trace_syscalls: Set event_enter_##sname->data to its metadata

Set event_enter_##sname->data to its metadata,
it makes codes simpler.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B14D282.7050709@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/syscalls.h

@@ -153,6 +153,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *unused)     \
 #define __SC_STR_TDECL6(t, a, ...)	#t, __SC_STR_TDECL5(__VA_ARGS__)
 
 #define SYSCALL_TRACE_ENTER_EVENT(sname)				\
+	static const struct syscall_metadata __syscall_meta_##sname;	\
 	static struct ftrace_event_call event_enter_##sname;		\
 	struct trace_event enter_syscall_print_##sname = {		\
 		.trace                  = print_syscall_enter,		\
@@ -184,11 +185,12 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *unused)     \
 		.define_fields		= syscall_enter_define_fields,	\
 		.regfunc		= reg_event_syscall_enter,	\
 		.unregfunc		= unreg_event_syscall_enter,	\
-		.data			= "sys"#sname,			\
+		.data			= (void *)&__syscall_meta_##sname,\
 		TRACE_SYS_ENTER_PROFILE_INIT(sname)			\
 	}
 
 #define SYSCALL_TRACE_EXIT_EVENT(sname)					\
+	static const struct syscall_metadata __syscall_meta_##sname;	\
 	static struct ftrace_event_call event_exit_##sname;		\
 	struct trace_event exit_syscall_print_##sname = {		\
 		.trace                  = print_syscall_exit,		\
@@ -220,7 +222,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *unused)     \
 		.define_fields		= syscall_exit_define_fields,	\
 		.regfunc		= reg_event_syscall_exit,	\
 		.unregfunc		= unreg_event_syscall_exit,	\
-		.data			= "sys"#sname,			\
+		.data			= (void *)&__syscall_meta_##sname,\
 		TRACE_SYS_EXIT_PROFILE_INIT(sname)			\
 	}
 

include/trace/syscall.h

@@ -34,7 +34,7 @@ struct syscall_metadata {
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 extern unsigned long arch_syscall_addr(int nr);
-extern int syscall_name_to_nr(char *name);
+extern int syscall_name_to_nr(const char *name);
 void set_syscall_enter_id(int num, int id);
 void set_syscall_exit_id(int num, int id);
 

kernel/trace/trace_syscalls.c

@@ -51,7 +51,7 @@ static struct syscall_metadata *syscall_nr_to_meta(int nr)
 	return syscalls_metadata[nr];
 }
 
-int syscall_name_to_nr(char *name)
+int syscall_name_to_nr(const char *name)
 {
 	int i;
 
@@ -172,18 +172,11 @@ extern char *__bad_type_size(void);
 int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
 {
 	int i;
-	int nr;
 	int ret;
-	struct syscall_metadata *entry;
+	struct syscall_metadata *entry = call->data;
 	struct syscall_trace_enter trace;
 	int offset = offsetof(struct syscall_trace_enter, args);
 
-	nr = syscall_name_to_nr(call->data);
-	entry = syscall_nr_to_meta(nr);
-
-	if (!entry)
-		return 0;
-
 	ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
 			       "\tsigned:%u;\n",
 			       SYSCALL_FIELD(int, nr));
@@ -245,18 +238,11 @@ int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
 int syscall_enter_define_fields(struct ftrace_event_call *call)
 {
 	struct syscall_trace_enter trace;
-	struct syscall_metadata *meta;
+	struct syscall_metadata *meta = call->data;
 	int ret;
-	int nr;
 	int i;
 	int offset = offsetof(typeof(trace), args);
 
-	nr = syscall_name_to_nr(call->data);
-	meta = syscall_nr_to_meta(nr);
-
-	if (!meta)
-		return 0;
-
 	ret = trace_define_common_fields(call);
 	if (ret)
 		return ret;
@@ -366,9 +352,9 @@ int reg_event_syscall_enter(struct ftrace_event_call *call)
 {
 	int ret = 0;
 	int num;
-	char *name;
+	const char *name;
 
-	name = (char *)call->data;
+	name = ((struct syscall_metadata *)call->data)->name;
 	num = syscall_name_to_nr(name);
 	if (num < 0 || num >= NR_syscalls)
 		return -ENOSYS;
@@ -389,9 +375,9 @@ int reg_event_syscall_enter(struct ftrace_event_call *call)
 void unreg_event_syscall_enter(struct ftrace_event_call *call)
 {
 	int num;
-	char *name;
+	const char *name;
 
-	name = (char *)call->data;
+	name = ((struct syscall_metadata *)call->data)->name;
 	num = syscall_name_to_nr(name);
 	if (num < 0 || num >= NR_syscalls)
 		return;
@@ -407,9 +393,9 @@ int reg_event_syscall_exit(struct ftrace_event_call *call)
 {
 	int ret = 0;
 	int num;
-	char *name;
+	const char *name;
 
-	name = call->data;
+	name = ((struct syscall_metadata *)call->data)->name;
 	num = syscall_name_to_nr(name);
 	if (num < 0 || num >= NR_syscalls)
 		return -ENOSYS;
@@ -430,9 +416,9 @@ int reg_event_syscall_exit(struct ftrace_event_call *call)
 void unreg_event_syscall_exit(struct ftrace_event_call *call)
 {
 	int num;
-	char *name;
+	const char *name;
 
-	name = call->data;
+	name = ((struct syscall_metadata *)call->data)->name;
 	num = syscall_name_to_nr(name);
 	if (num < 0 || num >= NR_syscalls)
 		return;