tracing/probe: Add trace_event_call accesses APIs

Add trace_event_call access APIs for trace_probe.
Instead of accessing trace_probe.call directly, use those
accesses by trace_probe_event_call() method. This hides
the relationship of trace_event_call and trace_probe from
trace_kprobe and trace_uprobe.

Link: http://lkml.kernel.org/r/155931587711.28323.8335129014686133120.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

4 files changed, 40 insertions, 28 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 3cf8cee4f276..62362ad1ad98 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -985,7 +985,7 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
         struct ring_buffer *buffer;
         int size, dsize, pc;
         unsigned long irq_flags;
-        struct trace_event_call *call = &tk->tp.call;
+        struct trace_event_call *call = trace_probe_event_call(&tk->tp);
 
         WARN_ON(call != trace_file->event_call);
 
@@ -1033,7 +1033,7 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
         struct ring_buffer *buffer;
         int size, pc, dsize;
         unsigned long irq_flags;
-        struct trace_event_call *call = &tk->tp.call;
+        struct trace_event_call *call = trace_probe_event_call(&tk->tp);
 
         WARN_ON(call != trace_file->event_call);
 
@@ -1163,7 +1163,7 @@ static int kretprobe_event_define_fields(struct trace_event_call *event_call)
 static int
 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
 {
-        struct trace_event_call *call = &tk->tp.call;
+        struct trace_event_call *call = trace_probe_event_call(&tk->tp);
         struct kprobe_trace_entry_head *entry;
         struct hlist_head *head;
         int size, __size, dsize;
@@ -1213,7 +1213,7 @@ static void
 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
                     struct pt_regs *regs)
 {
-        struct trace_event_call *call = &tk->tp.call;
+        struct trace_event_call *call = trace_probe_event_call(&tk->tp);
         struct kretprobe_trace_entry_head *entry;
         struct hlist_head *head;
         int size, __size, dsize;
@@ -1348,9 +1348,10 @@ static struct trace_event_functions kprobe_funcs = {
         .trace          = print_kprobe_event
 };
 
-static inline void init_trace_event_call(struct trace_kprobe *tk,
-                                         struct trace_event_call *call)
+static inline void init_trace_event_call(struct trace_kprobe *tk)
 {
+        struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+
         if (trace_kprobe_is_return(tk)) {
                 call->event.funcs = &kretprobe_funcs;
                 call->class->define_fields = kretprobe_event_define_fields;
@@ -1366,7 +1367,7 @@ static inline void init_trace_event_call(struct trace_kprobe *tk,
 
 static int register_kprobe_event(struct trace_kprobe *tk)
 {
-        init_trace_event_call(tk, &tk->tp.call);
+        init_trace_event_call(tk);
 
         return trace_probe_register_event_call(&tk->tp);
 }
@@ -1403,7 +1404,7 @@ create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
                 return ERR_CAST(tk);
         }
 
-        init_trace_event_call(tk, &tk->tp.call);
+        init_trace_event_call(tk);
 
         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
                 ret = -ENOMEM;
@@ -1414,7 +1415,7 @@ create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
         if (ret < 0)
                 goto error;
 
-        return &tk->tp.call;
+        return trace_probe_event_call(&tk->tp);
 error:
         free_trace_kprobe(tk);
         return ERR_PTR(ret);
@@ -1447,7 +1448,7 @@ static __init void enable_boot_kprobe_events(void)
         mutex_lock(&event_mutex);
         for_each_trace_kprobe(tk, pos) {
                 list_for_each_entry(file, &tr->events, list)
-                        if (file->event_call == &tk->tp.call)
+                        if (file->event_call == trace_probe_event_call(&tk->tp))
                                 trace_event_enable_disable(file, 1, 0);
         }
         mutex_unlock(&event_mutex);
@@ -1523,7 +1524,7 @@ find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
         struct trace_event_file *file;
 
         list_for_each_entry(file, &tr->events, list)
-                if (file->event_call == &tk->tp.call)
+                if (file->event_call == trace_probe_event_call(&tk->tp))
                         return file;
 
         return NULL;
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 323a11ad1dad..dbef0d135075 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -844,6 +844,7 @@ static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
 
 int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return)
 {
+        struct trace_event_call *call = trace_probe_event_call(tp);
         int len;
         char *print_fmt;
 
@@ -855,7 +856,7 @@ int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return)
 
         /* Second: actually write the @print_fmt */
         __set_print_fmt(tp, print_fmt, len + 1, is_return);
-        tp->call.print_fmt = print_fmt;
+        call->print_fmt = print_fmt;
 
         return 0;
 }
@@ -888,31 +889,34 @@ int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 
 void trace_probe_cleanup(struct trace_probe *tp)
 {
+        struct trace_event_call *call = trace_probe_event_call(tp);
         int i;
 
         for (i = 0; i < tp->nr_args; i++)
                 traceprobe_free_probe_arg(&tp->args[i]);
 
-        kfree(tp->call.class->system);
-        kfree(tp->call.name);
-        kfree(tp->call.print_fmt);
+        kfree(call->class->system);
+        kfree(call->name);
+        kfree(call->print_fmt);
 }
 
 int trace_probe_init(struct trace_probe *tp, const char *event,
                      const char *group)
 {
+        struct trace_event_call *call = trace_probe_event_call(tp);
+
         if (!event || !group)
                 return -EINVAL;
 
-        tp->call.class = &tp->class;
-        tp->call.name = kstrdup(event, GFP_KERNEL);
-        if (!tp->call.name)
+        call->class = &tp->class;
+        call->name = kstrdup(event, GFP_KERNEL);
+        if (!call->name)
                 return -ENOMEM;
 
         tp->class.system = kstrdup(group, GFP_KERNEL);
         if (!tp->class.system) {
-                kfree(tp->call.name);
-                tp->call.name = NULL;
+                kfree(call->name);
+                call->name = NULL;
                 return -ENOMEM;
         }
         INIT_LIST_HEAD(&tp->files);
@@ -923,7 +927,7 @@ int trace_probe_init(struct trace_probe *tp, const char *event,
 
 int trace_probe_register_event_call(struct trace_probe *tp)
 {
-        struct trace_event_call *call = &tp->call;
+        struct trace_event_call *call = trace_probe_event_call(tp);
         int ret;
 
         ret = register_trace_event(&call->event);
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 67424cb5d5d6..6c33d4aa36c3 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -276,6 +276,12 @@ static inline const char *trace_probe_group_name(struct trace_probe *tp)
         return tp->call.class->system;
 }
 
+static inline struct trace_event_call *
+        trace_probe_event_call(struct trace_probe *tp)
+{
+        return &tp->call;
+}
+
 static inline int trace_probe_unregister_event_call(struct trace_probe *tp)
 {
         /* tp->event is unregistered in trace_remove_event_call() */
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 09fdba3ee9d9..7fb9353b47d9 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -821,7 +821,7 @@ static void __uprobe_trace_func(struct trace_uprobe *tu,
         struct ring_buffer *buffer;
         void *data;
         int size, esize;
-        struct trace_event_call *call = &tu->tp.call;
+        struct trace_event_call *call = trace_probe_event_call(&tu->tp);
 
         WARN_ON(call != trace_file->event_call);
 
@@ -1113,7 +1113,7 @@ static void __uprobe_perf_func(struct trace_uprobe *tu,
                                unsigned long func, struct pt_regs *regs,
                                struct uprobe_cpu_buffer *ucb, int dsize)
 {
-        struct trace_event_call *call = &tu->tp.call;
+        struct trace_event_call *call = trace_probe_event_call(&tu->tp);
         struct uprobe_trace_entry_head *entry;
         struct hlist_head *head;
         void *data;
@@ -1316,9 +1316,10 @@ static struct trace_event_functions uprobe_funcs = {
         .trace          = print_uprobe_event
 };
 
-static inline void init_trace_event_call(struct trace_uprobe *tu,
-                                         struct trace_event_call *call)
+static inline void init_trace_event_call(struct trace_uprobe *tu)
 {
+        struct trace_event_call *call = trace_probe_event_call(&tu->tp);
+
         call->event.funcs = &uprobe_funcs;
         call->class->define_fields = uprobe_event_define_fields;
 
@@ -1329,7 +1330,7 @@ static inline void init_trace_event_call(struct trace_uprobe *tu,
 
 static int register_uprobe_event(struct trace_uprobe *tu)
 {
-        init_trace_event_call(tu, &tu->tp.call);
+        init_trace_event_call(tu);
 
         return trace_probe_register_event_call(&tu->tp);
 }
@@ -1376,14 +1377,14 @@ create_local_trace_uprobe(char *name, unsigned long offs,
         tu->path = path;
         tu->ref_ctr_offset = ref_ctr_offset;
         tu->filename = kstrdup(name, GFP_KERNEL);
-        init_trace_event_call(tu, &tu->tp.call);
+        init_trace_event_call(tu);
 
         if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
                 ret = -ENOMEM;
                 goto error;
         }
 
-        return &tu->tp.call;
+        return trace_probe_event_call(&tu->tp);
 error:
         free_trace_uprobe(tu);
         return ERR_PTR(ret);