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

John Garry <john.g.garry@xxxxxxxxxx> · Thu, 4 May 2023 15:24:20 +0100

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);







