[PATCH] libata-hp: implement ata_eh_detach_dev()

Implement ata_eh_detach_dev().  This function is responsible for
detaching an ATA device and offlining the associated SCSI device
atomically so that the detached device is not accessed after ATA
detach is complete.

Signed-off-by: Tejun Heo <htejun@gmail.com>

drivers/scsi/libata-eh.c

@@ -666,6 +666,34 @@ void ata_eh_qc_retry(struct ata_queued_cmd *qc)
 	__ata_eh_qc_complete(qc);
 }
 
+/**
+ *	ata_eh_detach_dev - detach ATA device
+ *	@dev: ATA device to detach
+ *
+ *	Detach @dev.
+ *
+ *	LOCKING:
+ *	None.
+ */
+static void ata_eh_detach_dev(struct ata_device *dev)
+{
+	struct ata_port *ap = dev->ap;
+	unsigned long flags;
+
+	ata_dev_disable(dev);
+
+	spin_lock_irqsave(&ap->host_set->lock, flags);
+
+	dev->flags &= ~ATA_DFLAG_DETACH;
+
+	if (ata_scsi_offline_dev(dev)) {
+		dev->flags |= ATA_DFLAG_DETACHED;
+		ap->flags |= ATA_FLAG_SCSI_HOTPLUG;
+	}
+
+	spin_unlock_irqrestore(&ap->host_set->lock, flags);
+}
+
 /**
  *	ata_eh_about_to_do - about to perform eh_action
  *	@ap: target ATA port

drivers/scsi/libata-scsi.c

@@ -2762,3 +2762,27 @@ void ata_scsi_scan_host(struct ata_port *ap)
 		}
 	}
 }
+
+/**
+ *	ata_scsi_offline_dev - offline attached SCSI device
+ *	@dev: ATA device to offline attached SCSI device for
+ *
+ *	This function is called from ata_eh_hotplug() and responsible
+ *	for taking the SCSI device attached to @dev offline.  This
+ *	function is called with host_set lock which protects dev->sdev
+ *	against clearing.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ *
+ *	RETURNS:
+ *	1 if attached SCSI device exists, 0 otherwise.
+ */
+int ata_scsi_offline_dev(struct ata_device *dev)
+{
+	if (dev->sdev) {
+		scsi_device_set_state(dev->sdev, SDEV_OFFLINE);
+		return 1;
+	}
+	return 0;
+}

drivers/scsi/libata.h

@@ -75,6 +75,7 @@ extern int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg);
 extern struct scsi_transport_template ata_scsi_transport_template;
 
 extern void ata_scsi_scan_host(struct ata_port *ap);
+extern int ata_scsi_offline_dev(struct ata_device *dev);
 extern unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,
 			       unsigned int buflen);