Add a new unreg_all() callback that can be used to remove all command-specific triggers from an event and arrange to have it called whenever a trigger file is opened with O_TRUNC set.
Commands that don't want truncate semantics, or existing commands that don't implement this function simply do nothing and their triggers remain intact. Signed-off-by: Tom Zanussi <[email protected]> --- kernel/trace/trace.h | 9 +++++++-- kernel/trace/trace_events_trigger.c | 13 +++++++++++++ 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 300add5..2028e98 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1299,8 +1299,8 @@ struct event_trigger_ops { * it (filters make a trigger require access to the trace record * but are not always present). * - * All the methods below, except for @set_filter(), must be - * implemented. + * All the methods below, except for @set_filter() and @unreg_all(), + * must be implemented. * * @func: The callback function responsible for parsing and * registering the trigger written to the 'trigger' file by the @@ -1325,6 +1325,10 @@ struct event_trigger_ops { * This is usually implemented by the generic utility function * @unregister_trigger() (see trace_event_triggers.c). * + * @unreg_all: An optional function called to remove all the triggers + * from the list of triggers associated with the event. Called + * when a trigger file is opened in truncate mode. + * * @set_filter: An optional function called to parse and set a filter * for the trigger. If no @set_filter() method is set for the * event command, filters set by the user for the command will be @@ -1351,6 +1355,7 @@ struct event_command { struct event_trigger_ops *ops, struct event_trigger_data *data, struct trace_event_file *file); + void (*unreg_all)(struct trace_event_file *file); int (*set_filter)(char *filter_str, struct event_trigger_data *data, struct trace_event_file *file); diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 2f881e9..362ae86 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -193,6 +193,19 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file) return -ENODEV; } + if ((file->f_mode & FMODE_WRITE) && + (file->f_flags & O_TRUNC)) { + struct trace_event_file *event_file; + struct event_command *p; + + event_file = event_file_data(file); + + list_for_each_entry(p, &trigger_commands, list) { + if (p->unreg_all) + p->unreg_all(event_file); + } + } + if (file->f_mode & FMODE_READ) { ret = seq_open(file, &event_triggers_seq_ops); if (!ret) { -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
