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Subject: Re: [PATCH v1 1/3] scsi: ufs: Distinguish between query REQ and query
 RSP in query trace
To:     Bean Huo <huobean@gmail.com>, alim.akhtar@samsung.com,
        avri.altman@wdc.com, asutoshd@codeaurora.org, jejb@linux.ibm.com,
        martin.petersen@oracle.com, stanley.chu@mediatek.com,
        beanhuo@micron.com, tomas.winkler@intel.com, cang@codeaurora.org
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        rostedt@goodmis.org
References: <20201206164226.6595-1-huobean@gmail.com>
 <20201206164226.6595-2-huobean@gmail.com>
From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <043235b9-e99a-8f7e-69fa-599b94ac2b12@acm.org>
Date:   Sun, 6 Dec 2020 10:51:50 -0800
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On 12/6/20 8:42 AM, Bean Huo wrote:
> From: Bean Huo <beanhuo@micron.com>
> 
> Currently, in the query completion trace print,  since we use
> hba->lrb[tag].ucd_req_ptr and didn't differentiate UPIU between
> request and response, thus header and transaction-specific field
> in UPIU printed by query trace are identical. This is not very
> practical. As below:
> 
> query_send: HDR:16 00 00 0e 00 81 00 00 00 00 00 00, CDB:06 0e 03 00 00 00 00 00 00 00 00 00 00 00 00 00
> query_complete: HDR:16 00 00 0e 00 81 00 00 00 00 00 00, CDB:06 0e 03 00 00 00 00 00 00 00 00 00 00 00 00 00
> 
> For the failure analysis, we want to understand the real response
> reported by the UFS device, however, the current query trace tells
> us nothing. After this patch, the query trace on the query_send, and
> the above a pair of query_send and query_complete will be:
> 
> query_send: HDR:16 00 00 0e 00 81 00 00 00 00 00 00, CDB:06 0e 03 00 00 00 00 00 00 00 00 00 00 00 00 00
> ufshcd_upiu: HDR:36 00 00 0e 00 81 00 00 00 00 00 00, CDB:06 0e 03 00 00 00 00 00 00 00 00 01 00 00 00 00
> 
> Signed-off-by: Bean Huo <beanhuo@micron.com>
> ---
>  drivers/scsi/ufs/ufshcd.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index ceb562accc39..e10de94adb3f 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -321,9 +321,15 @@ static void ufshcd_add_cmd_upiu_trace(struct ufs_hba *hba, unsigned int tag,
>  static void ufshcd_add_query_upiu_trace(struct ufs_hba *hba, unsigned int tag,
>  		const char *str)
>  {
> -	struct utp_upiu_req *rq = hba->lrb[tag].ucd_req_ptr;
> +	struct utp_upiu_req *rq_rsp;
> +
> +	if (!strcmp("query_send", str))
> +		rq_rsp = hba->lrb[tag].ucd_req_ptr;
> +	else
> +		rq_rsp = (struct utp_upiu_req *)hba->lrb[tag].ucd_rsp_ptr;
>  
> -	trace_ufshcd_upiu(dev_name(hba->dev), str, &rq->header, &rq->qr);
> +	trace_ufshcd_upiu(dev_name(hba->dev), str, &rq_rsp->header,
> +			  &rq_rsp->qr);
>  }

Please change the 'str' argument into an enum and let
ufshcd_add_query_upiu_trace() do the enum-to-string conversion. That
will allow to convert the strcmp() call into an integer comparison.

Thanks,

Bart.