Re: [RFC PATCH 2/9] cxl/mem: Implement Clear Event Records command

From: Ira Weiny <ira.weiny@intel.com>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	"Ben Widawsky" <bwidawsk@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	<linux-kernel@vger.kernel.org>, <linux-cxl@vger.kernel.org>
Subject: Re: [RFC PATCH 2/9] cxl/mem: Implement Clear Event Records command
Date: Fri, 9 Sep 2022 14:35:32 -0700	[thread overview]
Message-ID: <YxuxpIZ9Xh01247Y@iweiny-desk3> (raw)
In-Reply-To: <20220824165513.00000987@huawei.com>

On Wed, Aug 24, 2022 at 04:55:13PM +0100, Jonathan Cameron wrote:
> On Fri, 12 Aug 2022 22:32:36 -0700
> ira.weiny@intel.com wrote:
> 
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > CXL v3.0 section 8.2.9.2.3 defines the Clear Event Records mailbox
> > command.  After an event record is read it needs to be cleared from the
> > event log.
> > 
> > Implement cxl_clear_event_record() and call it for each record retrieved
> > from the device.
> > 
> > Each record is cleared individually.  A clear all bit is specified but
> > events could arrive between a get and the final clear all operation.
> > Therefore each event is cleared specifically.
> > 
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> Trivial suggestions inline, but other than that LGTM
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Thanks!

> 
> > ---
> >  drivers/cxl/core/mbox.c      | 31 ++++++++++++++++++++++++++++---
> >  drivers/cxl/cxlmem.h         | 15 +++++++++++++++
> >  include/uapi/linux/cxl_mem.h |  1 +
> >  3 files changed, 44 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> > index 2cceed8608dc..493f5ceb5d1c 100644
> > --- a/drivers/cxl/core/mbox.c
> > +++ b/drivers/cxl/core/mbox.c
> > @@ -52,6 +52,7 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
> >  #endif
> >  	CXL_CMD(GET_SUPPORTED_LOGS, 0, CXL_VARIABLE_PAYLOAD, CXL_CMD_FLAG_FORCE_ENABLE),
> >  	CXL_CMD(GET_EVENT_RECORD, 1, CXL_VARIABLE_PAYLOAD, 0),
> > +	CXL_CMD(CLEAR_EVENT_RECORD, CXL_VARIABLE_PAYLOAD, 0, 0),
> >  	CXL_CMD(GET_FW_INFO, 0, 0x50, 0),
> >  	CXL_CMD(GET_PARTITION_INFO, 0, 0x20, 0),
> >  	CXL_CMD(GET_LSA, 0x8, CXL_VARIABLE_PAYLOAD, 0),
> > @@ -708,6 +709,26 @@ int cxl_enumerate_cmds(struct cxl_dev_state *cxlds)
> >  }
> >  EXPORT_SYMBOL_NS_GPL(cxl_enumerate_cmds, CXL);
> >  
> > +static int cxl_clear_event_record(struct cxl_dev_state *cxlds,
> > +				  enum cxl_event_log_type log,
> > +				  __le16 handle)
> > +{
> > +	struct cxl_mbox_clear_event_payload payload;
> > +	int rc;
> > +
> > +	memset(&payload, 0, sizeof(payload));
> 
> Could just do payload = {};
> 
> Thouch as you are setting stuff, why not just do
> 
> payload = {
> 	.event_log = log,
> 	.nr_recs = 1,
> 	.handle = handle,
> };
> and let the compiler zero anything else (I think there are no holes to complicate
> things).

Yea!  Done.

> 
> > +	payload.event_log = log;
> > +	payload.nr_recs = 1;
> > +	payload.handle = handle;
> > +
> > +	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_CLEAR_EVENT_RECORD,
> > +			       &payload, sizeof(payload), NULL, 0);
> 
> return cxl_mbox_send_cmd() and drop rc definition.

And Done.  I've also used the return value now!  ;-)

Thanks again!
Ira