Re: [PATCH] ata: libata-scsi: Fix get identity data failed

[John Garry]

On 04/05/2023 14:15, Xingui Yang wrote:
> The function ata_get_identity() uses the helper ata_scsi_find_dev() to get
> the ata_device structure of a scsi device.  However, when the ata device
> is managed by libsas, ata_scsi_find_dev() returns NULL, turning
> ata_get_identity() into a nop and always returns -ENOMSG.
>
> Fix this by replacing the pointer to the scsi_device struct argument with a
> pointer to the ata_device struct in ata_sas_scsi_ioctl() and
> ata_get_identity(). This pointer is provided by ata_scsi_ioctl() using
> ata_scsi_find_dev() in the case of a libata managed device and by
> sas_ioctl() using sas_to_ata_dev() in the case of a libsas managed ata
> device.

We made a similar change in commit 141f3d6256e5 ("ata: libata-sata: Fix 
device queue depth control"). Is there some better way to do this to 
make it all more scalable such that we don't need to keep replacing 
calls to ata_scsi_find_dev()?

This was discussed earlier, along with queue depth issue (which does not 
seem fixed, AFAIK):
https://lore.kernel.org/linux-scsi/13e5e5e5-7dc2-8f14-3dd2-43366343842d@xxxxxxxxxx/

Thanks,
John


> Signed-off-by: Xingui Yang <yangxingui@xxxxxxxxxx>
> ---
>   drivers/ata/libata-scsi.c           | 22 +++++++++++-----------
>   drivers/scsi/libsas/sas_scsi_host.c |  3 ++-
>   include/linux/libata.h              |  2 +-
>   3 files changed, 14 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index 7bb12deab70c..68f2404e61d0 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -327,8 +327,7 @@ EXPORT_SYMBOL_GPL(ata_scsi_unlock_native_capacity);
>   
>   /**
>    *	ata_get_identity - Handler for HDIO_GET_IDENTITY ioctl
> - *	@ap: target port
> - *	@sdev: SCSI device to get identify data for
> + *	@dev: ATA device to get identify data for
>    *	@arg: User buffer area for identify data
>    *
>    *	LOCKING:
> @@ -337,10 +336,8 @@ EXPORT_SYMBOL_GPL(ata_scsi_unlock_native_capacity);
>    *	RETURNS:
>    *	Zero on success, negative errno on error.
>    */
> -static int ata_get_identity(struct ata_port *ap, struct scsi_device *sdev,
> -			    void __user *arg)
> +static int ata_get_identity(struct ata_device *dev, void __user *arg)
>   {
> -	struct ata_device *dev = ata_scsi_find_dev(ap, sdev);
>   	u16 __user *dst = arg;
>   	char buf[40];
>   
> @@ -573,7 +570,7 @@ static bool ata_ioc32(struct ata_port *ap)
>    * This handles both native and compat commands, so anything added
>    * here must have a compatible argument, or check in_compat_syscall()
>    */
> -int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *scsidev,
> +int ata_sas_scsi_ioctl(struct ata_port *ap, struct ata_device *dev,
>   		     unsigned int cmd, void __user *arg)
>   {
>   	unsigned long val;
> @@ -608,17 +605,17 @@ int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *scsidev,
>   		return rc;
>   
>   	case HDIO_GET_IDENTITY:
> -		return ata_get_identity(ap, scsidev, arg);
> +		return ata_get_identity(dev, arg);
>   
>   	case HDIO_DRIVE_CMD:
>   		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
>   			return -EACCES;
> -		return ata_cmd_ioctl(scsidev, arg);
> +		return ata_cmd_ioctl(dev->sdev, arg);
>   
>   	case HDIO_DRIVE_TASK:
>   		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
>   			return -EACCES;
> -		return ata_task_ioctl(scsidev, arg);
> +		return ata_task_ioctl(dev->sdev, arg);
>   
>   	default:
>   		rc = -ENOTTY;
> @@ -632,8 +629,11 @@ EXPORT_SYMBOL_GPL(ata_sas_scsi_ioctl);
>   int ata_scsi_ioctl(struct scsi_device *scsidev, unsigned int cmd,
>   		   void __user *arg)
>   {
> -	return ata_sas_scsi_ioctl(ata_shost_to_port(scsidev->host),
> -				scsidev, cmd, arg);
> +	struct ata_port *ap = ata_shost_to_port(scsidev->host);
> +
> +	return ata_sas_scsi_ioctl(ap,
> +			ata_scsi_find_dev(ap, scsidev),
> +			cmd, arg);
>   }
>   EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
>   
> diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
> index a36fa1c128a8..c7a44ce7b2e2 100644
> --- a/drivers/scsi/libsas/sas_scsi_host.c
> +++ b/drivers/scsi/libsas/sas_scsi_host.c
> @@ -789,7 +789,8 @@ int sas_ioctl(struct scsi_device *sdev, unsigned int cmd, void __user *arg)
>   	struct domain_device *dev = sdev_to_domain_dev(sdev);
>   
>   	if (dev_is_sata(dev))
> -		return ata_sas_scsi_ioctl(dev->sata_dev.ap, sdev, cmd, arg);
> +		return ata_sas_scsi_ioctl(dev->sata_dev.ap,
> +				sas_to_ata_dev(dev), cmd, arg);
>   
>   	return -EINVAL;
>   }
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 311cd93377c7..d5dd60530a24 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -1085,7 +1085,7 @@ bool ata_scsi_dma_need_drain(struct request *rq);
>   #else
>   #define ata_scsi_dma_need_drain NULL
>   #endif
> -extern int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *dev,
> +extern int ata_sas_scsi_ioctl(struct ata_port *ap, struct ata_device *dev,
>   			    unsigned int cmd, void __user *arg);
>   extern bool ata_link_online(struct ata_link *link);
>   extern bool ata_link_offline(struct ata_link *link);