linux-kernel - Re: [PATCH 2/2] cxl/trace: Remove unnecessary memcpy's

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Date: Thu, 1 Feb 2024 09:16:49 -0700
From: Dave Jiang <dave.jiang@...el.com>
To: Ira Weiny <ira.weiny@...el.com>, Dan Williams <dan.j.williams@...el.com>,
	Jonathan Cameron <jonathan.cameron@...wei.com>
CC: Davidlohr Bueso <dave@...olabs.net>, Alison Schofield
	<alison.schofield@...el.com>, Vishal Verma <vishal.l.verma@...el.com>,
	<linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-efi@...r.kernel.org>, <linux-cxl@...r.kernel.org>
Subject: Re: [PATCH 2/2] cxl/trace: Remove unnecessary memcpy's



On 1/31/24 16:55, Ira Weiny wrote:
> CPER events don't have UUIDs.  Therefore UUIDs were removed from the
> records passed to trace events and replaced with hard coded values.
> 
> As pointed out by Jonathan, the new defines for the UUIDs present a more
> efficient way to assign UUID in trace records.[1]
> 
> Replace memcpy's with the use of static data.
> 
> [1] https://lore.kernel.org/all/20240108132325.00000e9c@Huawei.com/
> 
> Suggested-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> Signed-off-by: Ira Weiny <ira.weiny@...el.com>

Reviewed-by: Dave Jiang <dave.jiang@...el.com>
> ---
>  drivers/cxl/core/trace.h | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
> index 89445435303a..bdf117a33744 100644
> --- a/drivers/cxl/core/trace.h
> +++ b/drivers/cxl/core/trace.h
> @@ -338,7 +338,7 @@ TRACE_EVENT(cxl_general_media,
>  
>  	TP_fast_assign(
>  		CXL_EVT_TP_fast_assign(cxlmd, log, rec->hdr);
> -		memcpy(&__entry->hdr_uuid, &CXL_EVENT_GEN_MEDIA_UUID, sizeof(uuid_t));
> +		__entry->hdr_uuid = CXL_EVENT_GEN_MEDIA_UUID;
>  
>  		/* General Media */
>  		__entry->dpa = le64_to_cpu(rec->phys_addr);
> @@ -425,7 +425,7 @@ TRACE_EVENT(cxl_dram,
>  
>  	TP_fast_assign(
>  		CXL_EVT_TP_fast_assign(cxlmd, log, rec->hdr);
> -		memcpy(&__entry->hdr_uuid, &CXL_EVENT_DRAM_UUID, sizeof(uuid_t));
> +		__entry->hdr_uuid = CXL_EVENT_DRAM_UUID;
>  
>  		/* DRAM */
>  		__entry->dpa = le64_to_cpu(rec->phys_addr);
> @@ -573,7 +573,7 @@ TRACE_EVENT(cxl_memory_module,
>  
>  	TP_fast_assign(
>  		CXL_EVT_TP_fast_assign(cxlmd, log, rec->hdr);
> -		memcpy(&__entry->hdr_uuid, &CXL_EVENT_MEM_MODULE_UUID, sizeof(uuid_t));
> +		__entry->hdr_uuid = CXL_EVENT_MEM_MODULE_UUID;
>  
>  		/* Memory Module Event */
>  		__entry->event_type = rec->event_type;
>