scsi: ftrace based scsi tracer

This is the same patch from v1.

__print_hex() prints values in an array in hex (w/o '0x') (space separated) EX) 92 33 32 f3 ee 4d

Signed-off-by Li Zefan <[email protected]>

Signed-off-by Tomohiro Kusumi <[email protected]>

Signed-off-by Kei Tokunaga <[email protected]>

---

 linux-2.6.34-rc3-trace-kei/include/linux/ftrace_event.h |    3 +++
 linux-2.6.34-rc3-trace-kei/include/trace/ftrace.h       |    3 +++
 linux-2.6.34-rc3-trace-kei/kernel/trace/trace_output.c  |   15 +++++++++++++++
 3 files changed, 21 insertions(+)

diff -puN include/linux/ftrace_event.h~add__print_hex_to_ftrace include/linux/ftrace_event.h

include/linux/ftrace_event.h renamed from include/linux/ftrace_event.h~add__print_hex_to_ftrace +3 -0

@@ -25,6 +25,9 @@ const char *ftrace_print_flags_seq(struc
 const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
 				     const struct trace_print_flags *symbol_array);
 
+const char *ftrace_print_hex_seq(struct trace_seq *p,
+				 const unsigned char *buf, int len);
+
 /*
  * The trace entry - the most basic unit of tracing. This is what
  * is printed in the end as a single line in the trace output, such as:

diff -puN include/trace/ftrace.h~add__print_hex_to_ftrace include/trace/ftrace.h

include/trace/ftrace.h renamed from include/trace/ftrace.h~add__print_hex_to_ftrace +3 -0

@@ -198,6 +198,9 @@
 		ftrace_print_symbols_seq(p, value, symbols);		\
 	})
 
+#undef __print_hex
+#define __print_hex(buf, buf_len) ftrace_print_hex_seq(p, buf, buf_len)
+
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
 static notrace enum print_line_t					\

diff -puN kernel/trace/trace_output.c~add__print_hex_to_ftrace kernel/trace/trace_output.c

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +0 -0

@@ -355,6 +355,21 @@ ftrace_print_symbols_seq(struct trace_se
 }
 EXPORT_SYMBOL(ftrace_print_symbols_seq);
 

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +5 -0

+
+	return ret;
+}
+EXPORT_SYMBOL(ftrace_print_hex_seq);
+
 #ifdef CONFIG_KRETPROBES
 static inline const char *kretprobed(const char *name)
 {

_

kernel/trace/trace_output.c ftrace_print_symbols_seq(struct trace_se · line 367

Quoted 10 lines

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +10 -0

+const char *
+ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
+{
+	int i;
+	const char *ret = p->buffer + p->len;
+
+	for (i = 0; i < buf_len; i++)
+		trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
+
+	trace_seq_putc(p, 0);

Quoted 10 lines · Steven Rostedt

kernel/trace/trace_output.c ftrace_print_symbols_seq(struct trace_se · line 367

Quoted 10 lines

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +10 -0

+const char *
+ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
+{
+	int i;
+	const char *ret = p->buffer + p->len;
+
+	for (i = 0; i < buf_len; i++)
+		trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
+
+	trace_seq_putc(p, 0);

hex_dump_to_buffer?

Quoted 5 lines

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +5 -0

+const char *
+ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
+{
+	int i;
+	const char *ret = p->buffer + p->len;

kernel/trace/trace_output.c ftrace_print_symbols_seq(struct trace_se · line 367

Quoted 5 lines

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +5 -0

+
+	for (i = 0; i < buf_len; i++)
+		trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
+
+	trace_seq_putc(p, 0);

I would not put the putc(p, 0) into a helper function. This terminates the buffer, and strings added to the trace_seq will go after the '\0'.

What we need is this in trace_seq.h:

static inline trace_seq_terminate(struct trace_seq *s)

{
	if (!s->full)
		s->buffer[s->len] = 0;
}

This will add a '0' to the buffer after the last string, but will not increment length while doing it. Thus, new data added to the buffer would still be appended correctly.

-- Steve

Quoted 4 lines

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +4 -0

+
+	return ret;
+}
+EXPORT_SYMBOL(ftrace_print_hex_seq);

Quoted 5 lines

Quoted 5 lines

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +5 -0

+const char *
+ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
+{
+	int i;
+	const char *ret = p->buffer + p->len;

Quoted 9 lines

kernel/trace/trace_output.c ftrace_print_symbols_seq(struct trace_se · line 367

Quoted 5 lines

kernel/trace/trace_output.c renamed from kernel/trace/trace_output.c~add__print_hex_to_ftrace +5 -0

+
+	for (i = 0; i < buf_len; i++)
+		trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
+
+	trace_seq_putc(p, 0);

I would not put the putc(p, 0) into a helper function. This terminates the buffer, and strings added to the trace_seq will go after the '\0'.

This is exactly what ftrace_print_flags_seq() and ftrace_print_symbols_seq() do, and exactly what we want.

An example:

TP_printk("%s,%s", __print_flags(...), __print_flags(...));

We need 2 seperated strings, while trace_seq_terminate() will make it a single string.