iscsi_tcp.c

linux 内核源代码

		set_bit(XMSTATE_BIT_CMD_HDR_XMIT, &tcp_ctask->xmstate);
	}

	if (test_bit(XMSTATE_BIT_CMD_HDR_XMIT, &tcp_ctask->xmstate)) {
		rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->imm_count);
		if (rc)
			return rc;
		clear_bit(XMSTATE_BIT_CMD_HDR_XMIT, &tcp_ctask->xmstate);

		if (sc->sc_data_direction != DMA_TO_DEVICE)
			return 0;

		if (ctask->imm_count) {
			set_bit(XMSTATE_BIT_IMM_DATA, &tcp_ctask->xmstate);
			iscsi_set_padding(tcp_ctask, ctask->imm_count);

			if (ctask->conn->datadgst_en) {
				iscsi_data_digest_init(ctask->conn->dd_data,
						       tcp_ctask);
				tcp_ctask->immdigest = 0;
			}
		}

		if (ctask->unsol_count) {
			set_bit(XMSTATE_BIT_UNS_HDR, &tcp_ctask->xmstate);
			set_bit(XMSTATE_BIT_UNS_INIT, &tcp_ctask->xmstate);
		}
	}
	return rc;
}

static int
iscsi_send_padding(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
	int sent = 0, rc;

	if (test_bit(XMSTATE_BIT_W_PAD, &tcp_ctask->xmstate)) {
		iscsi_buf_init_iov(&tcp_ctask->sendbuf, (char*)&tcp_ctask->pad,
				   tcp_ctask->pad_count);
		if (conn->datadgst_en)
			crypto_hash_update(&tcp_conn->tx_hash,
					   &tcp_ctask->sendbuf.sg,
					   tcp_ctask->sendbuf.sg.length);
	} else if (!test_bit(XMSTATE_BIT_W_RESEND_PAD, &tcp_ctask->xmstate))
		return 0;

	clear_bit(XMSTATE_BIT_W_PAD, &tcp_ctask->xmstate);
	clear_bit(XMSTATE_BIT_W_RESEND_PAD, &tcp_ctask->xmstate);
	debug_scsi("sending %d pad bytes for itt 0x%x\n",
		   tcp_ctask->pad_count, ctask->itt);
	rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf, &tcp_ctask->pad_count,
			   &sent);
	if (rc) {
		debug_scsi("padding send failed %d\n", rc);
		set_bit(XMSTATE_BIT_W_RESEND_PAD, &tcp_ctask->xmstate);
	}
	return rc;
}

static int
iscsi_send_digest(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
			struct iscsi_buf *buf, uint32_t *digest)
{
	struct iscsi_tcp_cmd_task *tcp_ctask;
	struct iscsi_tcp_conn *tcp_conn;
	int rc, sent = 0;

	if (!conn->datadgst_en)
		return 0;

	tcp_ctask = ctask->dd_data;
	tcp_conn = conn->dd_data;

	if (!test_bit(XMSTATE_BIT_W_RESEND_DATA_DIGEST, &tcp_ctask->xmstate)) {
		crypto_hash_final(&tcp_conn->tx_hash, (u8*)digest);
		iscsi_buf_init_iov(buf, (char*)digest, 4);
	}
	clear_bit(XMSTATE_BIT_W_RESEND_DATA_DIGEST, &tcp_ctask->xmstate);

	rc = iscsi_sendpage(conn, buf, &tcp_ctask->digest_count, &sent);
	if (!rc)
		debug_scsi("sent digest 0x%x for itt 0x%x\n", *digest,
			  ctask->itt);
	else {
		debug_scsi("sending digest 0x%x failed for itt 0x%x!\n",
			  *digest, ctask->itt);
		set_bit(XMSTATE_BIT_W_RESEND_DATA_DIGEST, &tcp_ctask->xmstate);
	}
	return rc;
}

static int
iscsi_send_data(struct iscsi_cmd_task *ctask, struct iscsi_buf *sendbuf,
		struct scatterlist **sg, int *sent, int *count,
		struct iscsi_buf *digestbuf, uint32_t *digest)
{
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
	struct iscsi_conn *conn = ctask->conn;
	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
	int rc, buf_sent, offset;

	while (*count) {
		buf_sent = 0;
		offset = sendbuf->sent;

		rc = iscsi_sendpage(conn, sendbuf, count, &buf_sent);
		*sent = *sent + buf_sent;
		if (buf_sent && conn->datadgst_en)
			partial_sg_digest_update(&tcp_conn->tx_hash,
				&sendbuf->sg, sendbuf->sg.offset + offset,
				buf_sent);
		if (!iscsi_buf_left(sendbuf) && *sg != tcp_ctask->bad_sg) {
			iscsi_buf_init_sg(sendbuf, *sg);
			*sg = *sg + 1;
		}

		if (rc)
			return rc;
	}

	rc = iscsi_send_padding(conn, ctask);
	if (rc)
		return rc;

	return iscsi_send_digest(conn, ctask, digestbuf, digest);
}

static int
iscsi_send_unsol_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
	struct iscsi_data_task *dtask;
	int rc;

	set_bit(XMSTATE_BIT_UNS_DATA, &tcp_ctask->xmstate);
	if (test_bit(XMSTATE_BIT_UNS_INIT, &tcp_ctask->xmstate)) {
		dtask = &tcp_ctask->unsol_dtask;

		iscsi_prep_unsolicit_data_pdu(ctask, &dtask->hdr);
		iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)&dtask->hdr,
				   sizeof(struct iscsi_hdr));
		if (conn->hdrdgst_en)
			iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
					(u8*)dtask->hdrext);

		clear_bit(XMSTATE_BIT_UNS_INIT, &tcp_ctask->xmstate);
		iscsi_set_padding(tcp_ctask, ctask->data_count);
	}

	rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->data_count);
	if (rc) {
		clear_bit(XMSTATE_BIT_UNS_DATA, &tcp_ctask->xmstate);
		set_bit(XMSTATE_BIT_UNS_HDR, &tcp_ctask->xmstate);
		return rc;
	}

	if (conn->datadgst_en) {
		dtask = &tcp_ctask->unsol_dtask;
		iscsi_data_digest_init(ctask->conn->dd_data, tcp_ctask);
		dtask->digest = 0;
	}

	debug_scsi("uns dout [itt 0x%x dlen %d sent %d]\n",
		   ctask->itt, ctask->unsol_count, tcp_ctask->sent);
	return 0;
}

static int
iscsi_send_unsol_pdu(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
	int rc;

	if (test_and_clear_bit(XMSTATE_BIT_UNS_HDR, &tcp_ctask->xmstate)) {
		BUG_ON(!ctask->unsol_count);
send_hdr:
		rc = iscsi_send_unsol_hdr(conn, ctask);
		if (rc)
			return rc;
	}

	if (test_bit(XMSTATE_BIT_UNS_DATA, &tcp_ctask->xmstate)) {
		struct iscsi_data_task *dtask = &tcp_ctask->unsol_dtask;
		int start = tcp_ctask->sent;

		rc = iscsi_send_data(ctask, &tcp_ctask->sendbuf, &tcp_ctask->sg,
				     &tcp_ctask->sent, &ctask->data_count,
				     &dtask->digestbuf, &dtask->digest);
		ctask->unsol_count -= tcp_ctask->sent - start;
		if (rc)
			return rc;
		clear_bit(XMSTATE_BIT_UNS_DATA, &tcp_ctask->xmstate);
		/*
		 * Done with the Data-Out. Next, check if we need
		 * to send another unsolicited Data-Out.
		 */
		if (ctask->unsol_count) {
			debug_scsi("sending more uns\n");
			set_bit(XMSTATE_BIT_UNS_INIT, &tcp_ctask->xmstate);
			goto send_hdr;
		}
	}
	return 0;
}

static int iscsi_send_sol_pdu(struct iscsi_conn *conn,
			      struct iscsi_cmd_task *ctask)
{
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
	struct iscsi_session *session = conn->session;
	struct iscsi_r2t_info *r2t;
	struct iscsi_data_task *dtask;
	int left, rc;

	if (test_bit(XMSTATE_BIT_SOL_HDR_INIT, &tcp_ctask->xmstate)) {
		if (!tcp_ctask->r2t) {
			spin_lock_bh(&session->lock);
			__kfifo_get(tcp_ctask->r2tqueue, (void*)&tcp_ctask->r2t,
				    sizeof(void*));
			spin_unlock_bh(&session->lock);
		}
send_hdr:
		r2t = tcp_ctask->r2t;
		dtask = &r2t->dtask;

		if (conn->hdrdgst_en)
			iscsi_hdr_digest(conn, &r2t->headbuf,
					(u8*)dtask->hdrext);
		clear_bit(XMSTATE_BIT_SOL_HDR_INIT, &tcp_ctask->xmstate);
		set_bit(XMSTATE_BIT_SOL_HDR, &tcp_ctask->xmstate);
	}

	if (test_bit(XMSTATE_BIT_SOL_HDR, &tcp_ctask->xmstate)) {
		r2t = tcp_ctask->r2t;
		dtask = &r2t->dtask;

		rc = iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count);
		if (rc)
			return rc;
		clear_bit(XMSTATE_BIT_SOL_HDR, &tcp_ctask->xmstate);
		set_bit(XMSTATE_BIT_SOL_DATA, &tcp_ctask->xmstate);

		if (conn->datadgst_en) {
			iscsi_data_digest_init(conn->dd_data, tcp_ctask);
			dtask->digest = 0;
		}

		iscsi_set_padding(tcp_ctask, r2t->data_count);
		debug_scsi("sol dout [dsn %d itt 0x%x dlen %d sent %d]\n",
			r2t->solicit_datasn - 1, ctask->itt, r2t->data_count,
			r2t->sent);
	}

	if (test_bit(XMSTATE_BIT_SOL_DATA, &tcp_ctask->xmstate)) {
		r2t = tcp_ctask->r2t;
		dtask = &r2t->dtask;

		rc = iscsi_send_data(ctask, &r2t->sendbuf, &r2t->sg,
				     &r2t->sent, &r2t->data_count,
				     &dtask->digestbuf, &dtask->digest);
		if (rc)
			return rc;
		clear_bit(XMSTATE_BIT_SOL_DATA, &tcp_ctask->xmstate);

		/*
		 * Done with this Data-Out. Next, check if we have
		 * to send another Data-Out for this R2T.
		 */
		BUG_ON(r2t->data_length - r2t->sent < 0);
		left = r2t->data_length - r2t->sent;
		if (left) {
			iscsi_solicit_data_cont(conn, ctask, r2t, left);
			goto send_hdr;
		}

		/*
		 * Done with this R2T. Check if there are more
		 * outstanding R2Ts ready to be processed.
		 */
		spin_lock_bh(&session->lock);
		tcp_ctask->r2t = NULL;
		__kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t,
			    sizeof(void*));
		if (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t,
				sizeof(void*))) {
			tcp_ctask->r2t = r2t;
			spin_unlock_bh(&session->lock);
			goto send_hdr;
		}
		spin_unlock_bh(&session->lock);
	}
	return 0;
}

/**
 * iscsi_tcp_ctask_xmit - xmit normal PDU task
 * @conn: iscsi connection
 * @ctask: iscsi command task
 *
 * Notes:
 *	The function can return -EAGAIN in which case caller must
 *	call it again later, or recover. '0' return code means successful
 *	xmit.
 *	The function is devided to logical helpers (above) for the different
 *	xmit stages.
 *
 *iscsi_send_cmd_hdr()
 *	XMSTATE_BIT_CMD_HDR_INIT - prepare Header and Data buffers Calculate
 *	                           Header Digest
 *	XMSTATE_BIT_CMD_HDR_XMIT - Transmit header in progress
 *
 *iscsi_send_padding
 *	XMSTATE_BIT_W_PAD        - Prepare and send pading
 *	XMSTATE_BIT_W_RESEND_PAD - retry send pading
 *
 *iscsi_send_digest
 *	XMSTATE_BIT_W_RESEND_DATA_DIGEST - Finalize and send Data Digest
 *	XMSTATE_BIT_W_RESEND_DATA_DIGEST - retry sending digest
 *
 *iscsi_send_unsol_hdr
 *	XMSTATE_BIT_UNS_INIT     - prepare un-solicit data header and digest
 *	XMSTATE_BIT_UNS_HDR      - send un-solicit header
 *
 *iscsi_send_unsol_pdu
 *	XMSTATE_BIT_UNS_DATA     - send un-solicit data in progress
 *
 *iscsi_send_sol_pdu
 *	XMSTATE_BIT_SOL_HDR_INIT - solicit data header and digest initialize
 *	XMSTATE_BIT_SOL_HDR      - send solicit header
 *	XMSTATE_BIT_SOL_DATA     - send solicit data
 *
 *iscsi_tcp_ctask_xmit
 *	XMSTATE_BIT_IMM_DATA     - xmit managment data (??)
 **/
static int
iscsi_tcp_ctask_xmit(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
	int rc = 0;

	debug_scsi("ctask deq [cid %d xmstate %x itt 0x%x]\n",
		conn->id, tcp_ctask->xmstate, ctask->itt);

	rc = iscsi_send_cmd_hdr(conn, ctask);
	if (rc)
		return rc;
	if (ctask->sc->sc_data_direction != DMA_TO_DEVICE)
		return 0;

	if (test_bit(XMSTATE_BIT_IMM_DATA, &tcp_ctask->xmstate)) {
		rc = iscsi_send_data(ctask, &tcp_ctask->sendbuf, &tcp_ctask->sg,
				     &tcp_ctask->sent, &ctask->imm_count,
				     &tcp_ctask->immbuf, &tcp_ctask->immdigest);
		if (rc)
			return rc;
		clear_bit(XMSTATE_BIT_IMM_DATA, &tcp_ctask->xmstate);
	}

	rc = iscsi_send_unsol_pdu(conn, ctask);
	if (rc)
		return rc;

	rc = iscsi_send_sol_pdu(conn, ctask);
	if (rc)
		return rc;

	return rc;
}

static struct iscsi_cls_conn *
iscsi_tcp_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
{
	struct iscsi_conn *conn;
	struct iscsi_cls_conn *cls_conn;
	struct iscsi_tcp_conn *tcp_conn;

	cls_conn = iscsi_conn_setup(cls_session, conn_idx);
	if (!cls_conn)
		return NULL;
	conn = cls_conn->dd_data;
	/*
	 * due to strange issues with iser these are not set
	 * in iscsi_conn_setup
	 */
	conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;

	tcp_conn = kzalloc(sizeof(*tcp_conn), GFP_KERNEL);
	if (!tcp_conn)
		goto tcp_conn_alloc_fail;

	conn->dd_data = tcp_conn;
	tcp_conn->iscsi_conn = conn;
	tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
	/* initial operational parameters */
	tcp_conn->hdr_size = sizeof(struct iscsi_hdr);

	tcp_conn->tx_hash.tfm = crypto_alloc_hash("crc32c", 0,
						  CRYPTO_ALG_ASYNC);
	tcp_conn->tx_hash.flags = 0;
	if (IS_ERR(tcp_conn->tx_hash.tfm)) {
		printk(KERN_ERR "Could not create connection due to crc32c "
		       "loading error %ld. Make sure the crc32c module is "
		       "built as a module or into the kernel\n",
			PTR_ERR(tcp_conn->tx_hash.tfm));
		goto free_tcp_conn;
	}

	tcp_conn->rx_hash.tfm = crypto_alloc_hash("crc32c", 0,
						  CRYPTO_ALG_ASYNC);
	tcp_conn->rx_hash.flags = 0;
	if (IS_ERR(tcp_conn->rx_hash.tfm)) {
		printk(KERN_ERR "Could not create connection due to crc32c "
		       "loading error %ld. Make sure the crc32c module is "
		       "built as a module or into the kernel\n",
			PTR_ERR(tcp_conn->rx_hash.tfm));
		goto free_tx_tfm;
	}

	return cls_conn;

free_tx_tfm:
	crypto_free_hash(tcp_conn->tx_hash.tfm);
free_tcp_conn:
	kfree(tcp_conn);
tcp_conn_alloc_fail:
	iscsi_conn_teardown(cls_conn);
	return NULL;
}

static void
iscsi_tcp_release_conn(struct iscsi_conn *conn)
{
	struct iscsi_session *session = conn->session;
	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
	struct socket *sock = tcp_conn->sock;

	if (!sock)
		return;

	sock_hold(sock->sk);
	iscsi_conn_restore_callbacks(tcp_conn);
	sock_put(sock->sk);

	spin_lock_bh(&session->lock);
	tcp_conn->sock = NULL;
	conn->recv_lock = NULL;
	spin_unlock_bh(&session->lock);
	sockfd_put(sock);
}

static void
iscsi_tcp_conn_destroy(struct iscsi_cls_conn *cls_conn)
{
	struct iscsi_conn *conn = cls_conn->dd_data;
	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;

	iscsi_tcp_release_conn(conn);
	iscsi_conn_teardown(cls_conn);

	if (tcp_conn->tx_hash.tfm)
		crypto_free_hash(tcp_conn->tx_hash.tfm);
	if (tcp_conn->rx_hash.tfm)