Re: [PATCH v2] ufs: core: add hba parameter to trace events

[Steven Rostedt <rostedt@goodmis.org>]

On Thu, 13 Feb 2025 09:19:42 -0800
Bart Van Assche <bvanassche@acm.org> wrote:

> On 2/13/25 3:35 AM, peter.wang@mediatek.com wrote:
> > diff --git a/drivers/ufs/core/ufs_trace.h b/drivers/ufs/core/ufs_trace.h
> > index 84deca2b841d..2f79982846b6 100644
> > --- a/drivers/ufs/core/ufs_trace.h
> > +++ b/drivers/ufs/core/ufs_trace.h
> > @@ -83,16 +83,18 @@ UFS_CMD_TRACE_TSF_TYPES
> >   
> >   TRACE_EVENT(ufshcd_clk_gating,
> >   
> > -	TP_PROTO(const char *dev_name, int state),
> > +	TP_PROTO(struct ufs_hba *hba, int state),
> >   
> > -	TP_ARGS(dev_name, state),
> > +	TP_ARGS(hba, state),
> >   
> >   	TP_STRUCT__entry(
> > -		__string(dev_name, dev_name)
> > +		__field(struct ufs_hba *, hba)
> > +		__string(dev_name, dev_name(hba->dev))
> >   		__field(int, state)
> >   	),  
> 
> Please reduce the size of the tracing entries by removing dev_name from 
> TP_STRUCT__entry() and by replacing 'dev_name' with 'dev_name(hba->dev)'
> in the TP_printk() calls.

For future references, please do not recommend moving dereferences into the
TP_printk() callers. Those happen when the event is read by the user and
the hba pointer may no longer exist.

-- Steve