On 12/15/2022 12:54 PM, Steven Rostedt wrote:
On Thu, 15 Dec 2022 12:33:27 +0800
Linyu Yuan <quic_linyyuan@xxxxxxxxxxx> wrote:
there is one dwc3 trace event declare as below,
DECLARE_EVENT_CLASS(dwc3_log_event,
TP_PROTO(u32 event, struct dwc3 *dwc),
TP_ARGS(event, dwc),
TP_STRUCT__entry(
__field(u32, event)
__field(u32, ep0state)
__dynamic_array(char, str, DWC3_MSG_MAX)
),
TP_fast_assign(
__entry->event = event;
__entry->ep0state = dwc->ep0state;
),
TP_printk("event (%08x): %s", __entry->event,
dwc3_decode_event(__get_str(str), DWC3_MSG_MAX,
__entry->event, __entry->ep0state))
);
the problem is when trace function called, it will allocate up to
DWC3_MSG_MAX bytes from trace event buffer, but never fill the buffer
during fast assignment, it only fill the buffer when output function are
called, so this means if output function are not called, the buffer will
never used.
add __get_buf(len) which allocate space from iter->tmp_seq when trace
output function called, it allow user write any data to allocatd space.
the mentioned dwc3 trace event will changed as below,
DECLARE_EVENT_CLASS(dwc3_log_event,
TP_PROTO(u32 event, struct dwc3 *dwc),
TP_ARGS(event, dwc),
TP_STRUCT__entry(
__field(u32, event)
__field(u32, ep0state)
),
TP_fast_assign(
__entry->event = event;
__entry->ep0state = dwc->ep0state;
),
TP_printk("event (%08x): %s", __entry->event,
dwc3_decode_event(__get_buf(DWC3_MSG_MAX), DWC3_MSG_MAX,
__entry->event, __entry->ep0state))
);.
Signed-off-by: Linyu Yuan <quic_linyyuan@xxxxxxxxxxx>
No!
ok, so you don't like a common function in trace_seq.c ?
Here, I did it for you:
-- Steve
diff --git a/drivers/usb/dwc3/debug.h b/drivers/usb/dwc3/debug.h
index 48b44b88dc25..81abdcbfc660 100644
--- a/drivers/usb/dwc3/debug.h
+++ b/drivers/usb/dwc3/debug.h
@@ -11,6 +11,7 @@
#ifndef __DWC3_DEBUG_H
#define __DWC3_DEBUG_H
+#include <linux/trace_seq.h>
#include "core.h"
/**
@@ -381,6 +382,19 @@ static inline const char *dwc3_decode_event(char *str, size_t size, u32 event,
return dwc3_ep_event_string(str, size, &evt.depevt, ep0state);
}
+static inline const char *dwc3_decode_event_seq(struct trace_seq *p,
+ u32 event, u32 ep0state)
+{
+ char *str = trace_seq_buffer_ptr(p);
+ int size = seq_buf_buffer_left(&p->seq);
+
+ dwc3_decode_event(str, size, event, ep0state);
+
+ seq_buf_commit(&p->seq, strlen(str));
+
+ return str;
+}
+
static inline const char *dwc3_ep_cmd_status_string(int status)
{
switch (status) {
diff --git a/drivers/usb/dwc3/trace.h b/drivers/usb/dwc3/trace.h
index 1975aec8d36d..bee2589e85a8 100644
--- a/drivers/usb/dwc3/trace.h
+++ b/drivers/usb/dwc3/trace.h
@@ -54,15 +54,13 @@ DECLARE_EVENT_CLASS(dwc3_log_event,
TP_STRUCT__entry(
__field(u32, event)
__field(u32, ep0state)
- __dynamic_array(char, str, DWC3_MSG_MAX)
),
TP_fast_assign(
__entry->event = event;
__entry->ep0state = dwc->ep0state;
),
TP_printk("event (%08x): %s", __entry->event,
- dwc3_decode_event(__get_str(str), DWC3_MSG_MAX,
- __entry->event, __entry->ep0state))
+ dwc3_decode_event_seq(p, __entry->event, __entry->ep0state))
);
DEFINE_EVENT(dwc3_log_event, dwc3_event,
