[PATCH 3/5] bsg: accept varlen commands

[PATCH 3/5] bsg: accept varlen commands

[Pete Wyckoff]

Accept variable length SCSI commands through BSG.

Signed-off-by: Pete Wyckoff <pw@osc.edu>
---
 block/bsg.c |   34 +++++++++++++++++++++++++---------
 1 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/block/bsg.c b/block/bsg.c
index 8e181ab..0d9364d 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -175,14 +175,29 @@ unlock:
 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
 				struct sg_io_v4 *hdr, int has_write_perm)
 {
-	memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
-
-	if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
-			   hdr->request_len))
-		return -EFAULT;
+	void __user *buf = (void __user *)(unsigned long) hdr->request;
+	int len = hdr->request_len;
+	unsigned char *cmd;
+
+	if (len > BLK_MAX_CDB) {
+		rq->cmd_len = 0;
+		rq->varlen_cdb_len = len;
+		rq->varlen_cdb = kmalloc(len, GFP_KERNEL);
+		if (rq->varlen_cdb == NULL)
+			return -ENOMEM;
+		if (copy_from_user(rq->varlen_cdb, buf, len))
+			return -EFAULT;
+		cmd = &rq->varlen_cdb[0];
+	} else {
+		rq->cmd_len = len;
+		memset(rq->cmd, 0, BLK_MAX_CDB);  /* for ATAPI */
+		if (copy_from_user(rq->cmd, buf, len))
+			return -EFAULT;
+		cmd = &rq->cmd[0];
+	}
 
 	if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
-		if (blk_verify_command(rq->cmd, has_write_perm))
+		if (blk_verify_command(cmd, has_write_perm))
 			return -EPERM;
 	} else if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
@@ -190,7 +205,6 @@ static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
 	/*
 	 * fill in request structure
 	 */
-	rq->cmd_len = hdr->request_len;
 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
 
 	rq->timeout = (hdr->timeout * HZ) / 1000;
@@ -212,8 +226,6 @@ bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
 
 	if (hdr->guard != 'Q')
 		return -EINVAL;
-	if (hdr->request_len > BLK_MAX_CDB)
-		return -EINVAL;
 	if (hdr->dout_xfer_len > (q->max_sectors << 9) ||
 	    hdr->din_xfer_len > (q->max_sectors << 9))
 		return -EIO;
@@ -302,6 +314,8 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
 	}
 	return rq;
 out:
+	if (rq->varlen_cdb_len)
+		kfree(rq->varlen_cdb);
 	blk_put_request(rq);
 	if (next_rq) {
 		blk_rq_unmap_user(next_rq->bio);
@@ -446,6 +460,8 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
 		hdr->dout_resid = rq->data_len;
 
 	blk_rq_unmap_user(bio);
+	if (rq->varlen_cdb_len)
+		kfree(rq->varlen_cdb);
 	blk_put_request(rq);
 
 	return ret;
-- 
1.5.3.6

[PATCH 1/5] iscsi: extended cdb support

[Pete Wyckoff]

From: Boaz Harrosh <bharrosh@panasas.com>

  Once varlen cdbs are supported by the block and scsi-ml layers
  we can apply this patch to support extended CDBs in iscsi.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Pete Wyckoff <pw@osc.edu>
---
 drivers/scsi/iscsi_tcp.c   |    2 +-
 drivers/scsi/libiscsi.c    |   56 ++++++++++++++++++++++++++++++++++++++++----
 include/scsi/iscsi_proto.h |    6 +++-
 3 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index e5be5fd..9fde5ce 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -1973,7 +1973,7 @@ static struct iscsi_transport iscsi_tcp_transport = {
 	.host_template		= &iscsi_sht,
 	.conndata_size		= sizeof(struct iscsi_conn),
 	.max_conn		= 1,
-	.max_cmd_len		= 16,
+	.max_cmd_len		= SCSI_MAX_VARLEN_CDB_SIZE,
 	/* session management */
 	.create_session		= iscsi_tcp_session_create,
 	.destroy_session	= iscsi_tcp_session_destroy,
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 553168a..94a8046 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -137,6 +137,45 @@ static int iscsi_add_hdr(struct iscsi_cmd_task *ctask, unsigned len)
 	return 0;
 }
 
+/*
+ * make an extended cdb AHS
+ */
+static int iscsi_prep_ecdb_ahs(struct iscsi_cmd_task *ctask)
+{
+	struct scsi_cmnd *cmd = ctask->sc;
+	unsigned rlen, pad_len;
+	unsigned short ahslength;
+	struct iscsi_ecdb_ahdr *ecdb_ahdr;
+	int rc;
+
+	ecdb_ahdr = iscsi_next_hdr(ctask);
+	rlen = cmd->cmd_len - ISCSI_CDB_SIZE;
+
+	BUG_ON(rlen > sizeof(ecdb_ahdr->ecdb));
+	ahslength = rlen + sizeof(ecdb_ahdr->reserved);
+
+	pad_len = iscsi_padding(rlen);
+
+	rc = iscsi_add_hdr(ctask, sizeof(ecdb_ahdr->ahslength) +
+			   sizeof(ecdb_ahdr->ahstype) + ahslength + pad_len);
+	if (rc)
+		return rc;
+
+	if (pad_len)
+		memset(&ecdb_ahdr->ecdb[rlen], 0, pad_len);
+
+	ecdb_ahdr->ahslength = cpu_to_be16(ahslength);
+	ecdb_ahdr->ahstype = ISCSI_AHSTYPE_CDB;
+	ecdb_ahdr->reserved = 0;
+	memcpy(ecdb_ahdr->ecdb, cmd->cmnd + ISCSI_CDB_SIZE, rlen);
+
+	debug_scsi("iscsi_prep_ecdb_ahs: varlen_cdb_len %d "
+		"rlen %d pad_len %d ahs_length %d iscsi_headers_size %u\n",
+		cmd->cmd_len, rlen, pad_len, ahslength, ctask->hdr_len);
+
+	return 0;
+}
+
 /**
  * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
  * @ctask: iscsi cmd task
@@ -150,7 +189,7 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 	struct iscsi_session *session = conn->session;
 	struct iscsi_cmd *hdr = ctask->hdr;
 	struct scsi_cmnd *sc = ctask->sc;
-	unsigned hdrlength;
+	unsigned hdrlength, cmd_len;
 	int rc;
 
 	ctask->hdr_len = 0;
@@ -165,10 +204,17 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 	hdr->cmdsn = cpu_to_be32(session->cmdsn);
 	session->cmdsn++;
 	hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
-	memcpy(hdr->cdb, sc->cmnd, sc->cmd_len);
-	if (sc->cmd_len < MAX_COMMAND_SIZE)
-		memset(&hdr->cdb[sc->cmd_len], 0,
-			MAX_COMMAND_SIZE - sc->cmd_len);
+	cmd_len = sc->cmd_len;
+	if (cmd_len < ISCSI_CDB_SIZE)
+		memset(&hdr->cdb[cmd_len], 0,
+			ISCSI_CDB_SIZE - cmd_len);
+	else if (cmd_len > ISCSI_CDB_SIZE) {
+		rc = iscsi_prep_ecdb_ahs(ctask);
+		if (rc)
+			return rc;
+		cmd_len = ISCSI_CDB_SIZE;
+	}
+	memcpy(hdr->cdb, sc->cmnd, cmd_len);
 
 	ctask->imm_count = 0;
 	if (sc->sc_data_direction == DMA_TO_DEVICE) {
diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h
index 318a909..8c591ac 100644
--- a/include/scsi/iscsi_proto.h
+++ b/include/scsi/iscsi_proto.h
@@ -112,6 +112,7 @@ struct iscsi_ahs_hdr {
 
 #define ISCSI_AHSTYPE_CDB		1
 #define ISCSI_AHSTYPE_RLENGTH		2
+#define ISCSI_CDB_SIZE			16
 
 /* iSCSI PDU Header */
 struct iscsi_cmd {
@@ -125,7 +126,7 @@ struct iscsi_cmd {
 	__be32 data_length;
 	__be32 cmdsn;
 	__be32 exp_statsn;
-	uint8_t cdb[16];	/* SCSI Command Block */
+	uint8_t cdb[ISCSI_CDB_SIZE];	/* SCSI Command Block */
 	/* Additional Data (Command Dependent) */
 };
 
@@ -154,7 +155,8 @@ struct iscsi_ecdb_ahdr {
 	__be16 ahslength;	/* CDB length - 15, including reserved byte */
 	uint8_t ahstype;
 	uint8_t reserved;
-	uint8_t ecdb[260 - 16];	/* 4-byte aligned extended CDB spillover */
+	/* 4-byte aligned extended CDB spillover */
+	uint8_t ecdb[260 - ISCSI_CDB_SIZE];
 };
 
 /* SCSI Response Header */
-- 
1.5.3.6

[PATCH 2/5] iscsi bidi support

[Pete Wyckoff]

From: Boaz Harrosh <bharrosh@panasas.com>

Adapted from separate libiscsi and TCP patches by Boaz to update for
iscsi changes and iscsi-tcp rewrite.  Dropped some needless conversion
to scsi_out() in some places.  Original log follows.

Once bidi support is accepted at block and scsi-ml layers
below bidi support to iscsi can be applied.
The assumed bidi API from scsi-ml is based on scsi_sgtables
but it is not at all far from any other implementation as far
as iscsi code is concerned:
- scsi_bidi_cmd() - return true if the command is bidi. Note
		    that this is a deviation from previous RFCs
		    in that we no longer have sc_dma_direction
		    == DMA_BIDIRECTIONAL. The command direction is DMA_TO_DEVICE
		    but with this flag on.
- scsi_{in,out}() - Which will return the right sg_table for IN or OUT
		    operation, in a generic way.
		    The small difference here due to sgtable implementation
		    is that in the past we had scsi_in()->sglist == NULL for
		    DMA_NONE and now we have scsi_in() == NULL.

At the generic libiscsi level
- prepare the additional bidi_read rlength header.
- access the right scsi_in() and/or scsi_out() side of things.
also for resid.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Pete Wyckoff <pw@osc.edu>
---
 drivers/scsi/iscsi_tcp.c |   14 ++++---
 drivers/scsi/libiscsi.c  |   81 +++++++++++++++++++++++++++++++++++++++------
 2 files changed, 78 insertions(+), 17 deletions(-)

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 9fde5ce..373639a 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -542,10 +542,11 @@ iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
 	tcp_ctask->exp_datasn++;
 
 	tcp_ctask->data_offset = be32_to_cpu(rhdr->offset);
-	if (tcp_ctask->data_offset + tcp_conn->in.datalen > scsi_bufflen(sc)) {
+	if (tcp_ctask->data_offset + tcp_conn->in.datalen >
+							scsi_in(sc)->length) {
 		debug_tcp("%s: data_offset(%d) + data_len(%d) > total_length_in(%d)\n",
 		          __FUNCTION__, tcp_ctask->data_offset,
-		          tcp_conn->in.datalen, scsi_bufflen(sc));
+			  tcp_conn->in.datalen, scsi_in(sc)->length);
 		return ISCSI_ERR_DATA_OFFSET;
 	}
 
@@ -558,8 +559,8 @@ iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
 
 			if (res_count > 0 &&
 			    (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
-			     res_count <= scsi_bufflen(sc)))
-				scsi_set_resid(sc, res_count);
+			     res_count <= scsi_in(sc)->length))
+				scsi_in(sc)->resid = res_count;
 			else
 				sc->result = (DID_BAD_TARGET << 16) |
 					rhdr->cmd_status;
@@ -783,8 +784,9 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 				  tcp_ctask->data_offset,
 				  tcp_conn->in.datalen);
 			return iscsi_segment_seek_sg(&tcp_conn->in.segment,
-						     scsi_sglist(ctask->sc),
-						     scsi_sg_count(ctask->sc),
+						     scsi_in(ctask->sc)->sglist,
+						     scsi_in(ctask->sc)->
+								sg_count,
 						     tcp_ctask->data_offset,
 						     tcp_conn->in.datalen,
 						     iscsi_tcp_process_data_in,
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 94a8046..cb7f539 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -176,6 +176,30 @@ static int iscsi_prep_ecdb_ahs(struct iscsi_cmd_task *ctask)
 	return 0;
 }
 
+static int iscsi_prep_bidi_ahs(struct iscsi_cmd_task *ctask)
+{
+	struct scsi_cmnd *sc = ctask->sc;
+	struct iscsi_rlength_ahdr *rlen_ahdr;
+	int rc;
+
+	rlen_ahdr = iscsi_next_hdr(ctask);
+	rc = iscsi_add_hdr(ctask, sizeof(*rlen_ahdr));
+	if (rc)
+		return rc;
+
+	rlen_ahdr->ahslength = cpu_to_be16(sizeof(rlen_ahdr->read_length) +
+					   sizeof(rlen_ahdr->reserved));
+	rlen_ahdr->ahstype = ISCSI_AHSTYPE_RLENGTH;
+	rlen_ahdr->reserved = 0;
+	rlen_ahdr->read_length = cpu_to_be32(scsi_in(sc)->length);
+
+	debug_scsi("bidi-in rlen_ahdr->read_length(%d) "
+		   "rlen_ahdr->ahslength(%d)\n",
+		   be32_to_cpu(rlen_ahdr->read_length),
+		   be16_to_cpu(rlen_ahdr->ahslength));
+	return 0;
+}
+
 /**
  * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
  * @ctask: iscsi cmd task
@@ -200,7 +224,6 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 	hdr->flags = ISCSI_ATTR_SIMPLE;
 	int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
 	hdr->itt = build_itt(ctask->itt, conn->id, session->age);
-	hdr->data_length = cpu_to_be32(scsi_bufflen(sc));
 	hdr->cmdsn = cpu_to_be32(session->cmdsn);
 	session->cmdsn++;
 	hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
@@ -216,9 +239,18 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 	}
 	memcpy(hdr->cdb, sc->cmnd, cmd_len);
 
+	if (scsi_bidi_cmnd(sc)) {
+		hdr->flags |= ISCSI_FLAG_CMD_READ;
+		rc = iscsi_prep_bidi_ahs(ctask);
+		if (rc)
+			return rc;
+	}
+
 	ctask->imm_count = 0;
 	if (sc->sc_data_direction == DMA_TO_DEVICE) {
+		unsigned int out_len = scsi_out(sc)->length;
 		hdr->flags |= ISCSI_FLAG_CMD_WRITE;
+		hdr->data_length = cpu_to_be32(out_len);
 		/*
 		 * Write counters:
 		 *
@@ -238,19 +270,19 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 		ctask->unsol_datasn = 0;
 
 		if (session->imm_data_en) {
-			if (scsi_bufflen(sc) >= session->first_burst)
+			if (out_len >= session->first_burst)
 				ctask->imm_count = min(session->first_burst,
 							conn->max_xmit_dlength);
 			else
-				ctask->imm_count = min(scsi_bufflen(sc),
+				ctask->imm_count = min(out_len,
 							conn->max_xmit_dlength);
 			hton24(hdr->dlength, ctask->imm_count);
 		} else
 			zero_data(hdr->dlength);
 
 		if (!session->initial_r2t_en) {
-			ctask->unsol_count = min((session->first_burst),
-				(scsi_bufflen(sc))) - ctask->imm_count;
+			ctask->unsol_count = min(session->first_burst, out_len)
+					     - ctask->imm_count;
 			ctask->unsol_offset = ctask->imm_count;
 		}
 
@@ -259,6 +291,7 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 			hdr->flags |= ISCSI_FLAG_CMD_FINAL;
 	} else {
 		hdr->flags |= ISCSI_FLAG_CMD_FINAL;
+		hdr->data_length = cpu_to_be32(scsi_bufflen(sc));
 		zero_data(hdr->dlength);
 
 		if (sc->sc_data_direction == DMA_FROM_DEVICE)
@@ -279,9 +312,11 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 
 	conn->scsicmd_pdus_cnt++;
 	debug_scsi("iscsi prep [%s cid %d sc %p cdb 0x%x itt 0x%x len %d "
-		"cmdsn %d win %d]\n",
+		"bidi_len %d cmdsn %d win %d]\n",
+		scsi_bidi_cmnd(sc) ? "bidirectional" :
 		sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",
 		conn->id, sc, sc->cmnd[0], ctask->itt, scsi_bufflen(sc),
+		scsi_bidi_cmnd(sc) ? scsi_in(sc)->length : 0,
 		session->cmdsn, session->max_cmdsn - session->exp_cmdsn + 1);
 	return 0;
 }
@@ -344,7 +379,12 @@ static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
 		conn->session->tt->cleanup_cmd_task(conn, ctask);
 
 	sc->result = err;
-	scsi_set_resid(sc, scsi_bufflen(sc));
+	if (scsi_bidi_cmnd(sc)) {
+		scsi_out(sc)->resid = scsi_out(sc)->length;
+		scsi_in(sc)->resid = scsi_in(sc)->length;
+	} else {
+		scsi_set_resid(sc, scsi_bufflen(sc));
+	}
 	if (conn->ctask == ctask)
 		conn->ctask = NULL;
 	/* release ref from queuecommand */
@@ -488,9 +528,23 @@ invalid_datalen:
 			scsi_set_resid(sc, res_count);
 		else
 			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
-	} else if (rhdr->flags & (ISCSI_FLAG_CMD_BIDI_UNDERFLOW |
-	                          ISCSI_FLAG_CMD_BIDI_OVERFLOW))
-		sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
+	}
+	if (rhdr->flags & (ISCSI_FLAG_CMD_BIDI_UNDERFLOW |
+			   ISCSI_FLAG_CMD_BIDI_OVERFLOW)) {
+		if (scsi_bidi_cmnd(sc)) {
+			int res_count = be32_to_cpu(rhdr->bi_residual_count);
+
+			if (res_count > 0 &&
+			    (rhdr->flags & ISCSI_FLAG_CMD_BIDI_OVERFLOW ||
+			     res_count <= scsi_in(sc)->length))
+				scsi_in(sc)->resid = res_count;
+			else
+				sc->result = (DID_BAD_TARGET << 16) |
+					     rhdr->cmd_status;
+		} else {
+			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
+		}
+	}
 
 out:
 	debug_scsi("done [sc %lx res %d itt 0x%x]\n",
@@ -1140,7 +1194,12 @@ fault:
 	printk(KERN_ERR "iscsi: cmd 0x%x is not queued (%d)\n",
 	       sc->cmnd[0], reason);
 	sc->result = (DID_NO_CONNECT << 16);
-	scsi_set_resid(sc, scsi_bufflen(sc));
+	if (scsi_bidi_cmnd(sc)) {
+		scsi_out(sc)->resid = scsi_out(sc)->length;
+		scsi_in(sc)->resid = scsi_in(sc)->length;
+	} else {
+		scsi_set_resid(sc, scsi_bufflen(sc));
+	}
 	sc->scsi_done(sc);
 	spin_lock(host->host_lock);
 	return 0;
-- 
1.5.3.6

[PATCH 4/5] bsg: bidi fix

[Pete Wyckoff]

Fixes for bsg to handle bidirectional commands.  The next_rq part
of a bidi command must be marked REQ_TYPE_BLOCK_PC for scsi_init_sgtable.

Signed-off-by: Pete Wyckoff <pw@osc.edu>
---
 block/bsg.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/block/bsg.c b/block/bsg.c
index 0d9364d..fc3a024 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -291,6 +291,7 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
 			goto out;
 		}
 		rq->next_rq = next_rq;
+		next_rq->cmd_type = REQ_TYPE_BLOCK_PC;
 
 		dxferp = (void*)(unsigned long)hdr->din_xferp;
 		ret =  blk_rq_map_user(q, next_rq, dxferp, hdr->din_xfer_len);
-- 
1.5.3.6

[PATCH 5/5] iscsi tcp bidi capable

[Pete Wyckoff]

Mark iscsi_tcp as being capable of bidirectional transfers.  Perhaps
instead we could remove the check in bsg, as that is the only entry
to SCSI that bothers to check the flag.

Signed-off-by: Pete Wyckoff <pw@osc.edu>
---
 drivers/scsi/iscsi_tcp.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 373639a..ecae470 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -1915,6 +1915,12 @@ static void iscsi_tcp_session_destroy(struct iscsi_cls_session *cls_session)
 	iscsi_session_teardown(cls_session);
 }
 
+static int iscsi_tcp_slave_alloc(struct scsi_device *sdev)
+{
+	set_bit(QUEUE_FLAG_BIDI, &sdev->request_queue->queue_flags);
+	return 0;
+}
+
 static int iscsi_tcp_slave_configure(struct scsi_device *sdev)
 {
 	blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_ANY);
@@ -1936,6 +1942,7 @@ static struct scsi_host_template iscsi_sht = {
 	.eh_host_reset_handler	= iscsi_eh_host_reset,
 	.use_clustering         = DISABLE_CLUSTERING,
 	.use_sg_chaining	= ENABLE_SG_CHAINING,
+	.slave_alloc		= iscsi_tcp_slave_alloc,
 	.slave_configure        = iscsi_tcp_slave_configure,
 	.proc_name		= "iscsi_tcp",
 	.this_id		= -1,
-- 
1.5.3.6

bidi, varlen, bsg success report

[Pete Wyckoff]

I spent the last couple of days rebasing my working set of kernel
patches from 2.6.22-rc5 to 2.6.24-rc6.  I want to use the BSG
interface from userspace to submit variable-length bidirectional
SCSI commands to targets via iSCSI TCP.

Many thanks to all the work with scsi data accessors and iscsi that
makes this much easier, and to Boaz for continuing to maintain
patches.  Here's what I needed to do to make it work.

Start with linus-2.6.24-rc6.
Merge scsi-misc.
Apply the following outstanding patches from Boaz:

bidi
    scsi: scsi_data_buffer
    http://marc.info/?l=linux-scsi&m=119754650614813&w=2

    scsi: bidi support
    http://marc.info/?l=linux-scsi&m=119754667915055&w=2

varlen
    [PATCH 1/3] Let scsi_cmnd->cmnd use request->cmd buffer
    http://marc.info/?l=linux-scsi&m=119798523823750&w=2

    [PATCH 2/2] block layer varlen-cdb
    http://marc.info/?l=linux-scsi&m=119798548624218&w=2

    [PATCH 3/3] scsi: varlen extended and vendor-specific cdbs
    http://marc.info/?l=linux-scsi&m=119798563924476&w=2

Then a few more, two modified from earlier Boaz patches, and three
new ones by me, mainly to make bsg work.  They follow.

1. iscsi: extended cdb support
Adapted from Boaz
http://marc.info/?l=linux-scsi&m=119394074127857&w=2

2. iscsi: bidi support
Adapted from two old Boaz patches that can be found in this git:
http://www.bhalevy.com/git/gitweb.cgi?p=open-osd/.git;a=commitdiff;h=b5a97649eadb9434acbc4170a8aebd962af6d960
http://www.bhalevy.com/git/gitweb.cgi?p=open-osd/.git;a=commitdiff;h=cf3d4684a22bde6787f2eccee66d7b0ee9c9182c

3. bsg: accept varlen commands

4. bsg: bidi fix

5. iscsi tcp: bidi capable

Suggestions:  Boaz is probably the best qualified to shepherd his
outstanding five patches plus the two others I mention above (#1,
#2).  The first bsg patch (#3) won't apply without the varlen
patches.  The last two (#4, #5) are harmless and can go in now, but
won't matter until the bidi patches are in.  Comments on these
welcome.

Hope this is helpful.  I'm definitely looking forward to seeing
all this merged into mainline eventually.

		-- Pete

[PATCH 1/5] iscsi: extended cdb support

[Pete Wyckoff]

[Resend, date was in ancient history.]

From: Boaz Harrosh <bharrosh@panasas.com>

  Once varlen cdbs are supported by the block and scsi-ml layers
  we can apply this patch to support extended CDBs in iscsi.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Pete Wyckoff <pw@osc.edu>
---
 drivers/scsi/iscsi_tcp.c   |    2 +-
 drivers/scsi/libiscsi.c    |   56 ++++++++++++++++++++++++++++++++++++++++----
 include/scsi/iscsi_proto.h |    6 +++-
 3 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index e5be5fd..9fde5ce 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -1973,7 +1973,7 @@ static struct iscsi_transport iscsi_tcp_transport = {
 	.host_template		= &iscsi_sht,
 	.conndata_size		= sizeof(struct iscsi_conn),
 	.max_conn		= 1,
-	.max_cmd_len		= 16,
+	.max_cmd_len		= SCSI_MAX_VARLEN_CDB_SIZE,
 	/* session management */
 	.create_session		= iscsi_tcp_session_create,
 	.destroy_session	= iscsi_tcp_session_destroy,
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 553168a..94a8046 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -137,6 +137,45 @@ static int iscsi_add_hdr(struct iscsi_cmd_task *ctask, unsigned len)
 	return 0;
 }
 
+/*
+ * make an extended cdb AHS
+ */
+static int iscsi_prep_ecdb_ahs(struct iscsi_cmd_task *ctask)
+{
+	struct scsi_cmnd *cmd = ctask->sc;
+	unsigned rlen, pad_len;
+	unsigned short ahslength;
+	struct iscsi_ecdb_ahdr *ecdb_ahdr;
+	int rc;
+
+	ecdb_ahdr = iscsi_next_hdr(ctask);
+	rlen = cmd->cmd_len - ISCSI_CDB_SIZE;
+
+	BUG_ON(rlen > sizeof(ecdb_ahdr->ecdb));
+	ahslength = rlen + sizeof(ecdb_ahdr->reserved);
+
+	pad_len = iscsi_padding(rlen);
+
+	rc = iscsi_add_hdr(ctask, sizeof(ecdb_ahdr->ahslength) +
+			   sizeof(ecdb_ahdr->ahstype) + ahslength + pad_len);
+	if (rc)
+		return rc;
+
+	if (pad_len)
+		memset(&ecdb_ahdr->ecdb[rlen], 0, pad_len);
+
+	ecdb_ahdr->ahslength = cpu_to_be16(ahslength);
+	ecdb_ahdr->ahstype = ISCSI_AHSTYPE_CDB;
+	ecdb_ahdr->reserved = 0;
+	memcpy(ecdb_ahdr->ecdb, cmd->cmnd + ISCSI_CDB_SIZE, rlen);
+
+	debug_scsi("iscsi_prep_ecdb_ahs: varlen_cdb_len %d "
+		"rlen %d pad_len %d ahs_length %d iscsi_headers_size %u\n",
+		cmd->cmd_len, rlen, pad_len, ahslength, ctask->hdr_len);
+
+	return 0;
+}
+
 /**
  * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
  * @ctask: iscsi cmd task
@@ -150,7 +189,7 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 	struct iscsi_session *session = conn->session;
 	struct iscsi_cmd *hdr = ctask->hdr;
 	struct scsi_cmnd *sc = ctask->sc;
-	unsigned hdrlength;
+	unsigned hdrlength, cmd_len;
 	int rc;
 
 	ctask->hdr_len = 0;
@@ -165,10 +204,17 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
 	hdr->cmdsn = cpu_to_be32(session->cmdsn);
 	session->cmdsn++;
 	hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
-	memcpy(hdr->cdb, sc->cmnd, sc->cmd_len);
-	if (sc->cmd_len < MAX_COMMAND_SIZE)
-		memset(&hdr->cdb[sc->cmd_len], 0,
-			MAX_COMMAND_SIZE - sc->cmd_len);
+	cmd_len = sc->cmd_len;
+	if (cmd_len < ISCSI_CDB_SIZE)
+		memset(&hdr->cdb[cmd_len], 0,
+			ISCSI_CDB_SIZE - cmd_len);
+	else if (cmd_len > ISCSI_CDB_SIZE) {
+		rc = iscsi_prep_ecdb_ahs(ctask);
+		if (rc)
+			return rc;
+		cmd_len = ISCSI_CDB_SIZE;
+	}
+	memcpy(hdr->cdb, sc->cmnd, cmd_len);
 
 	ctask->imm_count = 0;
 	if (sc->sc_data_direction == DMA_TO_DEVICE) {
diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h
index 318a909..8c591ac 100644
--- a/include/scsi/iscsi_proto.h
+++ b/include/scsi/iscsi_proto.h
@@ -112,6 +112,7 @@ struct iscsi_ahs_hdr {
 
 #define ISCSI_AHSTYPE_CDB		1
 #define ISCSI_AHSTYPE_RLENGTH		2
+#define ISCSI_CDB_SIZE			16
 
 /* iSCSI PDU Header */
 struct iscsi_cmd {
@@ -125,7 +126,7 @@ struct iscsi_cmd {
 	__be32 data_length;
 	__be32 cmdsn;
 	__be32 exp_statsn;
-	uint8_t cdb[16];	/* SCSI Command Block */
+	uint8_t cdb[ISCSI_CDB_SIZE];	/* SCSI Command Block */
 	/* Additional Data (Command Dependent) */
 };
 
@@ -154,7 +155,8 @@ struct iscsi_ecdb_ahdr {
 	__be16 ahslength;	/* CDB length - 15, including reserved byte */
 	uint8_t ahstype;
 	uint8_t reserved;
-	uint8_t ecdb[260 - 16];	/* 4-byte aligned extended CDB spillover */
+	/* 4-byte aligned extended CDB spillover */
+	uint8_t ecdb[260 - ISCSI_CDB_SIZE];
 };
 
 /* SCSI Response Header */
-- 
1.5.3.6

[PATCH 3/5] bsg: accept varlen commands

[Pete Wyckoff]

[Resend, date was in ancient history.]

Accept variable length SCSI commands through BSG.

Signed-off-by: Pete Wyckoff <pw@osc.edu>
---
 block/bsg.c |   34 +++++++++++++++++++++++++---------
 1 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/block/bsg.c b/block/bsg.c
index 8e181ab..0d9364d 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -175,14 +175,29 @@ unlock:
 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
 				struct sg_io_v4 *hdr, int has_write_perm)
 {
-	memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
-
-	if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request,
-			   hdr->request_len))
-		return -EFAULT;
+	void __user *buf = (void __user *)(unsigned long) hdr->request;
+	int len = hdr->request_len;
+	unsigned char *cmd;
+
+	if (len > BLK_MAX_CDB) {
+		rq->cmd_len = 0;
+		rq->varlen_cdb_len = len;
+		rq->varlen_cdb = kmalloc(len, GFP_KERNEL);
+		if (rq->varlen_cdb == NULL)
+			return -ENOMEM;
+		if (copy_from_user(rq->varlen_cdb, buf, len))
+			return -EFAULT;
+		cmd = &rq->varlen_cdb[0];
+	} else {
+		rq->cmd_len = len;
+		memset(rq->cmd, 0, BLK_MAX_CDB);  /* for ATAPI */
+		if (copy_from_user(rq->cmd, buf, len))
+			return -EFAULT;
+		cmd = &rq->cmd[0];
+	}
 
 	if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
-		if (blk_verify_command(rq->cmd, has_write_perm))
+		if (blk_verify_command(cmd, has_write_perm))
 			return -EPERM;
 	} else if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
@@ -190,7 +205,6 @@ static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
 	/*
 	 * fill in request structure
 	 */
-	rq->cmd_len = hdr->request_len;
 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
 
 	rq->timeout = (hdr->timeout * HZ) / 1000;
@@ -212,8 +226,6 @@ bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
 
 	if (hdr->guard != 'Q')
 		return -EINVAL;
-	if (hdr->request_len > BLK_MAX_CDB)
-		return -EINVAL;
 	if (hdr->dout_xfer_len > (q->max_sectors << 9) ||
 	    hdr->din_xfer_len > (q->max_sectors << 9))
 		return -EIO;
@@ -302,6 +314,8 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
 	}
 	return rq;
 out:
+	if (rq->varlen_cdb_len)
+		kfree(rq->varlen_cdb);
 	blk_put_request(rq);
 	if (next_rq) {
 		blk_rq_unmap_user(next_rq->bio);
@@ -446,6 +460,8 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
 		hdr->dout_resid = rq->data_len;
 
 	blk_rq_unmap_user(bio);
+	if (rq->varlen_cdb_len)
+		kfree(rq->varlen_cdb);
 	blk_put_request(rq);
 
 	return ret;
-- 
1.5.3.6

Re: bidi, varlen, bsg success report

[Boaz Harrosh]

On Sat, Dec 22 2007 at 22:15 +0200, Pete Wyckoff <pw@osc.edu> wrote:
> I spent the last couple of days rebasing my working set of kernel
> patches from 2.6.22-rc5 to 2.6.24-rc6.  I want to use the BSG
> interface from userspace to submit variable-length bidirectional
> SCSI commands to targets via iSCSI TCP.
> 
> Many thanks to all the work with scsi data accessors and iscsi that
> makes this much easier, and to Boaz for continuing to maintain
> patches.  Here's what I needed to do to make it work.
> 
> Start with linus-2.6.24-rc6.
> Merge scsi-misc.
> Apply the following outstanding patches from Boaz:
> 
> bidi
>     scsi: scsi_data_buffer
>     http://marc.info/?l=linux-scsi&m=119754650614813&w=2
> 
>     scsi: bidi support
>     http://marc.info/?l=linux-scsi&m=119754667915055&w=2
> 
> varlen
>     [PATCH 1/3] Let scsi_cmnd->cmnd use request->cmd buffer
>     http://marc.info/?l=linux-scsi&m=119798523823750&w=2
> 
>     [PATCH 2/2] block layer varlen-cdb
>     http://marc.info/?l=linux-scsi&m=119798548624218&w=2
> 
>     [PATCH 3/3] scsi: varlen extended and vendor-specific cdbs
>     http://marc.info/?l=linux-scsi&m=119798563924476&w=2
> 
> Then a few more, two modified from earlier Boaz patches, and three
> new ones by me, mainly to make bsg work.  They follow.
> 
> 1. iscsi: extended cdb support
> Adapted from Boaz
> http://marc.info/?l=linux-scsi&m=119394074127857&w=2
> 
> 2. iscsi: bidi support
> Adapted from two old Boaz patches that can be found in this git:
> http://www.bhalevy.com/git/gitweb.cgi?p=open-osd/.git;a=commitdiff;h=b5a97649eadb9434acbc4170a8aebd962af6d960
> http://www.bhalevy.com/git/gitweb.cgi?p=open-osd/.git;a=commitdiff;h=cf3d4684a22bde6787f2eccee66d7b0ee9c9182c
> 
> 3. bsg: accept varlen commands
> 
> 4. bsg: bidi fix
> 
> 5. iscsi tcp: bidi capable
> 
> Suggestions:  Boaz is probably the best qualified to shepherd his
> outstanding five patches plus the two others I mention above (#1,
> #2).  The first bsg patch (#3) won't apply without the varlen
> patches.  The last two (#4, #5) are harmless and can go in now, but
> won't matter until the bidi patches are in.  Comments on these
> welcome.
> 
> Hope this is helpful.  I'm definitely looking forward to seeing
> all this merged into mainline eventually.
> 
> 		-- Pete
> -
Dear peter.

This is grate to know. I know from passed experience that code
might work well for your own set of tests, but otherwise hide bugs.

Please forgive me about the iSCSI patches, I have an updated set
here in my trees, but I have not posted them, because I thought
that no one cares, but me.

I did not yet get any principle OK about the varlen API. that
is - scsi_cmnd->cmnd changes to a pointer that points to either
a static buffer at request or a dynamic buffer at ULD - Because
if this principle is accepted, than please Note that the patch
"iscsi: extended cdb support" can be applied now, before the actual
cleanups and implementation are applied.
I attributed the complete silence treatment from both block and scsi 
maintainers, to the holiday session. I hope they come with renewed 
strength next year ;)

I will compare our iscsi patches and put a freshen set at:
git://git.bhalevy.com/open-osd osd_dev
or on the web
http://git.bhalevy.com/git/gitweb.cgi?p=open-osd/.git;a=summary
(give me until the end of today)

I have inspected your other patches, and they all look good.
I will include them in above git.

Happy holidays
Boaz