On 01/30/2017 09:44 PM, Steven Rostedt wrote:

On Wed, 25 Jan 2017 02:28:16 +0100
Daniel Borkmann [off-list ref] wrote:

quoted

For upcoming tracepoint support for BPF, we want to dump the program's
tag. Format should be similar to __print_hex(), but without spacing.
Add a __print_hex_str() variant for exactly that purpose that reuses
trace_print_hex_seq().

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <redacted>
---
  include/linux/trace_events.h | 3 ++-
  include/trace/trace_events.h | 8 +++++++-
  kernel/trace/trace_output.c  | 7 ++++---
  3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index be00761..cfa475a 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h

@@ -33,7 +33,8 @@ const char *trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
  				    unsigned int bitmask_size);

  const char *trace_print_hex_seq(struct trace_seq *p,
-				const unsigned char *buf, int len);
+				const unsigned char *buf, int len,
+				bool spacing);

Hmm, "spacing" doesn't really mean much. What about the invert of it,
and have "concatenate"?

Sure, I'm fine with that.

quoted

  const char *trace_print_array_seq(struct trace_seq *p,
  				   const void *buf, int count,

diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index 467e12f..9f68462 100644
--- a/include/trace/trace_events.h
+++ b/include/trace/trace_events.h

@@ -297,7 +297,12 @@
  #endif

  #undef __print_hex
-#define __print_hex(buf, buf_len) trace_print_hex_seq(p, buf, buf_len)
+#define __print_hex(buf, buf_len)					\
+	trace_print_hex_seq(p, buf, buf_len, true)
+
+#undef __print_hex_str
+#define __print_hex_str(buf, buf_len)					\
+	trace_print_hex_seq(p, buf, buf_len, false)

  #undef __print_array
  #define __print_array(array, count, el_size)				\

@@ -711,6 +716,7 @@
  #undef __print_flags
  #undef __print_symbolic
  #undef __print_hex
+#undef __print_hex_str
  #undef __get_dynamic_array
  #undef __get_dynamic_array_len
  #undef __get_str

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 5d33a73..30a144b1 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c

@@ -163,14 +163,15 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
  EXPORT_SYMBOL_GPL(trace_print_bitmask_seq);

With the addition of this boolean parameter, this function shold
probably have a kernel doc header, that can explain the parameters.

Yeah, I can add that. Since the patch got already applied, I will send
a follow-up for adding the kdoc and for changing the bool logic/name as
concatenate.

Thanks for your review!
Daniel