File:  [DragonFly] / src / sys / bus / cam / scsi / scsi_targ_bh.c
Revision 1.5: download - view: text, annotated - select for diffs
Mon Dec 29 06:42:10 2003 UTC (10 years, 10 months ago) by dillon
Branches: MAIN
CVS tags: HEAD
Synchronize the USB, CAM, and TASKQUEUE subsystems with FreeBSD RELENG_4.
Also update the $FreeBSD$ ids in the files to the synchronized rev numbers.

This has the side effect of bringing in some additional SCSI robustness
checks, bug fixes, quirk inheritance between subsystems (e.g. USB now sets
PIM_NO_6_BYTE by default and CAM now understands it).

This also brings in a huge amount of SCSI CD code that had been MFCd to
FreeBSD-4 from FreeBSD-5.

/*
 * Implementation of the Target Mode 'Black Hole device' for CAM.
 *
 * Copyright (c) 1999 Justin T. Gibbs.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/cam/scsi/scsi_targ_bh.c,v 1.4.2.6 2003/11/14 11:31:25 simokawa Exp $
 * $DragonFly: src/sys/bus/cam/scsi/scsi_targ_bh.c,v 1.5 2003/12/29 06:42:10 dillon Exp $
 */
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/devicestat.h>
#include <sys/malloc.h>
#include <sys/uio.h>

#include "../cam.h"
#include "../cam_ccb.h"
#include "../cam_extend.h"
#include "../cam_periph.h"
#include "../cam_queue.h"
#include "../cam_xpt_periph.h"
#include "../cam_debug.h"

#include "scsi_all.h"
#include "scsi_message.h"

typedef enum {
	TARGBH_STATE_NORMAL,
	TARGBH_STATE_EXCEPTION,
	TARGBH_STATE_TEARDOWN
} targbh_state;

typedef enum {
	TARGBH_FLAG_NONE	 = 0x00,
	TARGBH_FLAG_LUN_ENABLED	 = 0x01
} targbh_flags;

typedef enum {
	TARGBH_CCB_WORKQ,
	TARGBH_CCB_WAITING
} targbh_ccb_types;

#define MAX_ACCEPT	8
#define MAX_IMMEDIATE	16
#define MAX_BUF_SIZE	256	/* Max inquiry/sense/mode page transfer */

/* Offsets into our private CCB area for storing accept information */
#define ccb_type	ppriv_field0
#define ccb_descr	ppriv_ptr1

/* We stick a pointer to the originating accept TIO in each continue I/O CCB */
#define ccb_atio	ppriv_ptr1

TAILQ_HEAD(ccb_queue, ccb_hdr);

struct targbh_softc {
	struct		ccb_queue pending_queue;
	struct		ccb_queue work_queue;
	struct		ccb_queue unknown_atio_queue;
	struct		devstat device_stats;
	targbh_state	state;
	targbh_flags	flags;	
	u_int		init_level;
	u_int		inq_data_len;
	struct		ccb_accept_tio *accept_tio_list;
	struct		ccb_hdr_slist immed_notify_slist;
};

struct targbh_cmd_desc {
	struct	  ccb_accept_tio* atio_link;
	u_int	  data_resid;	/* How much left to transfer */
	u_int	  data_increment;/* Amount to send before next disconnect */
	void*	  data;		/* The data. Can be from backing_store or not */
	void*	  backing_store;/* Backing store allocated for this descriptor*/
	u_int	  max_size;	/* Size of backing_store */
	u_int32_t timeout;	
	u_int8_t  status;	/* Status to return to initiator */
};

static struct scsi_inquiry_data no_lun_inq_data =
{
	T_NODEVICE | (SID_QUAL_BAD_LU << 5), 0,
	/* version */2, /* format version */2
};

static struct scsi_sense_data no_lun_sense_data =
{
	SSD_CURRENT_ERROR|SSD_ERRCODE_VALID,
	0,
	SSD_KEY_NOT_READY, 
	{ 0, 0, 0, 0 },
	/*extra_len*/offsetof(struct scsi_sense_data, fru)
                   - offsetof(struct scsi_sense_data, extra_len),
	{ 0, 0, 0, 0 },
	/* Logical Unit Not Supported */
	/*ASC*/0x25, /*ASCQ*/0
};

static const int request_sense_size = offsetof(struct scsi_sense_data, fru);

static periph_init_t	targbhinit;
static void		targbhasync(void *callback_arg, u_int32_t code,
				    struct cam_path *path, void *arg);
static cam_status	targbhenlun(struct cam_periph *periph);
static cam_status	targbhdislun(struct cam_periph *periph);
static periph_ctor_t	targbhctor;
static periph_dtor_t	targbhdtor;
static periph_start_t	targbhstart;
static void		targbhdone(struct cam_periph *periph,
				   union ccb *done_ccb);
#ifdef NOTYET
static  int		targbherror(union ccb *ccb, u_int32_t cam_flags,
				    u_int32_t sense_flags);
#endif
static struct targbh_cmd_desc*	targbhallocdescr(void);
static void		targbhfreedescr(struct targbh_cmd_desc *buf);
					
static struct periph_driver targbhdriver =
{
	targbhinit, "targbh",
	TAILQ_HEAD_INITIALIZER(targbhdriver.units), /* generation */ 0
};

DATA_SET(periphdriver_set, targbhdriver);

static void
targbhinit(void)
{
	cam_status status;
	struct cam_path *path;

	/*
	 * Install a global async callback.  This callback will
	 * receive async callbacks like "new path registered".
	 */
	status = xpt_create_path(&path, /*periph*/NULL, CAM_XPT_PATH_ID,
				 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);

	if (status == CAM_REQ_CMP) {
		struct ccb_setasync csa;

		xpt_setup_ccb(&csa.ccb_h, path, /*priority*/5);
		csa.ccb_h.func_code = XPT_SASYNC_CB;
		csa.event_enable = AC_PATH_REGISTERED | AC_PATH_DEREGISTERED;
		csa.callback = targbhasync;
		csa.callback_arg = NULL;
		xpt_action((union ccb *)&csa);
		status = csa.ccb_h.status;
		xpt_free_path(path);
        }

	if (status != CAM_REQ_CMP) {
		printf("targbh: Failed to attach master async callback "
		       "due to status 0x%x!\n", status);
	}
}

static void
targbhasync(void *callback_arg, u_int32_t code,
	    struct cam_path *path, void *arg)
{
	struct cam_path *new_path;
	struct ccb_pathinq *cpi;
	path_id_t bus_path_id;
	cam_status status;

	cpi = (struct ccb_pathinq *)arg;
	if (code == AC_PATH_REGISTERED)
		bus_path_id = cpi->ccb_h.path_id;
	else
		bus_path_id = xpt_path_path_id(path);
	/*
	 * Allocate a peripheral instance for
	 * this target instance.
	 */
	status = xpt_create_path(&new_path, NULL,
				 bus_path_id,
				 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
	if (status != CAM_REQ_CMP) {
		printf("targbhasync: Unable to create path "
			"due to status 0x%x\n", status);
		return;
	}

	switch (code) {
	case AC_PATH_REGISTERED:
	{
		/* Only attach to controllers that support target mode */
		if ((cpi->target_sprt & PIT_PROCESSOR) == 0)
			break;

		status = cam_periph_alloc(targbhctor, NULL, targbhdtor,
					  targbhstart,
					  "targbh", CAM_PERIPH_BIO,
					  new_path, targbhasync,
					  AC_PATH_REGISTERED,
					  cpi);
		break;
	}
	case AC_PATH_DEREGISTERED:
	{
		struct cam_periph *periph;

		if ((periph = cam_periph_find(new_path, "targbh")) != NULL)
			cam_periph_invalidate(periph);
		break;
	}
	default:
		break;
	}
	xpt_free_path(new_path);
}

/* Attempt to enable our lun */
static cam_status
targbhenlun(struct cam_periph *periph)
{
	union ccb immed_ccb;
	struct targbh_softc *softc;
	cam_status status;
	int i;

	softc = (struct targbh_softc *)periph->softc;

	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) != 0)
		return (CAM_REQ_CMP);

	xpt_setup_ccb(&immed_ccb.ccb_h, periph->path, /*priority*/1);
	immed_ccb.ccb_h.func_code = XPT_EN_LUN;

	/* Don't need support for any vendor specific commands */
	immed_ccb.cel.grp6_len = 0;
	immed_ccb.cel.grp7_len = 0;
	immed_ccb.cel.enable = 1;
	xpt_action(&immed_ccb);
	status = immed_ccb.ccb_h.status;
	if (status != CAM_REQ_CMP) {
		xpt_print_path(periph->path);
		printf("targbhenlun - Enable Lun Rejected with status 0x%x\n",
		       status);
		return (status);
	}
	
	softc->flags |= TARGBH_FLAG_LUN_ENABLED;

	/*
	 * Build up a buffer of accept target I/O
	 * operations for incoming selections.
	 */
	for (i = 0; i < MAX_ACCEPT; i++) {
		struct ccb_accept_tio *atio;

		atio = (struct ccb_accept_tio*)malloc(sizeof(*atio), M_DEVBUF,
						      M_NOWAIT);
		if (atio == NULL) {
			status = CAM_RESRC_UNAVAIL;
			break;
		}

		atio->ccb_h.ccb_descr = targbhallocdescr();

		if (atio->ccb_h.ccb_descr == NULL) {
			free(atio, M_DEVBUF);
			status = CAM_RESRC_UNAVAIL;
			break;
		}

		xpt_setup_ccb(&atio->ccb_h, periph->path, /*priority*/1);
		atio->ccb_h.func_code = XPT_ACCEPT_TARGET_IO;
		atio->ccb_h.cbfcnp = targbhdone;
		xpt_action((union ccb *)atio);
		status = atio->ccb_h.status;
		if (status != CAM_REQ_INPROG) {
			targbhfreedescr(atio->ccb_h.ccb_descr);
			free(atio, M_DEVBUF);
			break;
		}
		((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link =
		    softc->accept_tio_list;
		softc->accept_tio_list = atio;
	}

	if (i == 0) {
		xpt_print_path(periph->path);
		printf("targbhenlun - Could not allocate accept tio CCBs: "
		       "status = 0x%x\n", status);
		targbhdislun(periph);
		return (CAM_REQ_CMP_ERR);
	}

	/*
	 * Build up a buffer of immediate notify CCBs
	 * so the SIM can tell us of asynchronous target mode events.
	 */
	for (i = 0; i < MAX_ACCEPT; i++) {
		struct ccb_immed_notify *inot;

		inot = (struct ccb_immed_notify*)malloc(sizeof(*inot), M_DEVBUF,
						        M_NOWAIT);

		if (inot == NULL) {
			status = CAM_RESRC_UNAVAIL;
			break;
		}

		xpt_setup_ccb(&inot->ccb_h, periph->path, /*priority*/1);
		inot->ccb_h.func_code = XPT_IMMED_NOTIFY;
		inot->ccb_h.cbfcnp = targbhdone;
		xpt_action((union ccb *)inot);
		status = inot->ccb_h.status;
		if (status != CAM_REQ_INPROG) {
			free(inot, M_DEVBUF);
			break;
		}
		SLIST_INSERT_HEAD(&softc->immed_notify_slist, &inot->ccb_h,
				  periph_links.sle);
	}

	if (i == 0) {
		xpt_print_path(periph->path);
		printf("targbhenlun - Could not allocate immediate notify "
		       "CCBs: status = 0x%x\n", status);
		targbhdislun(periph);
		return (CAM_REQ_CMP_ERR);
	}

	return (CAM_REQ_CMP);
}

static cam_status
targbhdislun(struct cam_periph *periph)
{
	union ccb ccb;
	struct targbh_softc *softc;
	struct ccb_accept_tio* atio;
	struct ccb_hdr *ccb_h;

	softc = (struct targbh_softc *)periph->softc;
	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) == 0)
		return CAM_REQ_CMP;

	/* XXX Block for Continue I/O completion */

	/* Kill off all ACCECPT and IMMEDIATE CCBs */
	while ((atio = softc->accept_tio_list) != NULL) {
		
		softc->accept_tio_list =
		    ((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link;
		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
		ccb.cab.ccb_h.func_code = XPT_ABORT;
		ccb.cab.abort_ccb = (union ccb *)atio;
		xpt_action(&ccb);
	}

	while ((ccb_h = SLIST_FIRST(&softc->immed_notify_slist)) != NULL) {
		SLIST_REMOVE_HEAD(&softc->immed_notify_slist, periph_links.sle);
		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
		ccb.cab.ccb_h.func_code = XPT_ABORT;
		ccb.cab.abort_ccb = (union ccb *)ccb_h;
		xpt_action(&ccb);
	}

	/*
	 * Dissable this lun.
	 */
	xpt_setup_ccb(&ccb.cel.ccb_h, periph->path, /*priority*/1);
	ccb.cel.ccb_h.func_code = XPT_EN_LUN;
	ccb.cel.enable = 0;
	xpt_action(&ccb);

	if (ccb.cel.ccb_h.status != CAM_REQ_CMP)
		printf("targbhdislun - Disabling lun on controller failed "
		       "with status 0x%x\n", ccb.cel.ccb_h.status);
	else 
		softc->flags &= ~TARGBH_FLAG_LUN_ENABLED;
	return (ccb.cel.ccb_h.status);
}

static cam_status
targbhctor(struct cam_periph *periph, void *arg)
{
	struct ccb_pathinq *cpi;
	struct targbh_softc *softc;

	cpi = (struct ccb_pathinq *)arg;

	/* Allocate our per-instance private storage */
	softc = (struct targbh_softc *)malloc(sizeof(*softc),
					      M_DEVBUF, M_NOWAIT);
	if (softc == NULL) {
		printf("targctor: unable to malloc softc\n");
		return (CAM_REQ_CMP_ERR);
	}

	bzero(softc, sizeof(*softc));
	TAILQ_INIT(&softc->pending_queue);
	TAILQ_INIT(&softc->work_queue);
	softc->accept_tio_list = NULL;
	SLIST_INIT(&softc->immed_notify_slist);
	softc->state = TARGBH_STATE_NORMAL;
	periph->softc = softc;
	softc->init_level++;

	return (targbhenlun(periph));
}

static void
targbhdtor(struct cam_periph *periph)
{
	struct targbh_softc *softc;

	softc = (struct targbh_softc *)periph->softc;

	softc->state = TARGBH_STATE_TEARDOWN;

	targbhdislun(periph);

	switch (softc->init_level) {
	case 0:
		panic("targdtor - impossible init level");;
	case 1:
		/* FALLTHROUGH */
	default:
		/* XXX Wait for callback of targbhdislun() */
		tsleep(softc, PRIBIO, "targbh", hz/2);
		free(softc, M_DEVBUF);
		break;
	}
}

static void
targbhstart(struct cam_periph *periph, union ccb *start_ccb)
{
	struct targbh_softc *softc;
	struct ccb_hdr *ccbh;
	struct ccb_accept_tio *atio;
	struct targbh_cmd_desc *desc;
	struct ccb_scsiio *csio;
	ccb_flags flags;
	int    s;

	softc = (struct targbh_softc *)periph->softc;
	
	s = splbio();
	ccbh = TAILQ_FIRST(&softc->work_queue);
	if (periph->immediate_priority <= periph->pinfo.priority) {
		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WAITING;			
		SLIST_INSERT_HEAD(&periph->ccb_list, &start_ccb->ccb_h,
				  periph_links.sle);
		periph->immediate_priority = CAM_PRIORITY_NONE;
		splx(s);
		wakeup(&periph->ccb_list);
	} else if (ccbh == NULL) {
		splx(s);
		xpt_release_ccb(start_ccb);	
	} else {
		TAILQ_REMOVE(&softc->work_queue, ccbh, periph_links.tqe);
		TAILQ_INSERT_HEAD(&softc->pending_queue, ccbh,
				  periph_links.tqe);
		splx(s);	
		atio = (struct ccb_accept_tio*)ccbh;
		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;

		/* Is this a tagged request? */
		flags = atio->ccb_h.flags & (CAM_TAG_ACTION_VALID|CAM_DIR_MASK);

		csio = &start_ccb->csio;
		/*
		 * If we are done with the transaction, tell the
		 * controller to send status and perform a CMD_CMPLT.
		 * If we have associated sense data, see if we can
		 * send that too.
		 */
		if (desc->data_resid == desc->data_increment) {
			flags |= CAM_SEND_STATUS;
			if (atio->sense_len) {
				csio->sense_len = atio->sense_len;
				csio->sense_data = atio->sense_data;
				flags |= CAM_SEND_SENSE;
			}

		}

		cam_fill_ctio(csio,
			      /*retries*/2,
			      targbhdone,
			      flags,
			      (flags & CAM_TAG_ACTION_VALID)?
				MSG_SIMPLE_Q_TAG : 0,
			      atio->tag_id,
			      atio->init_id,
			      desc->status,
			      /*data_ptr*/desc->data_increment == 0
					  ? NULL : desc->data,
			      /*dxfer_len*/desc->data_increment,
			      /*timeout*/desc->timeout);

		/* Override our wildcard attachment */
		start_ccb->ccb_h.target_id = atio->ccb_h.target_id;
		start_ccb->ccb_h.target_lun = atio->ccb_h.target_lun;

		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WORKQ;
		start_ccb->ccb_h.ccb_atio = atio;
		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
			  ("Sending a CTIO\n"));
		xpt_action(start_ccb);
		s = splbio();
		ccbh = TAILQ_FIRST(&softc->work_queue);
		splx(s);
	}
	if (ccbh != NULL)
		xpt_schedule(periph, /*priority*/1);
}

static void
targbhdone(struct cam_periph *periph, union ccb *done_ccb)
{
	struct targbh_softc *softc;

	softc = (struct targbh_softc *)periph->softc;

	if (done_ccb->ccb_h.ccb_type == TARGBH_CCB_WAITING) {
		/* Caller will release the CCB */
		wakeup(&done_ccb->ccb_h.cbfcnp);
		return;
	}

	switch (done_ccb->ccb_h.func_code) {
	case XPT_ACCEPT_TARGET_IO:
	{
		struct ccb_accept_tio *atio;
		struct targbh_cmd_desc *descr;
		u_int8_t *cdb;

		atio = &done_ccb->atio;
		descr = (struct targbh_cmd_desc*)atio->ccb_h.ccb_descr;
		cdb = atio->cdb_io.cdb_bytes;
		if (softc->state == TARGBH_STATE_TEARDOWN
		 || atio->ccb_h.status == CAM_REQ_ABORTED) {
			targbhfreedescr(descr);
			free(done_ccb, M_DEVBUF);
			return;
		}

		/*
		 * Determine the type of incoming command and
		 * setup our buffer for a response.
		 */
		switch (cdb[0]) {
		case INQUIRY:
		{
			struct scsi_inquiry *inq;

			inq = (struct scsi_inquiry *)cdb;
			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
				  ("Saw an inquiry!\n"));
			/*
			 * Validate the command.  We don't
			 * support any VPD pages, so complain
			 * if EVPD is set.
			 */
			if ((inq->byte2 & SI_EVPD) != 0
			 || inq->page_code != 0) {
				atio->ccb_h.flags &= ~CAM_DIR_MASK;
				atio->ccb_h.flags |= CAM_DIR_NONE;
				/*
				 * This needs to have other than a
				 * no_lun_sense_data response.
				 */
				atio->sense_data = no_lun_sense_data;
				atio->sense_len = sizeof(no_lun_sense_data);
				descr->data_resid = 0;
				descr->data_increment = 0;
				descr->status = SCSI_STATUS_CHECK_COND;
				break;
			}
			/*
			 * Direction is always relative
			 * to the initator.
			 */
			atio->ccb_h.flags &= ~CAM_DIR_MASK;
			atio->ccb_h.flags |= CAM_DIR_IN;
			descr->data = &no_lun_inq_data;
			descr->data_resid = MIN(sizeof(no_lun_inq_data),
						SCSI_CDB6_LEN(inq->length));
			descr->data_increment = descr->data_resid;
			descr->timeout = 5 * 1000;
			descr->status = SCSI_STATUS_OK;
			break;
		}
		case REQUEST_SENSE:
		{
			struct scsi_request_sense *rsense;

			rsense = (struct scsi_request_sense *)cdb;
			/* Refer to static sense data */
			atio->ccb_h.flags &= ~CAM_DIR_MASK;
			atio->ccb_h.flags |= CAM_DIR_IN;
			descr->data = &no_lun_sense_data;
			descr->data_resid = request_sense_size;
			descr->data_resid = MIN(descr->data_resid,
						SCSI_CDB6_LEN(rsense->length));
			descr->data_increment = descr->data_resid;
			descr->timeout = 5 * 1000;
			descr->status = SCSI_STATUS_OK;
			break;
		}
		default:
			/* Constant CA, tell initiator */
			/* Direction is always relative to the initator */
			atio->ccb_h.flags &= ~CAM_DIR_MASK;
			atio->ccb_h.flags |= CAM_DIR_NONE;
			atio->sense_data = no_lun_sense_data;
			atio->sense_len = sizeof (no_lun_sense_data);
			descr->data_resid = 0;
			descr->data_increment = 0;
			descr->timeout = 5 * 1000;
			descr->status = SCSI_STATUS_CHECK_COND;
			break;
		}

		/* Queue us up to receive a Continue Target I/O ccb. */
		TAILQ_INSERT_TAIL(&softc->work_queue, &atio->ccb_h,
				  periph_links.tqe);
		xpt_schedule(periph, /*priority*/1);
		break;
	}
	case XPT_CONT_TARGET_IO:
	{
		struct ccb_accept_tio *atio;
		struct targbh_cmd_desc *desc;

		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
			  ("Received completed CTIO\n"));
		atio = (struct ccb_accept_tio*)done_ccb->ccb_h.ccb_atio;
		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;

		TAILQ_REMOVE(&softc->pending_queue, &atio->ccb_h,
			     periph_links.tqe);

		/*
		 * We could check for CAM_SENT_SENSE bein set here,
		 * but since we're not maintaining any CA/UA state,
		 * there's no point.
		 */
		atio->sense_len = 0;
		done_ccb->ccb_h.flags &= ~CAM_SEND_SENSE;
		done_ccb->ccb_h.status &= ~CAM_SENT_SENSE;

		/* XXX Check for errors */
		desc->data_resid -= desc->data_increment;
		xpt_release_ccb(done_ccb);
		if (softc->state != TARGBH_STATE_TEARDOWN) {

			/*
			 * Send the original accept TIO back to the
			 * controller to handle more work.
			 */
			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
				  ("Returning ATIO to target\n"));
			/* Restore wildcards */
			atio->ccb_h.target_id = CAM_TARGET_WILDCARD;
			atio->ccb_h.target_lun = CAM_LUN_WILDCARD;
			xpt_action((union ccb *)atio);
			break;
		} else {
			targbhfreedescr(desc);
			free(atio, M_DEVBUF);
		}
		break;
	}
	case XPT_IMMED_NOTIFY:
	{
		if (softc->state == TARGBH_STATE_TEARDOWN
		 || done_ccb->ccb_h.status == CAM_REQ_ABORTED) {
			printf("Freed an immediate notify\n");
			free(done_ccb, M_DEVBUF);
		}
		break;
	}
	default:
		panic("targbhdone: Unexpected ccb opcode");
		break;
	}
}

#ifdef NOTYET
static int
targbherror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
{
	return 0;
}
#endif

static struct targbh_cmd_desc*
targbhallocdescr()
{
	struct targbh_cmd_desc* descr;

	/* Allocate the targbh_descr structure */
	descr = (struct targbh_cmd_desc *)malloc(sizeof(*descr),
					       M_DEVBUF, M_NOWAIT);
	if (descr == NULL)
		return (NULL);

	bzero(descr, sizeof(*descr));

	/* Allocate buffer backing store */
	descr->backing_store = malloc(MAX_BUF_SIZE, M_DEVBUF, M_NOWAIT);
	if (descr->backing_store == NULL) {
		free(descr, M_DEVBUF);
		return (NULL);
	}
	descr->max_size = MAX_BUF_SIZE;
	return (descr);
}

static void
targbhfreedescr(struct targbh_cmd_desc *descr)
{
	free(descr->backing_store, M_DEVBUF);
	free(descr, M_DEVBUF);
}