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Commit 004d6530 authored by Boaz Harrosh's avatar Boaz Harrosh Committed by James Bottomley
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[SCSI] iscsi_tcp, libiscsi: initial AHS Support 



  at libiscsi generic code
  - currently code assumes a storage space of pdu header is allocated
    at llds ctask and is pointed to by iscsi_cmd_task->hdr. Here I add
    a hdr_max field pertaining to that storage, and an hdr_len that
    accumulates the current use of the pdu-header.

  - Add an iscsi_next_hdr() inline which returns the next free space
    to write new Header at. Also iscsi_next_hdr() is used to retrieve
    the address at which to write the header-digest.

  - Add iscsi_add_hdr(length). What the user do is calls iscsi_next_hdr()
    for address of the new header, than calls iscsi_add_hdr(length) with
    the size of the new header. iscsi_add_hdr() will check if space is
    available and update to the new size. length must be padded according
    to standard.

  - Add 2 padding inline helpers thanks to Olaf. Current patch does not
    use them but Following patches will.
    Also moved definition of ISCSI_PAD_LEN to iscsi_proto.h which had
    PAD_WORD_LEN that was never used anywhere.

  - Let iscsi_prep_scsi_cmd_pdu() signal an Error return since now  it is
    possible that it will fail.

  - I was tired of yet again writing a "this is a digest" comment next to
    sizeof(__u32) so I defined a new ISCSI_DIGEST_SIZE. Now I don't need
    any comments. Changed all places that used sizeof(__u32) or "4" in
    connection to a digest.

  iscsi_tcp specific code
  - At struct iscsi_tcp_cmd_task allocate maximum space allowed in
    standard for all headers following the iscsi_cmd header. and mark
    it so in iscsi_tcp_session_create()
  - At iscsi_send_cmd_hdr() retrieve the correct headers size and
    write header digest at iscsi_next_hdr().

Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: default avatarOlaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent 7207fea4

drivers/scsi/iscsi_tcp.c

+8 −8
Original line number Diff line number Diff line
@@ -113,7 +113,7 @@ iscsi_hdr_digest(struct iscsi_conn *conn, struct iscsi_buf *buf, 
	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;



	crypto_hash_digest(&tcp_conn->tx_hash, &buf->sg, buf->sg.length, crc);

	buf->sg.length += sizeof(u32);

	buf->sg.length += ISCSI_DIGEST_SIZE;

}



/*
@@ -220,6 +220,7 @@ static inline int 
iscsi_tcp_chunk_done(struct iscsi_chunk *chunk)

{

	static unsigned char padbuf[ISCSI_PAD_LEN];

	unsigned int pad;



	if (chunk->copied < chunk->size) {

		iscsi_tcp_chunk_map(chunk);
@@ -243,10 +244,8 @@ iscsi_tcp_chunk_done(struct iscsi_chunk *chunk) 
	}



	/* Do we need to handle padding? */

	if (chunk->total_copied & (ISCSI_PAD_LEN-1)) {

		unsigned int pad;



		pad = ISCSI_PAD_LEN - (chunk->total_copied & (ISCSI_PAD_LEN-1));

	pad = iscsi_padding(chunk->total_copied);

	if (pad != 0) {

		debug_tcp("consume %d pad bytes\n", pad);

		chunk->total_size += pad;

		chunk->size = pad;
@@ -1385,11 +1384,11 @@ iscsi_send_cmd_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
		}



		iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)ctask->hdr,

				  sizeof(struct iscsi_hdr));

				  ctask->hdr_len);



		if (conn->hdrdgst_en)

			iscsi_hdr_digest(conn, &tcp_ctask->headbuf,

					 (u8*)tcp_ctask->hdrext);

					 iscsi_next_hdr(ctask));

		tcp_ctask->xmstate &= ~XMSTATE_CMD_HDR_INIT;

		tcp_ctask->xmstate |= XMSTATE_CMD_HDR_XMIT;

	}
@@ -2176,7 +2175,8 @@ iscsi_tcp_session_create(struct iscsi_transport *iscsit, 
		struct iscsi_cmd_task *ctask = session->cmds[cmd_i];

		struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;



		ctask->hdr = &tcp_ctask->hdr;

		ctask->hdr = &tcp_ctask->hdr.cmd_hdr;

		ctask->hdr_max = sizeof(tcp_ctask->hdr) - ISCSI_DIGEST_SIZE;

	}



	for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {

drivers/scsi/iscsi_tcp.h

+7 −6
Original line number Diff line number Diff line
@@ -41,7 +41,6 @@ 
#define XMSTATE_IMM_HDR_INIT		0x1000

#define XMSTATE_SOL_HDR_INIT		0x2000



#define ISCSI_PAD_LEN			4

#define ISCSI_SG_TABLESIZE		SG_ALL

#define ISCSI_TCP_MAX_CMD_LEN		16
@@ -130,14 +129,14 @@ struct iscsi_buf { 


struct iscsi_data_task {

	struct iscsi_data	hdr;			/* PDU */

	char			hdrext[sizeof(__u32)];	/* Header-Digest */

	char			hdrext[ISCSI_DIGEST_SIZE];/* Header-Digest */

	struct iscsi_buf	digestbuf;		/* digest buffer */

	uint32_t		digest;			/* data digest */

};



struct iscsi_tcp_mgmt_task {

	struct iscsi_hdr	hdr;

	char			hdrext[sizeof(__u32)]; /* Header-Digest */

	char			hdrext[ISCSI_DIGEST_SIZE]; /* Header-Digest */

	int			xmstate;	/* mgmt xmit progress */

	struct iscsi_buf	headbuf;	/* header buffer */

	struct iscsi_buf	sendbuf;	/* in progress buffer */
@@ -159,9 +158,11 @@ struct iscsi_r2t_info { 
};



struct iscsi_tcp_cmd_task {

	struct iscsi_cmd	hdr;

	char			hdrext[4*sizeof(__u16)+	/* AHS */

				    sizeof(__u32)];	/* HeaderDigest */

	struct iscsi_hdr_buff {

		struct iscsi_cmd	cmd_hdr;

		char			hdrextbuf[ISCSI_MAX_AHS_SIZE +

		                                  ISCSI_DIGEST_SIZE];

	} hdr;

	char			pad[ISCSI_PAD_LEN];

	int			pad_count;		/* padded bytes */

	struct iscsi_buf	headbuf;		/* header buf (xmit) */

drivers/scsi/libiscsi.c

+39 −2
Original line number Diff line number Diff line
@@ -37,6 +37,9 @@ 
#include <scsi/scsi_transport_iscsi.h>

#include <scsi/libiscsi.h>



static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,

			 int err);



struct iscsi_session *

class_to_transport_session(struct iscsi_cls_session *cls_session)

{
@@ -122,6 +125,20 @@ void iscsi_prep_unsolicit_data_pdu(struct iscsi_cmd_task *ctask, 
}

EXPORT_SYMBOL_GPL(iscsi_prep_unsolicit_data_pdu);



static int iscsi_add_hdr(struct iscsi_cmd_task *ctask, unsigned len)

{

	unsigned exp_len = ctask->hdr_len + len;



	if (exp_len > ctask->hdr_max) {

		WARN_ON(1);

		return -EINVAL;

	}



	WARN_ON(len & (ISCSI_PAD_LEN - 1)); /* caller must pad the AHS */

	ctask->hdr_len = exp_len;

	return 0;

}



/**

 * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu

 * @ctask: iscsi cmd task
@@ -129,13 +146,19 @@ EXPORT_SYMBOL_GPL(iscsi_prep_unsolicit_data_pdu); 
 * Prep basic iSCSI PDU fields for a scsi cmd pdu. The LLD should set

 * fields like dlength or final based on how much data it sends

 */

static void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)

static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)

{

	struct iscsi_conn *conn = ctask->conn;

	struct iscsi_session *session = conn->session;

	struct iscsi_cmd *hdr = ctask->hdr;

	struct scsi_cmnd *sc = ctask->sc;

	unsigned hdrlength;

	int rc;



	ctask->hdr_len = 0;

	rc = iscsi_add_hdr(ctask, sizeof(*hdr));

	if (rc)

		return rc;

        hdr->opcode = ISCSI_OP_SCSI_CMD;

        hdr->flags = ISCSI_ATTR_SIMPLE;

        int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
@@ -199,6 +222,15 @@ static void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask) 
			hdr->flags |= ISCSI_FLAG_CMD_READ;

	}



	/* calculate size of additional header segments (AHSs) */

	hdrlength = ctask->hdr_len - sizeof(*hdr);



	WARN_ON(hdrlength & (ISCSI_PAD_LEN-1));

	hdrlength /= ISCSI_PAD_LEN;



	WARN_ON(hdrlength >= 256);

	hdr->hlength = hdrlength & 0xFF;



	conn->scsicmd_pdus_cnt++;



        debug_scsi("iscsi prep [%s cid %d sc %p cdb 0x%x itt 0x%x len %d "
@@ -206,6 +238,7 @@ static void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask) 
                sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",

		conn->id, sc, sc->cmnd[0], ctask->itt, scsi_bufflen(sc),

                session->cmdsn, session->max_cmdsn - session->exp_cmdsn + 1);

	return 0;

}



/**
@@ -744,7 +777,10 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 


		conn->ctask = list_entry(conn->xmitqueue.next,

					 struct iscsi_cmd_task, running);

		iscsi_prep_scsi_cmd_pdu(conn->ctask);

		if (iscsi_prep_scsi_cmd_pdu(conn->ctask)) {

			fail_command(conn, conn->ctask, DID_ABORT << 16);

			continue;

		}

		conn->session->tt->init_cmd_task(conn->ctask);

		conn->ctask->state = ISCSI_TASK_RUNNING;

		list_move_tail(conn->xmitqueue.next, &conn->run_list);
@@ -1534,6 +1570,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, 
		if (cmd_task_size)

			ctask->dd_data = &ctask[1];

		ctask->itt = cmd_i;

		ctask->hdr_max = sizeof(struct iscsi_cmd);

		INIT_LIST_HEAD(&ctask->running);

	}

include/scsi/iscsi_proto.h

+9 −1
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ 
#define ISCSI_LISTEN_PORT	3260



/* Padding word length */

#define PAD_WORD_LEN		4

#define ISCSI_PAD_LEN		4



/*

 * useful common(control and data pathes) macro
@@ -147,6 +147,14 @@ struct iscsi_rlength_ahdr { 
	__be32 read_length;

};



/* Extended CDB AHS */

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 */

};



/* SCSI Response Header */

struct iscsi_cmd_rsp {

	uint8_t opcode;

include/scsi/libiscsi.h

+31 −2
Original line number Diff line number Diff line
@@ -78,6 +78,9 @@ enum { 
#define ISCSI_ADDRESS_BUF_LEN		64



enum {

	/* this is the maximum possible storage for AHSs */

	ISCSI_MAX_AHS_SIZE = sizeof(struct iscsi_ecdb_ahdr) +

				sizeof(struct iscsi_rlength_ahdr),

	ISCSI_DIGEST_SIZE = sizeof(__u32),

};
@@ -102,10 +105,13 @@ enum { 


struct iscsi_cmd_task {

	/*

	 * Becuae LLDs allocate their hdr differently, this is a pointer to

	 * that storage. It must be setup at session creation time.

	 * Because LLDs allocate their hdr differently, this is a pointer

	 * and length to that storage. It must be setup at session

	 * creation time.

	 */

	struct iscsi_cmd	*hdr;

	unsigned short		hdr_max;

	unsigned short		hdr_len;	/* accumulated size of hdr used */

	int			itt;		/* this ITT */



	uint32_t		unsol_datasn;
@@ -124,6 +130,11 @@ struct iscsi_cmd_task { 
	void			*dd_data;	/* driver/transport data */

};



static inline void* iscsi_next_hdr(struct iscsi_cmd_task *ctask)

{

	return (void*)ctask->hdr + ctask->hdr_len;

}



struct iscsi_conn {

	struct iscsi_cls_conn	*cls_conn;	/* ptr to class connection */

	void			*dd_data;	/* iscsi_transport data */
@@ -342,4 +353,22 @@ extern void iscsi_requeue_ctask(struct iscsi_cmd_task *ctask); 
extern void iscsi_pool_free(struct iscsi_queue *, void **);

extern int iscsi_pool_init(struct iscsi_queue *, int, void ***, int);



/*

 * inline functions to deal with padding.

 */

static inline unsigned int

iscsi_padded(unsigned int len)

{

	return (len + ISCSI_PAD_LEN - 1) & ~(ISCSI_PAD_LEN - 1);

}



static inline unsigned int

iscsi_padding(unsigned int len)

{

	len &= (ISCSI_PAD_LEN - 1);

	if (len)

		len = ISCSI_PAD_LEN - len;

	return len;

}



#endif