linux-kernel - Re: [PATCH v7 7/8] scsi: ufs: Move dumps in IRQ handler to error handler

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Date:   Wed, 29 Jul 2020 15:45:31 -0700
From:   "Asutosh Das (asd)" <asutoshd@...eaurora.org>
To:     Can Guo <cang@...eaurora.org>
Cc:     nguyenb@...eaurora.org, hongwus@...eaurora.org,
        rnayak@...eaurora.org, sh425.lee@...sung.com,
        linux-scsi@...r.kernel.org, kernel-team@...roid.com,
        saravanak@...gle.com, salyzyn@...gle.com,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Bean Huo <beanhuo@...ron.com>,
        Bart Van Assche <bvanassche@....org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 7/8] scsi: ufs: Move dumps in IRQ handler to error
 handler

On 7/29/2020 6:02 AM, Can Guo wrote:
> Hi Asutosh,
> 
> On 2020-07-29 02:06, Asutosh Das (asd) wrote:
>> On 7/27/2020 10:00 PM, Can Guo wrote:
>>> Sometime dumps in IRQ handler are heavy enough to cause system stability
>>> issues, move them to error handler.
>>>
>>> Signed-off-by: Can Guo <cang@...eaurora.org>
>>> ---
>>>   drivers/scsi/ufs/ufshcd.c | 31 +++++++++++++++----------------
>>>   1 file changed, 15 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>>> index c480823..b2bafa3 100644
>>> --- a/drivers/scsi/ufs/ufshcd.c
>>> +++ b/drivers/scsi/ufs/ufshcd.c
>>> @@ -5682,6 +5682,21 @@ static void ufshcd_err_handler(struct 
>>> work_struct *work)
>>>                       UFSHCD_UIC_DL_TCx_REPLAY_ERROR))))
>>>           needs_reset = true;
>>>   +    if (hba->saved_err & (INT_FATAL_ERRORS | UIC_ERROR |
>>> +                  UFSHCD_UIC_HIBERN8_MASK)) {
>>> +        bool pr_prdt = !!(hba->saved_err & SYSTEM_BUS_FATAL_ERROR);
>>> +
>>> +        dev_err(hba->dev, "%s: saved_err 0x%x saved_uic_err 0x%x\n",
>>> +                __func__, hba->saved_err, hba->saved_uic_err);
>>> +        spin_unlock_irqrestore(hba->host->host_lock, flags);
>>> +        ufshcd_print_host_state(hba);
>>> +        ufshcd_print_pwr_info(hba);
>>> +        ufshcd_print_host_regs(hba);
>>> +        ufshcd_print_tmrs(hba, hba->outstanding_tasks);
>>> +        ufshcd_print_trs(hba, hba->outstanding_reqs, pr_prdt);
>>> +        spin_lock_irqsave(hba->host->host_lock, flags);
>>> +    }
>>> +
>>>       /*
>>>        * if host reset is required then skip clearing the pending
>>>        * transfers forcefully because they will get cleared during
>>> @@ -5900,22 +5915,6 @@ static irqreturn_t ufshcd_check_errors(struct 
>>> ufs_hba *hba)
>>>             /* block commands from scsi mid-layer */
>>>           ufshcd_scsi_block_requests(hba);
>>> -
>>> -        /* dump controller state before resetting */
>>> -        if (hba->saved_err & (INT_FATAL_ERRORS | UIC_ERROR)) {
>>> -            bool pr_prdt = !!(hba->saved_err &
>>> -                    SYSTEM_BUS_FATAL_ERROR);
>>> -
>>> -            dev_err(hba->dev, "%s: saved_err 0x%x saved_uic_err 
>>> 0x%x\n",
>>> -                    __func__, hba->saved_err,
>>> -                    hba->saved_uic_err);
>>> -
>>> -            ufshcd_print_host_regs(hba);
>>> -            ufshcd_print_pwr_info(hba);
>> How about keep the above prints and move the tmrs and trs to eh?
>> Sometimes in system instability, the eh may not get a chance to run
>> even. Still the above prints would provide some clues.
> 
> Here is the IRQ handler, ufshcd_print_host_regs() is sometime heavy
> enough to cause stability issues during my fault injection test, since
> it prints host regs, reg's history, crypto debug infos plus prints
> from vops_dump.
> 
> How about just printing host regs and reg history here? Most time, these
> infos are enough.
> 
That'd work too.

> Thanks,
> 
> Can Guo.
> 
>>> -            ufshcd_print_tmrs(hba, hba->outstanding_tasks);
>>> -            ufshcd_print_trs(hba, hba->outstanding_reqs,
>>> -                    pr_prdt);
>>> -        }
>>>           ufshcd_schedule_eh_work(hba);
>>>           retval |= IRQ_HANDLED;
>>>       }
>>>


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