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Commit 38d1c069 authored by Boaz Harrosh's avatar Boaz Harrosh Committed by James Bottomley
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[SCSI] iscsi: extended cdb support 



Support for extended CDBs in iscsi.
All we need is to check if command spills over 16 bytes then allocate
an iscsi-extended-header for the leftovers.

Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
Reviewed-by: default avatarPete Wyckoff <pw@osc.edu>
Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent 57b7658a

drivers/scsi/libiscsi.c

+50 −5
Original line number Diff line number Diff line
@@ -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 +204,16 @@ 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) {

include/scsi/iscsi_proto.h

+4 −2
Original line number Diff line number Diff line
@@ -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 */