text: /* Target based USB-Gadget
   *
   * UAS protocol handling, target callbacks, configfs handling,
   * BBB (USB Mass Storage Class Bulk-Only (BBB) and Transport protocol handling.
   *
   * Author: Sebastian Andrzej Siewior <bigeasy at linutronix dot de>
   * License: GPLv2 as published by FSF.
   */
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/string.h>
  #include <linux/configfs.h>
  #include <linux/ctype.h>
  #include <linux/usb/ch9.h>
  #include <linux/usb/composite.h>
  #include <linux/usb/gadget.h>
  #include <linux/usb/storage.h>
  #include <scsi/scsi_tcq.h>
  #include <target/target_core_base.h>
  #include <target/target_core_fabric.h>
  #include <asm/unaligned.h>
  
  #include "tcm.h"
  #include "u_tcm.h"
  #include "configfs.h"
  
  #define TPG_INSTANCES		1
  
  struct tpg_instance {
  	struct usb_function_instance	*func_inst;
  	struct usbg_tpg			*tpg;
  };
  
  static struct tpg_instance tpg_instances[TPG_INSTANCES];
  
  static DEFINE_MUTEX(tpg_instances_lock);
  
  static inline struct f_uas *to_f_uas(struct usb_function *f)
  {
  	return container_of(f, struct f_uas, function);
  }
  
  /* Start bot.c code */
  
  static int bot_enqueue_cmd_cbw(struct f_uas *fu)
  {
  	int ret;
  
  	if (fu->flags & USBG_BOT_CMD_PEND)
  		return 0;
  
  	ret = usb_ep_queue(fu->ep_out, fu->cmd.req, GFP_ATOMIC);
  	if (!ret)
  		fu->flags |= USBG_BOT_CMD_PEND;
  	return ret;
  }
  
  static void bot_status_complete(struct usb_ep *ep, struct usb_request *req)
  {
  	struct usbg_cmd *cmd = req->context;
  	struct f_uas *fu = cmd->fu;
  
  	transport_generic_free_cmd(&cmd->se_cmd, 0);
  	if (req->status < 0) {
  		pr_err("ERR %s(%d)\n", __func__, __LINE__);
  		return;
  	}
  
  	/* CSW completed, wait for next CBW */
  	bot_enqueue_cmd_cbw(fu);
  }
  
  static void bot_enqueue_sense_code(struct f_uas *fu, struct usbg_cmd *cmd)
  {
  	struct bulk_cs_wrap *csw = &fu->bot_status.csw;
  	int ret;
  	unsigned int csw_stat;
  
  	csw_stat = cmd->csw_code;
  	csw->Tag = cmd->bot_tag;
  	csw->Status = csw_stat;
  	fu->bot_status.req->context = cmd;
  	ret = usb_ep_queue(fu->ep_in, fu->bot_status.req, GFP_ATOMIC);
  	if (ret)
  		pr_err("%s(%d) ERR: %d\n", __func__, __LINE__, ret);
  }
  
  static void bot_err_compl(struct usb_ep *ep, struct usb_request *req)
  {
  	struct usbg_cmd *cmd = req->context;
  	struct f_uas *fu = cmd->fu;
  
  	if (req->status < 0)
  		pr_err("ERR %s(%d)\n", __func__, __LINE__);
  
  	if (cmd->data_len) {
  		if (cmd->data_len > ep->maxpacket) {
  			req->length = ep->maxpacket;
  			cmd->data_len -= ep->maxpacket;
  		} else {
  			req->length = cmd->data_len;
  			cmd->data_len = 0;
  		}
  
  		usb_ep_queue(ep, req, GFP_ATOMIC);
  		return;
  	}
  	bot_enqueue_sense_code(fu, cmd);
  }
  
  static void bot_send_bad_status(struct usbg_cmd *cmd)
  {
  	struct f_uas *fu = cmd->fu;
  	struct bulk_cs_wrap *csw = &fu->bot_status.csw;
  	struct usb_request *req;
  	struct usb_ep *ep;
  
  	csw->Residue = cpu_to_le32(cmd->data_len);
  
  	if (cmd->data_len) {
  		if (cmd->is_read) {
  			ep = fu->ep_in;
  			req = fu->bot_req_in;
  		} else {
  			ep = fu->ep_out;
  			req = fu->bot_req_out;
  		}
  
  		if (cmd->data_len > fu->ep_in->maxpacket) {
  			req->length = ep->maxpacket;
  			cmd->data_len -= ep->maxpacket;
  		} else {
  			req->length = cmd->data_len;
  			cmd->data_len = 0;
  		}
  		req->complete = bot_err_compl;
  		req->context = cmd;
  		req->buf = fu->cmd.buf;
  		usb_ep_queue(ep, req, GFP_KERNEL);
  	} else {
  		bot_enqueue_sense_code(fu, cmd);
  	}
  }
  
  static int bot_send_status(struct usbg_cmd *cmd, bool moved_data)
  {
  	struct f_uas *fu = cmd->fu;
  	struct bulk_cs_wrap *csw = &fu->bot_status.csw;
  	int ret;
  
  	if (cmd->se_cmd.scsi_status == SAM_STAT_GOOD) {
  		if (!moved_data && cmd->data_len) {
  			/*
  			 * the host wants to move data, we don't. Fill / empty
  			 * the pipe and then send the csw with reside set.
  			 */
  			cmd->csw_code = US_BULK_STAT_OK;
  			bot_send_bad_status(cmd);
  			return 0;
  		}
  
  		csw->Tag = cmd->bot_tag;
  		csw->Residue = cpu_to_le32(0);
  		csw->Status = US_BULK_STAT_OK;
  		fu->bot_status.req->context = cmd;
  
  		ret = usb_ep_queue(fu->ep_in, fu->bot_status.req, GFP_KERNEL);
  		if (ret)
  			pr_err("%s(%d) ERR: %d\n", __func__, __LINE__, ret);
  	} else {
  		cmd->csw_code = US_BULK_STAT_FAIL;
  		bot_send_bad_status(cmd);
  	}
  	return 0;
  }
  
  /*
   * Called after command (no data transfer) or after the write (to device)
   * operation is completed
   */
  static int bot_send_status_response(struct usbg_cmd *cmd)
  {
  	bool moved_data = false;
  
  	if (!cmd->is_read)
  		moved_data = true;
  	return bot_send_status(cmd, moved_data);
  }
  
  /* Read request completed, now we have to send the CSW */
  static void bot_read_compl(struct usb_ep *ep, struct usb_request *req)
  {
  	struct usbg_cmd *cmd = req->context;
  
  	if (req->status < 0)
  		pr_err("ERR %s(%d)\n", __func__, __LINE__);
  
  	bot_send_status(cmd, true);
  }
  
  static int bot_send_read_response(struct usbg_cmd *cmd)
  {
  	struct f_uas *fu = cmd->fu;
  	struct se_cmd *se_cmd = &cmd->se_cmd;
  	struct usb_gadget *gadget = fuas_to_gadget(fu);
  	int ret;
  
  	if (!cmd->data_len) {
  		cmd->csw_code = US_BULK_STAT_PHASE;
  		bot_send_bad_status(cmd);
  		return 0;
  	}
  
  	if (!gadget->sg_supported) {
  		cmd->data_buf = kmalloc(se_cmd->data_length, GFP_ATOMIC);
  		if (!cmd->data_buf)
  			return -ENOMEM;
  
  		sg_copy_to_buffer(se_cmd->t_data_sg,
  				se_cmd->t_data_nents,
  				cmd->data_buf,
  				se_cmd->data_length);
  
  		fu->bot_req_in->buf = cmd->data_buf;
  	} else {
  		fu->bot_req_in->buf = NULL;
  		fu->bot_req_in->num_sgs = se_cmd->t_data_nents;
  		fu->bot_req_in->sg = se_cmd->t_data_sg;
  	}
  
  	fu->bot_req_in->complete = bot_read_compl;
  	fu->bot_req_in->length = se_cmd->data_length;
  	fu->bot_req_in->context = cmd;
  	ret = usb_ep_queue(fu->ep_in, fu->bot_req_in, GFP_ATOMIC);
  	if (ret)
  		pr_err("%s(%d)\n", __func__, __LINE__);
  	return 0;
  }
  
  static void usbg_data_write_cmpl(struct usb_ep *, struct usb_request *);
  static int usbg_prepare_w_request(struct usbg_cmd *, struct usb_request *);
  
  static int bot_send_write_request(struct usbg_cmd *cmd)
  {
  	struct f_uas *fu = cmd->fu;
  	struct se_cmd *se_cmd = &cmd->se_cmd;
  	struct usb_gadget *gadget = fuas_to_gadget(fu);
  	int ret;
  
  	init_completion(&cmd->write_complete);
  	cmd->fu = fu;
  
  	if (!cmd->data_len) {
  		cmd->csw_code = US_BULK_STAT_PHASE;
  		return -EINVAL;
  	}
  
  	if (!gadget->sg_supported) {
  		cmd->data_buf = kmalloc(se_cmd->data_length, GFP_KERNEL);
  		if (!cmd->data_buf)
  			return -ENOMEM;
  
  		fu->bot_req_out->buf = cmd->data_buf;
  	} else {
  		fu->bot_req_out->buf = NULL;
  		fu->bot_req_out->num_sgs = se_cmd->t_data_nents;
  		fu->bot_req_out->sg = se_cmd->t_data_sg;
  	}
  
  	fu->bot_req_out->complete = usbg_data_write_cmpl;
  	fu->bot_req_out->length = se_cmd->data_length;
  	fu->bot_req_out->context = cmd;
  
  	ret = usbg_prepare_w_request(cmd, fu->bot_req_out);
  	if (ret)
  		goto cleanup;
  	ret = usb_ep_queue(fu->ep_out, fu->bot_req_out, GFP_KERNEL);
  	if (ret)
  		pr_err("%s(%d)\n", __func__, __LINE__);
  
  	wait_for_completion(&cmd->write_complete);
  	target_execute_cmd(se_cmd);
  cleanup:
  	return ret;
  }
  
  static int bot_submit_command(struct f_uas *, void *, unsigned int);
  
  static void bot_cmd_complete(struct usb_ep *ep, struct usb_request *req)
  {
  	struct f_uas *fu = req->context;
  	int ret;
  
  	fu->flags &= ~USBG_BOT_CMD_PEND;
  
  	if (req->status < 0)
  		return;
  
  	ret = bot_submit_command(fu, req->buf, req->actual);
  	if (ret)
  		pr_err("%s(%d): %d\n", __func__, __LINE__, ret);
  }
  
  static int bot_prepare_reqs(struct f_uas *fu)
  {
  	int ret;
  
  	fu->bot_req_in = usb_ep_alloc_request(fu->ep_in, GFP_KERNEL);
  	if (!fu->bot_req_in)
  		goto err;
  
  	fu->bot_req_out = usb_ep_alloc_request(fu->ep_out, GFP_KERNEL);
  	if (!fu->bot_req_out)
  		goto err_out;
  
  	fu->cmd.req = usb_ep_alloc_request(fu->ep_out, GFP_KERNEL);
  	if (!fu->cmd.req)
  		goto err_cmd;
  
  	fu->bot_status.req = usb_ep_alloc_request(fu->ep_in, GFP_KERNEL);
  	if (!fu->bot_status.req)
  		goto err_sts;
  
  	fu->bot_status.req->buf = &fu->bot_status.csw;
  	fu->bot_status.req->length = US_BULK_CS_WRAP_LEN;
  	fu->bot_status.req->complete = bot_status_complete;
  	fu->bot_status.csw.Signature = cpu_to_le32(US_BULK_CS_SIGN);
  
  	fu->cmd.buf = kmalloc(fu->ep_out->maxpacket, GFP_KERNEL);
  	if (!fu->cmd.buf)
  		goto err_buf;
  
  	fu->cmd.req->complete = bot_cmd_complete;
  	fu->cmd.req->buf = fu->cmd.buf;
  	fu->cmd.req->length = fu->ep_out->maxpacket;
  	fu->cmd.req->context = fu;
  
  	ret = bot_enqueue_cmd_cbw(fu);
  	if (ret)
  		goto err_queue;
  	return 0;
  err_queue:
  	kfree(fu->cmd.buf);
  	fu->cmd.buf = NULL;
  err_buf:
  	usb_ep_free_request(fu->ep_in, fu->bot_status.req);
  err_sts:
  	usb_ep_free_request(fu->ep_out, fu->cmd.req);
  	fu->cmd.req = NULL;
  err_cmd:
  	usb_ep_free_request(fu->ep_out, fu->bot_req_out);
  	fu->bot_req_out = NULL;
  err_out:
  	usb_ep_free_request(fu->ep_in, fu->bot_req_in);
  	fu->bot_req_in = NULL;
  err:
  	pr_err("BOT: endpoint setup failed\n");
  	return -ENOMEM;
  }
  
  static void bot_cleanup_old_alt(struct f_uas *fu)
  {
  	if (!(fu->flags & USBG_ENABLED))
  		return;
  
  	usb_ep_disable(fu->ep_in);
  	usb_ep_disable(fu->ep_out);
  
  	if (!fu->bot_req_in)
  		return;
  
  	usb_ep_free_request(fu->ep_in, fu->bot_req_in);
  	usb_ep_free_request(fu->ep_out, fu->bot_req_out);
  	usb_ep_free_request(fu->ep_out, fu->cmd.req);
  	usb_ep_free_request(fu->ep_in, fu->bot_status.req);
  
  	kfree(fu->cmd.buf);
  
  	fu->bot_req_in = NULL;
  	fu->bot_req_out = NULL;
  	fu->cmd.req = NULL;
  	fu->bot_status.req = NULL;
  	fu->cmd.buf = NULL;
  }
  
  static void bot_set_alt(struct f_uas *fu)
  {
  	struct usb_function *f = &fu->function;
  	struct usb_gadget *gadget = f->config->cdev->gadget;
  	int ret;
  
  	fu->flags = USBG_IS_BOT;
  
  	config_ep_by_speed(gadget, f, fu->ep_in);
  	ret = usb_ep_enable(fu->ep_in);
  	if (ret)
  		goto err_b_in;
  
  	config_ep_by_speed(gadget, f, fu->ep_out);
  	ret = usb_ep_enable(fu->ep_out);
  	if (ret)
  		goto err_b_out;
  
  	ret = bot_prepare_reqs(fu);
  	if (ret)
  		goto err_wq;
  	fu->flags |= USBG_ENABLED;
  	pr_info("Using the BOT protocol\n");
  	return;
  err_wq:
  	usb_ep_disable(fu->ep_out);
  err_b_out:
  	usb_ep_disable(fu->ep_in);
  err_b_in:
  	fu->flags = USBG_IS_BOT;
  }
  
  static int usbg_bot_setup(struct usb_function *f,
  		const struct usb_ctrlrequest *ctrl)
  {
  	struct f_uas *fu = to_f_uas(f);
  	struct usb_composite_dev *cdev = f->config->cdev;
  	u16 w_value = le16_to_cpu(ctrl->wValue);
  	u16 w_length = le16_to_cpu(ctrl->wLength);
  	int luns;
  	u8 *ret_lun;
  
  	switch (ctrl->bRequest) {
  	case US_BULK_GET_MAX_LUN:
  		if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_CLASS |
  					USB_RECIP_INTERFACE))
  			return -ENOTSUPP;
  
  		if (w_length < 1)
  			return -EINVAL;
  		if (w_value != 0)
  			return -EINVAL;
  		luns = atomic_read(&fu->tpg->tpg_port_count);
  		if (!luns) {
  			pr_err("No LUNs configured?\n");
  			return -EINVAL;
  		}
  		/*
  		 * If 4 LUNs are present we return 3 i.e. LUN 0..3 can be
  		 * accessed. The upper limit is 0xf
  		 */
  		luns--;
  		if (luns > 0xf) {
  			pr_info_once("Limiting the number of luns to 16\n");
  			luns = 0xf;
  		}
  		ret_lun = cdev->req->buf;
  		*ret_lun = luns;
  		cdev->req->length = 1;
  		return usb_ep_queue(cdev->gadget->ep0, cdev->req, GFP_ATOMIC);
  
  	case US_BULK_RESET_REQUEST:
  		/* XXX maybe we should remove previous requests for IN + OUT */
  		bot_enqueue_cmd_cbw(fu);
  		return 0;
  	}
  	return -ENOTSUPP;
  }
  
  /* Start uas.c code */
  
  static void uasp_cleanup_one_stream(struct f_uas *fu, struct uas_stream *stream)
  {
  	/* We have either all three allocated or none */
  	if (!stream->req_in)
  		return;
  
  	usb_ep_free_request(fu->ep_in, stream->req_in);
  	usb_ep_free_request(fu->ep_out, stream->req_out);
  	usb_ep_free_request(fu->ep_status, stream->req_status);
  
  	stream->req_in = NULL;
  	stream->req_out = NULL;
  	stream->req_status = NULL;
  }
  
  static void uasp_free_cmdreq(struct f_uas *fu)
  {
  	usb_ep_free_request(fu->ep_cmd, fu->cmd.req);
  	kfree(fu->cmd.buf);
  	fu->cmd.req = NULL;
  	fu->cmd.buf = NULL;
  }
  
  static void uasp_cleanup_old_alt(struct f_uas *fu)
  {
  	int i;
  
  	if (!(fu->flags & USBG_ENABLED))
  		return;
  
  	usb_ep_disable(fu->ep_in);
  	usb_ep_disable(fu->ep_out);
  	usb_ep_disable(fu->ep_status);
  	usb_ep_disable(fu->ep_cmd);
  
  	for (i = 0; i < UASP_SS_EP_COMP_NUM_STREAMS; i++)
  		uasp_cleanup_one_stream(fu, &fu->stream[i]);
  	uasp_free_cmdreq(fu);
  }
  
  static void uasp_status_data_cmpl(struct usb_ep *ep, struct usb_request *req);
  
  static int uasp_prepare_r_request(struct usbg_cmd *cmd)
  {
  	struct se_cmd *se_cmd = &cmd->se_cmd;
  	struct f_uas *fu = cmd->fu;
  	struct usb_gadget *gadget = fuas_to_gadget(fu);
  	struct uas_stream *stream = cmd->stream;
  
  	if (!gadget->sg_supported) {
  		cmd->data_buf = kmalloc(se_cmd->data_length, GFP_ATOMIC);
  		if (!cmd->data_buf)
  			return -ENOMEM;
  
  		sg_copy_to_buffer(se_cmd->t_data_sg,
  				se_cmd->t_data_nents,
  				cmd->data_buf,
  				se_cmd->data_length);
  
  		stream->req_in->buf = cmd->data_buf;
  	} else {
  		stream->req_in->buf = NULL;
  		stream->req_in->num_sgs = se_cmd->t_data_nents;
  		stream->req_in->sg = se_cmd->t_data_sg;
  	}
  
  	stream->req_in->complete = uasp_status_data_cmpl;
  	stream->req_in->length = se_cmd->data_length;
  	stream->req_in->context = cmd;
  
  	cmd->state = UASP_SEND_STATUS;
  	return 0;
  }
  
  static void uasp_prepare_status(struct usbg_cmd *cmd)
  {
  	struct se_cmd *se_cmd = &cmd->se_cmd;
  	struct sense_iu *iu = &cmd->sense_iu;
  	struct uas_stream *stream = cmd->stream;
  
  	cmd->state = UASP_QUEUE_COMMAND;
  	iu->iu_id = IU_ID_STATUS;
  	iu->tag = cpu_to_be16(cmd->tag);
  
  	/*
  	 * iu->status_qual = cpu_to_be16(STATUS QUALIFIER SAM-4. Where R U?);
  	 */
  	iu->len = cpu_to_be16(se_cmd->scsi_sense_length);
  	iu->status = se_cmd->scsi_status;
  	stream->req_status->context = cmd;
  	stream->req_status->length = se_cmd->scsi_sense_length + 16;
  	stream->req_status->buf = iu;
  	stream->req_status->complete = uasp_status_data_cmpl;
  }
  
  static void uasp_status_data_cmpl(struct usb_ep *ep, struct usb_request *req)
  {
  	struct usbg_cmd *cmd = req->context;
  	struct uas_stream *stream = cmd->stream;
  	struct f_uas *fu = cmd->fu;
  	int ret;
  
  	if (req->status < 0)
  		goto cleanup;
  
  	switch (cmd->state) {
  	case UASP_SEND_DATA:
  		ret = uasp_prepare_r_request(cmd);
  		if (ret)
  			goto cleanup;
  		ret = usb_ep_queue(fu->ep_in, stream->req_in, GFP_ATOMIC);
  		if (ret)
  			pr_err("%s(%d) => %d\n", __func__, __LINE__, ret);
  		break;
  
  	case UASP_RECEIVE_DATA:
  		ret = usbg_prepare_w_request(cmd, stream->req_out);
  		if (ret)
  			goto cleanup;
  		ret = usb_ep_queue(fu->ep_out, stream->req_out, GFP_ATOMIC);
  		if (ret)
  			pr_err("%s(%d) => %d\n", __func__, __LINE__, ret);
  		break;
  
  	case UASP_SEND_STATUS:
  		uasp_prepare_status(cmd);
  		ret = usb_ep_queue(fu->ep_status, stream->req_status,
  				GFP_ATOMIC);
  		if (ret)
  			pr_err("%s(%d) => %d\n", __func__, __LINE__, ret);
  		break;
  
  	case UASP_QUEUE_COMMAND:
  		transport_generic_free_cmd(&cmd->se_cmd, 0);
  		usb_ep_queue(fu->ep_cmd, fu->cmd.req, GFP_ATOMIC);
  		break;
  
  	default:
  		BUG();
  	}
  	return;
  
  cleanup:
  	transport_generic_free_cmd(&cmd->se_cmd, 0);
  }
  
  static int uasp_send_status_response(struct usbg_cmd *cmd)
  {
  	struct f_uas *fu = cmd->fu;
  	struct uas_stream *stream = cmd->stream;
  	struct sense_iu *iu = &cmd->sense_iu;
  
  	iu->tag = cpu_to_be16(cmd->tag);
  	stream->req_status->complete = uasp_status_data_cmpl;
  	stream->req_status->context = cmd;
  	cmd->fu = fu;
  	uasp_prepare_status(cmd);
  	return usb_ep_queue(fu->ep_status, stream->req_status, GFP_ATOMIC);
  }
  
  static int uasp_send_read_response(struct usbg_cmd *cmd)
  {
  	struct f_uas *fu = cmd->fu;
  	struct uas_stream *stream = cmd->stream;
  	struct sense_iu *iu = &cmd->sense_iu;
  	int ret;
  
  	cmd->fu = fu;
  
  	iu->tag = cpu_to_be16(cmd->tag);
  	if (fu->flags & USBG_USE_STREAMS) {
  
  		ret = uasp_prepare_r_request(cmd);
  		if (ret)
  			goto out;
  		ret = usb_ep_queue(fu->ep_in, stream->req_in, GFP_ATOMIC);
  		if (ret) {
  			pr_err("%s(%d) => %d\n", __func__, __LINE__, ret);
  			kfree(cmd->data_buf);
  			cmd->data_buf = NULL;
  		}
  
  	} else {
  
  		iu->iu_id = IU_ID_READ_READY;
  		iu->tag = cpu_to_be16(cmd->tag);
  
  		stream->req_status->complete = uasp_status_data_cmpl;
  		stream->req_status->context = cmd;
  
  		cmd->state = UASP_SEND_DATA;
  		stream->req_status->buf = iu;
  		stream->req_status->length = sizeof(struct iu);
  
  		ret = usb_ep_queue(fu->ep_status, stream->req_status,
  				GFP_ATOMIC);
  		if (ret)
  			pr_err("%s(%d) => %d\n", __func__, __LINE__, ret);
  	}
  out:
  	return ret;
  }
  
  static int uasp_send_write_request(struct usbg_cmd *cmd)
  {
  	struct f_uas *fu = cmd->fu;
  	struct se_cmd *se_cmd = &cmd->se_cmd;
  	struct uas_stream *stream = cmd->stream;
  	struct sense_iu *iu = &cmd->sense_iu;
  	int ret;
  
  	init_completion(&cmd->write_complete);
  	cmd->fu = fu;
  
  	iu->tag = cpu_to_be16(cmd->tag);
  
  	if (fu->flags & USBG_USE_STREAMS) {
  
  		ret = usbg_prepare_w_request(cmd, stream->req_out);
  		if (ret)
  			goto cleanup;
  		ret = usb_ep_queue(fu->ep_out, stream->req_out, GFP_ATOMIC);
  		if (ret)
  			pr_err("%s(%d)\n", __func__, __LINE__);
  
  	} else {
  
  		iu->iu_id = IU_ID_WRITE_READY;
  		iu->tag = cpu_to_be16(cmd->tag);
  
  		stream->req_status->complete = uasp_status_data_cmpl;
  		stream->req_status->context = cmd;
  
  		cmd->state = UASP_RECEIVE_DATA;
  		stream->req_status->buf = iu;
  		stream->req_status->length = sizeof(struct iu);
  
  		ret = usb_ep_queue(fu->ep_status, stream->req_status,
  				GFP_ATOMIC);
  		if (ret)
  			pr_err("%s(%d)\n", __func__, __LINE__);
  	}
  
  	wait_for_completion(&cmd->write_complete);
  	target_execute_cmd(se_cmd);
  cleanup:
  	return ret;
  }
  
  static int usbg_submit_command(struct f_uas *, void *, unsigned int);
  
  static void uasp_cmd_complete(struct usb_ep *ep, struct usb_request *req)
  {
  	struct f_uas *fu = req->context;
  	int ret;
  
  	if (req->status < 0)
  		return;
  
  	ret = usbg_submit_command(fu, req->buf, req->actual);
  	/*
  	 * Once we tune for performance enqueue the command req here again so
  	 * we can receive a second command while we processing this one. Pay
  	 * attention to properly sync STAUS endpoint with DATA IN + OUT so you
  	 * don't break HS.
  	 */
  	if (!ret)
  		return;
  	usb_ep_queue(fu->ep_cmd, fu->cmd.req, GFP_ATOMIC);
  }
  
  static int uasp_alloc_stream_res(struct f_uas *fu, struct uas_stream *stream)
  {
  	stream->req_in = usb_ep_alloc_request(fu->ep_in, GFP_KERNEL);
  	if (!stream->req_in)
  		goto out;
  
  	stream->req_out = usb_ep_alloc_request(fu->ep_out, GFP_KERNEL);
  	if (!stream->req_out)
  		goto err_out;
  
  	stream->req_status = usb_ep_alloc_request(fu->ep_status, GFP_KERNEL);
  	if (!stream->req_status)
  		goto err_sts;
  
  	return 0;
  err_sts:
  	usb_ep_free_request(fu->ep_status, stream->req_status);
  	stream->req_status = NULL;
  err_out:
  	usb_ep_free_request(fu->ep_out, stream->req_out);
  	stream->req_out = NULL;
  out:
  	return -ENOMEM;
  }
  
  static int uasp_alloc_cmd(struct f_uas *fu)
  {
  	fu->cmd.req = usb_ep_alloc_request(fu->ep_cmd, GFP_KERNEL);
  	if (!fu->cmd.req)
  		goto err;
  
  	fu->cmd.buf = kmalloc(fu->ep_cmd->maxpacket, GFP_KERNEL);
  	if (!fu->cmd.buf)
  		goto err_buf;
  
  	fu->cmd.req->complete = uasp_cmd_complete;
  	fu->cmd.req->buf = fu->cmd.buf;
  	fu->cmd.req->length = fu->ep_cmd->maxpacket;
  	fu->cmd.req->context = fu;
  	return 0;
  
  err_buf:
  	usb_ep_free_request(fu->ep_cmd, fu->cmd.req);
  err:
  	return -ENOMEM;
  }
  
  static void uasp_setup_stream_res(struct f_uas *fu, int max_streams)
  {
  	int i;
  
  	for (i = 0; i < max_streams; i++) {
  		struct uas_stream *s = &fu->stream[i];
  
  		s->req_in->stream_id = i + 1;
  		s->req_out->stream_id = i + 1;
  		s->req_status->stream_id = i + 1;
  	}
  }
  
  static int uasp_prepare_reqs(struct f_uas *fu)
  {
  	int ret;
  	int i;
  	int max_streams;
  
  	if (fu->flags & USBG_USE_STREAMS)
  		max_streams = UASP_SS_EP_COMP_NUM_STREAMS;
  	else
  		max_streams = 1;
  
  	for (i = 0; i < max_streams; i++) {
  		ret = uasp_alloc_stream_res(fu, &fu->stream[i]);
  		if (ret)
  			goto err_cleanup;
  	}
  
  	ret = uasp_alloc_cmd(fu);
  	if (ret)
  		goto err_free_stream;
  	uasp_setup_stream_res(fu, max_streams);
  
  	ret = usb_ep_queue(fu->ep_cmd, fu->cmd.req, GFP_ATOMIC);
  	if (ret)
  		goto err_free_stream;
  
  	return 0;
  
  err_free_stream:
  	uasp_free_cmdreq(fu);
  
  err_cleanup:
  	if (i) {
  		do {
  			uasp_cleanup_one_stream(fu, &fu->stream[i - 1]);
  			i--;
  		} while (i);
  	}
  	pr_err("UASP: endpoint setup failed\n");
  	return ret;
  }
  
  static void uasp_set_alt(struct f_uas *fu)
  {
  	struct usb_function *f = &fu->function;
  	struct usb_gadget *gadget = f->config->cdev->gadget;
  	int ret;
  
  	fu->flags = USBG_IS_UAS;
  
  	if (gadget->speed == USB_SPEED_SUPER)
  		fu->flags |= USBG_USE_STREAMS;
  
  	config_ep_by_speed(gadget, f, fu->ep_in);
  	ret = usb_ep_enable(fu->ep_in);
  	if (ret)
  		goto err_b_in;
  
  	config_ep_by_speed(gadget, f, fu->ep_out);
  	ret = usb_ep_enable(fu->ep_out);
  	if (ret)
  		goto err_b_out;
  
  	config_ep_by_speed(gadget, f, fu->ep_cmd);
  	ret = usb_ep_enable(fu->ep_cmd);
  	if (ret)
  		goto err_cmd;
  	config_ep_by_speed(gadget, f, fu->ep_status);
  	ret = usb_ep_enable(fu->ep_status);
  	if (ret)
  		goto err_status;
  
  	ret = uasp_prepare_reqs(fu);
  	if (ret)
  		goto err_wq;
  	fu->flags |= USBG_ENABLED;
  
  	pr_info("Using the UAS protocol\n");
  	return;
  err_wq:
  	usb_ep_disable(fu->ep_status);
  err_status:
  	usb_ep_disable(fu->ep_cmd);
  err_cmd:
  	usb_ep_disable(fu->ep_out);
  err_b_out:
  	usb_ep_disable(fu->ep_in);
  err_b_in:
  	fu->flags = 0;
  }
  
  static int get_cmd_dir(const unsigned char *cdb)
  {
  	int ret;
  
  	switch (cdb[0]) {
  	case READ_6:
  	case READ_10:
  	case READ_12:
  	case READ_16:
  	case INQUIRY:
  	case MODE_SENSE:
  	case MODE_SENSE_10:
  	case SERVICE_ACTION_IN_16:
  	case MAINTENANCE_IN:
  	case PERSISTENT_RESERVE_IN:
  	case SECURITY_PROTOCOL_IN:
  	case ACCESS_CONTROL_IN:
  	case REPORT_LUNS:
  	case READ_BLOCK_LIMITS:
  	case READ_POSITION:
  	case READ_CAPACITY:
  	case READ_TOC:
  	case READ_FORMAT_CAPACITIES:
  	case REQUEST_SENSE:
  		ret = DMA_FROM_DEVICE;
  		break;
  
  	case WRITE_6:
  	case WRITE_10:
  	case WRITE_12:
  	case WRITE_16:
  	case MODE_SELECT:
  	case MODE_SELECT_10:
  	case WRITE_VERIFY:
  	case WRITE_VERIFY_12:
  	case PERSISTENT_RESERVE_OUT:
  	case MAINTENANCE_OUT:
  	case SECURITY_PROTOCOL_OUT:
  	case ACCESS_CONTROL_OUT:
  		ret = DMA_TO_DEVICE;
  		break;
  	case ALLOW_MEDIUM_REMOVAL:
  	case TEST_UNIT_READY:
  	case SYNCHRONIZE_CACHE:
  	case START_STOP:
  	case ERASE:
  	case REZERO_UNIT:
  	case SEEK_10:
  	case SPACE:
  	case VERIFY:
  	case WRITE_FILEMARKS:
  		ret = DMA_NONE;
  		break;
  	default:
  #define CMD_DIR_MSG "target: Unknown data direction for SCSI Opcode 0x%02x\n"
  		pr_warn(CMD_DIR_MSG, cdb[0]);
  #undef CMD_DIR_MSG
  		ret = -EINVAL;
  	}
  	return ret;
  }
  
  static void usbg_data_write_cmpl(struct usb_ep *ep, struct usb_request *req)
  {
  	struct usbg_cmd *cmd = req->context;
  	struct se_cmd *se_cmd = &cmd->se_cmd;
  
  	if (req->status < 0) {
  		pr_err("%s() state %d transfer failed\n", __func__, cmd->state);
  		goto cleanup;
  	}
  
  	if (req->num_sgs == 0) {
  		sg_copy_from_buffer(se_cmd->t_data_sg,
  				se_cmd->t_data_nents,
  				cmd->data_buf,
  				se_cmd->data_length);
  	}
  
  	complete(&cmd->write_complete);
  	return;
  
  cleanup:
  	transport_generic_free_cmd(&cmd->se_cmd, 0);
  }
  
  static int usbg_prepare_w_request(struct usbg_cmd *cmd, struct usb_request *req)
  {
  	struct se_cmd *se_cmd = &cmd->se_cmd;
  	struct f_uas *fu = cmd->fu;
  	struct usb_gadget *gadget = fuas_to_gadget(fu);
  
  	if (!gadget->sg_supported) {
  		cmd->data_buf = kmalloc(se_cmd->data_length, GFP_ATOMIC);
  		if (!cmd->data_buf)
  			return -ENOMEM;
  
  		req->buf = cmd->data_buf;
  	} else {
  		req->buf = NULL;
  		req->num_sgs = se_cmd->t_data_nents;
  		req->sg = se_cmd->t_data_sg;
  	}
  
  	req->complete = usbg_data_write_cmpl;
  	req->length = se_cmd->data_length;
  	req->context = cmd;
  	return 0;
  }
  
  static int usbg_send_status_response(struct se_cmd *se_cmd)
  {
  	struct usbg_cmd *cmd = container_of(se_cmd, struct usbg_cmd,
  			se_cmd);
  	struct f_uas *fu = cmd->fu;
  
  	if (fu->flags & USBG_IS_BOT)
  		return bot_send_status_response(cmd);
  	else
  		return uasp_send_status_response(cmd);
  }
  
  static int usbg_send_write_request(struct se_cmd *se_cmd)
  {
  	struct usbg_cmd *cmd = container_of(se_cmd, struct usbg_cmd,
  			se_cmd);
  	struct f_uas *fu = cmd->fu;
  
  	if (fu->flags & USBG_IS_BOT)
  		return bot_send_write_request(cmd);
  	else
  		return uasp_send_write_request(cmd);
  }
  
  static int usbg_send_read_response(struct se_cmd *se_cmd)
  {
  	struct usbg_cmd *cmd = container_of(se_cmd, struct usbg_cmd,
  			se_cmd);
  	struct f_uas *fu = cmd->fu;
  
  	if (fu->flags & USBG_IS_BOT)
  		return bot_send_read_response(cmd);
  	else
  		return uasp_send_read_response(cmd);
  }
  
  static void usbg_cmd_work(struct work_struct *work)
  {
  	struct usbg_cmd *cmd = container_of(work, struct usbg_cmd, work);
  	struct se_cmd *se_cmd;
  	struct tcm_usbg_nexus *tv_nexus;
  	struct usbg_tpg *tpg;
  	int dir, flags = (TARGET_SCF_UNKNOWN_SIZE | TARGET_SCF_ACK_KREF);
  
  	se_cmd = &cmd->se_cmd;
  	tpg = cmd->fu->tpg;
  	tv_nexus = tpg->tpg_nexus;
  	dir = get_cmd_dir(cmd->cmd_buf);
  	if (dir < 0) {
  		transport_init_se_cmd(se_cmd,
  				tv_nexus->tvn_se_sess->se_tpg->se_tpg_tfo,
  				tv_nexus->tvn_se_sess, cmd->data_len, DMA_NONE,
  				cmd->prio_attr, cmd->sense_iu.sense);
  		goto out;
  	}
  
  	if (target_submit_cmd(se_cmd, tv_nexus->tvn_se_sess, cmd->cmd_buf,
  			      cmd->sense_iu.sense, cmd->unpacked_lun, 0,
  			      cmd->prio_attr, dir, flags) < 0)
  		goto out;
  
  	return;
  
  out:
  	transport_send_check_condition_and_sense(se_cmd,
  			TCM_UNSUPPORTED_SCSI_OPCODE, 1);
  	transport_generic_free_cmd(&cmd->se_cmd, 0);
  }
  
  static struct usbg_cmd *usbg_get_cmd(struct f_uas *fu,
  		struct tcm_usbg_nexus *tv_nexus, u32 scsi_tag)
  {
  	struct se_session *se_sess = tv_nexus->tvn_se_sess;
  	struct usbg_cmd *cmd;
  	int tag;
  
  	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
  	if (tag < 0)
  		return ERR_PTR(-ENOMEM);
  
  	cmd = &((struct usbg_cmd *)se_sess->sess_cmd_map)[tag];
  	memset(cmd, 0, sizeof(*cmd));
  	cmd->se_cmd.map_tag = tag;
  	cmd->se_cmd.tag = cmd->tag = scsi_tag;
  	cmd->fu = fu;
  
  	return cmd;
  }
  
  static void usbg_release_cmd(struct se_cmd *);
  
  static int usbg_submit_command(struct f_uas *fu,
  		void *cmdbuf, unsigned int len)
  {
  	struct command_iu *cmd_iu = cmdbuf;
  	struct usbg_cmd *cmd;
  	struct usbg_tpg *tpg = fu->tpg;
  	struct tcm_usbg_nexus *tv_nexus = tpg->tpg_nexus;
  	u32 cmd_len;
  	u16 scsi_tag;
  
  	if (cmd_iu->iu_id != IU_ID_COMMAND) {
  		pr_err("Unsupported type %d\n", cmd_iu->iu_id);
  		return -EINVAL;
  	}
  
  	tv_nexus = tpg->tpg_nexus;
  	if (!tv_nexus) {
  		pr_err("Missing nexus, ignoring command\n");
  		return -EINVAL;
  	}
  
  	cmd_len = (cmd_iu->len & ~0x3) + 16;
  	if (cmd_len > USBG_MAX_CMD)
  		return -EINVAL;
  
  	scsi_tag = be16_to_cpup(&cmd_iu->tag);
  	cmd = usbg_get_cmd(fu, tv_nexus, scsi_tag);
  	if (IS_ERR(cmd)) {
  		pr_err("usbg_get_cmd failed\n");
  		return -ENOMEM;
  	}
  	memcpy(cmd->cmd_buf, cmd_iu->cdb, cmd_len);
  
  	if (fu->flags & USBG_USE_STREAMS) {
  		if (cmd->tag > UASP_SS_EP_COMP_NUM_STREAMS)
  			goto err;
  		if (!cmd->tag)
  			cmd->stream = &fu->stream[0];
  		else
  			cmd->stream = &fu->stream[cmd->tag - 1];
  	} else {
  		cmd->stream = &fu->stream[0];
  	}
  
  	switch (cmd_iu->prio_attr & 0x7) {
  	case UAS_HEAD_TAG:
  		cmd->prio_attr = TCM_HEAD_TAG;
  		break;
  	case UAS_ORDERED_TAG:
  		cmd->prio_attr = TCM_ORDERED_TAG;
  		break;
  	case UAS_ACA:
  		cmd->prio_attr = TCM_ACA_TAG;
  		break;
  	default:
  		pr_debug_once("Unsupported prio_attr: %02x.\n",
  				cmd_iu->prio_attr);
  	case UAS_SIMPLE_TAG:
  		cmd->prio_attr = TCM_SIMPLE_TAG;
  		break;
  	}
  
  	cmd->unpacked_lun = scsilun_to_int(&cmd_iu->lun);
  
  	INIT_WORK(&cmd->work, usbg_cmd_work);
  	queue_work(tpg->workqueue, &cmd->work);
  
  	return 0;
  err:
  	usbg_release_cmd(&cmd->se_cmd);
  	return -EINVAL;
  }
  
  static void bot_cmd_work(struct work_struct *work)
  {
  	struct usbg_cmd *cmd = container_of(work, struct usbg_cmd, work);
  	struct se_cmd *se_cmd;
  	struct tcm_usbg_nexus *tv_nexus;
  	struct usbg_tpg *tpg;
  	int dir;
  
  	se_cmd = &cmd->se_cmd;
  	tpg = cmd->fu->tpg;
  	tv_nexus = tpg->tpg_nexus;
  	dir = get_cmd_dir(cmd->cmd_buf);
  	if (dir < 0) {
  		transport_init_se_cmd(se_cmd,
  				tv_nexus->tvn_se_sess->se_tpg->se_tpg_tfo,
  				tv_nexus->tvn_se_sess, cmd->data_len, DMA_NONE,
  				cmd->prio_attr, cmd->sense_iu.sense);
  		goto out;
  	}
  
  	if (target_submit_cmd(se_cmd, tv_nexus->tvn_se_sess,
  			cmd->cmd_buf, cmd->sense_iu.sense, cmd->unpacked_lun,
  			cmd->data_len, cmd->prio_attr, dir, 0) < 0)
  		goto out;
  
  	return;
  
  out:
  	transport_send_check_condition_and_sense(se_cmd,
  				TCM_UNSUPPORTED_SCSI_OPCODE, 1);
  	transport_generic_free_cmd(&cmd->se_cmd, 0);
  }
  
  static int bot_submit_command(struct f_uas *fu,
  		void *cmdbuf, unsigned int len)
  {
  	struct bulk_cb_wrap *cbw = cmdbuf;
  	struct usbg_cmd *cmd;
  	struct usbg_tpg *tpg = fu->tpg;
  	struct tcm_usbg_nexus *tv_nexus;
  	u32 cmd_len;
  
  	if (cbw->Signature != cpu_to_le32(US_BULK_CB_SIGN)) {
  		pr_err("Wrong signature on CBW\n");
  		return -EINVAL;
  	}
  	if (len != 31) {
  		pr_err("Wrong length for CBW\n");
  		return -EINVAL;
  	}
  
  	cmd_len = cbw->Length;
  	if (cmd_len < 1 || cmd_len > 16)
  		return -EINVAL;
  
  	tv_nexus = tpg->tpg_nexus;
  	if (!tv_nexus) {
  		pr_err("Missing nexus, ignoring command\n");
  		return -ENODEV;
  	}
  
  	cmd = usbg_get_cmd(fu, tv_nexus, cbw->Tag);
  	if (IS_ERR(cmd)) {
  		pr_err("usbg_get_cmd failed\n");
  		return -ENOMEM;
  	}
  	memcpy(cmd->cmd_buf, cbw->CDB, cmd_len);
  
  	cmd->bot_tag = cbw->Tag;
  	cmd->prio_attr = TCM_SIMPLE_TAG;
  	cmd->unpacked_lun = cbw->Lun;
  	cmd->is_read = cbw->Flags & US_BULK_FLAG_IN ? 1 : 0;
  	cmd->data_len = le32_to_cpu(cbw->DataTransferLength);
  	cmd->se_cmd.tag = le32_to_cpu(cmd->bot_tag);
  
  	INIT_WORK(&cmd->work, bot_cmd_work);
  	queue_work(tpg->workqueue, &cmd->work);
  
  	return 0;
  }
  
  /* Start fabric.c code */
  
  static int usbg_check_true(struct se_portal_group *se_tpg)
  {
  	return 1;
  }
  
  static int usbg_check_false(struct se_portal_group *se_tpg)
  {
  	return 0;
  }
  
  static char *usbg_get_fabric_name(void)
  {
  	return "usb_gadget";
  }
  
  static char *usbg_get_fabric_wwn(struct se_portal_group *se_tpg)
  {
  	struct usbg_tpg *tpg = container_of(se_tpg,
  				struct usbg_tpg, se_tpg);
  	struct usbg_tport *tport = tpg->tport;
  
  	return &tport->tport_name[0];
  }
  
  static u16 usbg_get_tag(struct se_portal_group *se_tpg)
  {
  	struct usbg_tpg *tpg = container_of(se_tpg,
  				struct usbg_tpg, se_tpg);
  	return tpg->tport_tpgt;
  }
  
  static u32 usbg_tpg_get_inst_index(struct se_portal_group *se_tpg)
  {
  	return 1;
  }
  
  static void usbg_release_cmd(struct se_cmd *se_cmd)
  {
  	struct usbg_cmd *cmd = container_of(se_cmd, struct usbg_cmd,
  			se_cmd);
  	struct se_session *se_sess = se_cmd->se_sess;
  
  	kfree(cmd->data_buf);
  	percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
  }
  
  static u32 usbg_sess_get_index(struct se_session *se_sess)
  {
  	return 0;
  }
  
  /*
   * XXX Error recovery: return != 0 if we expect writes. Dunno when that could be
   */
  static int usbg_write_pending_status(struct se_cmd *se_cmd)
  {
  	return 0;
  }
  
  static void usbg_set_default_node_attrs(struct se_node_acl *nacl)
  {
  }
  
  static int usbg_get_cmd_state(struct se_cmd *se_cmd)
  {
  	return 0;
  }
  
  static void usbg_queue_tm_rsp(struct se_cmd *se_cmd)
  {
  }
  
  static void usbg_aborted_task(struct se_cmd *se_cmd)
  {
  }
  
  static const char *usbg_check_wwn(const char *name)
  {
  	const char *n;
  	unsigned int len;
  
  	n = strstr(name, "naa.");
  	if (!n)
  		return NULL;
  	n += 4;
  	len = strlen(n);
  	if (len == 0 || len > USBG_NAMELEN - 1)
  		return NULL;
  	return n;
  }
  
  static int usbg_init_nodeacl(struct se_node_acl *se_nacl, const char *name)
  {
  	if (!usbg_check_wwn(name))
  		return -EINVAL;
  	return 0;
  }
  
  static struct se_portal_group *usbg_make_tpg(
  	struct se_wwn *wwn,
  	struct config_group *group,
  	const char *name)
  {
  	struct usbg_tport *tport = container_of(wwn, struct usbg_tport,
  			tport_wwn);
  	struct usbg_tpg *tpg;
  	unsigned long tpgt;
  	int ret;
  	struct f_tcm_opts *opts;
  	unsigned i;
  
  	if (strstr(name, "tpgt_") != name)
  		return ERR_PTR(-EINVAL);
  	if (kstrtoul(name + 5, 0, &tpgt) || tpgt > UINT_MAX)
  		return ERR_PTR(-EINVAL);
  	ret = -ENODEV;
  	mutex_lock(&tpg_instances_lock);
  	for (i = 0; i < TPG_INSTANCES; ++i)
  		if (tpg_instances[i].func_inst && !tpg_instances[i].tpg)
  			break;
  	if (i == TPG_INSTANCES)
  		goto unlock_inst;
  
  	opts = container_of(tpg_instances[i].func_inst, struct f_tcm_opts,
  		func_inst);
  	mutex_lock(&opts->dep_lock);
  	if (!opts->ready)
  		goto unlock_dep;
  
  	if (opts->has_dep) {
  		if (!try_module_get(opts->dependent))
  			goto unlock_dep;
  	} else {
  		ret = configfs_depend_item_unlocked(
  			group->cg_subsys,
  			&opts->func_inst.group.cg_item);
  		if (ret)
  			goto unlock_dep;
  	}
  
  	tpg = kzalloc(sizeof(struct usbg_tpg), GFP_KERNEL);
  	ret = -ENOMEM;
  	if (!tpg)
  		goto unref_dep;
  	mutex_init(&tpg->tpg_mutex);
  	atomic_set(&tpg->tpg_port_count, 0);
  	tpg->workqueue = alloc_workqueue("tcm_usb_gadget", 0, 1);
  	if (!tpg->workqueue)
  		goto free_tpg;
  
  	tpg->tport = tport;
  	tpg->tport_tpgt = tpgt;
  
  	/*
  	 * SPC doesn't assign a protocol identifier for USB-SCSI, so we
  	 * pretend to be SAS..
  	 */
  	ret = core_tpg_register(wwn, &tpg->se_tpg, SCSI_PROTOCOL_SAS);
  	if (ret < 0)
  		goto free_workqueue;
  
  	tpg_instances[i].tpg = tpg;
  	tpg->fi = tpg_instances[i].func_inst;
  	mutex_unlock(&opts->dep_lock);
  	mutex_unlock(&tpg_instances_lock);
  	return &tpg->se_tpg;
  
  free_workqueue:
  	destroy_workqueue(tpg->workqueue);
  free_tpg:
  	kfree(tpg);
  unref_dep:
  	if (opts->has_dep)
  		module_put(opts->dependent);
  	else
  		configfs_undepend_item_unlocked(&opts->func_inst.group.cg_item);
  unlock_dep:
  	mutex_unlock(&opts->dep_lock);
  unlock_inst:
  	mutex_unlock(&tpg_instances_lock);
  
  	return ERR_PTR(ret);
  }
  
  static int tcm_usbg_drop_nexus(struct usbg_tpg *);
  
  static void usbg_drop_tpg(struct se_portal_group *se_tpg)
  {
  	struct usbg_tpg *tpg = container_of(se_tpg,
  				struct usbg_tpg, se_tpg);
  	unsigned i;
  	struct f_tcm_opts *opts;
  
  	tcm_usbg_drop_nexus(tpg);
  	core_tpg_deregister(se_tpg);
  	destroy_workqueue(tpg->workqueue);
  
  	mutex_lock(&tpg_instances_lock);
  	for (i = 0; i < TPG_INSTANCES; ++i)
  		if (tpg_instances[i].tpg == tpg)
  			break;
  	if (i < TPG_INSTANCES) {
  		tpg_instances[i].tpg = NULL;
  		opts = container_of(tpg_instances[i].func_inst,
  			struct f_tcm_opts, func_inst);
  		mutex_lock(&opts->dep_lock);
  		if (opts->has_dep)
  			module_put(opts->dependent);
  		else
  			configfs_undepend_item_unlocked(
  				&opts->func_inst.group.cg_item);
  		mutex_unlock(&opts->dep_lock);
  	}
  	mutex_unlock(&tpg_instances_lock);
  
  	kfree(tpg);
  }
  
  static struct se_wwn *usbg_make_tport(
  	struct target_fabric_configfs *tf,
  	struct config_group *group,
  	const char *name)
  {
  	struct usbg_tport *tport;
  	const char *wnn_name;
  	u64 wwpn = 0;
  
  	wnn_name = usbg_check_wwn(name);
  	if (!wnn_name)
  		return ERR_PTR(-EINVAL);
  
  	tport = kzalloc(sizeof(struct usbg_tport), GFP_KERNEL);
  	if (!(tport))
  		return ERR_PTR(-ENOMEM);
  
  	tport->tport_wwpn = wwpn;
  	snprintf(tport->tport_name, sizeof(tport->tport_name), "%s", wnn_name);
  	return &tport->tport_wwn;
  }
  
  static void usbg_drop_tport(struct se_wwn *wwn)
  {
  	struct usbg_tport *tport = container_of(wwn,
  				struct usbg_tport, tport_wwn);
  	kfree(tport);
  }
  
  /*
   * If somebody feels like dropping the version property, go ahead.
   */
  static ssize_t usbg_wwn_version_show(struct config_item *item,  char *page)
  {
  	return sprintf(page, "usb-gadget fabric module\n");
  }
  
  CONFIGFS_ATTR_RO(usbg_wwn_, version);
  
  static struct configfs_attribute *usbg_wwn_attrs[] = {
  	&usbg_wwn_attr_version,
  	NULL,
  };
  
  static ssize_t tcm_usbg_tpg_enable_show(struct config_item *item, char *page)
  {
  	struct se_portal_group *se_tpg = to_tpg(item);
  	struct usbg_tpg  *tpg = container_of(se_tpg, struct usbg_tpg, se_tpg);
  
  	return snprintf(page, PAGE_SIZE, "%u\n", tpg->gadget_connect);
  }
  
  static int usbg_attach(struct usbg_tpg *);
  static void usbg_detach(struct usbg_tpg *);
  
  static ssize_t tcm_usbg_tpg_enable_store(struct config_item *item,
  		const char *page, size_t count)
  {
  	struct se_portal_group *se_tpg = to_tpg(item);
  	struct usbg_tpg  *tpg = container_of(se_tpg, struct usbg_tpg, se_tpg);
  	bool op;
  	ssize_t ret;
  
  	ret = strtobool(page, &op);
  	if (ret)
  		return ret;
  
  	if ((op && tpg->gadget_connect) || (!op && !tpg->gadget_connect))
  		return -EINVAL;
  
  	if (op)
  		ret = usbg_attach(tpg);
  	else
  		usbg_detach(tpg);
  	if (ret)
  		return ret;
  
  	tpg->gadget_connect = op;
  
  	return count;
  }
  
  static ssize_t tcm_usbg_tpg_nexus_show(struct config_item *item, char *page)
  {
  	struct se_portal_group *se_tpg = to_tpg(item);
  	struct usbg_tpg *tpg = container_of(se_tpg, struct usbg_tpg, se_tpg);
  	struct tcm_usbg_nexus *tv_nexus;
  	ssize_t ret;
  
  	mutex_lock(&tpg->tpg_mutex);
  	tv_nexus = tpg->tpg_nexus;
  	if (!tv_nexus) {
  		ret = -ENODEV;
  		goto out;
  	}
  	ret = snprintf(page, PAGE_SIZE, "%s\n",
  			tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
  out:
  	mutex_unlock(&tpg->tpg_mutex);
  	return ret;
  }
  
  static int usbg_alloc_sess_cb(struct se_portal_group *se_tpg,
  			      struct se_session *se_sess, void *p)
  {
  	struct usbg_tpg *tpg = container_of(se_tpg,
  				struct usbg_tpg, se_tpg);
  
  	tpg->tpg_nexus = p;
  	return 0;
  }
  
  static int tcm_usbg_make_nexus(struct usbg_tpg *tpg, char *name)
  {
  	struct tcm_usbg_nexus *tv_nexus;
  	int ret = 0;
  
  	mutex_lock(&tpg->tpg_mutex);
  	if (tpg->tpg_nexus) {
  		ret = -EEXIST;
  		pr_debug("tpg->tpg_nexus already exists\n");
  		goto out_unlock;
  	}
  
  	tv_nexus = kzalloc(sizeof(*tv_nexus), GFP_KERNEL);
  	if (!tv_nexus) {
  		ret = -ENOMEM;
  		goto out_unlock;
  	}
  
  	tv_nexus->tvn_se_sess = target_alloc_session(&tpg->se_tpg,
  						     USB_G_DEFAULT_SESSION_TAGS,
  						     sizeof(struct usbg_cmd),
  						     TARGET_PROT_NORMAL, name,
  						     tv_nexus, usbg_alloc_sess_cb);
  	if (IS_ERR(tv_nexus->tvn_se_sess)) {
  #define MAKE_NEXUS_MSG "core_tpg_check_initiator_node_acl() failed for %s\n"
  		pr_debug(MAKE_NEXUS_MSG, name);
  #undef MAKE_NEXUS_MSG
  		ret = PTR_ERR(tv_nexus->tvn_se_sess);
  		kfree(tv_nexus);
  	}
  
  out_unlock:
  	mutex_unlock(&tpg->tpg_mutex);
  	return ret;
  }
  
  static int tcm_usbg_drop_nexus(struct usbg_tpg *tpg)
  {
  	struct se_session *se_sess;
  	struct tcm_usbg_nexus *tv_nexus;
  	int ret = -ENODEV;
  
  	mutex_lock(&tpg->tpg_mutex);
  	tv_nexus = tpg->tpg_nexus;
  	if (!tv_nexus)
  		goto out;
  
  	se_sess = tv_nexus->tvn_se_sess;
  	if (!se_sess)
  		goto out;
  
  	if (atomic_read(&tpg->tpg_port_count)) {
  		ret = -EPERM;
  #define MSG "Unable to remove Host I_T Nexus with active TPG port count: %d\n"
  		pr_err(MSG, atomic_read(&tpg->tpg_port_count));
  #undef MSG
  		goto out;
  	}
  
  	pr_debug("Removing I_T Nexus to Initiator Port: %s\n",
  			tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
  	/*
  	 * Release the SCSI I_T Nexus to the emulated vHost Target Port
  	 */
  	transport_deregister_session(tv_nexus->tvn_se_sess);
  	tpg->tpg_nexus = NULL;
  
  	kfree(tv_nexus);
  	ret = 0;
  out:
  	mutex_unlock(&tpg->tpg_mutex);
  	return ret;
  }
  
  static ssize_t tcm_usbg_tpg_nexus_store(struct config_item *item,
  		const char *page, size_t count)
  {
  	struct se_portal_group *se_tpg = to_tpg(item);
  	struct usbg_tpg *tpg = container_of(se_tpg, struct usbg_tpg, se_tpg);
  	unsigned char i_port[USBG_NAMELEN], *ptr;
  	int ret;
  
  	if (!strncmp(page, "NULL", 4)) {
  		ret = tcm_usbg_drop_nexus(tpg);
  		return (!ret) ? count : ret;
  	}
  	if (strlen(page) >= USBG_NAMELEN) {
  
  #define NEXUS_STORE_MSG "Emulated NAA Sas Address: %s, exceeds max: %d\n"
  		pr_err(NEXUS_STORE_MSG, page, USBG_NAMELEN);
  #undef NEXUS_STORE_MSG
  		return -EINVAL;
  	}
  	snprintf(i_port, USBG_NAMELEN, "%s", page);
  
  	ptr = strstr(i_port, "naa.");
  	if (!ptr) {
  		pr_err("Missing 'naa.' prefix\n");
  		return -EINVAL;
  	}
  
  	if (i_port[strlen(i_port) - 1] == '\n')
  		i_port[strlen(i_port) - 1] = '\0';
  
  	ret = tcm_usbg_make_nexus(tpg, &i_port[0]);
  	if (ret < 0)
  		return ret;
  	return count;
  }
  
  CONFIGFS_ATTR(tcm_usbg_tpg_, enable);
  CONFIGFS_ATTR(tcm_usbg_tpg_, nexus);
  
  static struct configfs_attribute *usbg_base_attrs[] = {
  	&tcm_usbg_tpg_attr_enable,
  	&tcm_usbg_tpg_attr_nexus,
  	NULL,
  };
  
  static int usbg_port_link(struct se_portal_group *se_tpg, struct se_lun *lun)
  {
  	struct usbg_tpg *tpg = container_of(se_tpg, struct usbg_tpg, se_tpg);
  
  	atomic_inc(&tpg->tpg_port_count);
  	smp_mb__after_atomic();
  	return 0;
  }
  
  static void usbg_port_unlink(struct se_portal_group *se_tpg,
  		struct se_lun *se_lun)
  {
  	struct usbg_tpg *tpg = container_of(se_tpg, struct usbg_tpg, se_tpg);
  
  	atomic_dec(&tpg->tpg_port_count);
  	smp_mb__after_atomic();
  }
  
  static int usbg_check_stop_free(struct se_cmd *se_cmd)
  {
  	return target_put_sess_cmd(se_cmd);
  }
  
  static const struct target_core_fabric_ops usbg_ops = {
  	.module				= THIS_MODULE,
  	.name				= "usb_gadget",
  	.get_fabric_name		= usbg_get_fabric_name,
  	.tpg_get_wwn			= usbg_get_fabric_wwn,
  	.tpg_get_tag			= usbg_get_tag,
  	.tpg_check_demo_mode		= usbg_check_true,
  	.tpg_check_demo_mode_cache	= usbg_check_false,
  	.tpg_check_demo_mode_write_protect = usbg_check_false,
  	.tpg_check_prod_mode_write_protect = usbg_check_false,
  	.tpg_get_inst_index		= usbg_tpg_get_inst_index,
  	.release_cmd			= usbg_release_cmd,
  	.sess_get_index			= usbg_sess_get_index,
  	.sess_get_initiator_sid		= NULL,
  	.write_pending			= usbg_send_write_request,
  	.write_pending_status		= usbg_write_pending_status,
  	.set_default_node_attributes	= usbg_set_default_node_attrs,
  	.get_cmd_state			= usbg_get_cmd_state,
  	.queue_data_in			= usbg_send_read_response,
  	.queue_status			= usbg_send_status_response,
  	.queue_tm_rsp			= usbg_queue_tm_rsp,
  	.aborted_task			= usbg_aborted_task,
  	.check_stop_free		= usbg_check_stop_free,
  
  	.fabric_make_wwn		= usbg_make_tport,
  	.fabric_drop_wwn		= usbg_drop_tport,
  	.fabric_make_tpg		= usbg_make_tpg,
  	.fabric_drop_tpg		= usbg_drop_tpg,
  	.fabric_post_link		= usbg_port_link,
  	.fabric_pre_unlink		= usbg_port_unlink,
  	.fabric_init_nodeacl		= usbg_init_nodeacl,
  
  	.tfc_wwn_attrs			= usbg_wwn_attrs,
  	.tfc_tpg_base_attrs		= usbg_base_attrs,
  };
  
  /* Start gadget.c code */
  
  static struct usb_interface_descriptor bot_intf_desc = {
  	.bLength =              sizeof(bot_intf_desc),
  	.bDescriptorType =      USB_DT_INTERFACE,
  	.bNumEndpoints =        2,
  	.bAlternateSetting =	USB_G_ALT_INT_BBB,
  	.bInterfaceClass =      USB_CLASS_MASS_STORAGE,
  	.bInterfaceSubClass =   USB_SC_SCSI,
  	.bInterfaceProtocol =   USB_PR_BULK,
  };
  
  static struct usb_interface_descriptor uasp_intf_desc = {
  	.bLength =		sizeof(uasp_intf_desc),
  	.bDescriptorType =	USB_DT_INTERFACE,
  	.bNumEndpoints =	4,
  	.bAlternateSetting =	USB_G_ALT_INT_UAS,
  	.bInterfaceClass =	USB_CLASS_MASS_STORAGE,
  	.bInterfaceSubClass =	USB_SC_SCSI,
  	.bInterfaceProtocol =	USB_PR_UAS,
  };
  
  static struct usb_endpoint_descriptor uasp_bi_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(512),
  };
  
  static struct usb_endpoint_descriptor uasp_fs_bi_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  };
  
  static struct usb_pipe_usage_descriptor uasp_bi_pipe_desc = {
  	.bLength =		sizeof(uasp_bi_pipe_desc),
  	.bDescriptorType =	USB_DT_PIPE_USAGE,
  	.bPipeID =		DATA_IN_PIPE_ID,
  };
  
  static struct usb_endpoint_descriptor uasp_ss_bi_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(1024),
  };
  
  static struct usb_ss_ep_comp_descriptor uasp_bi_ep_comp_desc = {
  	.bLength =		sizeof(uasp_bi_ep_comp_desc),
  	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
  	.bMaxBurst =		0,
  	.bmAttributes =		UASP_SS_EP_COMP_LOG_STREAMS,
  	.wBytesPerInterval =	0,
  };
  
  static struct usb_ss_ep_comp_descriptor bot_bi_ep_comp_desc = {
  	.bLength =		sizeof(bot_bi_ep_comp_desc),
  	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
  	.bMaxBurst =		0,
  };
  
  static struct usb_endpoint_descriptor uasp_bo_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_OUT,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(512),
  };
  
  static struct usb_endpoint_descriptor uasp_fs_bo_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_OUT,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  };
  
  static struct usb_pipe_usage_descriptor uasp_bo_pipe_desc = {
  	.bLength =		sizeof(uasp_bo_pipe_desc),
  	.bDescriptorType =	USB_DT_PIPE_USAGE,
  	.bPipeID =		DATA_OUT_PIPE_ID,
  };
  
  static struct usb_endpoint_descriptor uasp_ss_bo_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_OUT,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(0x400),
  };
  
  static struct usb_ss_ep_comp_descriptor uasp_bo_ep_comp_desc = {
  	.bLength =		sizeof(uasp_bo_ep_comp_desc),
  	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
  	.bmAttributes =		UASP_SS_EP_COMP_LOG_STREAMS,
  };
  
  static struct usb_ss_ep_comp_descriptor bot_bo_ep_comp_desc = {
  	.bLength =		sizeof(bot_bo_ep_comp_desc),
  	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
  };
  
  static struct usb_endpoint_descriptor uasp_status_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(512),
  };
  
  static struct usb_endpoint_descriptor uasp_fs_status_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  };
  
  static struct usb_pipe_usage_descriptor uasp_status_pipe_desc = {
  	.bLength =		sizeof(uasp_status_pipe_desc),
  	.bDescriptorType =	USB_DT_PIPE_USAGE,
  	.bPipeID =		STATUS_PIPE_ID,
  };
  
  static struct usb_endpoint_descriptor uasp_ss_status_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(1024),
  };
  
  static struct usb_ss_ep_comp_descriptor uasp_status_in_ep_comp_desc = {
  	.bLength =		sizeof(uasp_status_in_ep_comp_desc),
  	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
  	.bmAttributes =		UASP_SS_EP_COMP_LOG_STREAMS,
  };
  
  static struct usb_endpoint_descriptor uasp_cmd_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_OUT,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(512),
  };
  
  static struct usb_endpoint_descriptor uasp_fs_cmd_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_OUT,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  };
  
  static struct usb_pipe_usage_descriptor uasp_cmd_pipe_desc = {
  	.bLength =		sizeof(uasp_cmd_pipe_desc),
  	.bDescriptorType =	USB_DT_PIPE_USAGE,
  	.bPipeID =		CMD_PIPE_ID,
  };
  
  static struct usb_endpoint_descriptor uasp_ss_cmd_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  	.bEndpointAddress =	USB_DIR_OUT,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(1024),
  };
  
  static struct usb_ss_ep_comp_descriptor uasp_cmd_comp_desc = {
  	.bLength =		sizeof(uasp_cmd_comp_desc),
  	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
  };
  
  static struct usb_descriptor_header *uasp_fs_function_desc[] = {
  	(struct usb_descriptor_header *) &bot_intf_desc,
  	(struct usb_descriptor_header *) &uasp_fs_bi_desc,
  	(struct usb_descriptor_header *) &uasp_fs_bo_desc,
  
  	(struct usb_descriptor_header *) &uasp_intf_desc,
  	(struct usb_descriptor_header *) &uasp_fs_bi_desc,
  	(struct usb_descriptor_header *) &uasp_bi_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_fs_bo_desc,
  	(struct usb_descriptor_header *) &uasp_bo_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_fs_status_desc,
  	(struct usb_descriptor_header *) &uasp_status_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_fs_cmd_desc,
  	(struct usb_descriptor_header *) &uasp_cmd_pipe_desc,
  	NULL,
  };
  
  static struct usb_descriptor_header *uasp_hs_function_desc[] = {
  	(struct usb_descriptor_header *) &bot_intf_desc,
  	(struct usb_descriptor_header *) &uasp_bi_desc,
  	(struct usb_descriptor_header *) &uasp_bo_desc,
  
  	(struct usb_descriptor_header *) &uasp_intf_desc,
  	(struct usb_descriptor_header *) &uasp_bi_desc,
  	(struct usb_descriptor_header *) &uasp_bi_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_bo_desc,
  	(struct usb_descriptor_header *) &uasp_bo_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_status_desc,
  	(struct usb_descriptor_header *) &uasp_status_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_cmd_desc,
  	(struct usb_descriptor_header *) &uasp_cmd_pipe_desc,
  	NULL,
  };
  
  static struct usb_descriptor_header *uasp_ss_function_desc[] = {
  	(struct usb_descriptor_header *) &bot_intf_desc,
  	(struct usb_descriptor_header *) &uasp_ss_bi_desc,
  	(struct usb_descriptor_header *) &bot_bi_ep_comp_desc,
  	(struct usb_descriptor_header *) &uasp_ss_bo_desc,
  	(struct usb_descriptor_header *) &bot_bo_ep_comp_desc,
  
  	(struct usb_descriptor_header *) &uasp_intf_desc,
  	(struct usb_descriptor_header *) &uasp_ss_bi_desc,
  	(struct usb_descriptor_header *) &uasp_bi_ep_comp_desc,
  	(struct usb_descriptor_header *) &uasp_bi_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_ss_bo_desc,
  	(struct usb_descriptor_header *) &uasp_bo_ep_comp_desc,
  	(struct usb_descriptor_header *) &uasp_bo_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_ss_status_desc,
  	(struct usb_descriptor_header *) &uasp_status_in_ep_comp_desc,
  	(struct usb_descriptor_header *) &uasp_status_pipe_desc,
  	(struct usb_descriptor_header *) &uasp_ss_cmd_desc,
  	(struct usb_descriptor_header *) &uasp_cmd_comp_desc,
  	(struct usb_descriptor_header *) &uasp_cmd_pipe_desc,
  	NULL,
  };
  
  static struct usb_string	tcm_us_strings[] = {
  	[USB_G_STR_INT_UAS].s		= "USB Attached SCSI",
  	[USB_G_STR_INT_BBB].s		= "Bulk Only Transport",
  	{ },
  };
  
  static struct usb_gadget_strings tcm_stringtab = {
  	.language = 0x0409,
  	.strings = tcm_us_strings,
  };
  
  static struct usb_gadget_strings *tcm_strings[] = {
  	&tcm_stringtab,
  	NULL,
  };
  
  static int tcm_bind(struct usb_configuration *c, struct usb_function *f)
  {
  	struct f_uas		*fu = to_f_uas(f);
  	struct usb_string	*us;
  	struct usb_gadget	*gadget = c->cdev->gadget;
  	struct usb_ep		*ep;
  	struct f_tcm_opts	*opts;
  	int			iface;
  	int			ret;
  
  	opts = container_of(f->fi, struct f_tcm_opts, func_inst);
  
  	mutex_lock(&opts->dep_lock);
  	if (!opts->can_attach) {
  		mutex_unlock(&opts->dep_lock);
  		return -ENODEV;
  	}
  	mutex_unlock(&opts->dep_lock);
  	us = usb_gstrings_attach(c->cdev, tcm_strings,
  		ARRAY_SIZE(tcm_us_strings));
  	if (IS_ERR(us))
  		return PTR_ERR(us);
  	bot_intf_desc.iInterface = us[USB_G_STR_INT_BBB].id;
  	uasp_intf_desc.iInterface = us[USB_G_STR_INT_UAS].id;
  
  	iface = usb_interface_id(c, f);
  	if (iface < 0)
  		return iface;
  
  	bot_intf_desc.bInterfaceNumber = iface;
  	uasp_intf_desc.bInterfaceNumber = iface;
  	fu->iface = iface;
  	ep = usb_ep_autoconfig_ss(gadget, &uasp_ss_bi_desc,
  			&uasp_bi_ep_comp_desc);
  	if (!ep)
  		goto ep_fail;
  
  	fu->ep_in = ep;
  
  	ep = usb_ep_autoconfig_ss(gadget, &uasp_ss_bo_desc,
  			&uasp_bo_ep_comp_desc);
  	if (!ep)
  		goto ep_fail;
  	fu->ep_out = ep;
  
  	ep = usb_ep_autoconfig_ss(gadget, &uasp_ss_status_desc,
  			&uasp_status_in_ep_comp_desc);
  	if (!ep)
  		goto ep_fail;
  	fu->ep_status = ep;
  
  	ep = usb_ep_autoconfig_ss(gadget, &uasp_ss_cmd_desc,
  			&uasp_cmd_comp_desc);
  	if (!ep)
  		goto ep_fail;
  	fu->ep_cmd = ep;
  
  	/* Assume endpoint addresses are the same for both speeds */
  	uasp_bi_desc.bEndpointAddress =	uasp_ss_bi_desc.bEndpointAddress;
  	uasp_bo_desc.bEndpointAddress = uasp_ss_bo_desc.bEndpointAddress;
  	uasp_status_desc.bEndpointAddress =
  		uasp_ss_status_desc.bEndpointAddress;
  	uasp_cmd_desc.bEndpointAddress = uasp_ss_cmd_desc.bEndpointAddress;
  
  	uasp_fs_bi_desc.bEndpointAddress = uasp_ss_bi_desc.bEndpointAddress;
  	uasp_fs_bo_desc.bEndpointAddress = uasp_ss_bo_desc.bEndpointAddress;
  	uasp_fs_status_desc.bEndpointAddress =
  		uasp_ss_status_desc.bEndpointAddress;
  	uasp_fs_cmd_desc.bEndpointAddress = uasp_ss_cmd_desc.bEndpointAddress;
  
  	ret = usb_assign_descriptors(f, uasp_fs_function_desc,
  			uasp_hs_function_desc, uasp_ss_function_desc, NULL);
  	if (ret)
  		goto ep_fail;
  
  	return 0;
  ep_fail:
  	pr_err("Can't claim all required eps\n");
  
  	return -ENOTSUPP;
  }
  
  struct guas_setup_wq {
  	struct work_struct work;
  	struct f_uas *fu;
  	unsigned int alt;
  };
  
  static void tcm_delayed_set_alt(struct work_struct *wq)
  {
  	struct guas_setup_wq *work = container_of(wq, struct guas_setup_wq,
  			work);
  	struct f_uas *fu = work->fu;
  	int alt = work->alt;
  
  	kfree(work);
  
  	if (fu->flags & USBG_IS_BOT)
  		bot_cleanup_old_alt(fu);
  	if (fu->flags & USBG_IS_UAS)
  		uasp_cleanup_old_alt(fu);
  
  	if (alt == USB_G_ALT_INT_BBB)
  		bot_set_alt(fu);
  	else if (alt == USB_G_ALT_INT_UAS)
  		uasp_set_alt(fu);
  	usb_composite_setup_continue(fu->function.config->cdev);
  }
  
  static int tcm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
  {
  	struct f_uas *fu = to_f_uas(f);
  
  	if ((alt == USB_G_ALT_INT_BBB) || (alt == USB_G_ALT_INT_UAS)) {
  		struct guas_setup_wq *work;
  
  		work = kmalloc(sizeof(*work), GFP_ATOMIC);
  		if (!work)
  			return -ENOMEM;
  		INIT_WORK(&work->work, tcm_delayed_set_alt);
  		work->fu = fu;
  		work->alt = alt;
  		schedule_work(&work->work);
  		return USB_GADGET_DELAYED_STATUS;
  	}
  	return -EOPNOTSUPP;
  }
  
  static void tcm_disable(struct usb_function *f)
  {
  	struct f_uas *fu = to_f_uas(f);
  
  	if (fu->flags & USBG_IS_UAS)
  		uasp_cleanup_old_alt(fu);
  	else if (fu->flags & USBG_IS_BOT)
  		bot_cleanup_old_alt(fu);
  	fu->flags = 0;
  }
  
  static int tcm_setup(struct usb_function *f,
  		const struct usb_ctrlrequest *ctrl)
  {
  	struct f_uas *fu = to_f_uas(f);
  
  	if (!(fu->flags & USBG_IS_BOT))
  		return -EOPNOTSUPP;
  
  	return usbg_bot_setup(f, ctrl);
  }
  
  static inline struct f_tcm_opts *to_f_tcm_opts(struct config_item *item)
  {
  	return container_of(to_config_group(item), struct f_tcm_opts,
  		func_inst.group);
  }
  
  static void tcm_attr_release(struct config_item *item)
  {
  	struct f_tcm_opts *opts = to_f_tcm_opts(item);
  
  	usb_put_function_instance(&opts->func_inst);
  }
  
  static struct configfs_item_operations tcm_item_ops = {
  	.release		= tcm_attr_release,
  };
  
  static struct config_item_type tcm_func_type = {
  	.ct_item_ops	= &tcm_item_ops,
  	.ct_owner	= THIS_MODULE,
  };
  
  static void tcm_free_inst(struct usb_function_instance *f)
  {
  	struct f_tcm_opts *opts;
  	unsigned i;
  
  	opts = container_of(f, struct f_tcm_opts, func_inst);
  
  	mutex_lock(&tpg_instances_lock);
  	for (i = 0; i < TPG_INSTANCES; ++i)
  		if (tpg_instances[i].func_inst == f)
  			break;
  	if (i < TPG_INSTANCES)
  		tpg_instances[i].func_inst = NULL;
  	mutex_unlock(&tpg_instances_lock);
  
  	kfree(opts);
  }
  
  static int tcm_register_callback(struct usb_function_instance *f)
  {
  	struct f_tcm_opts *opts = container_of(f, struct f_tcm_opts, func_inst);
  
  	mutex_lock(&opts->dep_lock);
  	opts->can_attach = true;
  	mutex_unlock(&opts->dep_lock);
  
  	return 0;
  }
  
  static void tcm_unregister_callback(struct usb_function_instance *f)
  {
  	struct f_tcm_opts *opts = container_of(f, struct f_tcm_opts, func_inst);
  
  	mutex_lock(&opts->dep_lock);
  	unregister_gadget_item(opts->
  		func_inst.group.cg_item.ci_parent->ci_parent);
  	opts->can_attach = false;
  	mutex_unlock(&opts->dep_lock);
  }
  
  static int usbg_attach(struct usbg_tpg *tpg)
  {
  	struct usb_function_instance *f = tpg->fi;
  	struct f_tcm_opts *opts = container_of(f, struct f_tcm_opts, func_inst);
  
  	if (opts->tcm_register_callback)
  		return opts->tcm_register_callback(f);
  
  	return 0;
  }
  
  static void usbg_detach(struct usbg_tpg *tpg)
  {
  	struct usb_function_instance *f = tpg->fi;
  	struct f_tcm_opts *opts = container_of(f, struct f_tcm_opts, func_inst);
  
  	if (opts->tcm_unregister_callback)
  		opts->tcm_unregister_callback(f);
  }
  
  static int tcm_set_name(struct usb_function_instance *f, const char *name)
  {
  	struct f_tcm_opts *opts = container_of(f, struct f_tcm_opts, func_inst);
  
  	pr_debug("tcm: Activating %s\n", name);
  
  	mutex_lock(&opts->dep_lock);
  	opts->ready = true;
  	mutex_unlock(&opts->dep_lock);
  
  	return 0;
  }
  
  static struct usb_function_instance *tcm_alloc_inst(void)
  {
  	struct f_tcm_opts *opts;
  	int i;
  
  
  	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
  	if (!opts)
  		return ERR_PTR(-ENOMEM);
  
  	mutex_lock(&tpg_instances_lock);
  	for (i = 0; i < TPG_INSTANCES; ++i)
  		if (!tpg_instances[i].func_inst)
  			break;
  
  	if (i == TPG_INSTANCES) {
  		mutex_unlock(&tpg_instances_lock);
  		kfree(opts);
  		return ERR_PTR(-EBUSY);
  	}
  	tpg_instances[i].func_inst = &opts->func_inst;
  	mutex_unlock(&tpg_instances_lock);
  
  	mutex_init(&opts->dep_lock);
  	opts->func_inst.set_inst_name = tcm_set_name;
  	opts->func_inst.free_func_inst = tcm_free_inst;
  	opts->tcm_register_callback = tcm_register_callback;
  	opts->tcm_unregister_callback = tcm_unregister_callback;
  
  	config_group_init_type_name(&opts->func_inst.group, "",
  			&tcm_func_type);
  
  	return &opts->func_inst;
  }
  
  static void tcm_free(struct usb_function *f)
  {
  	struct f_uas *tcm = to_f_uas(f);
  
  	kfree(tcm);
  }
  
  static void tcm_unbind(struct usb_configuration *c, struct usb_function *f)
  {
  	usb_free_all_descriptors(f);
  }
  
  static struct usb_function *tcm_alloc(struct usb_function_instance *fi)
  {
  	struct f_uas *fu;
  	unsigned i;
  
  	mutex_lock(&tpg_instances_lock);
  	for (i = 0; i < TPG_INSTANCES; ++i)
  		if (tpg_instances[i].func_inst == fi)
  			break;
  	if (i == TPG_INSTANCES) {
  		mutex_unlock(&tpg_instances_lock);
  		return ERR_PTR(-ENODEV);
  	}
  
  	fu = kzalloc(sizeof(*fu), GFP_KERNEL);
  	if (!fu) {
  		mutex_unlock(&tpg_instances_lock);
  		return ERR_PTR(-ENOMEM);
  	}
  
  	fu->function.name = "Target Function";
  	fu->function.bind = tcm_bind;
  	fu->function.unbind = tcm_unbind;
  	fu->function.set_alt = tcm_set_alt;
  	fu->function.setup = tcm_setup;
  	fu->function.disable = tcm_disable;
  	fu->function.free_func = tcm_free;
  	fu->tpg = tpg_instances[i].tpg;
  	mutex_unlock(&tpg_instances_lock);
  
  	return &fu->function;
  }
  
  DECLARE_USB_FUNCTION(tcm, tcm_alloc_inst, tcm_alloc);
  
  static int tcm_init(void)
  {
  	int ret;
  
  	ret = usb_function_register(&tcmusb_func);
  	if (ret)
  		return ret;
  
  	ret = target_register_template(&usbg_ops);
  	if (ret)
  		usb_function_unregister(&tcmusb_func);
  
  	return ret;
  }
  module_init(tcm_init);
  
  static void tcm_exit(void)
  {
  	target_unregister_template(&usbg_ops);
  	usb_function_unregister(&tcmusb_func);
  }
  module_exit(tcm_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Sebastian Andrzej Siewior");
  