tracing: Kill trace_create_file_ops() and friends
trace_create_file_ops() allocates the copy of id/filter/format/enable file_operations to set "f_op->owner = mod" for fops_get(). However after the recent changes there is no reason to prevent rmmod even if one of these files is opened. A file operation can do nothing but fail after remove_event_file_dir() clears ->i_private for every file removed by trace_module_remove_events(). Kill "struct ftrace_module_file_ops" and fix the compilation errors. Link: http://lkml.kernel.org/r/20130731173132.GA31033@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Oleg Nesterov
Steven Rostedt
parent
3ddc77f6f4
commit
779c5e3791
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@ -1683,8 +1683,7 @@ __trace_early_add_new_event(struct ftrace_event_call *call,
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}
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struct ftrace_module_file_ops;
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static void __add_event_to_tracers(struct ftrace_event_call *call,
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struct ftrace_module_file_ops *file_ops);
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static void __add_event_to_tracers(struct ftrace_event_call *call);
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/* Add an additional event_call dynamically */
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int trace_add_event_call(struct ftrace_event_call *call)
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@ -1695,7 +1694,7 @@ int trace_add_event_call(struct ftrace_event_call *call)
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ret = __register_event(call, NULL);
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if (ret >= 0)
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__add_event_to_tracers(call, NULL);
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__add_event_to_tracers(call);
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mutex_unlock(&event_mutex);
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mutex_unlock(&trace_types_lock);
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@ -1769,100 +1768,21 @@ int trace_remove_event_call(struct ftrace_event_call *call)
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#ifdef CONFIG_MODULES
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static LIST_HEAD(ftrace_module_file_list);
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/*
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* Modules must own their file_operations to keep up with
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* reference counting.
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*/
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struct ftrace_module_file_ops {
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struct list_head list;
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struct module *mod;
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struct file_operations id;
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struct file_operations enable;
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struct file_operations format;
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struct file_operations filter;
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};
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static struct ftrace_module_file_ops *
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find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
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{
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/*
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* As event_calls are added in groups by module,
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* when we find one file_ops, we don't need to search for
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* each call in that module, as the rest should be the
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* same. Only search for a new one if the last one did
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* not match.
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*/
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if (file_ops && mod == file_ops->mod)
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return file_ops;
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list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
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if (file_ops->mod == mod)
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return file_ops;
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}
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return NULL;
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}
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static struct ftrace_module_file_ops *
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trace_create_file_ops(struct module *mod)
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{
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struct ftrace_module_file_ops *file_ops;
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/*
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* This is a bit of a PITA. To allow for correct reference
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* counting, modules must "own" their file_operations.
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* To do this, we allocate the file operations that will be
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* used in the event directory.
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*/
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file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
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if (!file_ops)
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return NULL;
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file_ops->mod = mod;
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file_ops->id = ftrace_event_id_fops;
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file_ops->id.owner = mod;
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file_ops->enable = ftrace_enable_fops;
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file_ops->enable.owner = mod;
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file_ops->filter = ftrace_event_filter_fops;
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file_ops->filter.owner = mod;
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file_ops->format = ftrace_event_format_fops;
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file_ops->format.owner = mod;
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list_add(&file_ops->list, &ftrace_module_file_list);
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return file_ops;
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}
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static void trace_module_add_events(struct module *mod)
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{
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struct ftrace_module_file_ops *file_ops = NULL;
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struct ftrace_event_call **call, **start, **end;
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start = mod->trace_events;
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end = mod->trace_events + mod->num_trace_events;
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if (start == end)
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return;
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file_ops = trace_create_file_ops(mod);
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if (!file_ops)
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return;
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for_each_event(call, start, end) {
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__register_event(*call, mod);
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__add_event_to_tracers(*call, file_ops);
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__add_event_to_tracers(*call);
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}
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}
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static void trace_module_remove_events(struct module *mod)
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{
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struct ftrace_module_file_ops *file_ops;
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struct ftrace_event_call *call, *p;
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bool clear_trace = false;
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@ -1874,16 +1794,6 @@ static void trace_module_remove_events(struct module *mod)
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__trace_remove_event_call(call);
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}
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}
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/* Now free the file_operations */
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list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
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if (file_ops->mod == mod)
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break;
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}
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if (&file_ops->list != &ftrace_module_file_list) {
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list_del(&file_ops->list);
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kfree(file_ops);
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}
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up_write(&trace_event_sem);
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/*
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@ -1919,62 +1829,22 @@ static int trace_module_notify(struct notifier_block *self,
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return 0;
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}
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static int
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__trace_add_new_mod_event(struct ftrace_event_call *call,
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struct trace_array *tr,
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struct ftrace_module_file_ops *file_ops)
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{
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return __trace_add_new_event(call, tr,
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&file_ops->id, &file_ops->enable,
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&file_ops->filter, &file_ops->format);
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}
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#else
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static inline struct ftrace_module_file_ops *
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find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
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{
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return NULL;
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}
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static inline int trace_module_notify(struct notifier_block *self,
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unsigned long val, void *data)
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{
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return 0;
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}
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static inline int
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__trace_add_new_mod_event(struct ftrace_event_call *call,
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struct trace_array *tr,
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struct ftrace_module_file_ops *file_ops)
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{
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return -ENODEV;
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}
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#endif /* CONFIG_MODULES */
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/* Create a new event directory structure for a trace directory. */
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static void
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__trace_add_event_dirs(struct trace_array *tr)
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{
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struct ftrace_module_file_ops *file_ops = NULL;
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struct ftrace_event_call *call;
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int ret;
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list_for_each_entry(call, &ftrace_events, list) {
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if (call->mod) {
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/*
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* Directories for events by modules need to
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* keep module ref counts when opened (as we don't
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* want the module to disappear when reading one
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* of these files). The file_ops keep account of
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* the module ref count.
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*/
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file_ops = find_ftrace_file_ops(file_ops, call->mod);
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if (!file_ops)
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continue; /* Warn? */
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ret = __trace_add_new_mod_event(call, tr, file_ops);
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if (ret < 0)
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pr_warning("Could not create directory for event %s\n",
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call->name);
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continue;
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}
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ret = __trace_add_new_event(call, tr,
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&ftrace_event_id_fops,
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&ftrace_enable_fops,
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@ -2332,21 +2202,16 @@ __trace_remove_event_dirs(struct trace_array *tr)
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remove_event_file_dir(file);
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}
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static void
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__add_event_to_tracers(struct ftrace_event_call *call,
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struct ftrace_module_file_ops *file_ops)
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static void __add_event_to_tracers(struct ftrace_event_call *call)
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{
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struct trace_array *tr;
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list_for_each_entry(tr, &ftrace_trace_arrays, list) {
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if (file_ops)
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__trace_add_new_mod_event(call, tr, file_ops);
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else
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__trace_add_new_event(call, tr,
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&ftrace_event_id_fops,
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&ftrace_enable_fops,
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&ftrace_event_filter_fops,
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&ftrace_event_format_fops);
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__trace_add_new_event(call, tr,
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&ftrace_event_id_fops,
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&ftrace_enable_fops,
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&ftrace_event_filter_fops,
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&ftrace_event_format_fops);
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}
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}
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