drivers/target/tcm_fc/tfc_cmd.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright (c) 2010 Cisco Systems, Inc.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  */

 /* XXX TBD some includes may be extraneous */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/utsname.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/kthread.h>
 #include <linux/types.h>
 #include <linux/string.h>
 #include <linux/configfs.h>
 #include <linux/ctype.h>
 #include <linux/hash.h>
 #include <linux/percpu_ida.h>
 #include <asm/unaligned.h>
 #include <scsi/scsi_tcq.h>
 #include <scsi/libfc.h>
 #include <scsi/fc_encode.h>

 #include <target/target_core_base.h>
 #include <target/target_core_fabric.h>
 #include <target/target_core_configfs.h>
 #include <target/configfs_macros.h>

 #include "tcm_fc.h"

 /*
  * Dump cmd state for debugging.
  */
 static void _ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
 {
 	struct fc_exch *ep;
 	struct fc_seq *sp;
 	struct se_cmd *se_cmd;
 	struct scatterlist *sg;
 	int count;

 	se_cmd = &cmd->se_cmd;
 	pr_debug("%s: cmd %p sess %p seq %p se_cmd %p\n",
 		caller, cmd, cmd->sess, cmd->seq, se_cmd);

 	pr_debug("%s: cmd %p data_nents %u len %u se_cmd_flags <0x%x>\n",
 		caller, cmd, se_cmd->t_data_nents,
 	       se_cmd->data_length, se_cmd->se_cmd_flags);

 	for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, count)
 		pr_debug("%s: cmd %p sg %p page %p "
 			"len 0x%x off 0x%x\n",
 			caller, cmd, sg,
 			sg_page(sg), sg->length, sg->offset);

 	sp = cmd->seq;
 	if (sp) {
 		ep = fc_seq_exch(sp);
 		pr_debug("%s: cmd %p sid %x did %x "
 			"ox_id %x rx_id %x seq_id %x e_stat %x\n",
 			caller, cmd, ep->sid, ep->did, ep->oxid, ep->rxid,
 			sp->id, ep->esb_stat);
 	}
 }

 void ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
 {
 	if (unlikely(ft_debug_logging))
 		_ft_dump_cmd(cmd, caller);
 }

 static void ft_free_cmd(struct ft_cmd *cmd)
 {
 	struct fc_frame *fp;
 	struct fc_lport *lport;
 	struct ft_sess *sess;

 	if (!cmd)
 		return;
 	sess = cmd->sess;
 	fp = cmd->req_frame;
 	lport = fr_dev(fp);
 	if (fr_seq(fp))
 		lport->tt.seq_release(fr_seq(fp));
 	fc_frame_free(fp);
 	percpu_ida_free(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag);
 	ft_sess_put(sess);	/* undo get from lookup at recv */
 }

 void ft_release_cmd(struct se_cmd *se_cmd)
 {
 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);

 	ft_free_cmd(cmd);
 }

 int ft_check_stop_free(struct se_cmd *se_cmd)
 {
 	transport_generic_free_cmd(se_cmd, 0);
 	return 1;
 }

 /*
  * Send response.
  */
 int ft_queue_status(struct se_cmd *se_cmd)
 {
 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
 	struct fc_frame *fp;
 	struct fcp_resp_with_ext *fcp;
 	struct fc_lport *lport;
 	struct fc_exch *ep;
 	size_t len;
 	int rc;

 	if (cmd->aborted)
 		return 0;
 	ft_dump_cmd(cmd, __func__);
 	ep = fc_seq_exch(cmd->seq);
 	lport = ep->lp;
 	len = sizeof(*fcp) + se_cmd->scsi_sense_length;
 	fp = fc_frame_alloc(lport, len);
 	if (!fp) {
 		se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
 		return -ENOMEM;
 	}

 	fcp = fc_frame_payload_get(fp, len);
 	memset(fcp, 0, len);
 	fcp->resp.fr_status = se_cmd->scsi_status;

 	len = se_cmd->scsi_sense_length;
 	if (len) {
 		fcp->resp.fr_flags |= FCP_SNS_LEN_VAL;
 		fcp->ext.fr_sns_len = htonl(len);
 		memcpy((fcp + 1), se_cmd->sense_buffer, len);
 	}

 	/*
 	 * Test underflow and overflow with one mask.  Usually both are off.
 	 * Bidirectional commands are not handled yet.
 	 */
 	if (se_cmd->se_cmd_flags & (SCF_OVERFLOW_BIT | SCF_UNDERFLOW_BIT)) {
 		if (se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT)
 			fcp->resp.fr_flags |= FCP_RESID_OVER;
 		else
 			fcp->resp.fr_flags |= FCP_RESID_UNDER;
 		fcp->ext.fr_resid = cpu_to_be32(se_cmd->residual_count);
 	}

 	/*
 	 * Send response.
 	 */
 	cmd->seq = lport->tt.seq_start_next(cmd->seq);
 	fc_fill_fc_hdr(fp, FC_RCTL_DD_CMD_STATUS, ep->did, ep->sid, FC_TYPE_FCP,
 		       FC_FC_EX_CTX | FC_FC_LAST_SEQ | FC_FC_END_SEQ, 0);

 	rc = lport->tt.seq_send(lport, cmd->seq, fp);
 	if (rc) {
 		pr_info_ratelimited("%s: Failed to send response frame %p, "
 				    "xid <0x%x>\n", __func__, fp, ep->xid);
 		/*
 		 * Generate a TASK_SET_FULL status to notify the initiator
 		 * to reduce it's queue_depth after the se_cmd response has
 		 * been re-queued by target-core.
 		 */
 		se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
 		return -ENOMEM;
 	}
 	lport->tt.exch_done(cmd->seq);
 	return 0;
 }

 int ft_write_pending_status(struct se_cmd *se_cmd)
 {
 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);

 	return cmd->write_data_len != se_cmd->data_length;
 }

 /*
  * Send TX_RDY (transfer ready).
  */
 int ft_write_pending(struct se_cmd *se_cmd)
 {
 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
 	struct fc_frame *fp;
 	struct fcp_txrdy *txrdy;
 	struct fc_lport *lport;
 	struct fc_exch *ep;
 	struct fc_frame_header *fh;
 	u32 f_ctl;

 	ft_dump_cmd(cmd, __func__);

 	if (cmd->aborted)
 		return 0;
 	ep = fc_seq_exch(cmd->seq);
 	lport = ep->lp;
 	fp = fc_frame_alloc(lport, sizeof(*txrdy));
 	if (!fp)
 		return -ENOMEM; /* Signal QUEUE_FULL */

 	txrdy = fc_frame_payload_get(fp, sizeof(*txrdy));
 	memset(txrdy, 0, sizeof(*txrdy));
 	txrdy->ft_burst_len = htonl(se_cmd->data_length);

 	cmd->seq = lport->tt.seq_start_next(cmd->seq);
 	fc_fill_fc_hdr(fp, FC_RCTL_DD_DATA_DESC, ep->did, ep->sid, FC_TYPE_FCP,
 		       FC_FC_EX_CTX | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);

 	fh = fc_frame_header_get(fp);
 	f_ctl = ntoh24(fh->fh_f_ctl);

 	/* Only if it is 'Exchange Responder' */
 	if (f_ctl & FC_FC_EX_CTX) {
 		/* Target is 'exchange responder' and sending XFER_READY
 		 * to 'exchange initiator (initiator)'
 		 */
 		if ((ep->xid <= lport->lro_xid) &&
 		    (fh->fh_r_ctl == FC_RCTL_DD_DATA_DESC)) {
 			if ((se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
 			    lport->tt.ddp_target(lport, ep->xid,
 						 se_cmd->t_data_sg,
 						 se_cmd->t_data_nents))
 				cmd->was_ddp_setup = 1;
 		}
 	}
 	lport->tt.seq_send(lport, cmd->seq, fp);
 	return 0;
 }

 u32 ft_get_task_tag(struct se_cmd *se_cmd)
 {
 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);

 	if (cmd->aborted)
 		return ~0;
 	return fc_seq_exch(cmd->seq)->rxid;
 }

 int ft_get_cmd_state(struct se_cmd *se_cmd)
 {
 	return 0;
 }

 /*
  * FC sequence response handler for follow-on sequences (data) and aborts.
  */
 static void ft_recv_seq(struct fc_seq *sp, struct fc_frame *fp, void *arg)
 {
 	struct ft_cmd *cmd = arg;
 	struct fc_frame_header *fh;

 	if (unlikely(IS_ERR(fp))) {
 		/* XXX need to find cmd if queued */
 		cmd->seq = NULL;
 		cmd->aborted = true;
 		return;
 	}

 	fh = fc_frame_header_get(fp);

 	switch (fh->fh_r_ctl) {
 	case FC_RCTL_DD_SOL_DATA:	/* write data */
 		ft_recv_write_data(cmd, fp);
 		break;
 	case FC_RCTL_DD_UNSOL_CTL:	/* command */
 	case FC_RCTL_DD_SOL_CTL:	/* transfer ready */
 	case FC_RCTL_DD_DATA_DESC:	/* transfer ready */
 	default:
 		pr_debug("%s: unhandled frame r_ctl %x\n",
 		       __func__, fh->fh_r_ctl);
 		ft_invl_hw_context(cmd);
 		fc_frame_free(fp);
 		transport_generic_free_cmd(&cmd->se_cmd, 0);
 		break;
 	}
 }

 /*
  * Send a FCP response including SCSI status and optional FCP rsp_code.
  * status is SAM_STAT_GOOD (zero) iff code is valid.
  * This is used in error cases, such as allocation failures.
  */
 static void ft_send_resp_status(struct fc_lport *lport,
 				const struct fc_frame *rx_fp,
 				u32 status, enum fcp_resp_rsp_codes code)
 {
 	struct fc_frame *fp;
 	struct fc_seq *sp;
 	const struct fc_frame_header *fh;
 	size_t len;
 	struct fcp_resp_with_ext *fcp;
 	struct fcp_resp_rsp_info *info;

 	fh = fc_frame_header_get(rx_fp);
 	pr_debug("FCP error response: did %x oxid %x status %x code %x\n",
 		  ntoh24(fh->fh_s_id), ntohs(fh->fh_ox_id), status, code);
 	len = sizeof(*fcp);
 	if (status == SAM_STAT_GOOD)
 		len += sizeof(*info);
 	fp = fc_frame_alloc(lport, len);
 	if (!fp)
 		return;
 	fcp = fc_frame_payload_get(fp, len);
 	memset(fcp, 0, len);
 	fcp->resp.fr_status = status;
 	if (status == SAM_STAT_GOOD) {
 		fcp->ext.fr_rsp_len = htonl(sizeof(*info));
 		fcp->resp.fr_flags |= FCP_RSP_LEN_VAL;
 		info = (struct fcp_resp_rsp_info *)(fcp + 1);
 		info->rsp_code = code;
 	}

 	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_DD_CMD_STATUS, 0);
 	sp = fr_seq(fp);
 	if (sp) {
 		lport->tt.seq_send(lport, sp, fp);
 		lport->tt.exch_done(sp);
 	} else {
 		lport->tt.frame_send(lport, fp);
 	}
 }

 /*
  * Send error or task management response.
  */
 static void ft_send_resp_code(struct ft_cmd *cmd,
 			      enum fcp_resp_rsp_codes code)
 {
 	ft_send_resp_status(cmd->sess->tport->lport,
 			    cmd->req_frame, SAM_STAT_GOOD, code);
 }


 /*
  * Send error or task management response.
  * Always frees the cmd and associated state.
  */
 static void ft_send_resp_code_and_free(struct ft_cmd *cmd,
 				      enum fcp_resp_rsp_codes code)
 {
 	ft_send_resp_code(cmd, code);
 	ft_free_cmd(cmd);
 }

 /*
  * Handle Task Management Request.
  */
 static void ft_send_tm(struct ft_cmd *cmd)
 {
 	struct fcp_cmnd *fcp;
 	int rc;
 	u8 tm_func;

 	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));

 	switch (fcp->fc_tm_flags) {
 	case FCP_TMF_LUN_RESET:
 		tm_func = TMR_LUN_RESET;
 		break;
 	case FCP_TMF_TGT_RESET:
 		tm_func = TMR_TARGET_WARM_RESET;
 		break;
 	case FCP_TMF_CLR_TASK_SET:
 		tm_func = TMR_CLEAR_TASK_SET;
 		break;
 	case FCP_TMF_ABT_TASK_SET:
 		tm_func = TMR_ABORT_TASK_SET;
 		break;
 	case FCP_TMF_CLR_ACA:
 		tm_func = TMR_CLEAR_ACA;
 		break;
 	default:
 		/*
 		 * FCP4r01 indicates having a combination of
 		 * tm_flags set is invalid.
 		 */
 		pr_debug("invalid FCP tm_flags %x\n", fcp->fc_tm_flags);
 		ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
 		return;
 	}

 	/* FIXME: Add referenced task tag for ABORT_TASK */
 	rc = target_submit_tmr(&cmd->se_cmd, cmd->sess->se_sess,
 		&cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
 		cmd, tm_func, GFP_KERNEL, 0, 0);
 	if (rc < 0)
 		ft_send_resp_code_and_free(cmd, FCP_TMF_FAILED);
 }

 /*
  * Send status from completed task management request.
  */
 void ft_queue_tm_resp(struct se_cmd *se_cmd)
 {
 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
 	struct se_tmr_req *tmr = se_cmd->se_tmr_req;
 	enum fcp_resp_rsp_codes code;

 	if (cmd->aborted)
 		return;
 	switch (tmr->response) {
 	case TMR_FUNCTION_COMPLETE:
 		code = FCP_TMF_CMPL;
 		break;
 	case TMR_LUN_DOES_NOT_EXIST:
 		code = FCP_TMF_INVALID_LUN;
 		break;
 	case TMR_FUNCTION_REJECTED:
 		code = FCP_TMF_REJECTED;
 		break;
 	case TMR_TASK_DOES_NOT_EXIST:
 	case TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED:
 	default:
 		code = FCP_TMF_FAILED;
 		break;
 	}
 	pr_debug("tmr fn %d resp %d fcp code %d\n",
 		  tmr->function, tmr->response, code);
 	ft_send_resp_code(cmd, code);
 }

 void ft_aborted_task(struct se_cmd *se_cmd)
 {
 	return;
 }

 static void ft_send_work(struct work_struct *work);

 /*
  * Handle incoming FCP command.
  */
 static void ft_recv_cmd(struct ft_sess *sess, struct fc_frame *fp)
 {
 	struct ft_cmd *cmd;
 	struct fc_lport *lport = sess->tport->lport;
 	struct se_session *se_sess = sess->se_sess;
 	int tag;

 	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
 	if (tag < 0)
 		goto busy;

 	cmd = &((struct ft_cmd *)se_sess->sess_cmd_map)[tag];
 	memset(cmd, 0, sizeof(struct ft_cmd));

 	cmd->se_cmd.map_tag = tag;
 	cmd->sess = sess;
 	cmd->seq = lport->tt.seq_assign(lport, fp);
 	if (!cmd->seq) {
 		percpu_ida_free(&se_sess->sess_tag_pool, tag);
 		goto busy;
 	}
 	cmd->req_frame = fp;		/* hold frame during cmd */

 	INIT_WORK(&cmd->work, ft_send_work);
 	queue_work(sess->tport->tpg->workqueue, &cmd->work);
 	return;

 busy:
 	pr_debug("cmd or seq allocation failure - sending BUSY\n");
 	ft_send_resp_status(lport, fp, SAM_STAT_BUSY, 0);
 	fc_frame_free(fp);
 	ft_sess_put(sess);		/* undo get from lookup */
 }


 /*
  * Handle incoming FCP frame.
  * Caller has verified that the frame is type FCP.
  */
 void ft_recv_req(struct ft_sess *sess, struct fc_frame *fp)
 {
 	struct fc_frame_header *fh = fc_frame_header_get(fp);

 	switch (fh->fh_r_ctl) {
 	case FC_RCTL_DD_UNSOL_CMD:	/* command */
 		ft_recv_cmd(sess, fp);
 		break;
 	case FC_RCTL_DD_SOL_DATA:	/* write data */
 	case FC_RCTL_DD_UNSOL_CTL:
 	case FC_RCTL_DD_SOL_CTL:
 	case FC_RCTL_DD_DATA_DESC:	/* transfer ready */
 	case FC_RCTL_ELS4_REQ:		/* SRR, perhaps */
 	default:
 		pr_debug("%s: unhandled frame r_ctl %x\n",
 		       __func__, fh->fh_r_ctl);
 		fc_frame_free(fp);
 		ft_sess_put(sess);	/* undo get from lookup */
 		break;
 	}
 }

 /*
  * Send new command to target.
  */
 static void ft_send_work(struct work_struct *work)
 {
 	struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
 	struct fc_frame_header *fh = fc_frame_header_get(cmd->req_frame);
 	struct fcp_cmnd *fcp;
 	int data_dir = 0;
 	int task_attr;

 	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));
 	if (!fcp)
 		goto err;

 	if (fcp->fc_flags & FCP_CFL_LEN_MASK)
 		goto err;		/* not handling longer CDBs yet */

 	/*
 	 * Check for FCP task management flags
 	 */
 	if (fcp->fc_tm_flags) {
 		ft_send_tm(cmd);
 		return;
 	}

 	switch (fcp->fc_flags & (FCP_CFL_RDDATA | FCP_CFL_WRDATA)) {
 	case 0:
 		data_dir = DMA_NONE;
 		break;
 	case FCP_CFL_RDDATA:
 		data_dir = DMA_FROM_DEVICE;
 		break;
 	case FCP_CFL_WRDATA:
 		data_dir = DMA_TO_DEVICE;
 		break;
 	case FCP_CFL_WRDATA | FCP_CFL_RDDATA:
 		goto err;	/* TBD not supported by tcm_fc yet */
 	}
 	/*
 	 * Locate the SAM Task Attr from fc_pri_ta
 	 */
 	switch (fcp->fc_pri_ta & FCP_PTA_MASK) {
 	case FCP_PTA_HEADQ:
 		task_attr = TCM_HEAD_TAG;
 		break;
 	case FCP_PTA_ORDERED:
 		task_attr = TCM_ORDERED_TAG;
 		break;
 	case FCP_PTA_ACA:
 		task_attr = TCM_ACA_TAG;
 		break;
 	case FCP_PTA_SIMPLE: /* Fallthrough */
 	default:
 		task_attr = TCM_SIMPLE_TAG;
 	}

 	fc_seq_exch(cmd->seq)->lp->tt.seq_set_resp(cmd->seq, ft_recv_seq, cmd);
 	/*
 	 * Use a single se_cmd->cmd_kref as we expect to release se_cmd
 	 * directly from ft_check_stop_free callback in response path.
 	 */
 	if (target_submit_cmd(&cmd->se_cmd, cmd->sess->se_sess, fcp->fc_cdb,
 			      &cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
 			      ntohl(fcp->fc_dl), task_attr, data_dir, 0))
 		goto err;

 	pr_debug("r_ctl %x alloc target_submit_cmd\n", fh->fh_r_ctl);
 	return;

 err:
 	ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
 }
	/*
	* Copyright (c) 2010 Cisco Systems, Inc.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
	*/

	/* XXX TBD some includes may be extraneous */

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/utsname.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/kthread.h>
	#include <linux/types.h>
	#include <linux/string.h>
	#include <linux/configfs.h>
	#include <linux/ctype.h>
	#include <linux/hash.h>
	#include <linux/percpu_ida.h>
	#include <asm/unaligned.h>
	#include <scsi/scsi_tcq.h>
	#include <scsi/libfc.h>
	#include <scsi/fc_encode.h>

	#include <target/target_core_base.h>
	#include <target/target_core_fabric.h>
	#include <target/target_core_configfs.h>
	#include <target/configfs_macros.h>

	#include "tcm_fc.h"

	/*
	* Dump cmd state for debugging.
	*/
	static void _ft_dump_cmd(struct ft_cmd cmd, const char caller)
	{
	struct fc_exch *ep;
	struct fc_seq *sp;
	struct se_cmd *se_cmd;
	struct scatterlist *sg;
	int count;

	se_cmd = &cmd->se_cmd;
	pr_debug("%s: cmd %p sess %p seq %p se_cmd %p\n",
	caller, cmd, cmd->sess, cmd->seq, se_cmd);

	pr_debug("%s: cmd %p data_nents %u len %u se_cmd_flags <0x%x>\n",
	caller, cmd, se_cmd->t_data_nents,
	se_cmd->data_length, se_cmd->se_cmd_flags);

	for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, count)
	pr_debug("%s: cmd %p sg %p page %p "
	"len 0x%x off 0x%x\n",
	caller, cmd, sg,
	sg_page(sg), sg->length, sg->offset);

	sp = cmd->seq;
	if (sp) {
	ep = fc_seq_exch(sp);
	pr_debug("%s: cmd %p sid %x did %x "
	"ox_id %x rx_id %x seq_id %x e_stat %x\n",
	caller, cmd, ep->sid, ep->did, ep->oxid, ep->rxid,
	sp->id, ep->esb_stat);
	}
	}

	void ft_dump_cmd(struct ft_cmd cmd, const char caller)
	{
	if (unlikely(ft_debug_logging))
	_ft_dump_cmd(cmd, caller);
	}

	static void ft_free_cmd(struct ft_cmd *cmd)
	{
	struct fc_frame *fp;
	struct fc_lport *lport;
	struct ft_sess *sess;

	if (!cmd)
	return;
	sess = cmd->sess;
	fp = cmd->req_frame;
	lport = fr_dev(fp);
	if (fr_seq(fp))
	lport->tt.seq_release(fr_seq(fp));
	fc_frame_free(fp);
	percpu_ida_free(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag);
	ft_sess_put(sess); /* undo get from lookup at recv */
	}

	void ft_release_cmd(struct se_cmd *se_cmd)
	{
	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);

	ft_free_cmd(cmd);
	}

	int ft_check_stop_free(struct se_cmd *se_cmd)
	{
	transport_generic_free_cmd(se_cmd, 0);
	return 1;
	}

	/*
	* Send response.
	*/
	int ft_queue_status(struct se_cmd *se_cmd)
	{
	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
	struct fc_frame *fp;
	struct fcp_resp_with_ext *fcp;
	struct fc_lport *lport;
	struct fc_exch *ep;
	size_t len;
	int rc;

	if (cmd->aborted)
	return 0;
	ft_dump_cmd(cmd, __func__);
	ep = fc_seq_exch(cmd->seq);
	lport = ep->lp;
	len = sizeof(*fcp) + se_cmd->scsi_sense_length;
	fp = fc_frame_alloc(lport, len);
	if (!fp) {
	se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
	return -ENOMEM;
	}

	fcp = fc_frame_payload_get(fp, len);
	memset(fcp, 0, len);
	fcp->resp.fr_status = se_cmd->scsi_status;

	len = se_cmd->scsi_sense_length;
	if (len) {
	fcp->resp.fr_flags \|= FCP_SNS_LEN_VAL;
	fcp->ext.fr_sns_len = htonl(len);
	memcpy((fcp + 1), se_cmd->sense_buffer, len);
	}

	/*
	* Test underflow and overflow with one mask. Usually both are off.
	* Bidirectional commands are not handled yet.
	*/
	if (se_cmd->se_cmd_flags & (SCF_OVERFLOW_BIT \| SCF_UNDERFLOW_BIT)) {
	if (se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT)
	fcp->resp.fr_flags \|= FCP_RESID_OVER;
	else
	fcp->resp.fr_flags \|= FCP_RESID_UNDER;
	fcp->ext.fr_resid = cpu_to_be32(se_cmd->residual_count);
	}

	/*
	* Send response.
	*/
	cmd->seq = lport->tt.seq_start_next(cmd->seq);
	fc_fill_fc_hdr(fp, FC_RCTL_DD_CMD_STATUS, ep->did, ep->sid, FC_TYPE_FCP,
	FC_FC_EX_CTX \| FC_FC_LAST_SEQ \| FC_FC_END_SEQ, 0);

	rc = lport->tt.seq_send(lport, cmd->seq, fp);
	if (rc) {
	pr_info_ratelimited("%s: Failed to send response frame %p, "
	"xid <0x%x>\n", __func__, fp, ep->xid);
	/*
	* Generate a TASK_SET_FULL status to notify the initiator
	* to reduce it's queue_depth after the se_cmd response has
	* been re-queued by target-core.
	*/
	se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
	return -ENOMEM;
	}
	lport->tt.exch_done(cmd->seq);
	return 0;
	}

	int ft_write_pending_status(struct se_cmd *se_cmd)
	{
	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);

	return cmd->write_data_len != se_cmd->data_length;
	}

	/*
	* Send TX_RDY (transfer ready).
	*/
	int ft_write_pending(struct se_cmd *se_cmd)
	{
	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
	struct fc_frame *fp;
	struct fcp_txrdy *txrdy;
	struct fc_lport *lport;
	struct fc_exch *ep;
	struct fc_frame_header *fh;
	u32 f_ctl;

	ft_dump_cmd(cmd, __func__);

	if (cmd->aborted)
	return 0;
	ep = fc_seq_exch(cmd->seq);
	lport = ep->lp;
	fp = fc_frame_alloc(lport, sizeof(*txrdy));
	if (!fp)
	return -ENOMEM; /* Signal QUEUE_FULL */

	txrdy = fc_frame_payload_get(fp, sizeof(*txrdy));
	memset(txrdy, 0, sizeof(*txrdy));
	txrdy->ft_burst_len = htonl(se_cmd->data_length);

	cmd->seq = lport->tt.seq_start_next(cmd->seq);
	fc_fill_fc_hdr(fp, FC_RCTL_DD_DATA_DESC, ep->did, ep->sid, FC_TYPE_FCP,
	FC_FC_EX_CTX \| FC_FC_END_SEQ \| FC_FC_SEQ_INIT, 0);

	fh = fc_frame_header_get(fp);
	f_ctl = ntoh24(fh->fh_f_ctl);

	/* Only if it is 'Exchange Responder' */
	if (f_ctl & FC_FC_EX_CTX) {
	/* Target is 'exchange responder' and sending XFER_READY
	* to 'exchange initiator (initiator)'
	*/
	if ((ep->xid <= lport->lro_xid) &&
	(fh->fh_r_ctl == FC_RCTL_DD_DATA_DESC)) {
	if ((se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
	lport->tt.ddp_target(lport, ep->xid,
	se_cmd->t_data_sg,
	se_cmd->t_data_nents))
	cmd->was_ddp_setup = 1;
	}
	}
	lport->tt.seq_send(lport, cmd->seq, fp);
	return 0;
	}

	u32 ft_get_task_tag(struct se_cmd *se_cmd)
	{
	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);

	if (cmd->aborted)
	return ~0;
	return fc_seq_exch(cmd->seq)->rxid;
	}

	int ft_get_cmd_state(struct se_cmd *se_cmd)
	{
	return 0;
	}

	/*
	* FC sequence response handler for follow-on sequences (data) and aborts.
	*/
	static void ft_recv_seq(struct fc_seq sp, struct fc_frame fp, void *arg)
	{
	struct ft_cmd *cmd = arg;
	struct fc_frame_header *fh;

	if (unlikely(IS_ERR(fp))) {
	/* XXX need to find cmd if queued */
	cmd->seq = NULL;
	cmd->aborted = true;
	return;
	}

	fh = fc_frame_header_get(fp);

	switch (fh->fh_r_ctl) {
	case FC_RCTL_DD_SOL_DATA: /* write data */
	ft_recv_write_data(cmd, fp);
	break;
	case FC_RCTL_DD_UNSOL_CTL: /* command */
	case FC_RCTL_DD_SOL_CTL: /* transfer ready */
	case FC_RCTL_DD_DATA_DESC: /* transfer ready */
	default:
	pr_debug("%s: unhandled frame r_ctl %x\n",
	__func__, fh->fh_r_ctl);
	ft_invl_hw_context(cmd);
	fc_frame_free(fp);
	transport_generic_free_cmd(&cmd->se_cmd, 0);
	break;
	}
	}

	/*
	* Send a FCP response including SCSI status and optional FCP rsp_code.
	* status is SAM_STAT_GOOD (zero) iff code is valid.
	* This is used in error cases, such as allocation failures.
	*/
	static void ft_send_resp_status(struct fc_lport *lport,
	const struct fc_frame *rx_fp,
	u32 status, enum fcp_resp_rsp_codes code)
	{
	struct fc_frame *fp;
	struct fc_seq *sp;
	const struct fc_frame_header *fh;
	size_t len;
	struct fcp_resp_with_ext *fcp;
	struct fcp_resp_rsp_info *info;

	fh = fc_frame_header_get(rx_fp);
	pr_debug("FCP error response: did %x oxid %x status %x code %x\n",
	ntoh24(fh->fh_s_id), ntohs(fh->fh_ox_id), status, code);
	len = sizeof(*fcp);
	if (status == SAM_STAT_GOOD)
	len += sizeof(*info);
	fp = fc_frame_alloc(lport, len);
	if (!fp)
	return;
	fcp = fc_frame_payload_get(fp, len);
	memset(fcp, 0, len);
	fcp->resp.fr_status = status;
	if (status == SAM_STAT_GOOD) {
	fcp->ext.fr_rsp_len = htonl(sizeof(*info));
	fcp->resp.fr_flags \|= FCP_RSP_LEN_VAL;
	info = (struct fcp_resp_rsp_info *)(fcp + 1);
	info->rsp_code = code;
	}

	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_DD_CMD_STATUS, 0);
	sp = fr_seq(fp);
	if (sp) {
	lport->tt.seq_send(lport, sp, fp);
	lport->tt.exch_done(sp);
	} else {
	lport->tt.frame_send(lport, fp);
	}
	}

	/*
	* Send error or task management response.
	*/
	static void ft_send_resp_code(struct ft_cmd *cmd,
	enum fcp_resp_rsp_codes code)
	{
	ft_send_resp_status(cmd->sess->tport->lport,
	cmd->req_frame, SAM_STAT_GOOD, code);
	}


	/*
	* Send error or task management response.
	* Always frees the cmd and associated state.
	*/
	static void ft_send_resp_code_and_free(struct ft_cmd *cmd,
	enum fcp_resp_rsp_codes code)
	{
	ft_send_resp_code(cmd, code);
	ft_free_cmd(cmd);
	}

	/*
	* Handle Task Management Request.
	*/
	static void ft_send_tm(struct ft_cmd *cmd)
	{
	struct fcp_cmnd *fcp;
	int rc;
	u8 tm_func;

	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));

	switch (fcp->fc_tm_flags) {
	case FCP_TMF_LUN_RESET:
	tm_func = TMR_LUN_RESET;
	break;
	case FCP_TMF_TGT_RESET:
	tm_func = TMR_TARGET_WARM_RESET;
	break;
	case FCP_TMF_CLR_TASK_SET:
	tm_func = TMR_CLEAR_TASK_SET;
	break;
	case FCP_TMF_ABT_TASK_SET:
	tm_func = TMR_ABORT_TASK_SET;
	break;
	case FCP_TMF_CLR_ACA:
	tm_func = TMR_CLEAR_ACA;
	break;
	default:
	/*
	* FCP4r01 indicates having a combination of
	* tm_flags set is invalid.
	*/
	pr_debug("invalid FCP tm_flags %x\n", fcp->fc_tm_flags);
	ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
	return;
	}

	/* FIXME: Add referenced task tag for ABORT_TASK */
	rc = target_submit_tmr(&cmd->se_cmd, cmd->sess->se_sess,
	&cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
	cmd, tm_func, GFP_KERNEL, 0, 0);
	if (rc < 0)
	ft_send_resp_code_and_free(cmd, FCP_TMF_FAILED);
	}

	/*
	* Send status from completed task management request.
	*/
	void ft_queue_tm_resp(struct se_cmd *se_cmd)
	{
	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
	struct se_tmr_req *tmr = se_cmd->se_tmr_req;
	enum fcp_resp_rsp_codes code;

	if (cmd->aborted)
	return;
	switch (tmr->response) {
	case TMR_FUNCTION_COMPLETE:
	code = FCP_TMF_CMPL;
	break;
	case TMR_LUN_DOES_NOT_EXIST:
	code = FCP_TMF_INVALID_LUN;
	break;
	case TMR_FUNCTION_REJECTED:
	code = FCP_TMF_REJECTED;
	break;
	case TMR_TASK_DOES_NOT_EXIST:
	case TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED:
	default:
	code = FCP_TMF_FAILED;
	break;
	}
	pr_debug("tmr fn %d resp %d fcp code %d\n",
	tmr->function, tmr->response, code);
	ft_send_resp_code(cmd, code);
	}

	void ft_aborted_task(struct se_cmd *se_cmd)
	{
	return;
	}

	static void ft_send_work(struct work_struct *work);

	/*
	* Handle incoming FCP command.
	*/
	static void ft_recv_cmd(struct ft_sess sess, struct fc_frame fp)
	{
	struct ft_cmd *cmd;
	struct fc_lport *lport = sess->tport->lport;
	struct se_session *se_sess = sess->se_sess;
	int tag;

	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
	if (tag < 0)
	goto busy;

	cmd = &((struct ft_cmd *)se_sess->sess_cmd_map)[tag];
	memset(cmd, 0, sizeof(struct ft_cmd));

	cmd->se_cmd.map_tag = tag;
	cmd->sess = sess;
	cmd->seq = lport->tt.seq_assign(lport, fp);
	if (!cmd->seq) {
	percpu_ida_free(&se_sess->sess_tag_pool, tag);
	goto busy;
	}
	cmd->req_frame = fp; /* hold frame during cmd */

	INIT_WORK(&cmd->work, ft_send_work);
	queue_work(sess->tport->tpg->workqueue, &cmd->work);
	return;

	busy:
	pr_debug("cmd or seq allocation failure - sending BUSY\n");
	ft_send_resp_status(lport, fp, SAM_STAT_BUSY, 0);
	fc_frame_free(fp);
	ft_sess_put(sess); /* undo get from lookup */
	}


	/*
	* Handle incoming FCP frame.
	* Caller has verified that the frame is type FCP.
	*/
	void ft_recv_req(struct ft_sess sess, struct fc_frame fp)
	{
	struct fc_frame_header *fh = fc_frame_header_get(fp);

	switch (fh->fh_r_ctl) {
	case FC_RCTL_DD_UNSOL_CMD: /* command */
	ft_recv_cmd(sess, fp);
	break;
	case FC_RCTL_DD_SOL_DATA: /* write data */
	case FC_RCTL_DD_UNSOL_CTL:
	case FC_RCTL_DD_SOL_CTL:
	case FC_RCTL_DD_DATA_DESC: /* transfer ready */
	case FC_RCTL_ELS4_REQ: /* SRR, perhaps */
	default:
	pr_debug("%s: unhandled frame r_ctl %x\n",
	__func__, fh->fh_r_ctl);
	fc_frame_free(fp);
	ft_sess_put(sess); /* undo get from lookup */
	break;
	}
	}

	/*
	* Send new command to target.
	*/
	static void ft_send_work(struct work_struct *work)
	{
	struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
	struct fc_frame_header *fh = fc_frame_header_get(cmd->req_frame);
	struct fcp_cmnd *fcp;
	int data_dir = 0;
	int task_attr;

	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));
	if (!fcp)
	goto err;

	if (fcp->fc_flags & FCP_CFL_LEN_MASK)
	goto err; /* not handling longer CDBs yet */

	/*
	* Check for FCP task management flags
	*/
	if (fcp->fc_tm_flags) {
	ft_send_tm(cmd);
	return;
	}

	switch (fcp->fc_flags & (FCP_CFL_RDDATA \| FCP_CFL_WRDATA)) {
	case 0:
	data_dir = DMA_NONE;
	break;
	case FCP_CFL_RDDATA:
	data_dir = DMA_FROM_DEVICE;
	break;
	case FCP_CFL_WRDATA:
	data_dir = DMA_TO_DEVICE;
	break;
	case FCP_CFL_WRDATA \| FCP_CFL_RDDATA:
	goto err; /* TBD not supported by tcm_fc yet */
	}
	/*
	* Locate the SAM Task Attr from fc_pri_ta
	*/
	switch (fcp->fc_pri_ta & FCP_PTA_MASK) {
	case FCP_PTA_HEADQ:
	task_attr = TCM_HEAD_TAG;
	break;
	case FCP_PTA_ORDERED:
	task_attr = TCM_ORDERED_TAG;
	break;
	case FCP_PTA_ACA:
	task_attr = TCM_ACA_TAG;
	break;
	case FCP_PTA_SIMPLE: /* Fallthrough */
	default:
	task_attr = TCM_SIMPLE_TAG;
	}

	fc_seq_exch(cmd->seq)->lp->tt.seq_set_resp(cmd->seq, ft_recv_seq, cmd);
	/*
	* Use a single se_cmd->cmd_kref as we expect to release se_cmd
	* directly from ft_check_stop_free callback in response path.
	*/
	if (target_submit_cmd(&cmd->se_cmd, cmd->sess->se_sess, fcp->fc_cdb,
	&cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
	ntohl(fcp->fc_dl), task_attr, data_dir, 0))
	goto err;

	pr_debug("r_ctl %x alloc target_submit_cmd\n", fh->fh_r_ctl);
	return;

	err:
	ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
	}