6 files changed, 83 insertions, 31 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 911e9864e94a..c88c563a59a5 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -794,6 +794,9 @@ extern void print_subsystem_event_filter(struct event_subsystem *system,
                                          struct trace_seq *s);
 extern int filter_assign_type(const char *type);
 
+struct list_head *
+trace_get_fields(struct ftrace_event_call *event_call);
+
 static inline int
 filter_check_discard(struct ftrace_event_call *call, void *rec,
                      struct ring_buffer *buffer,
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 19d1eb0a7188..acc0f55742c3 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -29,11 +29,23 @@ DEFINE_MUTEX(event_mutex);
 
 LIST_HEAD(ftrace_events);
 
+struct list_head *
+trace_get_fields(struct ftrace_event_call *event_call)
+{
+        if (!event_call->class->get_fields)
+                return &event_call->class->fields;
+        return event_call->class->get_fields(event_call);
+}
+
 int trace_define_field(struct ftrace_event_call *call, const char *type,
                        const char *name, int offset, int size, int is_signed,
                        int filter_type)
 {
         struct ftrace_event_field *field;
+        struct list_head *head;
+
+        if (WARN_ON(!call->class))
+                return 0;
 
         field = kzalloc(sizeof(*field), GFP_KERNEL);
         if (!field)
@@ -56,7 +68,8 @@ int trace_define_field(struct ftrace_event_call *call, const char *type,
         field->size = size;
         field->is_signed = is_signed;
 
-        list_add(&field->link, &call->fields);
+        head = trace_get_fields(call);
+        list_add(&field->link, head);
 
         return 0;
 
@@ -94,8 +107,10 @@ static int trace_define_common_fields(struct ftrace_event_call *call)
 void trace_destroy_fields(struct ftrace_event_call *call)
 {
         struct ftrace_event_field *field, *next;
+        struct list_head *head;
 
-        list_for_each_entry_safe(field, next, &call->fields, link) {
+        head = trace_get_fields(call);
+        list_for_each_entry_safe(field, next, head, link) {
                 list_del(&field->link);
                 kfree(field->type);
                 kfree(field->name);
@@ -111,7 +126,6 @@ int trace_event_raw_init(struct ftrace_event_call *call)
         if (!id)
                 return -ENODEV;
         call->id = id;
-        INIT_LIST_HEAD(&call->fields);
 
         return 0;
 }
@@ -537,6 +551,7 @@ event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
 {
         struct ftrace_event_call *call = filp->private_data;
         struct ftrace_event_field *field;
+        struct list_head *head;
         struct trace_seq *s;
         int common_field_count = 5;
         char *buf;
@@ -555,7 +570,8 @@ event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
         trace_seq_printf(s, "ID: %d\n", call->id);
         trace_seq_printf(s, "format:\n");
 
-        list_for_each_entry_reverse(field, &call->fields, link) {
+        head = trace_get_fields(call);
+        list_for_each_entry_reverse(field, head, link) {
                 /*
                  * Smartly shows the array type(except dynamic array).
                  * Normal:
@@ -931,6 +947,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
                  const struct file_operations *filter,
                  const struct file_operations *format)
 {
+        struct list_head *head;
         int ret;
 
         /*
@@ -957,14 +974,21 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
                                   id);
 #endif
 
-        if (call->define_fields) {
-                ret = trace_define_common_fields(call);
-                if (!ret)
-                        ret = call->define_fields(call);
-                if (ret < 0) {
-                        pr_warning("Could not initialize trace point"
-                                   " events/%s\n", call->name);
-                        return ret;
+        if (call->class->define_fields) {
+                /*
+                 * Other events may have the same class. Only update
+                 * the fields if they are not already defined.
+                 */
+                head = trace_get_fields(call);
+                if (list_empty(head)) {
+                        ret = trace_define_common_fields(call);
+                        if (!ret)
+                                ret = call->class->define_fields(call);
+                        if (ret < 0) {
+                                pr_warning("Could not initialize trace point"
+                                           " events/%s\n", call->name);
+                                return ret;
+                        }
                 }
                 trace_create_file("filter", 0644, call->dir, call,
                                   filter);
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index ca329603d0bf..961f99b74bdd 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -500,8 +500,10 @@ static struct ftrace_event_field *
 find_event_field(struct ftrace_event_call *call, char *name)
 {
         struct ftrace_event_field *field;
+        struct list_head *head;
 
-        list_for_each_entry(field, &call->fields, link) {
+        head = trace_get_fields(call);
+        list_for_each_entry(field, head, link) {
                 if (!strcmp(field->name, name))
                         return field;
         }
@@ -625,7 +627,7 @@ static int init_subsystem_preds(struct event_subsystem *system)
         int err;
 
         list_for_each_entry(call, &ftrace_events, list) {
-                if (!call->define_fields)
+                if (!call->class || !call->class->define_fields)
                         continue;
 
                 if (strcmp(call->class->system, system->name) != 0)
@@ -644,7 +646,7 @@ static void filter_free_subsystem_preds(struct event_subsystem *system)
         struct ftrace_event_call *call;
 
         list_for_each_entry(call, &ftrace_events, list) {
-                if (!call->define_fields)
+                if (!call->class || !call->class->define_fields)
                         continue;
 
                 if (strcmp(call->class->system, system->name) != 0)
@@ -1249,7 +1251,7 @@ static int replace_system_preds(struct event_subsystem *system,
         list_for_each_entry(call, &ftrace_events, list) {
                 struct event_filter *filter = call->filter;
 
-                if (!call->define_fields)
+                if (!call->class || !call->class->define_fields)
                         continue;
 
                 if (strcmp(call->class->system, system->name) != 0)
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index 7f16e2163817..e700a0c1803f 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -18,10 +18,6 @@
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM    ftrace
 
-struct ftrace_event_class event_class_ftrace = {
-        .system                 = __stringify(TRACE_SYSTEM),
-};
-
 /* not needed for this file */
 #undef __field_struct
 #define __field_struct(type, item)
@@ -131,7 +127,7 @@ ftrace_define_fields_##name(struct ftrace_event_call *event_call)	\
 
 static int ftrace_raw_init_event(struct ftrace_event_call *call)
 {
-        INIT_LIST_HEAD(&call->fields);
+        INIT_LIST_HEAD(&call->class->fields);
         return 0;
 }
 
@@ -159,15 +155,19 @@ static int ftrace_raw_init_event(struct ftrace_event_call *call)
 #undef FTRACE_ENTRY
 #define FTRACE_ENTRY(call, struct_name, type, tstruct, print)           \
                                                                         \
+struct ftrace_event_class event_class_ftrace_##call = {                 \
+        .system                 = __stringify(TRACE_SYSTEM),            \
+        .define_fields          = ftrace_define_fields_##call,          \
+};                                                                      \
+                                                                        \
 struct ftrace_event_call __used                                         \
 __attribute__((__aligned__(4)))                                         \
 __attribute__((section("_ftrace_events"))) event_##call = {             \
         .name                   = #call,                                \
         .id                     = type,                                 \
-        .class                  = &event_class_ftrace,                  \
+        .class                  = &event_class_ftrace_##call,           \
         .raw_init               = ftrace_raw_init_event,                \
         .print_fmt              = print,                                \
-        .define_fields          = ftrace_define_fields_##call,          \
 };                                                                      \
 
 #include "trace_entries.h"
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index f8af21a53f0c..b14bf745356f 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1112,8 +1112,6 @@ static void probe_event_disable(struct ftrace_event_call *call)
 
 static int probe_event_raw_init(struct ftrace_event_call *event_call)
 {
-        INIT_LIST_HEAD(&event_call->fields);
-
         return 0;
 }
 
@@ -1362,11 +1360,13 @@ static int register_probe_event(struct trace_probe *tp)
         if (probe_is_return(tp)) {
                 tp->event.trace = print_kretprobe_event;
                 call->raw_init = probe_event_raw_init;
-                call->define_fields = kretprobe_event_define_fields;
+                INIT_LIST_HEAD(&call->class->fields);
+                call->class->define_fields = kretprobe_event_define_fields;
         } else {
                 tp->event.trace = print_kprobe_event;
                 call->raw_init = probe_event_raw_init;
-                call->define_fields = kprobe_event_define_fields;
+                INIT_LIST_HEAD(&call->class->fields);
+                call->class->define_fields = kprobe_event_define_fields;
         }
         if (set_print_fmt(tp) < 0)
                 return -ENOMEM;
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index a21d366cae46..cceccf0d2e91 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -20,14 +20,37 @@ static int syscall_enter_register(struct ftrace_event_call *event,
 static int syscall_exit_register(struct ftrace_event_call *event,
                                  enum trace_reg type);
 
+static int syscall_enter_define_fields(struct ftrace_event_call *call);
+static int syscall_exit_define_fields(struct ftrace_event_call *call);
+
+static struct list_head *
+syscall_get_enter_fields(struct ftrace_event_call *call)
+{
+        struct syscall_metadata *entry = call->data;
+
+        return &entry->enter_fields;
+}
+
+static struct list_head *
+syscall_get_exit_fields(struct ftrace_event_call *call)
+{
+        struct syscall_metadata *entry = call->data;
+
+        return &entry->exit_fields;
+}
+
 struct ftrace_event_class event_class_syscall_enter = {
         .system                 = "syscalls",
-        .reg                    = syscall_enter_register
+        .reg                    = syscall_enter_register,
+        .define_fields          = syscall_enter_define_fields,
+        .get_fields             = syscall_get_enter_fields,
 };
 
 struct ftrace_event_class event_class_syscall_exit = {
         .system                 = "syscalls",
-        .reg                    = syscall_exit_register
+        .reg                    = syscall_exit_register,
+        .define_fields          = syscall_exit_define_fields,
+        .get_fields             = syscall_get_exit_fields,
 };
 
 extern unsigned long __start_syscalls_metadata[];
@@ -220,7 +243,7 @@ static void free_syscall_print_fmt(struct ftrace_event_call *call)
                 kfree(call->print_fmt);
 }
 
-int syscall_enter_define_fields(struct ftrace_event_call *call)
+static int syscall_enter_define_fields(struct ftrace_event_call *call)
 {
         struct syscall_trace_enter trace;
         struct syscall_metadata *meta = call->data;
@@ -243,7 +266,7 @@ int syscall_enter_define_fields(struct ftrace_event_call *call)
         return ret;
 }
 
-int syscall_exit_define_fields(struct ftrace_event_call *call)
+static int syscall_exit_define_fields(struct ftrace_event_call *call)
 {
         struct syscall_trace_exit trace;
         int ret;