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Subject: Re: [PATCH v3 1/3] scsi: ufs: Serialize eh_work with system PM events
 and async scan
To:     Can Guo <cang@codeaurora.org>, nguyenb@codeaurora.org,
        hongwus@codeaurora.org, ziqichen@codeaurora.org,
        rnayak@codeaurora.org, linux-scsi@vger.kernel.org,
        kernel-team@android.com, saravanak@google.com, salyzyn@google.com
Cc:     Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Satya Tangirala <satyat@google.com>,
        open list <linux-kernel@vger.kernel.org>
References: <1605596660-2987-1-git-send-email-cang@codeaurora.org>
 <1605596660-2987-2-git-send-email-cang@codeaurora.org>
From:   "Asutosh Das (asd)" <asutoshd@codeaurora.org>
Message-ID: <89c387c1-586a-3309-9dbb-f1903148df62@codeaurora.org>
Date:   Mon, 30 Nov 2020 18:41:15 -0800
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On 11/16/2020 11:04 PM, Can Guo wrote:
> Serialize eh_work with system PM events and async scan to make sure eh_work
> does not run in parallel with them.
> 
> Signed-off-by: Can Guo <cang@codeaurora.org>
> ---

Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>

>   drivers/scsi/ufs/ufshcd.c | 64 +++++++++++++++++++++++++++++------------------
>   drivers/scsi/ufs/ufshcd.h |  1 +
>   2 files changed, 41 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 1d8134e..7e764e8 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -5597,7 +5597,9 @@ static inline void ufshcd_schedule_eh_work(struct ufs_hba *hba)
>   static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
>   {
>   	pm_runtime_get_sync(hba->dev);
> -	if (pm_runtime_suspended(hba->dev)) {
> +	if (pm_runtime_status_suspended(hba->dev) || hba->is_sys_suspended) {
> +		enum ufs_pm_op pm_op;
> +
>   		/*
>   		 * Don't assume anything of pm_runtime_get_sync(), if
>   		 * resume fails, irq and clocks can be OFF, and powers
> @@ -5612,7 +5614,8 @@ static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
>   		if (!ufshcd_is_clkgating_allowed(hba))
>   			ufshcd_setup_clocks(hba, true);
>   		ufshcd_release(hba);
> -		ufshcd_vops_resume(hba, UFS_RUNTIME_PM);
> +		pm_op = hba->is_sys_suspended ? UFS_RUNTIME_PM : UFS_SYSTEM_PM;
> +		ufshcd_vops_resume(hba, pm_op);
>   	} else {
>   		ufshcd_hold(hba, false);
>   		if (hba->clk_scaling.is_allowed) {
> @@ -5633,7 +5636,7 @@ static void ufshcd_err_handling_unprepare(struct ufs_hba *hba)
>   
>   static inline bool ufshcd_err_handling_should_stop(struct ufs_hba *hba)
>   {
> -	return (hba->ufshcd_state == UFSHCD_STATE_ERROR ||
> +	return (!hba->is_powered || hba->ufshcd_state == UFSHCD_STATE_ERROR ||
>   		(!(hba->saved_err || hba->saved_uic_err || hba->force_reset ||
>   			ufshcd_is_link_broken(hba))));
>   }
> @@ -5646,6 +5649,7 @@ static void ufshcd_recover_pm_error(struct ufs_hba *hba)
>   	struct request_queue *q;
>   	int ret;
>   
> +	hba->is_sys_suspended = false;
>   	/*
>   	 * Set RPM status of hba device to RPM_ACTIVE,
>   	 * this also clears its runtime error.
> @@ -5704,11 +5708,13 @@ static void ufshcd_err_handler(struct work_struct *work)
>   
>   	hba = container_of(work, struct ufs_hba, eh_work);
>   
> +	down(&hba->eh_sem);
>   	spin_lock_irqsave(hba->host->host_lock, flags);
>   	if (ufshcd_err_handling_should_stop(hba)) {
>   		if (hba->ufshcd_state != UFSHCD_STATE_ERROR)
>   			hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
>   		spin_unlock_irqrestore(hba->host->host_lock, flags);
> +		up(&hba->eh_sem);
>   		return;
>   	}
>   	ufshcd_set_eh_in_progress(hba);
> @@ -5716,20 +5722,18 @@ static void ufshcd_err_handler(struct work_struct *work)
>   	ufshcd_err_handling_prepare(hba);
>   	spin_lock_irqsave(hba->host->host_lock, flags);
>   	ufshcd_scsi_block_requests(hba);
> -	/*
> -	 * A full reset and restore might have happened after preparation
> -	 * is finished, double check whether we should stop.
> -	 */
> -	if (ufshcd_err_handling_should_stop(hba)) {
> -		if (hba->ufshcd_state != UFSHCD_STATE_ERROR)
> -			hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
> -		goto out;
> -	}
>   	hba->ufshcd_state = UFSHCD_STATE_RESET;
>   
>   	/* Complete requests that have door-bell cleared by h/w */
>   	ufshcd_complete_requests(hba);
>   
> +	/*
> +	 * A full reset and restore might have happened after preparation
> +	 * is finished, double check whether we should stop.
> +	 */
> +	if (ufshcd_err_handling_should_stop(hba))
> +		goto skip_err_handling;
> +
>   	if (hba->dev_quirks & UFS_DEVICE_QUIRK_RECOVERY_FROM_DL_NAC_ERRORS) {
>   		bool ret;
>   
> @@ -5737,17 +5741,10 @@ static void ufshcd_err_handler(struct work_struct *work)
>   		/* release the lock as ufshcd_quirk_dl_nac_errors() may sleep */
>   		ret = ufshcd_quirk_dl_nac_errors(hba);
>   		spin_lock_irqsave(hba->host->host_lock, flags);
> -		if (!ret && !hba->force_reset && ufshcd_is_link_active(hba))
> +		if (!ret && ufshcd_err_handling_should_stop(hba))
>   			goto skip_err_handling;
>   	}
>   
> -	if (hba->force_reset || ufshcd_is_link_broken(hba) ||
> -	    ufshcd_is_saved_err_fatal(hba) ||
> -	    ((hba->saved_err & UIC_ERROR) &&
> -	     (hba->saved_uic_err & (UFSHCD_UIC_DL_NAC_RECEIVED_ERROR |
> -				    UFSHCD_UIC_DL_TCx_REPLAY_ERROR))))
> -		needs_reset = true;
> -
>   	if ((hba->saved_err & (INT_FATAL_ERRORS | UFSHCD_UIC_HIBERN8_MASK)) ||
>   	    (hba->saved_uic_err &&
>   	     (hba->saved_uic_err != UFSHCD_UIC_PA_GENERIC_ERROR))) {
> @@ -5767,8 +5764,14 @@ static void ufshcd_err_handler(struct work_struct *work)
>   	 * transfers forcefully because they will get cleared during
>   	 * host reset and restore
>   	 */
> -	if (needs_reset)
> +	if (hba->force_reset || ufshcd_is_link_broken(hba) ||
> +	    ufshcd_is_saved_err_fatal(hba) ||
> +	    ((hba->saved_err & UIC_ERROR) &&
> +	     (hba->saved_uic_err & (UFSHCD_UIC_DL_NAC_RECEIVED_ERROR |
> +				    UFSHCD_UIC_DL_TCx_REPLAY_ERROR)))) {
> +		needs_reset = true;
>   		goto do_reset;
> +	}
>   
>   	/*
>   	 * If LINERESET was caught, UFS might have been put to PWM mode,
> @@ -5876,12 +5879,11 @@ static void ufshcd_err_handler(struct work_struct *work)
>   			dev_err_ratelimited(hba->dev, "%s: exit: saved_err 0x%x saved_uic_err 0x%x",
>   			    __func__, hba->saved_err, hba->saved_uic_err);
>   	}
> -
> -out:
>   	ufshcd_clear_eh_in_progress(hba);
>   	spin_unlock_irqrestore(hba->host->host_lock, flags);
>   	ufshcd_scsi_unblock_requests(hba);
>   	ufshcd_err_handling_unprepare(hba);
> +	up(&hba->eh_sem);
>   }
>   
>   /**
> @@ -6856,6 +6858,7 @@ static int ufshcd_reset_and_restore(struct ufs_hba *hba)
>   	 */
>   	scsi_report_bus_reset(hba->host, 0);
>   	if (err) {
> +		hba->ufshcd_state = UFSHCD_STATE_ERROR;
>   		hba->saved_err |= saved_err;
>   		hba->saved_uic_err |= saved_uic_err;
>   	}
> @@ -7704,8 +7707,10 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
>   	struct ufs_hba *hba = (struct ufs_hba *)data;
>   	int ret;
>   
> +	down(&hba->eh_sem);
>   	/* Initialize hba, detect and initialize UFS device */
>   	ret = ufshcd_probe_hba(hba, true);
> +	up(&hba->eh_sem);
>   	if (ret)
>   		goto out;
>   
> @@ -8718,6 +8723,7 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
>   	int ret = 0;
>   	ktime_t start = ktime_get();
>   
> +	down(&hba->eh_sem);
>   	if (!hba || !hba->is_powered)
>   		return 0;
>   
> @@ -8748,6 +8754,8 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
>   		hba->curr_dev_pwr_mode, hba->uic_link_state);
>   	if (!ret)
>   		hba->is_sys_suspended = true;
> +	else
> +		up(&hba->eh_sem);
>   	return ret;
>   }
>   EXPORT_SYMBOL(ufshcd_system_suspend);
> @@ -8764,8 +8772,10 @@ int ufshcd_system_resume(struct ufs_hba *hba)
>   	int ret = 0;
>   	ktime_t start = ktime_get();
>   
> -	if (!hba)
> +	if (!hba) {
> +		up(&hba->eh_sem);
>   		return -EINVAL;
> +	}
>   
>   	if (!hba->is_powered || pm_runtime_suspended(hba->dev))
>   		/*
> @@ -8781,6 +8791,7 @@ int ufshcd_system_resume(struct ufs_hba *hba)
>   		hba->curr_dev_pwr_mode, hba->uic_link_state);
>   	if (!ret)
>   		hba->is_sys_suspended = false;
> +	up(&hba->eh_sem);
>   	return ret;
>   }
>   EXPORT_SYMBOL(ufshcd_system_resume);
> @@ -8872,6 +8883,7 @@ int ufshcd_shutdown(struct ufs_hba *hba)
>   {
>   	int ret = 0;
>   
> +	down(&hba->eh_sem);
>   	if (!hba->is_powered)
>   		goto out;
>   
> @@ -8888,6 +8900,8 @@ int ufshcd_shutdown(struct ufs_hba *hba)
>   out:
>   	if (ret)
>   		dev_err(hba->dev, "%s failed, err %d\n", __func__, ret);
> +	hba->is_powered = false;
> +	up(&hba->eh_sem);
>   	/* allow force shutdown even in case of errors */
>   	return 0;
>   }
> @@ -9082,6 +9096,8 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
>   	INIT_WORK(&hba->eh_work, ufshcd_err_handler);
>   	INIT_WORK(&hba->eeh_work, ufshcd_exception_event_handler);
>   
> +	sema_init(&hba->eh_sem, 1);
> +
>   	/* Initialize UIC command mutex */
>   	mutex_init(&hba->uic_cmd_mutex);
>   
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 47eb143..1e680bf 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -728,6 +728,7 @@ struct ufs_hba {
>   	u32 intr_mask;
>   	u16 ee_ctrl_mask;
>   	bool is_powered;
> +	struct semaphore eh_sem;
>   
>   	/* Work Queues */
>   	struct workqueue_struct *eh_wq;
> 


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