tfc_cmd.c

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/*
 * 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 <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.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;

    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);
}

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;

    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) {
        /* 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__);

    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.
 */
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;

    if (cmd->aborted)
        return 0;
    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;
    }
    pr_debug("tmr fn %d resp %d fcp code %d\n",
          tmr->function, tmr->response, code);
    ft_send_resp_code(cmd, code);
    return 0;
}

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;

    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 */

    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 = MSG_HEAD_TAG;
        break;
    case FCP_PTA_ORDERED:
        task_attr = MSG_ORDERED_TAG;
        break;
    case FCP_PTA_ACA:
        task_attr = MSG_ACA_TAG;
        break;
    case FCP_PTA_SIMPLE: /* Fallthrough */
    default:
        task_attr = MSG_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);
}