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 21:02:40 +0800
From:   Can Guo <cang@...eaurora.org>
To:     "Asutosh Das (asd)" <asutoshd@...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

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.

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;
>>   	}
>>