Re: [PATCH] scsi: sd: Fix TCG OPAL unlock on system resume

[Damien Le Moal <dlemoal@kernel.org>]

On 3/19/24 16:12, Damien Le Moal wrote:
> Commit 3cc2ffe5c16d introduced the manage_system_start_stop scsi device
> flag to allow libata to indicate to the scsi disk driver that nothing
> should be done when resuming a disk on system resume. This change turned
> the execution of sd_resume() into a no-op for ATA devices on system
> resume. While this solved deadlock issues during device resume, this
> change also wrongly removed the execution of opal_unlock_from_suspend().
> As a result, devices with TCG OPAL locking enabled remain locked and
> inaccessible after a system resume from sleep.
> 
> To fix this issue, introduce the scsi driver resume method and implement
> it with the sd_resume() function calling opal_unlock_from_suspend(). The
> former sd_resume() function is renamed to sd_resume_common() and
> modified to call the new sd_resume() function. For non-ata devices, this
> result in no functional changes.
> 
> Inorder for libata to explicitly execute sd_resume() when a device is
> resumed during system re-start, the function scsi_resume_device() is
> introduced. libata calls this function from the revalidation work
> executed on devie resume, a state that is indicated with the new device
> flag ATA_DFLAG_RESUMING. Doing so, locked TCG OPAL enabled devices are
> unlocked on resume, allowing normal operation.
> 
> Fixes: 3cc2ffe5c16d ("scsi: sd: Differentiate system and runtime start/stop management")
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218538
> Cc: stable@vger.kernel.org
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

Martin,

Ping ?

> ---
>  drivers/ata/libata-eh.c    |  5 ++++-
>  drivers/ata/libata-scsi.c  |  9 +++++++++
>  drivers/scsi/scsi_scan.c   | 34 ++++++++++++++++++++++++++++++++++
>  drivers/scsi/sd.c          | 23 +++++++++++++++++++----
>  include/linux/libata.h     |  1 +
>  include/scsi/scsi_driver.h |  1 +
>  include/scsi/scsi_host.h   |  1 +
>  7 files changed, 69 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
> index b0d6e69c4a5b..214b935c2ced 100644
> --- a/drivers/ata/libata-eh.c
> +++ b/drivers/ata/libata-eh.c
> @@ -712,8 +712,10 @@ void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap)
>  				ehc->saved_ncq_enabled |= 1 << devno;
>  
>  			/* If we are resuming, wake up the device */
> -			if (ap->pflags & ATA_PFLAG_RESUMING)
> +			if (ap->pflags & ATA_PFLAG_RESUMING) {
> +				dev->flags |= ATA_DFLAG_RESUMING;
>  				ehc->i.dev_action[devno] |= ATA_EH_SET_ACTIVE;
> +			}
>  		}
>  	}
>  
> @@ -3169,6 +3171,7 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
>  	return 0;
>  
>   err:
> +	dev->flags &= ~ATA_DFLAG_RESUMING;
>  	*r_failed_dev = dev;
>  	return rc;
>  }
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index 0a0f483124c3..2f4c58837641 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -4730,6 +4730,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
>  	struct ata_link *link;
>  	struct ata_device *dev;
>  	unsigned long flags;
> +	bool do_resume;
>  	int ret = 0;
>  
>  	mutex_lock(&ap->scsi_scan_mutex);
> @@ -4751,7 +4752,15 @@ void ata_scsi_dev_rescan(struct work_struct *work)
>  			if (scsi_device_get(sdev))
>  				continue;
>  
> +			do_resume = dev->flags & ATA_DFLAG_RESUMING;
> +
>  			spin_unlock_irqrestore(ap->lock, flags);
> +			if (do_resume) {
> +				ret = scsi_resume_device(sdev);
> +				if (ret == -EWOULDBLOCK)
> +					goto unlock;
> +				dev->flags &= ~ATA_DFLAG_RESUMING;
> +			}
>  			ret = scsi_rescan_device(sdev);
>  			scsi_device_put(sdev);
>  			spin_lock_irqsave(ap->lock, flags);
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 8d06475de17a..ffd7e7e72933 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -1642,6 +1642,40 @@ int scsi_add_device(struct Scsi_Host *host, uint channel,
>  }
>  EXPORT_SYMBOL(scsi_add_device);
>  
> +int scsi_resume_device(struct scsi_device *sdev)
> +{
> +	struct device *dev = &sdev->sdev_gendev;
> +	int ret = 0;
> +
> +	device_lock(dev);
> +
> +	/*
> +	 * Bail out if the device or its queue are not running. Otherwise,
> +	 * the rescan may block waiting for commands to be executed, with us
> +	 * holding the device lock. This can result in a potential deadlock
> +	 * in the power management core code when system resume is on-going.
> +	 */
> +	if (sdev->sdev_state != SDEV_RUNNING ||
> +	    blk_queue_pm_only(sdev->request_queue)) {
> +		ret = -EWOULDBLOCK;
> +		goto unlock;
> +	}
> +
> +	if (dev->driver && try_module_get(dev->driver->owner)) {
> +		struct scsi_driver *drv = to_scsi_driver(dev->driver);
> +
> +		if (drv->resume)
> +			ret = drv->resume(dev);
> +		module_put(dev->driver->owner);
> +	}
> +
> +unlock:
> +	device_unlock(dev);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(scsi_resume_device);
> +
>  int scsi_rescan_device(struct scsi_device *sdev)
>  {
>  	struct device *dev = &sdev->sdev_gendev;
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 2cc73c650ca6..7a5ad9b25ab7 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -4003,7 +4003,21 @@ static int sd_suspend_runtime(struct device *dev)
>  	return sd_suspend_common(dev, true);
>  }
>  
> -static int sd_resume(struct device *dev, bool runtime)
> +static int sd_resume(struct device *dev)
> +{
> +	struct scsi_disk *sdkp = dev_get_drvdata(dev);
> +
> +	sd_printk(KERN_NOTICE, sdkp, "Starting disk\n");
> +
> +	if (opal_unlock_from_suspend(sdkp->opal_dev)) {
> +		sd_printk(KERN_NOTICE, sdkp, "OPAL unlock failed\n");
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sd_resume_common(struct device *dev, bool runtime)
>  {
>  	struct scsi_disk *sdkp = dev_get_drvdata(dev);
>  	int ret;
> @@ -4019,7 +4033,7 @@ static int sd_resume(struct device *dev, bool runtime)
>  	sd_printk(KERN_NOTICE, sdkp, "Starting disk\n");
>  	ret = sd_start_stop_device(sdkp, 1);
>  	if (!ret) {
> -		opal_unlock_from_suspend(sdkp->opal_dev);
> +		sd_resume(dev);
>  		sdkp->suspended = false;
>  	}
>  
> @@ -4038,7 +4052,7 @@ static int sd_resume_system(struct device *dev)
>  		return 0;
>  	}
>  
> -	return sd_resume(dev, false);
> +	return sd_resume_common(dev, false);
>  }
>  
>  static int sd_resume_runtime(struct device *dev)
> @@ -4065,7 +4079,7 @@ static int sd_resume_runtime(struct device *dev)
>  				  "Failed to clear sense data\n");
>  	}
>  
> -	return sd_resume(dev, true);
> +	return sd_resume_common(dev, true);
>  }
>  
>  static const struct dev_pm_ops sd_pm_ops = {
> @@ -4088,6 +4102,7 @@ static struct scsi_driver sd_template = {
>  		.pm		= &sd_pm_ops,
>  	},
>  	.rescan			= sd_rescan,
> +	.resume			= sd_resume,
>  	.init_command		= sd_init_command,
>  	.uninit_command		= sd_uninit_command,
>  	.done			= sd_done,
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 26d68115afb8..324d792e7c78 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -107,6 +107,7 @@ enum {
>  
>  	ATA_DFLAG_NCQ_PRIO_ENABLED = (1 << 20), /* Priority cmds sent to dev */
>  	ATA_DFLAG_CDL_ENABLED	= (1 << 21), /* cmd duration limits is enabled */
> +	ATA_DFLAG_RESUMING	= (1 << 22),  /* Device is resuming */
>  	ATA_DFLAG_DETACH	= (1 << 24),
>  	ATA_DFLAG_DETACHED	= (1 << 25),
>  	ATA_DFLAG_DA		= (1 << 26), /* device supports Device Attention */
> diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
> index 4ce1988b2ba0..f40915d2ecee 100644
> --- a/include/scsi/scsi_driver.h
> +++ b/include/scsi/scsi_driver.h
> @@ -12,6 +12,7 @@ struct request;
>  struct scsi_driver {
>  	struct device_driver	gendrv;
>  
> +	int (*resume)(struct device *);
>  	void (*rescan)(struct device *);
>  	blk_status_t (*init_command)(struct scsi_cmnd *);
>  	void (*uninit_command)(struct scsi_cmnd *);
> diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
> index b259d42a1e1a..129001f600fc 100644
> --- a/include/scsi/scsi_host.h
> +++ b/include/scsi/scsi_host.h
> @@ -767,6 +767,7 @@ scsi_template_proc_dir(const struct scsi_host_template *sht);
>  #define scsi_template_proc_dir(sht) NULL
>  #endif
>  extern void scsi_scan_host(struct Scsi_Host *);
> +extern int scsi_resume_device(struct scsi_device *sdev);
>  extern int scsi_rescan_device(struct scsi_device *sdev);
>  extern void scsi_remove_host(struct Scsi_Host *);
>  extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);

-- 
Damien Le Moal
Western Digital Research