Re: [ndctl PATCH v11 4/7] cxl/event_trace: add helpers to retrieve tep fields by type

[Alison Schofield <alison.schofield@intel.com>]

On Fri, Mar 15, 2024 at 10:39:53AM -0700, Dan Williams wrote:
> alison.schofield@ wrote:
> > From: Alison Schofield <alison.schofield@intel.com>
> > 
> > Add helpers to extract the value of an event record field given the
> > field name. This is useful when the user knows the name and format
> > of the field and simply needs to get it. The helpers also return
> > the 'type'_MAX of the type when the field is
> > 
> > Since this is in preparation for adding a cxl_poison private parser
> > for 'cxl list --media-errors' support those specific required
> > types: u8, u32, u64.
> > 
> > Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> > ---
> >  cxl/event_trace.c | 37 +++++++++++++++++++++++++++++++++++++
> >  cxl/event_trace.h |  8 +++++++-
> >  2 files changed, 44 insertions(+), 1 deletion(-)
> > 
> > diff --git a/cxl/event_trace.c b/cxl/event_trace.c
> > index 640abdab67bf..324edb982888 100644
> > --- a/cxl/event_trace.c
> > +++ b/cxl/event_trace.c
> > @@ -15,6 +15,43 @@
> >  #define _GNU_SOURCE
> >  #include <string.h>
> >  
> > +u64 cxl_get_field_u64(struct tep_event *event, struct tep_record *record,
> > +		      const char *name)
> > +{
> > +	unsigned long long val;
> > +
> > +	if (tep_get_field_val(NULL, event, name, record, &val, 0))
> > +		return ULLONG_MAX;
> > +
> > +	return val;
> > +}
> 
> Hm, why are these prefixed "cxl_" there is nothing cxl specific in the
> internals. Maybe these event trace helpers grow non-CXL users in the
> future. Could be "trace_" or "util_" like other generic helpers in the
> codebase.

All the helpers in cxl/event_trace.c are prefixed "cxl_". The cxl
special-ness is only that ndctl/cxl is the only user of trace events
in ndctl/.  cxl/monitor.c and now cxl/json.c (this usage)

I can move: ndctl/cxl/event_trace.h,c to ndctl/utils/event_trace.h,c.
and update cxl/monitor.c to find.

Yay?