linux-kernel - Re: [PATCH 2/4] scsi: ufs: clear UAC for FFU and RPMB LUNs

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Message-ID: <3d9c3b844ac861c4cce7242e49e63059@codeaurora.org>
Date:   Tue, 20 Oct 2020 10:17:25 +0800
From:   Can Guo <cang@...eaurora.org>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
        kernel-team@...roid.com, Jaegeuk Kim <jaegeuk@...gle.com>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>
Subject: Re: [PATCH 2/4] scsi: ufs: clear UAC for FFU and RPMB LUNs

On 2020-10-06 06:36, Jaegeuk Kim wrote:
> From: Jaegeuk Kim <jaegeuk@...gle.com>
> 
> In order to conduct FFU or RPMB operations, UFS needs to clear UAC. 
> This patch
> clears it explicitly, so that we could get no failure given early 
> execution.
> 

Usually it is the user's/utility's/tool's responsiblity to clear UA by 
sending a
request sense cmd and retry previous cmd, now we are doing it for the 
users in driver?
As per my understanding, driver only reports UA to SCSI layer and let 
users decide
what to do with it - maybe users need to do something specifically regs 
it, but
the change clears it even before the users get to know it.

Besides, this change clears UA for W-LUs, but the UFS driver still 
reports UA to SCSI
layer for each SCSI device by calling scsi_report_bus_reset() in
ufshcd_reset_and_restore(). This will make SCSI layer treat 
sdev->expecting_cc_ua
wrongly, because for W-LUs, their expecting_cc_ua should not be set as 
you have
cleared their UAs.

Thanks,

Can Guo.

> Cc: Alim Akhtar <alim.akhtar@...sung.com>
> Cc: Avri Altman <avri.altman@....com>
> Cc: Can Guo <cang@...eaurora.org>
> Signed-off-by: Jaegeuk Kim <jaegeuk@...gle.com>
> ---
>  drivers/scsi/ufs/ufshcd.c | 70 +++++++++++++++++++++++++++++++++++----
>  drivers/scsi/ufs/ufshcd.h |  1 +
>  2 files changed, 65 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index d929c3d1e58cc..0bb07b50bd23e 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -6841,7 +6841,6 @@ static inline void
> ufshcd_blk_pm_runtime_init(struct scsi_device *sdev)
>  static int ufshcd_scsi_add_wlus(struct ufs_hba *hba)
>  {
>  	int ret = 0;
> -	struct scsi_device *sdev_rpmb;
>  	struct scsi_device *sdev_boot;
> 
>  	hba->sdev_ufs_device = __scsi_add_device(hba->host, 0, 0,
> @@ -6854,14 +6853,14 @@ static int ufshcd_scsi_add_wlus(struct ufs_hba 
> *hba)
>  	ufshcd_blk_pm_runtime_init(hba->sdev_ufs_device);
>  	scsi_device_put(hba->sdev_ufs_device);
> 
> -	sdev_rpmb = __scsi_add_device(hba->host, 0, 0,
> +	hba->sdev_rpmb = __scsi_add_device(hba->host, 0, 0,
>  		ufshcd_upiu_wlun_to_scsi_wlun(UFS_UPIU_RPMB_WLUN), NULL);
> -	if (IS_ERR(sdev_rpmb)) {
> -		ret = PTR_ERR(sdev_rpmb);
> +	if (IS_ERR(hba->sdev_rpmb)) {
> +		ret = PTR_ERR(hba->sdev_rpmb);
>  		goto remove_sdev_ufs_device;
>  	}
> -	ufshcd_blk_pm_runtime_init(sdev_rpmb);
> -	scsi_device_put(sdev_rpmb);
> +	ufshcd_blk_pm_runtime_init(hba->sdev_rpmb);
> +	scsi_device_put(hba->sdev_rpmb);
> 
>  	sdev_boot = __scsi_add_device(hba->host, 0, 0,
>  		ufshcd_upiu_wlun_to_scsi_wlun(UFS_UPIU_BOOT_WLUN), NULL);
> @@ -7385,6 +7384,63 @@ static int ufshcd_add_lus(struct ufs_hba *hba)
>  	return ret;
>  }
> 
> +static int
> +ufshcd_send_request_sense(struct ufs_hba *hba, struct scsi_device 
> *sdp);
> +
> +static int ufshcd_clear_ua_wlun(struct ufs_hba *hba, u8 wlun)
> +{
> +	struct scsi_device *sdp;
> +	unsigned long flags;
> +	int ret = 0;
> +
> +	spin_lock_irqsave(hba->host->host_lock, flags);
> +	if (wlun  == UFS_UPIU_UFS_DEVICE_WLUN)
> +		sdp = hba->sdev_ufs_device;
> +	else if (wlun  == UFS_UPIU_RPMB_WLUN)
> +		sdp = hba->sdev_rpmb;
> +	else
> +		BUG_ON(1);
> +	if (sdp) {
> +		ret = scsi_device_get(sdp);
> +		if (!ret && !scsi_device_online(sdp)) {
> +			ret = -ENODEV;
> +			scsi_device_put(sdp);
> +		}
> +	} else {
> +		ret = -ENODEV;
> +	}
> +	spin_unlock_irqrestore(hba->host->host_lock, flags);
> +	if (ret)
> +		goto out_err;
> +
> +	ret = ufshcd_send_request_sense(hba, sdp);
> +	scsi_device_put(sdp);
> +out_err:
> +	if (ret)
> +		dev_err(hba->dev, "%s: UAC clear LU=%x ret = %d\n",
> +				__func__, wlun, ret);
> +	return ret;
> +}
> +
> +static int ufshcd_clear_ua_wluns(struct ufs_hba *hba)
> +{
> +	int ret = 0;
> +
> +	if (!hba->wlun_dev_clr_ua)
> +		goto out;
> +
> +	ret = ufshcd_clear_ua_wlun(hba, UFS_UPIU_UFS_DEVICE_WLUN);
> +	if (!ret)
> +		ret = ufshcd_clear_ua_wlun(hba, UFS_UPIU_RPMB_WLUN);
> +	if (!ret)
> +		hba->wlun_dev_clr_ua = false;
> +out:
> +	if (ret)
> +		dev_err(hba->dev, "%s: Failed to clear UAC WLUNS ret = %d\n",
> +				__func__, ret);
> +	return ret;
> +}
> +
>  /**
>   * ufshcd_probe_hba - probe hba to detect device and initialize
>   * @hba: per-adapter instance
> @@ -7500,6 +7556,8 @@ static void ufshcd_async_scan(void *data,
> async_cookie_t cookie)
>  		pm_runtime_put_sync(hba->dev);
>  		ufshcd_exit_clk_scaling(hba);
>  		ufshcd_hba_exit(hba);
> +	} else {
> +		ufshcd_clear_ua_wluns(hba);
>  	}
>  }
> 
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 363589c0bd370..8344d8cb36786 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -662,6 +662,7 @@ struct ufs_hba {
>  	 * "UFS device" W-LU.
>  	 */
>  	struct scsi_device *sdev_ufs_device;
> +	struct scsi_device *sdev_rpmb;
> 
>  	enum ufs_dev_pwr_mode curr_dev_pwr_mode;
>  	enum uic_link_state uic_link_state;