cam.c

/*-
 * Generic utility routines for the Common Access Method layer.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1997 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.
 */

#include <sys/param.h>
#ifdef _KERNEL
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/memdesc.h>
#include <sys/sysctl.h>
#else /* _KERNEL */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <camlib.h>
#endif /* _KERNEL */

#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/scsi/scsi_all.h>
#include <cam/scsi/smp_all.h>
#include <sys/sbuf.h>

#ifdef _KERNEL
#include <sys/libkern.h>
#include <machine/bus.h>
#include <cam/cam_queue.h>
#include <cam/cam_xpt.h>

FEATURE(scbus, "SCSI devices support");

#endif

static int	camstatusentrycomp(const void *key, const void *member);

const struct cam_status_entry cam_status_table[] = {
	{ CAM_REQ_INPROG,	 "CCB request is in progress"		     },
	{ CAM_REQ_CMP,		 "CCB request completed without error"	     },
	{ CAM_REQ_ABORTED,	 "CCB request aborted by the host"	     },
	{ CAM_UA_ABORT,		 "Unable to abort CCB request"		     },
	{ CAM_REQ_CMP_ERR,	 "CCB request completed with an error"	     },
	{ CAM_BUSY,		 "CAM subsystem is busy"		     },
	{ CAM_REQ_INVALID,	 "CCB request was invalid"		     },
	{ CAM_PATH_INVALID,	 "Supplied Path ID is invalid"		     },
	{ CAM_DEV_NOT_THERE,	 "Device Not Present"			     },
	{ CAM_UA_TERMIO,	 "Unable to terminate I/O CCB request"	     },
	{ CAM_SEL_TIMEOUT,	 "Selection Timeout"			     },
	{ CAM_CMD_TIMEOUT,	 "Command timeout"			     },
	{ CAM_SCSI_STATUS_ERROR, "SCSI Status Error"			     },
	{ CAM_MSG_REJECT_REC,	 "Message Reject Reveived"		     },
	{ CAM_SCSI_BUS_RESET,	 "SCSI Bus Reset Sent/Received"		     },
	{ CAM_UNCOR_PARITY,	 "Uncorrectable parity/CRC error"	     },
	{ CAM_AUTOSENSE_FAIL,	 "Auto-Sense Retrieval Failed"		     },
	{ CAM_NO_HBA,		 "No HBA Detected"			     },
	{ CAM_DATA_RUN_ERR,	 "Data Overrun error"			     },
	{ CAM_UNEXP_BUSFREE,	 "Unexpected Bus Free"			     },
	{ CAM_SEQUENCE_FAIL,	 "Target Bus Phase Sequence Failure"	     },
	{ CAM_CCB_LEN_ERR,	 "CCB length supplied is inadequate"	     },
	{ CAM_PROVIDE_FAIL,	 "Unable to provide requested capability"    },
	{ CAM_BDR_SENT,		 "SCSI BDR Message Sent"		     },
	{ CAM_REQ_TERMIO,	 "CCB request terminated by the host"	     },
	{ CAM_UNREC_HBA_ERROR,	 "Unrecoverable Host Bus Adapter Error"	     },
	{ CAM_REQ_TOO_BIG,	 "The request was too large for this host"   },
	{ CAM_REQUEUE_REQ,	 "Unconditionally Re-queue Request"	     },
	{ CAM_ATA_STATUS_ERROR,	 "ATA Status Error"			     },
	{ CAM_SCSI_IT_NEXUS_LOST,"Initiator/Target Nexus Lost"               },
	{ CAM_SMP_STATUS_ERROR,	 "SMP Status Error"                          },
	{ CAM_REQ_SOFTTIMEOUT,   "Completed w/o error, but took too long"    },
	{ CAM_NVME_STATUS_ERROR, "NVME Status Error"			     },
	{ CAM_IDE,		 "Initiator Detected Error Message Received" },
	{ CAM_RESRC_UNAVAIL,	 "Resource Unavailable"			     },
	{ CAM_UNACKED_EVENT,	 "Unacknowledged Event by Host"		     },
	{ CAM_MESSAGE_RECV,	 "Message Received in Host Target Mode"	     },
	{ CAM_INVALID_CDB,	 "Invalid CDB received in Host Target Mode"  },
	{ CAM_LUN_INVALID,	 "Invalid Lun"				     },
	{ CAM_TID_INVALID,	 "Invalid Target ID"			     },
	{ CAM_FUNC_NOTAVAIL,	 "Function Not Available"		     },
	{ CAM_NO_NEXUS,		 "Nexus Not Established"		     },
	{ CAM_IID_INVALID,	 "Invalid Initiator ID"			     },
	{ CAM_CDB_RECVD,	 "CDB Received"				     },
	{ CAM_LUN_ALRDY_ENA,	 "LUN Already Enabled for Target Mode"	     },
	{ CAM_SCSI_BUSY,	 "SCSI Bus Busy"			     },
};

#ifdef _KERNEL
SYSCTL_NODE(_kern, OID_AUTO, cam, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
    "CAM Subsystem");

#ifndef CAM_DEFAULT_SORT_IO_QUEUES
#define CAM_DEFAULT_SORT_IO_QUEUES 1
#endif

int cam_sort_io_queues = CAM_DEFAULT_SORT_IO_QUEUES;
SYSCTL_INT(_kern_cam, OID_AUTO, sort_io_queues, CTLFLAG_RWTUN,
    &cam_sort_io_queues, 0, "Sort IO queues to try and optimise disk access patterns");
#endif

void
cam_strvis(uint8_t *dst, const uint8_t *src, int srclen, int dstlen)
{
	cam_strvis_flag(dst, src, srclen, dstlen,
	    CAM_STRVIS_FLAG_NONASCII_ESC);
}

void
cam_strvis_flag(uint8_t *dst, const uint8_t *src, int srclen, int dstlen,
		uint32_t flags)
{
	struct sbuf sb;

	sbuf_new(&sb, dst, dstlen, SBUF_FIXEDLEN);
	cam_strvis_sbuf(&sb, src, srclen, flags);
	sbuf_finish(&sb);
}

void
cam_strvis_sbuf(struct sbuf *sb, const uint8_t *src, int srclen,
		uint32_t flags)
{

	/* Trim leading/trailing spaces, nulls. */
	while (srclen > 0 && src[0] == ' ')
		src++, srclen--;
	while (srclen > 0
	    && (src[srclen-1] == ' ' || src[srclen-1] == '\0'))
		srclen--;

	while (srclen > 0) {
		if (*src < 0x20 || *src >= 0x80) {
			/* SCSI-II Specifies that these should never occur. */
			/* non-printable character */
			switch (flags & CAM_STRVIS_FLAG_NONASCII_MASK) {
			case CAM_STRVIS_FLAG_NONASCII_ESC:
				sbuf_printf(sb, "\\%c%c%c", 
				    ((*src & 0300) >> 6) + '0',
				    ((*src & 0070) >> 3) + '0',
				    ((*src & 0007) >> 0) + '0');
				break;
			case CAM_STRVIS_FLAG_NONASCII_RAW:
				/*
				 * If we run into a NUL, just transform it
				 * into a space.
				 */
				if (*src != 0x00)
					sbuf_putc(sb, *src);
				else
					sbuf_putc(sb, ' ');
				break;
			case CAM_STRVIS_FLAG_NONASCII_SPC:
				sbuf_putc(sb, ' ');
				break;
			case CAM_STRVIS_FLAG_NONASCII_TRIM:
			default:
				break;
			}
		} else {
			/* normal character */
			sbuf_putc(sb, *src);
		}
		src++;
		srclen--;
	}
}

/*
 * Compare string with pattern, returning 0 on match.
 * Short pattern matches trailing blanks in name,
 * Shell globbing rules apply: * matches 0 or more characters,
 * ? matchces one character, [...] denotes a set to match one char,
 * [^...] denotes a complimented set to match one character.
 * Spaces in str used to match anything in the pattern string
 * but was removed because it's a bug. No current patterns require
 * it, as far as I know, but it's impossible to know what drives
 * returned.
 *
 * Each '*' generates recursion, so keep the number of * in check.
 */
int
cam_strmatch(const uint8_t *str, const uint8_t *pattern, int str_len)
{

	while (*pattern != '\0' && str_len > 0) {  
		if (*pattern == '*') {
			pattern++;
			if (*pattern == '\0')
				return (0);
			do {
				if (cam_strmatch(str, pattern, str_len) == 0)
					return (0);
				str++;
				str_len--;
			} while (str_len > 0);
			return (1);
		} else if (*pattern == '[') {
			int negate_range, ok;
			uint8_t pc = UCHAR_MAX;
			uint8_t sc;

			ok = 0;
			sc = *str++;
			str_len--;
			pattern++;
			if ((negate_range = (*pattern == '^')) != 0)
				pattern++;
			while ((*pattern != ']') && *pattern != '\0') {
				if (*pattern == '-') {
					if (pattern[1] == '\0') /* Bad pattern */
						return (1);
					if (sc >= pc && sc <= pattern[1])
						ok = 1;
					pattern++;
				} else if (*pattern == sc)
					ok = 1;
				pc = *pattern;
				pattern++;
			}
			if (ok == negate_range)
				return (1);
			pattern++;
		} else if (*pattern == '?') {
			/*
			 * NB: || *str == ' ' of the old code is a bug and was
			 * removed.  If you add it back, keep this the last if
			 * before the naked else */
			pattern++;
			str++;
			str_len--;
		} else {
			if (*str != *pattern)
				return (1);
			pattern++;
			str++;
			str_len--;
		}
	}

	/* '*' is allowed to match nothing, so gobble it */
	while (*pattern == '*')
		pattern++;

	if ( *pattern != '\0') {
		/* Pattern not fully consumed.  Not a match */
		return (1);
	}

	/* Eat trailing spaces, which get added by SAT */
	while (str_len > 0 && *str == ' ') {
		str++;
		str_len--;
	}

	return (str_len);
}

caddr_t
cam_quirkmatch(caddr_t target, caddr_t quirk_table, int num_entries,
	       int entry_size, cam_quirkmatch_t *comp_func)
{
	for (; num_entries > 0; num_entries--, quirk_table += entry_size) {
		if ((*comp_func)(target, quirk_table) == 0)
			return (quirk_table);
	}
	return (NULL);
}

const struct cam_status_entry*
cam_fetch_status_entry(cam_status status)
{
	status &= CAM_STATUS_MASK;
	return (bsearch(&status, &cam_status_table,
			nitems(cam_status_table),
			sizeof(*cam_status_table),
			camstatusentrycomp));
}

static int
camstatusentrycomp(const void *key, const void *member)
{
	cam_status status;
	const struct cam_status_entry *table_entry;

	status = *(const cam_status *)key;
	table_entry = (const struct cam_status_entry *)member;

	return (status - table_entry->status_code);
}

#ifdef _KERNEL
char *
cam_error_string(union ccb *ccb, char *str, int str_len,
		 cam_error_string_flags flags,
		 cam_error_proto_flags proto_flags)
#else /* !_KERNEL */
char *
cam_error_string(struct cam_device *device, union ccb *ccb, char *str,
		 int str_len, cam_error_string_flags flags,
		 cam_error_proto_flags proto_flags)
#endif /* _KERNEL/!_KERNEL */
{
	char path_str[64];
	struct sbuf sb;

	if ((ccb == NULL)
	 || (str == NULL)
	 || (str_len <= 0))
		return(NULL);

	if (flags == CAM_ESF_NONE)
		return(NULL);

	switch (ccb->ccb_h.func_code) {
		case XPT_ATA_IO:
			switch (proto_flags & CAM_EPF_LEVEL_MASK) {
			case CAM_EPF_NONE:
				break;
			case CAM_EPF_ALL:
			case CAM_EPF_NORMAL:
				proto_flags |= CAM_EAF_PRINT_RESULT;
				/* FALLTHROUGH */
			case CAM_EPF_MINIMAL:
				proto_flags |= CAM_EAF_PRINT_STATUS;
				/* FALLTHROUGH */
			default:
				break;
			}
			break;
		case XPT_SCSI_IO:
			switch (proto_flags & CAM_EPF_LEVEL_MASK) {
			case CAM_EPF_NONE:
				break;
			case CAM_EPF_ALL:
			case CAM_EPF_NORMAL:
				proto_flags |= CAM_ESF_PRINT_SENSE;
				/* FALLTHROUGH */
			case CAM_EPF_MINIMAL:
				proto_flags |= CAM_ESF_PRINT_STATUS;
				/* FALLTHROUGH */
			default:
				break;
			}
			break;
		case XPT_SMP_IO:
			switch (proto_flags & CAM_EPF_LEVEL_MASK) {
			case CAM_EPF_NONE:
				break;
			case CAM_EPF_ALL:
				proto_flags |= CAM_ESMF_PRINT_FULL_CMD;
				/* FALLTHROUGH */
			case CAM_EPF_NORMAL:
			case CAM_EPF_MINIMAL:
				proto_flags |= CAM_ESMF_PRINT_STATUS;
				/* FALLTHROUGH */
			default:
				break;
			}
			break;
		case XPT_NVME_IO:
		case XPT_NVME_ADMIN:
			switch (proto_flags & CAM_EPF_LEVEL_MASK) {
			case CAM_EPF_NONE:
				break;
			case CAM_EPF_ALL:
			case CAM_EPF_NORMAL:
			case CAM_EPF_MINIMAL:
				proto_flags |= CAM_ENF_PRINT_STATUS;
				/* FALLTHROUGH */
			default:
				break;
			}
			break;
		default:
			break;
	}
#ifdef _KERNEL
	xpt_path_string(ccb->csio.ccb_h.path, path_str, sizeof(path_str));
#else /* !_KERNEL */
	cam_path_string(device, path_str, sizeof(path_str));
#endif /* _KERNEL/!_KERNEL */

	sbuf_new(&sb, str, str_len, 0);

	if (flags & CAM_ESF_COMMAND) {
		sbuf_cat(&sb, path_str);
		switch (ccb->ccb_h.func_code) {
		case XPT_ATA_IO:
			ata_command_sbuf(&ccb->ataio, &sb);
			break;
		case XPT_SCSI_IO:
#ifdef _KERNEL
			scsi_command_string(&ccb->csio, &sb);
#else /* !_KERNEL */
			scsi_command_string(device, &ccb->csio, &sb);
#endif /* _KERNEL/!_KERNEL */
			break;
		case XPT_SMP_IO:
			smp_command_sbuf(&ccb->smpio, &sb, path_str, 79 -
					 strlen(path_str), (proto_flags &
					 CAM_ESMF_PRINT_FULL_CMD) ? 79 : 0);
			break;
		case XPT_NVME_IO:
		case XPT_NVME_ADMIN:
			nvme_command_sbuf(&ccb->nvmeio, &sb);
			break;
		default:
			sbuf_printf(&sb, "CAM func %#x",
			    ccb->ccb_h.func_code);
			break;
		}
		sbuf_putc(&sb, '\n');
	}

	if (flags & CAM_ESF_CAM_STATUS) {
		cam_status status;
		const struct cam_status_entry *entry;

		sbuf_cat(&sb, path_str);
  
		status = ccb->ccb_h.status & CAM_STATUS_MASK;

		entry = cam_fetch_status_entry(status);

		if (entry == NULL)
			sbuf_printf(&sb, "CAM status: Unknown (%#x)\n",
				    ccb->ccb_h.status);
		else
			sbuf_printf(&sb, "CAM status: %s\n",
				    entry->status_text);
	}

	if (flags & CAM_ESF_PROTO_STATUS) {
  
		switch (ccb->ccb_h.func_code) {
		case XPT_ATA_IO:
			if ((ccb->ccb_h.status & CAM_STATUS_MASK) !=
			     CAM_ATA_STATUS_ERROR)
				break;
			if (proto_flags & CAM_EAF_PRINT_STATUS) {
				sbuf_cat(&sb, path_str);
				ata_status_sbuf(&ccb->ataio, &sb);
				sbuf_putc(&sb, '\n');
			}
			if (proto_flags & CAM_EAF_PRINT_RESULT) {
				sbuf_cat(&sb, path_str);
				sbuf_cat(&sb, "RES: ");
				ata_res_sbuf(&ccb->ataio.res, &sb);
				sbuf_putc(&sb, '\n');
			}

			break;
		case XPT_SCSI_IO:
			if ((ccb->ccb_h.status & CAM_STATUS_MASK) !=
			     CAM_SCSI_STATUS_ERROR)
				break;

			if (proto_flags & CAM_ESF_PRINT_STATUS) {
				sbuf_cat(&sb, path_str);
				sbuf_printf(&sb, "SCSI status: %s\n",
					    scsi_status_string(&ccb->csio));
			}

			if ((proto_flags & CAM_ESF_PRINT_SENSE)
			 && (ccb->csio.scsi_status == SCSI_STATUS_CHECK_COND)
			 && (ccb->ccb_h.status & CAM_AUTOSNS_VALID)) {
#ifdef _KERNEL
				scsi_sense_sbuf(&ccb->csio, &sb,
						SSS_FLAG_NONE);
#else /* !_KERNEL */
				scsi_sense_sbuf(device, &ccb->csio, &sb,
						SSS_FLAG_NONE);
#endif /* _KERNEL/!_KERNEL */
			}
			break;
		case XPT_SMP_IO:
			if ((ccb->ccb_h.status & CAM_STATUS_MASK) !=
			     CAM_SMP_STATUS_ERROR)
				break;

			if (proto_flags & CAM_ESF_PRINT_STATUS) {
				sbuf_cat(&sb, path_str);
				sbuf_printf(&sb, "SMP status: %s (%#x)\n",
				    smp_error_desc(ccb->smpio.smp_response[2]),
						   ccb->smpio.smp_response[2]);
			}
			/* There is no SMP equivalent to SCSI sense. */
			break;
		case XPT_NVME_IO:
		case XPT_NVME_ADMIN:
			if ((ccb->ccb_h.status & CAM_STATUS_MASK) !=
			     CAM_NVME_STATUS_ERROR)
				break;

			if (proto_flags & CAM_ESF_PRINT_STATUS) {
				sbuf_cat(&sb, path_str);
				sbuf_cat(&sb, "NVMe status: ");
				nvme_status_sbuf(&ccb->nvmeio, &sb);
				sbuf_putc(&sb, '\n');
			}

			break;
		default:
			break;
		}
	}

	sbuf_finish(&sb);

	return(sbuf_data(&sb));
}

#ifdef _KERNEL

void
cam_error_print(union ccb *ccb, cam_error_string_flags flags,
		cam_error_proto_flags proto_flags)
{
	char str[512];

	printf("%s", cam_error_string(ccb, str, sizeof(str), flags,
	       proto_flags));
}

#else /* !_KERNEL */

void
cam_error_print(struct cam_device *device, union ccb *ccb,
		cam_error_string_flags flags, cam_error_proto_flags proto_flags,
		FILE *ofile)
{
	char str[512];

	if ((device == NULL) || (ccb == NULL) || (ofile == NULL))
		return;

	fprintf(ofile, "%s", cam_error_string(device, ccb, str, sizeof(str),
		flags, proto_flags));
}

#endif /* _KERNEL/!_KERNEL */

/*
 * Common calculate geometry fuction
 *
 * Caller should set ccg->volume_size and block_size.
 * The extended parameter should be zero if extended translation
 * should not be used.
 */
void
cam_calc_geometry(struct ccb_calc_geometry *ccg, int extended)
{
	uint32_t size_mb, secs_per_cylinder;

	if (ccg->block_size == 0) {
		ccg->ccb_h.status = CAM_REQ_CMP_ERR;
		return;
	}
	size_mb = (1024L * 1024L) / ccg->block_size;
	if (size_mb == 0) {
		ccg->ccb_h.status = CAM_REQ_CMP_ERR;
		return;
	}
	size_mb = ccg->volume_size / size_mb;
	if (size_mb > 1024 && extended) {
		ccg->heads = 255;
		ccg->secs_per_track = 63;
	} else {
		ccg->heads = 64;
		ccg->secs_per_track = 32;
	}
	secs_per_cylinder = ccg->heads * ccg->secs_per_track;
	if (secs_per_cylinder == 0) {
		ccg->ccb_h.status = CAM_REQ_CMP_ERR;
		return;
	}
	ccg->cylinders = ccg->volume_size / secs_per_cylinder;
	ccg->ccb_h.status = CAM_REQ_CMP;
}

#ifdef _KERNEL
struct memdesc
memdesc_ccb(union ccb *ccb)
{
	struct ccb_hdr *ccb_h;
	void *data_ptr;
	uint32_t dxfer_len;
	uint16_t sglist_cnt;

	ccb_h = &ccb->ccb_h;
	switch (ccb_h->func_code) {
	case XPT_SCSI_IO: {
		struct ccb_scsiio *csio;

		csio = &ccb->csio;
		data_ptr = csio->data_ptr;
		dxfer_len = csio->dxfer_len;
		sglist_cnt = csio->sglist_cnt;
		break;
	}
	case XPT_CONT_TARGET_IO: {
		struct ccb_scsiio *ctio;

		ctio = &ccb->ctio;
		data_ptr = ctio->data_ptr;
		dxfer_len = ctio->dxfer_len;
		sglist_cnt = ctio->sglist_cnt;
		break;
	}
	case XPT_ATA_IO: {
		struct ccb_ataio *ataio;

		ataio = &ccb->ataio;
		data_ptr = ataio->data_ptr;
		dxfer_len = ataio->dxfer_len;
		sglist_cnt = 0;
		break;
	}
	case XPT_NVME_IO:
	case XPT_NVME_ADMIN: {
		struct ccb_nvmeio *nvmeio;

		nvmeio = &ccb->nvmeio;
		data_ptr = nvmeio->data_ptr;
		dxfer_len = nvmeio->dxfer_len;
		sglist_cnt = nvmeio->sglist_cnt;
		break;
	}
	default:
		panic("%s: Unsupported func code %d", __func__,
		    ccb_h->func_code);
	}

	switch ((ccb_h->flags & CAM_DATA_MASK)) {
	case CAM_DATA_VADDR:
		return (memdesc_vaddr(data_ptr, dxfer_len));
	case CAM_DATA_PADDR:
		return (memdesc_paddr((vm_paddr_t)(uintptr_t)data_ptr,
		    dxfer_len));
	case CAM_DATA_SG:
		return (memdesc_vlist(data_ptr, sglist_cnt));
	case CAM_DATA_SG_PADDR:
		return (memdesc_plist(data_ptr, sglist_cnt));
	case CAM_DATA_BIO:
		return (memdesc_bio(data_ptr));
	default:
		panic("%s: flags 0x%X unimplemented", __func__, ccb_h->flags);
	}
}

int
bus_dmamap_load_ccb(bus_dma_tag_t dmat, bus_dmamap_t map, union ccb *ccb,
		    bus_dmamap_callback_t *callback, void *callback_arg,
		    int flags)
{
	struct ccb_hdr *ccb_h;
	struct memdesc mem;

	ccb_h = &ccb->ccb_h;
	if ((ccb_h->flags & CAM_DIR_MASK) == CAM_DIR_NONE) {
		callback(callback_arg, NULL, 0, 0);
		return (0);
	}

	mem = memdesc_ccb(ccb);
	return (bus_dmamap_load_mem(dmat, map, &mem, callback, callback_arg,
	    flags));
}
#endif