RE: [PATCH v1 1/4] mmc: core: Add trace event for SD SCR response

[Avri Altman]

> 
> On Mon, 15 Apr 2019 16:52:38 -0600
> Raul E Rangel <rrangel@xxxxxxxxxxxx> wrote:
> 
> > Example:
> > sd_scr: mmc0: version: 2, spec3: 1, width: 5, cmds: 0, raw: {0x2b58000,0x0}
> >
> > Signed-off-by: Raul E Rangel <rrangel@xxxxxxxxxxxx>
> > ---
> >
> >  drivers/mmc/core/sd.c      |  4 ++++
> >  include/trace/events/mmc.h | 42
> ++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 46 insertions(+)
> >
> > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> > index 265e1aeeb9d8..3bed7c4b6d75 100644
> > --- a/drivers/mmc/core/sd.c
> > +++ b/drivers/mmc/core/sd.c
> > @@ -21,6 +21,8 @@
> >  #include <linux/mmc/mmc.h>
> >  #include <linux/mmc/sd.h>
> >
> > +#include <trace/events/mmc.h>
> > +
> >  #include "core.h"
> >  #include "card.h"
> >  #include "host.h"
> > @@ -200,6 +202,7 @@ static int mmc_decode_scr(struct mmc_card *card)
> >  	if (scr_struct != 0) {
> >  		pr_err("%s: unrecognised SCR structure version %d\n",
> >  			mmc_hostname(card->host), scr_struct);
> > +		trace_sd_scr(card, NULL);
> >  		return -EINVAL;
> >  	}
> >
> > @@ -221,6 +224,7 @@ static int mmc_decode_scr(struct mmc_card *card)
> >
> >  	if (scr->sda_spec3)
> >  		scr->cmds = UNSTUFF_BITS(resp, 32, 2);
> > +	trace_sd_scr(card, scr);
> >  	return 0;
> >  }
> >
> > diff --git a/include/trace/events/mmc.h b/include/trace/events/mmc.h
> > index 7b706ff21335..e45258e8a6cb 100644
> > --- a/include/trace/events/mmc.h
> > +++ b/include/trace/events/mmc.h
> > @@ -10,6 +10,48 @@
> >  #include <linux/mmc/host.h>
> >  #include <linux/tracepoint.h>
> >
> > +TRACE_EVENT(sd_scr,
As all 3 new trace events (csd, scr, and ssr) are pretty close,
You might want to find a common ground and declare an event class.

Thanks,
Avri

> > +
> > +	TP_PROTO(struct mmc_card *card, struct sd_scr *scr),
> > +
> > +	TP_ARGS(card, scr),
> > +
> > +	TP_STRUCT__entry(
> > +		__array(u32,			raw,	2)
> > +		__field(unsigned char,		sda_vsn)
> > +		__field(unsigned char,		sda_spec3)
> > +		__field(unsigned char,		bus_widths)
> > +		__field(unsigned char,		cmds)
> > +		__string(name,			mmc_hostname(card->host))
> > +	),
> > +
> > +	TP_fast_assign(
> > +		memcpy(__entry->raw, card->raw_scr, sizeof(card-
> >raw_scr));
> 
> Having the memcpy() size be that of the source is dangerous. Not that
> the destination will every be smaller, but I would highly suggest
> either trying to see if "sizeof(__entry->raw)" works or at worse,
> sizeof(u32)*2.
> 
> -- Steve
> 
> > +		if (scr) {
> > +			__entry->sda_vsn = scr->sda_vsn;
> > +			__entry->sda_spec3 = scr->sda_spec3;
> > +			__entry->bus_widths = scr->bus_widths;
> > +			__entry->cmds = scr->cmds;
> > +		} else {
> > +			__entry->sda_vsn = 0;
> > +			__entry->sda_spec3 = 0;
> > +			__entry->bus_widths = 0;
> > +			__entry->cmds = 0;
> > +		}
> > +		__assign_str(name, mmc_hostname(card->host));
> > +	),
> > +
> > +	TP_printk("%s: version: %d, spec3: %d, width: %d, cmds: %d, "
> > +		"raw: %s",
> > +		  __get_str(name),
> > +		  __entry->sda_vsn,
> > +		  __entry->sda_spec3,
> > +		  __entry->bus_widths,
> > +		  __entry->cmds,
> > +		  __print_array(__entry->raw, 2, sizeof(u32))
> > +	)
> > +);
> > +
> >  TRACE_EVENT(mmc_request_start,
> >
> >  	TP_PROTO(struct mmc_host *host, struct mmc_request *mrq),