[SCSI] tcm_fc: Adding FC_FC4 provider (tcm_fc) for FCoE target (TCM - target core) support

This is a comprehensive patch for FC-FC4 provider. tcm_fc is a FC-FC4
provider which glues target core (TCM) with Fiber channel library
(libfc). tcm_fc uses existing FC4 provider hooks from Fiber channel
library. This Fiber channel library is used by FCoE (transport - FC
over Ethernet) protocol driver as well.

Combination of modules such as Fiber channel library, tcm_fc, TCM
target core, and FCoE protocol driver enables functional FCoE target.

This patch includes initial commit for tcm_fc plus additional
enhancement, bug fixes.

This tcm_fc module essentially contains 3 entry points such as "prli",
"prlo", "recv".  When process login request (ELS_PRLI) request is
received, Fiber channel library (libfc) module calls passive providers
(FC-FC4, tcm_fc) (if any registered) "prli" function. Likewise when
LOGO request is received, "prlo" function of passive provider is
invoked by libfc.  For all other request (e.g. any read/write, task
management, LUN inquiry commands), "recv" function of passiver
provider is invoked by libfc. Those passive providers "prli, prlo,
recv" functions interact with TCM target core for requested operation.

This module was primarily developed by "Joe Eykholt" and there were
significant contributions from the people listed under signed-off.

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Kiran Patil <kiran.patil@intel.com>

Acked-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <jbottomley@parallels.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 696 insertions, 0 deletions

diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
new file mode 100644
index 000000000000..49e51778f733
--- /dev/null
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -0,0 +1,696 @@
+/*
+ * 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/version.h>
+#include <generated/utsrelease.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 <asm/unaligned.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/libfc.h>
+#include <scsi/fc_encode.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_transport.h>
+#include <target/target_core_fabric_ops.h>
+#include <target/target_core_device.h>
+#include <target/target_core_tpg.h>
+#include <target/target_core_configfs.h>
+#include <target/target_core_base.h>
+#include <target/target_core_tmr.h>
+#include <target/configfs_macros.h>
+
+#include "tcm_fc.h"
+
+/*
+ * Dump cmd state for debugging.
+ */
+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 se_mem *mem;
+	struct se_transport_task *task;
+
+	if (!(ft_debug_logging & FT_DEBUG_IO))
+		return;
+
+	se_cmd = &cmd->se_cmd;
+	printk(KERN_INFO "%s: cmd %p state %d sess %p seq %p se_cmd %p\n",
+		caller, cmd, cmd->state, cmd->sess, cmd->seq, se_cmd);
+	printk(KERN_INFO "%s: cmd %p cdb %p\n",
+		caller, cmd, cmd->cdb);
+	printk(KERN_INFO "%s: cmd %p lun %d\n", caller, cmd, cmd->lun);
+
+	task = T_TASK(se_cmd);
+	printk(KERN_INFO "%s: cmd %p task %p se_num %u buf %p len %u se_cmd_flags <0x%x>\n",
+	       caller, cmd, task, task->t_tasks_se_num,
+	       task->t_task_buf, se_cmd->data_length, se_cmd->se_cmd_flags);
+	if (task->t_mem_list)
+		list_for_each_entry(mem, task->t_mem_list, se_list)
+			printk(KERN_INFO "%s: cmd %p mem %p page %p "
+			       "len 0x%x off 0x%x\n",
+			       caller, cmd, mem,
+			       mem->se_page, mem->se_len, mem->se_off);
+	sp = cmd->seq;
+	if (sp) {
+		ep = fc_seq_exch(sp);
+		printk(KERN_INFO "%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);
+	}
+	print_hex_dump(KERN_INFO, "ft_dump_cmd ", DUMP_PREFIX_NONE,
+		16, 4, cmd->cdb, MAX_COMMAND_SIZE, 0);
+}
+
+/*
+ * Get LUN from CDB.
+ */
+static int ft_get_lun_for_cmd(struct ft_cmd *cmd, u8 *lunp)
+{
+	u64 lun;
+
+	lun = lunp[1];
+	switch (lunp[0] >> 6) {
+	case 0:
+		break;
+	case 1:
+		lun |= (lunp[0] & 0x3f) << 8;
+		break;
+	default:
+		return -1;
+	}
+	if (lun >= TRANSPORT_MAX_LUNS_PER_TPG)
+		return -1;
+	cmd->lun = lun;
+	return transport_get_lun_for_cmd(&cmd->se_cmd, NULL, lun);
+}
+
+static void ft_queue_cmd(struct ft_sess *sess, struct ft_cmd *cmd)
+{
+	struct se_queue_obj *qobj;
+	unsigned long flags;
+
+	qobj = &sess->tport->tpg->qobj;
+	spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
+	list_add_tail(&cmd->se_req.qr_list, &qobj->qobj_list);
+	spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
+	atomic_inc(&qobj->queue_cnt);
+	wake_up_interruptible(&qobj->thread_wq);
+}
+
+static struct ft_cmd *ft_dequeue_cmd(struct se_queue_obj *qobj)
+{
+	unsigned long flags;
+	struct se_queue_req *qr;
+
+	spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
+	if (list_empty(&qobj->qobj_list)) {
+		spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
+		return NULL;
+	}
+	qr = list_first_entry(&qobj->qobj_list, struct se_queue_req, qr_list);
+	list_del(&qr->qr_list);
+	atomic_dec(&qobj->queue_cnt);
+	spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
+	return container_of(qr, struct ft_cmd, se_req);
+}
+
+static void ft_free_cmd(struct ft_cmd *cmd)
+{
+	struct fc_frame *fp;
+	struct fc_lport *lport;
+
+	if (!cmd)
+		return;
+	fp = cmd->req_frame;
+	lport = fr_dev(fp);
+	if (fr_seq(fp))
+		lport->tt.seq_release(fr_seq(fp));
+	fc_frame_free(fp);
+	ft_sess_put(cmd->sess);	/* undo get from lookup at recv */
+	kfree(cmd);
+}
+
+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);
+}
+
+void ft_check_stop_free(struct se_cmd *se_cmd)
+{
+	transport_generic_free_cmd(se_cmd, 0, 1, 0);
+}
+
+/*
+ * 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;
+
+	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) {
+		/* XXX shouldn't just drop it - requeue and retry? */
+		return 0;
+	}
+	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);
+
+	lport->tt.seq_send(lport, cmd->seq, fp);
+	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__);
+
+	ep = fc_seq_exch(cmd->seq);
+	lport = ep->lp;
+	fp = fc_frame_alloc(lport, sizeof(*txrdy));
+	if (!fp)
+		return PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
+
+	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_SG_IO_CDB) {
+				/*
+				 * Map se_mem list to scatterlist, so that
+				 * DDP can be setup. DDP setup function require
+				 * scatterlist. se_mem_list is internal to
+				 * TCM/LIO target
+				 */
+				transport_do_task_sg_chain(se_cmd);
+				cmd->sg = T_TASK(se_cmd)->t_tasks_sg_chained;
+				cmd->sg_cnt =
+					T_TASK(se_cmd)->t_tasks_sg_chained_no;
+			}
+			if (cmd->sg && lport->tt.ddp_setup(lport, ep->xid,
+						    cmd->sg, cmd->sg_cnt))
+				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);
+
+	return fc_seq_exch(cmd->seq)->rxid;
+}
+
+int ft_get_cmd_state(struct se_cmd *se_cmd)
+{
+	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
+
+	return cmd->state;
+}
+
+int ft_is_state_remove(struct se_cmd *se_cmd)
+{
+	return 0;	/* XXX TBD */
+}
+
+void ft_new_cmd_failure(struct se_cmd *se_cmd)
+{
+	/* XXX TBD */
+	printk(KERN_INFO "%s: se_cmd %p\n", __func__, se_cmd);
+}
+
+/*
+ * 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 (IS_ERR(fp)) {
+		/* XXX need to find cmd if queued */
+		cmd->se_cmd.t_state = TRANSPORT_REMOVE;
+		cmd->seq = NULL;
+		transport_generic_free_cmd(&cmd->se_cmd, 0, 1, 0);
+		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:
+		printk(KERN_INFO "%s: unhandled frame r_ctl %x\n",
+		       __func__, fh->fh_r_ctl);
+		fc_frame_free(fp);
+		transport_generic_free_cmd(&cmd->se_cmd, 0, 1, 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);
+	FT_IO_DBG("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);
+	else
+		lport->tt.frame_send(lport, fp);
+}
+
+/*
+ * Send error or task management response.
+ * Always frees the cmd and associated state.
+ */
+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);
+	ft_free_cmd(cmd);
+}
+
+/*
+ * Handle Task Management Request.
+ */
+static void ft_send_tm(struct ft_cmd *cmd)
+{
+	struct se_tmr_req *tmr;
+	struct fcp_cmnd *fcp;
+	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;
+		if (ft_get_lun_for_cmd(cmd, fcp->fc_lun) < 0) {
+			ft_dump_cmd(cmd, __func__);
+			transport_send_check_condition_and_sense(&cmd->se_cmd,
+				cmd->se_cmd.scsi_sense_reason, 0);
+			ft_sess_put(cmd->sess);
+			return;
+		}
+		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.
+		 */
+		FT_TM_DBG("invalid FCP tm_flags %x\n", fcp->fc_tm_flags);
+		ft_send_resp_code(cmd, FCP_CMND_FIELDS_INVALID);
+		return;
+	}
+
+	FT_TM_DBG("alloc tm cmd fn %d\n", tm_func);
+	tmr = core_tmr_alloc_req(&cmd->se_cmd, cmd, tm_func);
+	if (!tmr) {
+		FT_TM_DBG("alloc failed\n");
+		ft_send_resp_code(cmd, FCP_TMF_FAILED);
+		return;
+	}
+	cmd->se_cmd.se_tmr_req = tmr;
+	transport_generic_handle_tmr(&cmd->se_cmd);
+}
+
+/*
+ * Send status from completed task management request.
+ */
+int 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;
+
+	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_STILL_ALLEGIANT:
+	case TMR_TASK_FAILOVER_NOT_SUPPORTED:
+	case TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED:
+	case TMR_FUNCTION_AUTHORIZATION_FAILED:
+	default:
+		code = FCP_TMF_FAILED;
+		break;
+	}
+	FT_TM_DBG("tmr fn %d resp %d fcp code %d\n",
+		  tmr->function, tmr->response, code);
+	ft_send_resp_code(cmd, code);
+	return 0;
+}
+
+/*
+ * 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;
+
+	cmd = kzalloc(sizeof(*cmd), GFP_ATOMIC);
+	if (!cmd)
+		goto busy;
+	cmd->sess = sess;
+	cmd->seq = lport->tt.seq_assign(lport, fp);
+	if (!cmd->seq) {
+		kfree(cmd);
+		goto busy;
+	}
+	cmd->req_frame = fp;		/* hold frame during cmd */
+	ft_queue_cmd(sess, cmd);
+	return;
+
+busy:
+	FT_IO_DBG("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:
+		printk(KERN_INFO "%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_cmd(struct ft_cmd *cmd)
+{
+	struct fc_frame_header *fh = fc_frame_header_get(cmd->req_frame);
+	struct se_cmd *se_cmd;
+	struct fcp_cmnd *fcp;
+	int data_dir;
+	u32 data_len;
+	int task_attr;
+	int ret;
+
+	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 */
+
+	if (fcp->fc_tm_flags) {
+		task_attr = FCP_PTA_SIMPLE;
+		data_dir = DMA_NONE;
+		data_len = 0;
+	} else {
+		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 */
+		}
+
+		/* FCP_PTA_ maps 1:1 to TASK_ATTR_ */
+		task_attr = fcp->fc_pri_ta & FCP_PTA_MASK;
+		data_len = ntohl(fcp->fc_dl);
+		cmd->cdb = fcp->fc_cdb;
+	}
+
+	se_cmd = &cmd->se_cmd;
+	/*
+	 * Initialize struct se_cmd descriptor from target_core_mod
+	 * infrastructure
+	 */
+	transport_init_se_cmd(se_cmd, &ft_configfs->tf_ops, cmd->sess->se_sess,
+			      data_len, data_dir, task_attr,
+			      &cmd->ft_sense_buffer[0]);
+	/*
+	 * Check for FCP task management flags
+	 */
+	if (fcp->fc_tm_flags) {
+		ft_send_tm(cmd);
+		return;
+	}
+
+	fc_seq_exch(cmd->seq)->lp->tt.seq_set_resp(cmd->seq, ft_recv_seq, cmd);
+
+	ret = ft_get_lun_for_cmd(cmd, fcp->fc_lun);
+	if (ret < 0) {
+		ft_dump_cmd(cmd, __func__);
+		transport_send_check_condition_and_sense(&cmd->se_cmd,
+			cmd->se_cmd.scsi_sense_reason, 0);
+		return;
+	}
+
+	ret = transport_generic_allocate_tasks(se_cmd, cmd->cdb);
+
+	FT_IO_DBG("r_ctl %x alloc task ret %d\n", fh->fh_r_ctl, ret);
+	ft_dump_cmd(cmd, __func__);
+
+	if (ret == -1) {
+		transport_send_check_condition_and_sense(se_cmd,
+				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
+		transport_generic_free_cmd(se_cmd, 0, 1, 0);
+		return;
+	}
+	if (ret == -2) {
+		if (se_cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)
+			ft_queue_status(se_cmd);
+		else
+			transport_send_check_condition_and_sense(se_cmd,
+					se_cmd->scsi_sense_reason, 0);
+		transport_generic_free_cmd(se_cmd, 0, 1, 0);
+		return;
+	}
+	transport_generic_handle_cdb(se_cmd);
+	return;
+
+err:
+	ft_send_resp_code(cmd, FCP_CMND_FIELDS_INVALID);
+	return;
+}
+
+/*
+ * Handle request in the command thread.
+ */
+static void ft_exec_req(struct ft_cmd *cmd)
+{
+	FT_IO_DBG("cmd state %x\n", cmd->state);
+	switch (cmd->state) {
+	case FC_CMD_ST_NEW:
+		ft_send_cmd(cmd);
+		break;
+	default:
+		break;
+	}
+}
+
+/*
+ * Processing thread.
+ * Currently one thread per tpg.
+ */
+int ft_thread(void *arg)
+{
+	struct ft_tpg *tpg = arg;
+	struct se_queue_obj *qobj = &tpg->qobj;
+	struct ft_cmd *cmd;
+	int ret;
+
+	set_user_nice(current, -20);
+
+	while (!kthread_should_stop()) {
+		ret = wait_event_interruptible(qobj->thread_wq,
+			atomic_read(&qobj->queue_cnt) || kthread_should_stop());
+		if (ret < 0 || kthread_should_stop())
+			goto out;
+		cmd = ft_dequeue_cmd(qobj);
+		if (cmd)
+			ft_exec_req(cmd);
+	}
+
+out:
+	return 0;
+}