Blackfin: bf548-ezkit/bf561-ezkit: update nor flash layout

[zen-stable.git] / drivers / target / tcm_fc / tfc_cmd.c

/*
 * 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;
}