tracing: Use defined fields and print_fmt to print formats

The calls ftrace_format_##call() and ftrace_define_fields_##call()
are almost duplicate in functionality. With the addition of the
print_fmt in previous patches, these two functions can be merged
into one.

The trace_define_field() defines the fields and links them into
the struct ftrace_event_call. The previous patches introduced
the print_fmt field and this can now be used with the trace_define_field()
to create the event format file fields and print_fmt field.

The struct ftrace_event_call->fields are used to print the fields
The struct ftrace_event_call->print_fmt is used to print
the "print fmt: XXXXXXXXXXX" line.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D49.5000006@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 189b09baf4fbfd1bb6a2340897c477d83d6de800..250ec865d5f5704b8f68751eb6c706011f9d621f 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -528,33 +528,16 @@ extern char *__bad_type_size(void);
        #type, "common_" #name, offsetof(typeof(field), name),          \
                sizeof(field.name), is_signed_type(type)
 
-static int trace_write_header(struct trace_seq *s)
-{
-       struct trace_entry field;
-
-       /* struct trace_entry */
-       return trace_seq_printf(s,
-                       "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
-                       "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
-                       "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
-                       "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
-                       "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
-                       "\n",
-                       FIELD(unsigned short, type),
-                       FIELD(unsigned char, flags),
-                       FIELD(unsigned char, preempt_count),
-                       FIELD(int, pid),
-                       FIELD(int, lock_depth));
-}
-
 static ssize_t
 event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
                  loff_t *ppos)
 {
        struct ftrace_event_call *call = filp->private_data;
+       struct ftrace_event_field *field;
        struct trace_seq *s;
+       int common_field_count = 5;
        char *buf;
-       int r;
+       int r = 0;
 
        if (*ppos)
                return 0;
@@ -565,14 +548,48 @@ event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
 
        trace_seq_init(s);
 
-       /* If any of the first writes fail, so will the show_format. */
-
        trace_seq_printf(s, "name: %s\n", call->name);
        trace_seq_printf(s, "ID: %d\n", call->id);
        trace_seq_printf(s, "format:\n");
-       trace_write_header(s);
 
-       r = call->show_format(call, s);
+       list_for_each_entry_reverse(field, &call->fields, link) {
+               /*
+                * Smartly shows the array type(except dynamic array).
+                * Normal:
+                *      field:TYPE VAR
+                * If TYPE := TYPE[LEN], it is shown:
+                *      field:TYPE VAR[LEN]
+                */
+               const char *array_descriptor = strchr(field->type, '[');
+
+               if (!strncmp(field->type, "__data_loc", 10))
+                       array_descriptor = NULL;
+
+               if (!array_descriptor) {
+                       r = trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;"
+                                       "\tsize:%u;\tsigned:%d;\n",
+                                       field->type, field->name, field->offset,
+                                       field->size, !!field->is_signed);
+               } else {
+                       r = trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;"
+                                       "\tsize:%u;\tsigned:%d;\n",
+                                       (int)(array_descriptor - field->type),
+                                       field->type, field->name,
+                                       array_descriptor, field->offset,
+                                       field->size, !!field->is_signed);
+               }
+
+               if (--common_field_count == 0)
+                       r = trace_seq_printf(s, "\n");
+
+               if (!r)
+                       break;
+       }
+
+       if (r)
+               r = trace_seq_printf(s, "\nprint fmt: %s\n",
+                               call->print_fmt);
+
        if (!r) {
                /*
                 * ug!  The format output is bigger than a PAGE!!