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ftrace: Have global_ops store the functions that are to be traced 

This is a step towards each ops structure defining its own set
of functions to trace. As the current code with pid's and such
are specific to the global_ops, it is restructured to be used
with the global ops.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2011-05-03 22:49:52 -04:00 committed by Steven Rostedt
parent bd69c30b1d
commit 2b499381bc
1 changed files with 61 additions and 24 deletions
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85
kernel/trace/ftrace.c
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@ -91,6 +91,7 @@ static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
static struct ftrace_ops global_ops;
/*
* Traverse the ftrace_list, invoking all entries. The reason that we
@ -153,7 +154,7 @@ static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
}
#endif
static void update_ftrace_function(void)
static void update_global_ops(void)
{
ftrace_func_t func;
@ -173,6 +174,18 @@ static void update_ftrace_function(void)
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
global_ops.func = func;
}
static void update_ftrace_function(void)
{
ftrace_func_t func;
update_global_ops();
func = global_ops.func;
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
@ -181,17 +194,51 @@ static void update_ftrace_function(void)
#endif
}
static int __register_ftrace_function(struct ftrace_ops *ops)
static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
{
ops->next = ftrace_list;
ops->next = *list;
/*
* We are entering ops into the ftrace_list but another
* CPU might be walking that list. We need to make sure
* the ops->next pointer is valid before another CPU sees
* the ops pointer included into the ftrace_list.
*/
rcu_assign_pointer(ftrace_list, ops);
rcu_assign_pointer(*list, ops);
}
static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
{
struct ftrace_ops **p;
/*
* If we are removing the last function, then simply point
* to the ftrace_stub.
*/
if (*list == ops && ops->next == &ftrace_list_end) {
*list = &ftrace_list_end;
return 0;
}
for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
if (*p == ops)
break;
if (*p != ops)
return -1;
*p = (*p)->next;
return 0;
}
static int __register_ftrace_function(struct ftrace_ops *ops)
{
if (ftrace_disabled)
return -ENODEV;
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
add_ftrace_ops(&ftrace_list, ops);
if (ftrace_enabled)
update_ftrace_function();
@ -200,27 +247,17 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
static int __unregister_ftrace_function(struct ftrace_ops *ops)
{
struct ftrace_ops **p;
int ret;
/*
* If we are removing the last function, then simply point
* to the ftrace_stub.
*/
if (ftrace_list == ops && ops->next == &ftrace_list_end) {
ftrace_trace_function = ftrace_stub;
ftrace_list = &ftrace_list_end;
return 0;
}
if (ftrace_disabled)
return -ENODEV;
for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
if (*p == ops)
break;
if (*p != ops)
return -1;
*p = (*p)->next;
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
ret = remove_ftrace_ops(&ftrace_list, ops);
if (ret < 0)
return ret;
if (ftrace_enabled)
update_ftrace_function();
@ -894,7 +931,7 @@ enum {
FTRACE_OPS_FL_ENABLED = 1,
};
struct ftrace_ops global_ops = {
static struct ftrace_ops global_ops = {
.func = ftrace_stub,
.notrace_hash = EMPTY_HASH,
.filter_hash = EMPTY_HASH,
@ -3263,7 +3300,7 @@ void __init ftrace_init(void)
#else
struct ftrace_ops global_ops = {
static struct ftrace_ops global_ops = {
.func = ftrace_stub,
};