block: sed-opal: add ioctl IOC_OPAL_SET_SID_PW

After a SED drive is provisioned, there is no way to change the SID
password via the ioctl() interface. A new ioctl IOC_OPAL_SET_SID_PW
will allow the password to be changed. The valid current password is
required.

Signed-off-by: Greg Joyce <[e-mail]>
Reviewed-by: Daniel Wagner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

block/sed-opal.c

···
 	return ret;
 }
 
+static int opal_set_new_sid_pw(struct opal_dev *dev, struct opal_new_pw *opal_pw)
+{
+	int ret;
+	struct opal_key *newkey = &opal_pw->new_user_pw.opal_key;
+	struct opal_key *oldkey = &opal_pw->session.opal_key;
+
+	const struct opal_step pw_steps[] = {
+		{ start_SIDASP_opal_session, oldkey },
+		{ set_sid_cpin_pin, newkey },
+		{ end_opal_session, }
+	};
+
+	if (!dev)
+		return -ENODEV;
+
+	mutex_lock(&dev->dev_lock);
+	setup_opal_dev(dev);
+	ret = execute_steps(dev, pw_steps, ARRAY_SIZE(pw_steps));
+	mutex_unlock(&dev->dev_lock);
+
+	return ret;
+}
+
 static int opal_activate_user(struct opal_dev *dev,
 			      struct opal_session_info *opal_session)
 {
···
 		break;
 	case IOC_OPAL_DISCOVERY:
 		ret = opal_get_discv(dev, p);
+		break;
+	case IOC_OPAL_SET_SID_PW:
+		ret = opal_set_new_sid_pw(dev, p);
 		break;
 
 	default:

include/linux/sed-opal.h

···
 	case IOC_OPAL_GET_GEOMETRY:
 	case IOC_OPAL_DISCOVERY:
 	case IOC_OPAL_REVERT_LSP:
+	case IOC_OPAL_SET_SID_PW:
 		return true;
 	}
 	return false;

include/uapi/linux/sed-opal.h

···
 #define IOC_OPAL_GET_GEOMETRY       _IOR('p', 238, struct opal_geometry)
 #define IOC_OPAL_DISCOVERY          _IOW('p', 239, struct opal_discovery)
 #define IOC_OPAL_REVERT_LSP         _IOW('p', 240, struct opal_revert_lsp)
+#define IOC_OPAL_SET_SID_PW         _IOW('p', 241, struct opal_new_pw)
 
 #endif /* _UAPI_SED_OPAL_H */