backout 4046204/6603211: causes 6607084

8 files changed, 56 insertions, 180 deletions

diff --git a/usr/src/uts/common/io/scsi/impl/scsi_subr.c b/usr/src/uts/common/io/scsi/impl/scsi_subr.c
index 666b30093f..94997005e3 100644
--- a/usr/src/uts/common/io/scsi/impl/scsi_subr.c
+++ b/usr/src/uts/common/io/scsi/impl/scsi_subr.c
@@ -2095,15 +2095,8 @@ scsi_uscsi_alloc_and_copyin(intptr_t arg, int flag, struct scsi_address *ap,
 		 * that uscmd->uscsi_rqbuf and uscmd->uscsi_rqlen are used
 		 * below to perform the copy back to the caller's buf.
 		 */
-		if (uicmd->uic_rqlen <= SENSE_LENGTH) {
-			uscmd->uscsi_rqlen = SENSE_LENGTH;
-			uscmd->uscsi_rqbuf = kmem_zalloc(SENSE_LENGTH,
-			    KM_SLEEP);
-		} else {
-			uscmd->uscsi_rqlen = MAX_SENSE_LENGTH;
-			uscmd->uscsi_rqbuf = kmem_zalloc(MAX_SENSE_LENGTH,
-			    KM_SLEEP);
-		}
+		uscmd->uscsi_rqlen = SENSE_LENGTH;
+		uscmd->uscsi_rqbuf = kmem_zalloc(SENSE_LENGTH, KM_SLEEP);
 		uscmd->uscsi_rqresid = uscmd->uscsi_rqlen;
 	} else {
 		uscmd->uscsi_rqbuf = NULL;
@@ -2276,7 +2269,6 @@ scsi_uscsi_copyout_and_free(intptr_t arg, struct uscsi_cmd *uscmd)
 #endif /* _MULTI_DATAMODEL */
 	struct uscsi_i_cmd	*uicmd = (struct uscsi_i_cmd *)uscmd;
 	caddr_t	k_rqbuf;
-	int	k_rqlen;
 	caddr_t	k_cdb;
 	int	rval = 0;
 
@@ -2305,7 +2297,6 @@ scsi_uscsi_copyout_and_free(intptr_t arg, struct uscsi_cmd *uscmd)
 	 * mapped in by a lower layer.
 	 */
 	k_rqbuf = uscmd->uscsi_rqbuf;
-	k_rqlen = uscmd->uscsi_rqlen;
 	k_cdb   = uscmd->uscsi_cdb;
 	uscmd->uscsi_rqbuf = uicmd->uic_rqbuf;
 	uscmd->uscsi_rqlen = uicmd->uic_rqlen;
@@ -2338,7 +2329,7 @@ scsi_uscsi_copyout_and_free(intptr_t arg, struct uscsi_cmd *uscmd)
 #endif /* _MULTI_DATAMODE */
 
 	if (k_rqbuf != NULL) {
-		kmem_free(k_rqbuf, k_rqlen);
+		kmem_free(k_rqbuf, SENSE_LENGTH);
 	}
 	if (k_cdb != NULL) {
 		kmem_free(k_cdb, (size_t)uscmd->uscsi_cdblen);
diff --git a/usr/src/uts/common/io/scsi/targets/sd.c b/usr/src/uts/common/io/scsi/targets/sd.c
index e3f702c08a..e828dbdd87 100644
--- a/usr/src/uts/common/io/scsi/targets/sd.c
+++ b/usr/src/uts/common/io/scsi/targets/sd.c
@@ -1332,7 +1332,7 @@ static void sd_handle_request_sense(struct sd_lun *un, struct buf *bp,
 static void sd_handle_auto_request_sense(struct sd_lun *un, struct buf *bp,
 	struct sd_xbuf *xp, struct scsi_pkt *pktp);
 static int sd_validate_sense_data(struct sd_lun *un, struct buf *bp,
-	struct sd_xbuf *xp, size_t actual_len);
+	struct sd_xbuf *xp);
 static void sd_decode_sense(struct sd_lun *un, struct buf *bp,
 	struct sd_xbuf *xp, struct scsi_pkt *pktp);
 
@@ -10469,13 +10469,7 @@ sd_uscsi_strategy(struct buf *bp)
 		break;
 	}
 
-	/*
-	 * We may allocate extra buf for external USCSI commands. If the
-	 * application asks for bigger than 20-byte sense data via USCSI,
-	 * SCSA layer will allocate 252 bytes sense buf for that command.
-	 */
-	xp = kmem_zalloc(sizeof (struct sd_xbuf) - SENSE_LENGTH +
-	    (int)(((struct uscsi_cmd *)(uip->ui_cmdp))->uscsi_rqlen), KM_SLEEP);
+	xp = kmem_alloc(sizeof (struct sd_xbuf), KM_SLEEP);
 	sd_xbuf_init(un, bp, xp, chain_type, uip->ui_cmdp);
 
 	/* Use the index obtained within xbuf_init */
@@ -10706,8 +10700,7 @@ sd_uscsi_iodone(int index, struct sd_lun *un, struct buf *bp)
 
 	mutex_exit(SD_MUTEX(un));
 
-	kmem_free(xp, sizeof (struct sd_xbuf) - SENSE_LENGTH +
-	    (int)(((struct uscsi_cmd *)(xp->xb_pktinfo))->uscsi_rqlen));
+	kmem_free(xp, sizeof (struct sd_xbuf));
 	biodone(bp);
 
 	SD_INFO(SD_LOG_IO, un, "sd_uscsi_iodone: exit.\n");
@@ -12185,20 +12178,11 @@ sd_initpkt_for_uscsi(struct buf *bp, struct scsi_pkt **pktpp)
 	 *	 retry. Besides, ucsci command does not allow DMA breakup,
 	 *	 so there is no need to set PKT_DMA_PARTIAL flag.
 	 */
-	if (uscmd->uscsi_rqlen > SENSE_LENGTH) {
-		pktp = scsi_init_pkt(SD_ADDRESS(un), NULL,
-		    ((bp->b_bcount != 0) ? bp : NULL), uscmd->uscsi_cdblen,
-		    ((int)(uscmd->uscsi_rqlen) + sizeof (struct scsi_arq_status)
-		    - sizeof (struct scsi_extended_sense)), 0,
-		    (un->un_pkt_flags & ~PKT_DMA_PARTIAL) | PKT_XARQ,
-		    sdrunout, (caddr_t)un);
-	} else {
-		pktp = scsi_init_pkt(SD_ADDRESS(un), NULL,
-		    ((bp->b_bcount != 0) ? bp : NULL), uscmd->uscsi_cdblen,
-		    sizeof (struct scsi_arq_status), 0,
-		    (un->un_pkt_flags & ~PKT_DMA_PARTIAL),
-		    sdrunout, (caddr_t)un);
-	}
+	pktp = scsi_init_pkt(SD_ADDRESS(un), NULL,
+	    ((bp->b_bcount != 0) ? bp : NULL), uscmd->uscsi_cdblen,
+	    sizeof (struct scsi_arq_status), 0,
+	    (un->un_pkt_flags & ~PKT_DMA_PARTIAL),
+	    sdrunout, (caddr_t)un);
 
 	if (pktp == NULL) {
 		*pktpp = NULL;
@@ -12367,8 +12351,7 @@ sd_destroypkt_for_uscsi(struct buf *bp)
 		 */
 		uscmd->uscsi_rqstatus = xp->xb_sense_status;
 		uscmd->uscsi_rqresid  = xp->xb_sense_resid;
-		bcopy(xp->xb_sense_data, uscmd->uscsi_rqbuf,
-		    uscmd->uscsi_rqlen);
+		bcopy(xp->xb_sense_data, uscmd->uscsi_rqbuf, SENSE_LENGTH);
 	}
 
 	/* We are done with the scsi_pkt; free it now */
@@ -14387,7 +14370,7 @@ sd_alloc_rqs(struct scsi_device *devp, struct sd_lun *un)
 	 * the CDB in the scsi_pkt for a REQUEST SENSE command.
 	 */
 	un->un_rqs_bp = scsi_alloc_consistent_buf(&devp->sd_address, NULL,
-	    MAX_SENSE_LENGTH, B_READ, SLEEP_FUNC, NULL);
+	    SENSE_LENGTH, B_READ, SLEEP_FUNC, NULL);
 	if (un->un_rqs_bp == NULL) {
 		return (DDI_FAILURE);
 	}
@@ -14402,7 +14385,7 @@ sd_alloc_rqs(struct scsi_device *devp, struct sd_lun *un)
 
 	/* Set up the CDB in the scsi_pkt for a REQUEST SENSE command. */
 	(void) scsi_setup_cdb((union scsi_cdb *)un->un_rqs_pktp->pkt_cdbp,
-	    SCMD_REQUEST_SENSE, 0, MAX_SENSE_LENGTH, 0);
+	    SCMD_REQUEST_SENSE, 0, SENSE_LENGTH, 0);
 
 	SD_FILL_SCSI1_LUN(un, un->un_rqs_pktp);
 
@@ -14765,7 +14748,6 @@ sdintr(struct scsi_pkt *pktp)
 	struct buf	*bp;
 	struct sd_xbuf	*xp;
 	struct sd_lun	*un;
-	size_t		actual_len;
 
 	ASSERT(pktp != NULL);
 	bp = (struct buf *)pktp->pkt_private;
@@ -14822,11 +14804,6 @@ sdintr(struct scsi_pkt *pktp)
 		goto exit;
 	}
 
-	if (pktp->pkt_state & STATE_XARQ_DONE) {
-		SD_TRACE(SD_LOG_COMMON, un,
-		    "sdintr: extra sense data received. pkt=%p\n", pktp);
-	}
-
 	/*
 	 * First see if the pkt has auto-request sense data with it....
 	 * Look at the packet state first so we don't take a performance
@@ -14850,26 +14827,9 @@ sdintr(struct scsi_pkt *pktp)
 			    *((uchar_t *)(&(asp->sts_rqpkt_status)));
 			xp->xb_sense_state  = asp->sts_rqpkt_state;
 			xp->xb_sense_resid  = asp->sts_rqpkt_resid;
-			if (pktp->pkt_state & STATE_XARQ_DONE) {
-				actual_len = MAX_SENSE_LENGTH -
-				    xp->xb_sense_resid;
-			} else {
-				if (xp->xb_sense_resid > SENSE_LENGTH) {
-					actual_len = MAX_SENSE_LENGTH -
-					    xp->xb_sense_resid;
-				} else {
-					actual_len = SENSE_LENGTH -
-					    xp->xb_sense_resid;
-				}
-				if (xp->xb_pkt_flags & SD_XB_USCSICMD) {
-					xp->xb_sense_resid =
-					    (int)(((struct uscsi_cmd *)
-					    (xp->xb_pktinfo))->
-					    uscsi_rqlen) - actual_len;
-				}
-			}
 			bcopy(&asp->sts_sensedata, xp->xb_sense_data,
-			    actual_len);
+			    min(sizeof (struct scsi_extended_sense),
+			    SENSE_LENGTH));
 
 			/* fail the command */
 			SD_TRACE(SD_LOG_IO_CORE | SD_LOG_ERROR, un,
@@ -15268,7 +15228,6 @@ sd_handle_request_sense(struct sd_lun *un, struct buf *sense_bp,
 	struct buf	*cmd_bp;	/* buf for the original command */
 	struct sd_xbuf	*cmd_xp;	/* sd_xbuf for the original command */
 	struct scsi_pkt *cmd_pktp;	/* pkt for the original command */
-	size_t		actual_len;	/* actual sense data length */
 
 	ASSERT(un != NULL);
 	ASSERT(mutex_owned(SD_MUTEX(un)));
@@ -15316,22 +15275,8 @@ sd_handle_request_sense(struct sd_lun *un, struct buf *sense_bp,
 	 */
 	cmd_xp->xb_sense_status = *(sense_pktp->pkt_scbp);
 	cmd_xp->xb_sense_state  = sense_pktp->pkt_state;
-	actual_len = MAX_SENSE_LENGTH - sense_pktp->pkt_resid;
-	if ((cmd_xp->xb_pkt_flags & SD_XB_USCSICMD) &&
-	    (((struct uscsi_cmd *)cmd_xp->xb_pktinfo)->uscsi_rqlen >
-	    SENSE_LENGTH)) {
-		bcopy(sense_bp->b_un.b_addr, cmd_xp->xb_sense_data,
-		    min(actual_len, MAX_SENSE_LENGTH));
-		cmd_xp->xb_sense_resid = sense_pktp->pkt_resid;
-	} else {
-		bcopy(sense_bp->b_un.b_addr, cmd_xp->xb_sense_data,
-		    min(actual_len, SENSE_LENGTH));
-		if (actual_len < SENSE_LENGTH) {
-			cmd_xp->xb_sense_resid = SENSE_LENGTH - actual_len;
-		} else {
-			cmd_xp->xb_sense_resid = 0;
-		}
-	}
+	cmd_xp->xb_sense_resid  = sense_pktp->pkt_resid;
+	bcopy(sense_bp->b_un.b_addr, cmd_xp->xb_sense_data, SENSE_LENGTH);
 
 	/*
 	 *  Free up the RQS command....
@@ -15352,7 +15297,7 @@ sd_handle_request_sense(struct sd_lun *un, struct buf *sense_bp,
 	 * action. Just fail a non-retryable command.
 	 */
 	if ((cmd_pktp->pkt_flags & FLAG_DIAGNOSE) == 0) {
-		if (sd_validate_sense_data(un, cmd_bp, cmd_xp, actual_len) ==
+		if (sd_validate_sense_data(un, cmd_bp, cmd_xp) ==
 		    SD_SENSE_DATA_IS_VALID) {
 			sd_decode_sense(un, cmd_bp, cmd_xp, cmd_pktp);
 		}
@@ -15386,7 +15331,6 @@ sd_handle_auto_request_sense(struct sd_lun *un, struct buf *bp,
 	struct sd_xbuf *xp, struct scsi_pkt *pktp)
 {
 	struct scsi_arq_status *asp;
-	size_t actual_len;
 
 	ASSERT(un != NULL);
 	ASSERT(mutex_owned(SD_MUTEX(un)));
@@ -15423,27 +15367,14 @@ sd_handle_auto_request_sense(struct sd_lun *un, struct buf *bp,
 	xp->xb_sense_status = *((uchar_t *)(&(asp->sts_rqpkt_status)));
 	xp->xb_sense_state  = asp->sts_rqpkt_state;
 	xp->xb_sense_resid  = asp->sts_rqpkt_resid;
-	if (xp->xb_sense_state & STATE_XARQ_DONE) {
-		actual_len = MAX_SENSE_LENGTH - xp->xb_sense_resid;
-	} else {
-		if (xp->xb_sense_resid > SENSE_LENGTH) {
-			actual_len = MAX_SENSE_LENGTH - xp->xb_sense_resid;
-		} else {
-			actual_len = SENSE_LENGTH - xp->xb_sense_resid;
-		}
-		if (xp->xb_pkt_flags & SD_XB_USCSICMD) {
-			xp->xb_sense_resid = (int)(((struct uscsi_cmd *)
-			    (xp->xb_pktinfo))->uscsi_rqlen) - actual_len;
-		}
-	}
-	bcopy(&asp->sts_sensedata, xp->xb_sense_data, actual_len);
+	bcopy(&asp->sts_sensedata, xp->xb_sense_data,
+	    min(sizeof (struct scsi_extended_sense), SENSE_LENGTH));
 
 	/*
 	 * See if we have valid sense data, if so then turn it over to
 	 * sd_decode_sense() to figure out the right course of action.
 	 */
-	if (sd_validate_sense_data(un, bp, xp, actual_len) ==
-	    SD_SENSE_DATA_IS_VALID) {
+	if (sd_validate_sense_data(un, bp, xp) == SD_SENSE_DATA_IS_VALID) {
 		sd_decode_sense(un, bp, xp, pktp);
 	}
 }
@@ -15493,11 +15424,11 @@ sd_print_sense_failed_msg(struct sd_lun *un, struct buf *bp, void *arg,
  */
 
 static int
-sd_validate_sense_data(struct sd_lun *un, struct buf *bp, struct sd_xbuf *xp,
-	size_t actual_len)
+sd_validate_sense_data(struct sd_lun *un, struct buf *bp, struct sd_xbuf *xp)
 {
 	struct scsi_extended_sense *esp;
 	struct	scsi_pkt *pktp;
+	size_t	actual_len;
 	char	*msgp = NULL;
 
 	ASSERT(un != NULL);
@@ -15549,6 +15480,7 @@ sd_validate_sense_data(struct sd_lun *un, struct buf *bp, struct sd_xbuf *xp,
 	 * Note: We are assuming the returned sense data is SENSE_LENGTH bytes
 	 * or less.
 	 */
+	actual_len = (int)(SENSE_LENGTH - xp->xb_sense_resid);
 	if (((xp->xb_sense_state & STATE_XFERRED_DATA) == 0) ||
 	    (actual_len == 0)) {
 		msgp = "Request Sense couldn't get sense data\n";
diff --git a/usr/src/uts/common/io/scsi/targets/sgen.c b/usr/src/uts/common/io/scsi/targets/sgen.c
index f2055cc357..29e01d7ec0 100644
--- a/usr/src/uts/common/io/scsi/targets/sgen.c
+++ b/usr/src/uts/common/io/scsi/targets/sgen.c
@@ -739,7 +739,7 @@ sgen_setup_sense(sgen_state_t *sg_state)
 	struct scsi_pkt *rqpkt;
 
 	if ((bp = scsi_alloc_consistent_buf(&sg_state->sgen_scsiaddr, NULL,
-	    MAX_SENSE_LENGTH, B_READ, SLEEP_FUNC, NULL)) == NULL) {
+	    SENSE_LENGTH, B_READ, SLEEP_FUNC, NULL)) == NULL) {
 		return (-1);
 	}
 
@@ -756,7 +756,7 @@ sgen_setup_sense(sgen_state_t *sg_state)
 	sg_state->sgen_sense = (struct scsi_extended_sense *)bp->b_un.b_addr;
 
 	(void) scsi_setup_cdb((union scsi_cdb *)rqpkt->pkt_cdbp,
-	    SCMD_REQUEST_SENSE, 0, MAX_SENSE_LENGTH, 0);
+	    SCMD_REQUEST_SENSE, 0, SENSE_LENGTH, 0);
 	FILL_SCSI1_LUN(sg_state->sgen_scsidev, rqpkt);
 
 	rqpkt->pkt_comp = sgen_callback;
@@ -1417,8 +1417,7 @@ sgen_make_uscsi_cmd(sgen_state_t *sg_state, struct buf *bp)
 {
 	struct scsi_pkt	*pkt;
 	struct uscsi_cmd *ucmd;
-	int stat_size = 1;
-	int flags = 0;
+	int stat_size;
 
 	ASSERT(bp);
 
@@ -1427,14 +1426,9 @@ sgen_make_uscsi_cmd(sgen_state_t *sg_state, struct buf *bp)
 	ucmd = (struct uscsi_cmd *)bp->b_private;
 
 	if (ucmd->uscsi_flags & USCSI_RQENABLE) {
-		if (ucmd->uscsi_rqlen > SENSE_LENGTH) {
-			stat_size = (int)(ucmd->uscsi_rqlen) +
-			    sizeof (struct scsi_arq_status) -
-			    sizeof (struct scsi_extended_sense);
-			flags = PKT_XARQ;
-		} else {
-			stat_size = sizeof (struct scsi_arq_status);
-		}
+		stat_size = sizeof (struct scsi_arq_status);
+	} else {
+		stat_size = 1;
 	}
 
 	sgen_log(sg_state, SGEN_DIAG3, "sgen_make_uscsi_cmd: b_bcount = %ld",
@@ -1445,7 +1439,7 @@ sgen_make_uscsi_cmd(sgen_state_t *sg_state, struct buf *bp)
 	    ucmd->uscsi_cdblen,		/* cmdlen */
 	    stat_size,			/* statuslen */
 	    0,				/* privatelen */
-	    flags,			/* flags */
+	    0,				/* flags */
 	    SLEEP_FUNC,			/* callback */
 	    (caddr_t)sg_state);		/* callback_arg */
 
@@ -1698,22 +1692,12 @@ sgen_handle_autosense(sgen_state_t *sg_state, struct scsi_pkt *pkt)
 		return (COMMAND_DONE_ERROR);
 	}
 
-	if (pkt->pkt_state & STATE_XARQ_DONE) {
-		amt = MAX_SENSE_LENGTH - arqstat->sts_rqpkt_resid;
-	} else {
-		if (arqstat->sts_rqpkt_resid > SENSE_LENGTH) {
-			amt = MAX_SENSE_LENGTH - arqstat->sts_rqpkt_resid;
-		} else {
-			amt = SENSE_LENGTH - arqstat->sts_rqpkt_resid;
-		}
-	}
-
 	if (ucmd->uscsi_flags & USCSI_RQENABLE) {
 		ucmd->uscsi_rqstatus = *((char *)&arqstat->sts_rqpkt_status);
-		uchar_t rqlen = min((uchar_t)amt, ucmd->uscsi_rqlen);
-		ucmd->uscsi_rqresid = ucmd->uscsi_rqlen - rqlen;
+		ucmd->uscsi_rqresid = arqstat->sts_rqpkt_resid;
 		ASSERT(ucmd->uscsi_rqlen && sg_state->sgen_rqs_sen);
-		bcopy(&(arqstat->sts_sensedata), sg_state->sgen_rqs_sen, rqlen);
+		bcopy(&(arqstat->sts_sensedata), sg_state->sgen_rqs_sen,
+		    ucmd->uscsi_rqlen);
 		sgen_log(sg_state, SGEN_DIAG2, "sgen_handle_autosense: "
 		    "uscsi_rqstatus=0x%x uscsi_rqresid=%d\n",
 		    ucmd->uscsi_rqstatus, ucmd->uscsi_rqresid);
@@ -1726,6 +1710,7 @@ sgen_handle_autosense(sgen_state_t *sg_state, struct scsi_pkt *pkt)
 		return (COMMAND_DONE_ERROR);
 	}
 
+	amt = SENSE_LENGTH - arqstat->sts_rqpkt_resid;
 	if (((arqstat->sts_rqpkt_state & STATE_XFERRED_DATA) == 0) ||
 	    (amt == 0)) {
 		sgen_log(sg_state, SGEN_DIAG1, "sgen_handle_autosense: got "
@@ -1779,14 +1764,12 @@ sgen_handle_sense(sgen_state_t *sg_state)
 
 	SGEN_DO_ERRSTATS(sg_state, sgen_sense_rcv);
 
-	amt = MAX_SENSE_LENGTH - rqpkt->pkt_resid;
-
 	if (ucmd->uscsi_flags & USCSI_RQENABLE) {
 		ucmd->uscsi_rqstatus = *((char *)rqstatus);
-		uchar_t rqlen = min((uchar_t)amt, ucmd->uscsi_rqlen);
-		ucmd->uscsi_rqresid = ucmd->uscsi_rqlen - rqlen;
+		ucmd->uscsi_rqresid = rqpkt->pkt_resid;
 		ASSERT(ucmd->uscsi_rqlen && sg_state->sgen_rqs_sen);
-		bcopy(sg_state->sgen_sense, sg_state->sgen_rqs_sen, rqlen);
+		bcopy(sg_state->sgen_sense, sg_state->sgen_rqs_sen,
+		    ucmd->uscsi_rqlen);
 		sgen_log(sg_state, SGEN_DIAG2, "sgen_handle_sense: "
 		    "uscsi_rqstatus=0x%x uscsi_rqresid=%d\n",
 		    ucmd->uscsi_rqstatus, ucmd->uscsi_rqresid);
@@ -1806,6 +1789,7 @@ sgen_handle_sense(sgen_state_t *sg_state)
 		return (COMMAND_DONE_ERROR);
 	}
 
+	amt = SENSE_LENGTH - rqpkt->pkt_resid;
 	if ((rqpkt->pkt_state & STATE_XFERRED_DATA) == 0 || amt == 0) {
 		sgen_log(sg_state, SGEN_DIAG1, "sgen_handle_sense: got "
 		    "sense, but it contains no data");
diff --git a/usr/src/uts/common/io/scsi/targets/st.c b/usr/src/uts/common/io/scsi/targets/st.c
index 2ebc20820b..7deb82e1ff 100644
--- a/usr/src/uts/common/io/scsi/targets/st.c
+++ b/usr/src/uts/common/io/scsi/targets/st.c
@@ -1433,7 +1433,7 @@ st_doattach(struct scsi_device *devp, int (*canwait)())
 	}
 
 	bp = scsi_alloc_consistent_buf(&devp->sd_address, (struct buf *)NULL,
-	    MAX_SENSE_LENGTH, B_READ, canwait, NULL);
+	    SENSE_LENGTH, B_READ, canwait, NULL);
 	if (!bp) {
 		goto error;
 	}
@@ -1446,7 +1446,7 @@ st_doattach(struct scsi_device *devp, int (*canwait)())
 	ASSERT(geterror(bp) == NULL);
 
 	(void) scsi_setup_cdb((union scsi_cdb *)rqpkt->pkt_cdbp,
-	    SCMD_REQUEST_SENSE, 0, MAX_SENSE_LENGTH, 0);
+	    SCMD_REQUEST_SENSE, 0, SENSE_LENGTH, 0);
 	FILL_SCSI1_LUN(devp, rqpkt);
 
 	/*
@@ -5365,8 +5365,8 @@ st_ioctl_cmd(dev_t dev, struct uscsi_cmd *ucmd, int flag)
 	if (uscmd->uscsi_cdb != NULL) {
 		bp->b_forw =
 		    (struct buf *)(uintptr_t)((char *)uscmd->uscsi_cdb)[0];
+		bp->b_back = (struct buf *)uscmd;
 	}
-	bp->b_back = (struct buf *)uscmd;
 
 	mutex_exit(ST_MUTEX);
 	err = scsi_uscsi_handle_cmd(dev, uioseg, uscmd,
@@ -7812,8 +7812,7 @@ st_make_uscsi_cmd(struct scsi_tape *un, struct uscsi_cmd *ucmd,
 	struct scsi_pkt *pkt;
 	caddr_t cdb;
 	int	cdblen;
-	int	stat_size = 1;
-	int	flags = 0;
+	int stat_size;
 
 	ST_FUNC(ST_DEVINFO, st_make_uscsi_cmd);
 
@@ -7821,16 +7820,10 @@ st_make_uscsi_cmd(struct scsi_tape *un, struct uscsi_cmd *ucmd,
 	    "st_make_uscsi_cmd(): dev = 0x%lx\n", un->un_dev);
 
 	if (ucmd->uscsi_flags & USCSI_RQENABLE) {
-		if (un->un_arq_enabled) {
-			if (ucmd->uscsi_rqlen > SENSE_LENGTH) {
-				stat_size = (int)(ucmd->uscsi_rqlen) +
-				    sizeof (struct scsi_arq_status) -
-				    sizeof (struct scsi_extended_sense);
-				flags = PKT_XARQ;
-			} else {
-				stat_size = sizeof (struct scsi_arq_status);
-			}
-		}
+		stat_size = (un->un_arq_enabled ?
+		    sizeof (struct scsi_arq_status) : 1);
+	} else {
+		stat_size = 1;
 	}
 
 	ASSERT(mutex_owned(ST_MUTEX));
@@ -7843,7 +7836,7 @@ st_make_uscsi_cmd(struct scsi_tape *un, struct uscsi_cmd *ucmd,
 	    ucmd->uscsi_buflen, bp->b_bcount);
 	pkt = scsi_init_pkt(ROUTE, NULL,
 	    (bp->b_bcount > 0) ? bp : NULL,
-	    cdblen, stat_size, 0, flags, func, (caddr_t)un);
+	    cdblen, stat_size, 0, 0, func, (caddr_t)un);
 	if (pkt == NULL) {
 		goto exit;
 	}
@@ -9179,7 +9172,7 @@ st_handle_sense(struct scsi_tape *un, struct buf *bp)
 	}
 
 	/* was there enough data? */
-	amt = (int)MAX_SENSE_LENGTH - rqpkt->pkt_resid;
+	amt = (int)SENSE_LENGTH - rqpkt->pkt_resid;
 	if ((rqpkt->pkt_state & STATE_XFERRED_DATA) == 0 ||
 	    (amt < SUN_MIN_SENSE_LENGTH)) {
 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
@@ -9259,15 +9252,7 @@ st_handle_autosense(struct scsi_tape *un, struct buf *bp)
 
 
 	/* was there enough data? */
-	if (pkt->pkt_state & STATE_XARQ_DONE) {
-		amt = (int)MAX_SENSE_LENGTH - arqstat->sts_rqpkt_resid;
-	} else {
-		if (arqstat->sts_rqpkt_resid > SENSE_LENGTH) {
-			amt = (int)MAX_SENSE_LENGTH - arqstat->sts_rqpkt_resid;
-		} else {
-			amt = (int)SENSE_LENGTH - arqstat->sts_rqpkt_resid;
-		}
-	}
+	amt = (int)SENSE_LENGTH - arqstat->sts_rqpkt_resid;
 	if ((arqstat->sts_rqpkt_state & STATE_XFERRED_DATA) == 0 ||
 	    (amt < SUN_MIN_SENSE_LENGTH)) {
 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
@@ -9275,17 +9260,13 @@ st_handle_autosense(struct scsi_tape *un, struct buf *bp)
 		return (rval);
 	}
 
-	if (pkt->pkt_state & STATE_XARQ_DONE) {
-		bcopy(&arqstat->sts_sensedata, ST_RQSENSE, MAX_SENSE_LENGTH);
-	} else {
-		bcopy(&arqstat->sts_sensedata, ST_RQSENSE, SENSE_LENGTH);
-	}
-
 	/*
 	 * copy one arqstat entry in the sense data buffer
 	 */
 	st_update_error_stack(un, pkt, arqstat);
 
+	bcopy(&arqstat->sts_sensedata, ST_RQSENSE, SENSE_LENGTH);
+
 	return (st_decode_sense(un, bp, amt, &arqstat->sts_rqpkt_status));
 }
 
diff --git a/usr/src/uts/common/sys/scsi/impl/sense.h b/usr/src/uts/common/sys/scsi/impl/sense.h
index d60ea2049b..dd219bd6a8 100644
--- a/usr/src/uts/common/sys/scsi/impl/sense.h
+++ b/usr/src/uts/common/sys/scsi/impl/sense.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -61,11 +61,6 @@ extern "C" {
 	(roundup(sizeof (struct scsi_extended_sense), sizeof (int)))
 
 /*
- * Per SPC-3 standard, the maximum length of sense data is 252 bytes.
- */
-#define	MAX_SENSE_LENGTH	252
-
-/*
  * Minimum useful Sense Length value
  */
 
diff --git a/usr/src/uts/common/sys/scsi/scsi_pkt.h b/usr/src/uts/common/sys/scsi/scsi_pkt.h
index 9196cc7b28..4a3f6be09b 100644
--- a/usr/src/uts/common/sys/scsi/scsi_pkt.h
+++ b/usr/src/uts/common/sys/scsi/scsi_pkt.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -177,7 +177,6 @@ struct scsi_pkt {
 #define	STATE_XFERRED_DATA	0x08	/* Data transfer took place */
 #define	STATE_GOT_STATUS	0x10	/* SCSI status received */
 #define	STATE_ARQ_DONE		0x20	/* auto rqsense took place */
-#define	STATE_XARQ_DONE		0X40	/* extra auto rqsense took place */
 
 /*
  * Definitions for the pkt_statistics field
diff --git a/usr/src/uts/common/sys/scsi/scsi_resource.h b/usr/src/uts/common/sys/scsi/scsi_resource.h
index f5c31ac948..2d12ab3ff8 100644
--- a/usr/src/uts/common/sys/scsi/scsi_resource.h
+++ b/usr/src/uts/common/sys/scsi/scsi_resource.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -54,7 +54,6 @@ extern "C" {
  */
 #define	PKT_CONSISTENT	0x0001		/* this is an 'iopb' packet */
 #define	PKT_DMA_PARTIAL	0x040000	/* partial xfer ok */
-#define	PKT_XARQ	0x080000	/* request for extra sense */
 
 /*
  * Old PKT_CONSISTENT value for binary compatibility with x86 2.1
diff --git a/usr/src/uts/common/sys/scsi/targets/sddef.h b/usr/src/uts/common/sys/scsi/targets/sddef.h
index 15537c843f..509e1ba681 100644
--- a/usr/src/uts/common/sys/scsi/targets/sddef.h
+++ b/usr/src/uts/common/sys/scsi/targets/sddef.h
@@ -1337,11 +1337,6 @@ struct sd_xbuf {
 	ssize_t	xb_sense_resid;		/* residual of RQS command */
 	uchar_t	xb_sense_status;	/* scsi status byte of RQS command */
 	uchar_t	xb_sense_data[SENSE_LENGTH];	/* sense data from RQS cmd */
-	/*
-	 * Extra sense larger than SENSE_LENGTH will be allocated
-	 * right after xb_sense_data[SENSE_LENGTH]. Please do not
-	 * add any new field after it.
-	 */
 };
 
 _NOTE(SCHEME_PROTECTS_DATA("unique per pkt", sd_xbuf))