Re: [PATCH net-next 1/3] trace: add variant without spacing in trace_print_hex_seq

[Daniel Borkmann]

On 01/30/2017 09:44 PM, Steven Rostedt wrote:
> On Wed, 25 Jan 2017 02:28:16 +0100
> Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
>
> > 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@xxxxxxxxxxxxx>
> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> > Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > ---
> >   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.

> >   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