tracing: Use a global field list for all syscall exit events

All syscall exit events have the same fields.

The kernel size drops 2.5K:

   text    data     bss     dec     hex filename
7018612 2034376 7251132 16304120         f8c7f8 vmlinux.o.orig
7018612 2031888 7251132 16301632         f8be40 vmlinux.o

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BFA3746.8070100@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

3 files changed, 4 insertions, 6 deletions

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 7f614ce274a..7994bd44eb5 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -165,7 +165,6 @@ extern struct trace_event_functions exit_syscall_print_funcs;
                 .enter_event    = &event_enter_##sname,         \
                 .exit_event     = &event_exit_##sname,          \
                 .enter_fields   = LIST_HEAD_INIT(__syscall_meta_##sname.enter_fields), \
-                .exit_fields    = LIST_HEAD_INIT(__syscall_meta_##sname.exit_fields), \
         };
 
 #define SYSCALL_DEFINE0(sname)                                  \
@@ -180,7 +179,6 @@ extern struct trace_event_functions exit_syscall_print_funcs;
                 .enter_event    = &event_enter__##sname,        \
                 .exit_event     = &event_exit__##sname,         \
                 .enter_fields   = LIST_HEAD_INIT(__syscall_meta__##sname.enter_fields), \
-                .exit_fields    = LIST_HEAD_INIT(__syscall_meta__##sname.exit_fields), \
         };                                                      \
         asmlinkage long sys_##sname(void)
 #else
diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 257e08960d7..31966a4fb8c 100644
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -26,7 +26,6 @@ struct syscall_metadata {
         const char      **types;
         const char      **args;
         struct list_head enter_fields;
-        struct list_head exit_fields;
 
         struct ftrace_event_call *enter_event;
         struct ftrace_event_call *exit_event;
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 34e35804304..bac752f0cfb 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -23,6 +23,9 @@ static int syscall_exit_register(struct ftrace_event_call *event,
 static int syscall_enter_define_fields(struct ftrace_event_call *call);
 static int syscall_exit_define_fields(struct ftrace_event_call *call);
 
+/* All syscall exit events have the same fields */
+static LIST_HEAD(syscall_exit_fields);
+
 static struct list_head *
 syscall_get_enter_fields(struct ftrace_event_call *call)
 {
@@ -34,9 +37,7 @@ syscall_get_enter_fields(struct ftrace_event_call *call)
 static struct list_head *
 syscall_get_exit_fields(struct ftrace_event_call *call)
 {
-        struct syscall_metadata *entry = call->data;
-
-        return &entry->exit_fields;
+        return &syscall_exit_fields;
 }
 
 struct trace_event_functions enter_syscall_print_funcs = {