Message-ID: <aed019c6-9729-1892-2c8f-c97bcc7efd35@quicinc.com>
Date:   Mon, 13 Mar 2023 19:29:52 +0800
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Subject: Re: [PATCH v1] scsi: ufs: core: print trs for pending requests in MCQ
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To:     Bart Van Assche <bvanassche@acm.org>, <quic_asutoshd@quicinc.com>,
        <quic_cang@quicinc.com>, <quic_nguyenb@quicinc.com>,
        <mani@kernel.org>, <stanley.chu@mediatek.com>,
        <adrian.hunter@intel.com>, <beanhuo@micron.com>,
        <avri.altman@wdc.com>, <junwoo80.lee@samsung.com>,
        <martin.petersen@oracle.com>
CC:     <linux-scsi@vger.kernel.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        open list <linux-kernel@vger.kernel.org>
References: <1678338122-88611-1-git-send-email-quic_ziqichen@quicinc.com>
 <3d858407-481b-a55b-4aa9-513e4a4ca44e@acm.org>
From:   Ziqi Chen <quic_ziqichen@quicinc.com>
In-Reply-To: <3d858407-481b-a55b-4aa9-513e4a4ca44e@acm.org>
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Precedence: bulk

Hi Bart,

Good idea, let met re-design it.

Thanks,
Ziqi

On 3/10/2023 1:28 AM, Bart Van Assche wrote:
> On 3/8/23 21:01, Ziqi Chen wrote:
>> +static void ufshcd_print_trs_all(struct ufs_hba *hba, bool pr_prdt)
>> +{
>> +    const struct ufshcd_lrb *lrbp;
>> +    int tag;
>> +
>> +    for (tag = 0; tag < hba->nutrs; tag++) {
>> +        lrbp = &hba->lrb[tag];
>> +
>> +        if (lrbp->cmd)
>> +            ufshcd_print_tr(hba, tag, pr_prdt);
>>       }
>>   }
> 
> There is a race in this code: lrbp->cmd may be cleared after it has been 
> read and before or while ufshcd_print_tr() is in progress. How about 
> preventing that race by blk_mq_tagset_busy_iter() to iterate over 
> pending SCSI commands?
> 
> Thanks,
> 
> Bart.