_trigger_print() functions are meant to be common implementations
of the event_trigger_ops init(), free(), and print() ops,
respectively.
Most trigger_ops implementations will use these, but some will
override and possibly reuse them.
Link: http://lkml.kernel.org/r/00a52816703b98d2072947478dd6e2d70cde5197.1382622043.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Tom Zanussi
Steven Rostedt
Родитель
85f2b08268
Коммит
2a2df32115
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|
@ -345,6 +345,7 @@ struct ftrace_event_file {
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enum event_trigger_type {
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ETT_NONE = (0),
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ETT_TRACE_ONOFF = (1 << 0),
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};
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extern void destroy_preds(struct ftrace_event_file *file);
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@ -28,6 +28,13 @@
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static LIST_HEAD(trigger_commands);
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static DEFINE_MUTEX(trigger_cmd_mutex);
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static void
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trigger_data_free(struct event_trigger_data *data)
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{
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synchronize_sched(); /* make sure current triggers exit before free */
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kfree(data);
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}
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/**
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* event_triggers_call - Call triggers associated with a trace event
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* @file: The ftrace_event_file associated with the event
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@ -224,6 +231,129 @@ const struct file_operations event_trigger_fops = {
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.release = event_trigger_release,
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};
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/*
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* Currently we only register event commands from __init, so mark this
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* __init too.
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*/
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static __init int register_event_command(struct event_command *cmd)
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{
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struct event_command *p;
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int ret = 0;
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mutex_lock(&trigger_cmd_mutex);
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list_for_each_entry(p, &trigger_commands, list) {
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if (strcmp(cmd->name, p->name) == 0) {
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ret = -EBUSY;
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goto out_unlock;
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}
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}
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list_add(&cmd->list, &trigger_commands);
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out_unlock:
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mutex_unlock(&trigger_cmd_mutex);
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return ret;
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}
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/*
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* Currently we only unregister event commands from __init, so mark
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* this __init too.
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*/
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static __init int unregister_event_command(struct event_command *cmd)
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{
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struct event_command *p, *n;
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int ret = -ENODEV;
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mutex_lock(&trigger_cmd_mutex);
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list_for_each_entry_safe(p, n, &trigger_commands, list) {
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if (strcmp(cmd->name, p->name) == 0) {
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ret = 0;
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list_del_init(&p->list);
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goto out_unlock;
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}
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}
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out_unlock:
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mutex_unlock(&trigger_cmd_mutex);
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return ret;
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}
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/**
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* event_trigger_print - Generic event_trigger_ops @print implementation
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* @name: The name of the event trigger
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* @m: The seq_file being printed to
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* @data: Trigger-specific data
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* @filter_str: filter_str to print, if present
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*
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* Common implementation for event triggers to print themselves.
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*
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* Usually wrapped by a function that simply sets the @name of the
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* trigger command and then invokes this.
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*
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* Return: 0 on success, errno otherwise
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*/
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static int
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event_trigger_print(const char *name, struct seq_file *m,
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void *data, char *filter_str)
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{
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long count = (long)data;
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seq_printf(m, "%s", name);
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if (count == -1)
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seq_puts(m, ":unlimited");
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else
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seq_printf(m, ":count=%ld", count);
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if (filter_str)
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seq_printf(m, " if %s\n", filter_str);
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else
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seq_puts(m, "\n");
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return 0;
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}
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/**
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* event_trigger_init - Generic event_trigger_ops @init implementation
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* @ops: The trigger ops associated with the trigger
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* @data: Trigger-specific data
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*
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* Common implementation of event trigger initialization.
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*
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* Usually used directly as the @init method in event trigger
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* implementations.
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*
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* Return: 0 on success, errno otherwise
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*/
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static int
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event_trigger_init(struct event_trigger_ops *ops,
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struct event_trigger_data *data)
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{
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data->ref++;
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return 0;
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}
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/**
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* event_trigger_free - Generic event_trigger_ops @free implementation
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* @ops: The trigger ops associated with the trigger
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* @data: Trigger-specific data
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*
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* Common implementation of event trigger de-initialization.
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*
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* Usually used directly as the @free method in event trigger
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* implementations.
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*/
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static void
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event_trigger_free(struct event_trigger_ops *ops,
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struct event_trigger_data *data)
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{
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if (WARN_ON_ONCE(data->ref <= 0))
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return;
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data->ref--;
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if (!data->ref)
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trigger_data_free(data);
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}
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static int trace_event_trigger_enable_disable(struct ftrace_event_file *file,
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int trigger_enable)
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{
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@ -272,7 +402,323 @@ clear_event_triggers(struct trace_array *tr)
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}
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}
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/**
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* register_trigger - Generic event_command @reg implementation
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* @glob: The raw string used to register the trigger
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* @ops: The trigger ops associated with the trigger
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* @data: Trigger-specific data to associate with the trigger
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* @file: The ftrace_event_file associated with the event
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*
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* Common implementation for event trigger registration.
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*
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* Usually used directly as the @reg method in event command
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* implementations.
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*
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* Return: 0 on success, errno otherwise
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*/
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static int register_trigger(char *glob, struct event_trigger_ops *ops,
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struct event_trigger_data *data,
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struct ftrace_event_file *file)
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{
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struct event_trigger_data *test;
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int ret = 0;
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list_for_each_entry_rcu(test, &file->triggers, list) {
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if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
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ret = -EEXIST;
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goto out;
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}
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}
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if (data->ops->init) {
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ret = data->ops->init(data->ops, data);
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if (ret < 0)
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goto out;
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}
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list_add_rcu(&data->list, &file->triggers);
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ret++;
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if (trace_event_trigger_enable_disable(file, 1) < 0) {
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list_del_rcu(&data->list);
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ret--;
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}
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out:
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return ret;
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}
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/**
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* unregister_trigger - Generic event_command @unreg implementation
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* @glob: The raw string used to register the trigger
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* @ops: The trigger ops associated with the trigger
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* @test: Trigger-specific data used to find the trigger to remove
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* @file: The ftrace_event_file associated with the event
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*
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* Common implementation for event trigger unregistration.
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*
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* Usually used directly as the @unreg method in event command
|
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* implementations.
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*/
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static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
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struct event_trigger_data *test,
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struct ftrace_event_file *file)
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{
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struct event_trigger_data *data;
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bool unregistered = false;
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list_for_each_entry_rcu(data, &file->triggers, list) {
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if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
|
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unregistered = true;
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list_del_rcu(&data->list);
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trace_event_trigger_enable_disable(file, 0);
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break;
|
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}
|
||||
}
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|
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if (unregistered && data->ops->free)
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data->ops->free(data->ops, data);
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}
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/**
|
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* event_trigger_callback - Generic event_command @func implementation
|
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* @cmd_ops: The command ops, used for trigger registration
|
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* @file: The ftrace_event_file associated with the event
|
||||
* @glob: The raw string used to register the trigger
|
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* @cmd: The cmd portion of the string used to register the trigger
|
||||
* @param: The params portion of the string used to register the trigger
|
||||
*
|
||||
* Common implementation for event command parsing and trigger
|
||||
* instantiation.
|
||||
*
|
||||
* Usually used directly as the @func method in event command
|
||||
* implementations.
|
||||
*
|
||||
* Return: 0 on success, errno otherwise
|
||||
*/
|
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static int
|
||||
event_trigger_callback(struct event_command *cmd_ops,
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struct ftrace_event_file *file,
|
||||
char *glob, char *cmd, char *param)
|
||||
{
|
||||
struct event_trigger_data *trigger_data;
|
||||
struct event_trigger_ops *trigger_ops;
|
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char *trigger = NULL;
|
||||
char *number;
|
||||
int ret;
|
||||
|
||||
/* separate the trigger from the filter (t:n [if filter]) */
|
||||
if (param && isdigit(param[0]))
|
||||
trigger = strsep(¶m, " \t");
|
||||
|
||||
trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
|
||||
|
||||
ret = -ENOMEM;
|
||||
trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
|
||||
if (!trigger_data)
|
||||
goto out;
|
||||
|
||||
trigger_data->count = -1;
|
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trigger_data->ops = trigger_ops;
|
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trigger_data->cmd_ops = cmd_ops;
|
||||
INIT_LIST_HEAD(&trigger_data->list);
|
||||
|
||||
if (glob[0] == '!') {
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||||
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
|
||||
kfree(trigger_data);
|
||||
ret = 0;
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (trigger) {
|
||||
number = strsep(&trigger, ":");
|
||||
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||||
ret = -EINVAL;
|
||||
if (!strlen(number))
|
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goto out_free;
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||||
|
||||
/*
|
||||
* We use the callback data field (which is a pointer)
|
||||
* as our counter.
|
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*/
|
||||
ret = kstrtoul(number, 0, &trigger_data->count);
|
||||
if (ret)
|
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goto out_free;
|
||||
}
|
||||
|
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if (!param) /* if param is non-empty, it's supposed to be a filter */
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||||
goto out_reg;
|
||||
|
||||
if (!cmd_ops->set_filter)
|
||||
goto out_reg;
|
||||
|
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ret = cmd_ops->set_filter(param, trigger_data, file);
|
||||
if (ret < 0)
|
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goto out_free;
|
||||
|
||||
out_reg:
|
||||
ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
|
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/*
|
||||
* The above returns on success the # of functions enabled,
|
||||
* but if it didn't find any functions it returns zero.
|
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* Consider no functions a failure too.
|
||||
*/
|
||||
if (!ret) {
|
||||
ret = -ENOENT;
|
||||
goto out_free;
|
||||
} else if (ret < 0)
|
||||
goto out_free;
|
||||
ret = 0;
|
||||
out:
|
||||
return ret;
|
||||
|
||||
out_free:
|
||||
kfree(trigger_data);
|
||||
goto out;
|
||||
}
|
||||
|
||||
static void
|
||||
traceon_trigger(struct event_trigger_data *data)
|
||||
{
|
||||
if (tracing_is_on())
|
||||
return;
|
||||
|
||||
tracing_on();
|
||||
}
|
||||
|
||||
static void
|
||||
traceon_count_trigger(struct event_trigger_data *data)
|
||||
{
|
||||
if (!data->count)
|
||||
return;
|
||||
|
||||
if (data->count != -1)
|
||||
(data->count)--;
|
||||
|
||||
traceon_trigger(data);
|
||||
}
|
||||
|
||||
static void
|
||||
traceoff_trigger(struct event_trigger_data *data)
|
||||
{
|
||||
if (!tracing_is_on())
|
||||
return;
|
||||
|
||||
tracing_off();
|
||||
}
|
||||
|
||||
static void
|
||||
traceoff_count_trigger(struct event_trigger_data *data)
|
||||
{
|
||||
if (!data->count)
|
||||
return;
|
||||
|
||||
if (data->count != -1)
|
||||
(data->count)--;
|
||||
|
||||
traceoff_trigger(data);
|
||||
}
|
||||
|
||||
static int
|
||||
traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
|
||||
struct event_trigger_data *data)
|
||||
{
|
||||
return event_trigger_print("traceon", m, (void *)data->count,
|
||||
data->filter_str);
|
||||
}
|
||||
|
||||
static int
|
||||
traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
|
||||
struct event_trigger_data *data)
|
||||
{
|
||||
return event_trigger_print("traceoff", m, (void *)data->count,
|
||||
data->filter_str);
|
||||
}
|
||||
|
||||
static struct event_trigger_ops traceon_trigger_ops = {
|
||||
.func = traceon_trigger,
|
||||
.print = traceon_trigger_print,
|
||||
.init = event_trigger_init,
|
||||
.free = event_trigger_free,
|
||||
};
|
||||
|
||||
static struct event_trigger_ops traceon_count_trigger_ops = {
|
||||
.func = traceon_count_trigger,
|
||||
.print = traceon_trigger_print,
|
||||
.init = event_trigger_init,
|
||||
.free = event_trigger_free,
|
||||
};
|
||||
|
||||
static struct event_trigger_ops traceoff_trigger_ops = {
|
||||
.func = traceoff_trigger,
|
||||
.print = traceoff_trigger_print,
|
||||
.init = event_trigger_init,
|
||||
.free = event_trigger_free,
|
||||
};
|
||||
|
||||
static struct event_trigger_ops traceoff_count_trigger_ops = {
|
||||
.func = traceoff_count_trigger,
|
||||
.print = traceoff_trigger_print,
|
||||
.init = event_trigger_init,
|
||||
.free = event_trigger_free,
|
||||
};
|
||||
|
||||
static struct event_trigger_ops *
|
||||
onoff_get_trigger_ops(char *cmd, char *param)
|
||||
{
|
||||
struct event_trigger_ops *ops;
|
||||
|
||||
/* we register both traceon and traceoff to this callback */
|
||||
if (strcmp(cmd, "traceon") == 0)
|
||||
ops = param ? &traceon_count_trigger_ops :
|
||||
&traceon_trigger_ops;
|
||||
else
|
||||
ops = param ? &traceoff_count_trigger_ops :
|
||||
&traceoff_trigger_ops;
|
||||
|
||||
return ops;
|
||||
}
|
||||
|
||||
static struct event_command trigger_traceon_cmd = {
|
||||
.name = "traceon",
|
||||
.trigger_type = ETT_TRACE_ONOFF,
|
||||
.func = event_trigger_callback,
|
||||
.reg = register_trigger,
|
||||
.unreg = unregister_trigger,
|
||||
.get_trigger_ops = onoff_get_trigger_ops,
|
||||
};
|
||||
|
||||
static struct event_command trigger_traceoff_cmd = {
|
||||
.name = "traceoff",
|
||||
.trigger_type = ETT_TRACE_ONOFF,
|
||||
.func = event_trigger_callback,
|
||||
.reg = register_trigger,
|
||||
.unreg = unregister_trigger,
|
||||
.get_trigger_ops = onoff_get_trigger_ops,
|
||||
};
|
||||
|
||||
static __init void unregister_trigger_traceon_traceoff_cmds(void)
|
||||
{
|
||||
unregister_event_command(&trigger_traceon_cmd);
|
||||
unregister_event_command(&trigger_traceoff_cmd);
|
||||
}
|
||||
|
||||
static __init int register_trigger_traceon_traceoff_cmds(void)
|
||||
{
|
||||
int ret;
|
||||
|
||||
ret = register_event_command(&trigger_traceon_cmd);
|
||||
if (WARN_ON(ret < 0))
|
||||
return ret;
|
||||
ret = register_event_command(&trigger_traceoff_cmd);
|
||||
if (WARN_ON(ret < 0))
|
||||
unregister_trigger_traceon_traceoff_cmds();
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
__init int register_trigger_cmds(void)
|
||||
{
|
||||
register_trigger_traceon_traceoff_cmds();
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
|
|||
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