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tracing: Fix trace events build without modules 

The new multi-buffers added a descriptor that kept track of module
events, and the directories they use, with struct ftace_module_file_ops.
This is used to add a ref count to keep modules from unloading while
their files are being accessed.

As the descriptor is only needed when CONFIG_MODULES is enabled, it
is only declared when the config is enabled. But that struct is
dereferenced in a few areas outside the #ifdef CONFIG_MODULES.

By adding some helper routines and moving code around a little,
events can be compiled again without modules.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2013-03-02 17:37:14 -05:00 committed by Steven Rostedt
parent 34ef61b1fa
commit 315326c16a
1 changed files with 36 additions and 19 deletions
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55
kernel/trace/trace_events.c
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@ -1546,9 +1546,18 @@ struct ftrace_module_file_ops {
struct file_operations filter;
};
static struct ftrace_module_file_ops *find_ftrace_file_ops(struct module *mod)
static struct ftrace_module_file_ops *
find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
{
struct ftrace_module_file_ops *file_ops;
/*
* As event_calls are added in groups by module,
* when we find one file_ops, we don't need to search for
* each call in that module, as the rest should be the
* same. Only search for a new one if the last one did
* not match.
*/
if (file_ops && mod == file_ops->mod)
return file_ops;
list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
if (file_ops->mod == mod)
@ -1664,16 +1673,35 @@ static int trace_module_notify(struct notifier_block *self,
return 0;
}
static int
__trace_add_new_mod_event(struct ftrace_event_call *call,
struct trace_array *tr,
struct ftrace_module_file_ops *file_ops)
{
return __trace_add_new_event(call, tr,
&file_ops->id, &file_ops->enable,
&file_ops->filter, &file_ops->format);
}
#else
static struct ftrace_module_file_ops *find_ftrace_file_ops(struct module *mod)
static inline struct ftrace_module_file_ops *
find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
{
return NULL;
}
static int trace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
static inline int trace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return 0;
}
static inline int
__trace_add_new_mod_event(struct ftrace_event_call *call,
struct trace_array *tr,
struct ftrace_module_file_ops *file_ops)
{
return -ENODEV;
}
#endif /* CONFIG_MODULES */
/* Create a new event directory structure for a trace directory. */
@ -1692,20 +1720,11 @@ __trace_add_event_dirs(struct trace_array *tr)
* want the module to disappear when reading one
* of these files). The file_ops keep account of
* the module ref count.
*
* As event_calls are added in groups by module,
* when we find one file_ops, we don't need to search for
* each call in that module, as the rest should be the
* same. Only search for a new one if the last one did
* not match.
*/
if (!file_ops || call->mod != file_ops->mod)
file_ops = find_ftrace_file_ops(call->mod);
file_ops = find_ftrace_file_ops(file_ops, call->mod);
if (!file_ops)
continue; /* Warn? */
ret = __trace_add_new_event(call, tr,
&file_ops->id, &file_ops->enable,
&file_ops->filter, &file_ops->format);
ret = __trace_add_new_mod_event(call, tr, file_ops);
if (ret < 0)
pr_warning("Could not create directory for event %s\n",
call->name);
@ -1794,9 +1813,7 @@ __add_event_to_tracers(struct ftrace_event_call *call,
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (file_ops)
__trace_add_new_event(call, tr,
&file_ops->id, &file_ops->enable,
&file_ops->filter, &file_ops->format);
__trace_add_new_mod_event(call, tr, file_ops);
else
__trace_add_new_event(call, tr,
&ftrace_event_id_fops,