ACK: [PATCH Wily SRU] Revert "[SCSI] libiscsi: Reduce locking contention in fast path"

Brad Figg brad.figg at canonical.com
Wed Jan 20 18:14:44 UTC 2016


On Wed, Jan 20, 2016 at 08:41:21AM -0700, tim.gardner at canonical.com wrote:
> From: Tim Gardner <tim.gardner at canonical.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1517142
> 
> This reverts commit 659743b02c411075b26601725947b21df0bb29c8.
> 
> Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
> 
> Conflicts:
> 	drivers/scsi/bnx2i/bnx2i_iscsi.c
> 	drivers/scsi/iscsi_tcp.c
> 	drivers/scsi/libiscsi.c
> ---
>  drivers/scsi/be2iscsi/be_main.c  |  26 ++---
>  drivers/scsi/bnx2i/bnx2i_hwi.c   |  46 ++++-----
>  drivers/scsi/bnx2i/bnx2i_iscsi.c |  10 +-
>  drivers/scsi/iscsi_tcp.c         |  22 ++--
>  drivers/scsi/libiscsi.c          | 214 +++++++++++++++++----------------------
>  drivers/scsi/libiscsi_tcp.c      |  28 ++---
>  drivers/scsi/qla4xxx/ql4_isr.c   |   4 +-
>  include/scsi/libiscsi.h          |  17 +---
>  include/scsi/libiscsi_tcp.h      |   2 -
>  9 files changed, 161 insertions(+), 208 deletions(-)
> 
> diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
> index 7a6dbfb..98d281a 100644
> --- a/drivers/scsi/be2iscsi/be_main.c
> +++ b/drivers/scsi/be2iscsi/be_main.c
> @@ -232,20 +232,20 @@ static int beiscsi_eh_abort(struct scsi_cmnd *sc)
>  	cls_session = starget_to_session(scsi_target(sc->device));
>  	session = cls_session->dd_data;
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (!aborted_task || !aborted_task->sc) {
>  		/* we raced */
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		return SUCCESS;
>  	}
>  
>  	aborted_io_task = aborted_task->dd_data;
>  	if (!aborted_io_task->scsi_cmnd) {
>  		/* raced or invalid command */
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		return SUCCESS;
>  	}
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	/* Invalidate WRB Posted for this Task */
>  	AMAP_SET_BITS(struct amap_iscsi_wrb, invld,
>  		      aborted_io_task->pwrb_handle->pwrb,
> @@ -310,9 +310,9 @@ static int beiscsi_eh_device_reset(struct scsi_cmnd *sc)
>  	/* invalidate iocbs */
>  	cls_session = starget_to_session(scsi_target(sc->device));
>  	session = cls_session->dd_data;
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN) {
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		return FAILED;
>  	}
>  	conn = session->leadconn;
> @@ -341,7 +341,7 @@ static int beiscsi_eh_device_reset(struct scsi_cmnd *sc)
>  		num_invalidate++;
>  		inv_tbl++;
>  	}
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	inv_tbl = phba->inv_tbl;
>  
>  	nonemb_cmd.va = pci_alloc_consistent(phba->ctrl.pdev,
> @@ -1137,9 +1137,9 @@ beiscsi_process_async_pdu(struct beiscsi_conn *beiscsi_conn,
>  		return 1;
>  	}
>  
> -	spin_lock_bh(&session->back_lock);
> +	spin_lock_bh(&session->lock);
>  	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)ppdu, pbuffer, buf_len);
> -	spin_unlock_bh(&session->back_lock);
> +	spin_unlock_bh(&session->lock);
>  	return 0;
>  }
>  
> @@ -1560,7 +1560,7 @@ static void hwi_complete_cmd(struct beiscsi_conn *beiscsi_conn,
>  	pwrb = pwrb_handle->pwrb;
>  	type = ((struct beiscsi_io_task *)task->dd_data)->wrb_type;
>  
> -	spin_lock_bh(&session->back_lock);
> +	spin_lock_bh(&session->lock);
>  	switch (type) {
>  	case HWH_TYPE_IO:
>  	case HWH_TYPE_IO_RD:
> @@ -1599,7 +1599,7 @@ static void hwi_complete_cmd(struct beiscsi_conn *beiscsi_conn,
>  		break;
>  	}
>  
> -	spin_unlock_bh(&session->back_lock);
> +	spin_unlock_bh(&session->lock);
>  }
>  
>  static struct list_head *hwi_get_async_busy_list(struct hwi_async_pdu_context
> @@ -4688,9 +4688,9 @@ beiscsi_offload_connection(struct beiscsi_conn *beiscsi_conn,
>  	 * login/startup related tasks.
>  	 */
>  	beiscsi_conn->login_in_progress = 0;
> -	spin_lock_bh(&session->back_lock);
> +	spin_lock_bh(&session->lock);
>  	beiscsi_cleanup_task(task);
> -	spin_unlock_bh(&session->back_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	pwrb_handle = alloc_wrb_handle(phba, beiscsi_conn->beiscsi_conn_cid);
>  
> diff --git a/drivers/scsi/bnx2i/bnx2i_hwi.c b/drivers/scsi/bnx2i/bnx2i_hwi.c
> index fb072cc..9bfc3d6 100644
> --- a/drivers/scsi/bnx2i/bnx2i_hwi.c
> +++ b/drivers/scsi/bnx2i/bnx2i_hwi.c
> @@ -1363,7 +1363,7 @@ int bnx2i_process_scsi_cmd_resp(struct iscsi_session *session,
>  	u32 datalen = 0;
>  
>  	resp_cqe = (struct bnx2i_cmd_response *)cqe;
> -	spin_lock_bh(&session->back_lock);
> +	spin_lock_bh(&session->lock);
>  	task = iscsi_itt_to_task(conn,
>  				 resp_cqe->itt & ISCSI_CMD_RESPONSE_INDEX);
>  	if (!task)
> @@ -1434,7 +1434,7 @@ done:
>  	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)hdr,
>  			     conn->data, datalen);
>  fail:
> -	spin_unlock_bh(&session->back_lock);
> +	spin_unlock_bh(&session->lock);
>  	return 0;
>  }
>  
> @@ -1459,7 +1459,7 @@ static int bnx2i_process_login_resp(struct iscsi_session *session,
>  	int pad_len;
>  
>  	login = (struct bnx2i_login_response *) cqe;
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	task = iscsi_itt_to_task(conn,
>  				 login->itt & ISCSI_LOGIN_RESPONSE_INDEX);
>  	if (!task)
> @@ -1502,7 +1502,7 @@ static int bnx2i_process_login_resp(struct iscsi_session *session,
>  		bnx2i_conn->gen_pdu.resp_buf,
>  		bnx2i_conn->gen_pdu.resp_wr_ptr - bnx2i_conn->gen_pdu.resp_buf);
>  done:
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  	return 0;
>  }
>  
> @@ -1527,7 +1527,7 @@ static int bnx2i_process_text_resp(struct iscsi_session *session,
>  	int pad_len;
>  
>  	text = (struct bnx2i_text_response *) cqe;
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	task = iscsi_itt_to_task(conn, text->itt & ISCSI_LOGIN_RESPONSE_INDEX);
>  	if (!task)
>  		goto done;
> @@ -1563,7 +1563,7 @@ static int bnx2i_process_text_resp(struct iscsi_session *session,
>  			     bnx2i_conn->gen_pdu.resp_wr_ptr -
>  			     bnx2i_conn->gen_pdu.resp_buf);
>  done:
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  	return 0;
>  }
>  
> @@ -1586,7 +1586,7 @@ static int bnx2i_process_tmf_resp(struct iscsi_session *session,
>  	struct iscsi_tm_rsp *resp_hdr;
>  
>  	tmf_cqe = (struct bnx2i_tmf_response *)cqe;
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	task = iscsi_itt_to_task(conn,
>  				 tmf_cqe->itt & ISCSI_TMF_RESPONSE_INDEX);
>  	if (!task)
> @@ -1602,7 +1602,7 @@ static int bnx2i_process_tmf_resp(struct iscsi_session *session,
>  
>  	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)resp_hdr, NULL, 0);
>  done:
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  	return 0;
>  }
>  
> @@ -1625,7 +1625,7 @@ static int bnx2i_process_logout_resp(struct iscsi_session *session,
>  	struct iscsi_logout_rsp *resp_hdr;
>  
>  	logout = (struct bnx2i_logout_response *) cqe;
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	task = iscsi_itt_to_task(conn,
>  				 logout->itt & ISCSI_LOGOUT_RESPONSE_INDEX);
>  	if (!task)
> @@ -1649,7 +1649,7 @@ static int bnx2i_process_logout_resp(struct iscsi_session *session,
>  
>  	bnx2i_conn->ep->state = EP_STATE_LOGOUT_RESP_RCVD;
>  done:
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  	return 0;
>  }
>  
> @@ -1670,12 +1670,12 @@ static void bnx2i_process_nopin_local_cmpl(struct iscsi_session *session,
>  	struct iscsi_task *task;
>  
>  	nop_in = (struct bnx2i_nop_in_msg *)cqe;
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	task = iscsi_itt_to_task(conn,
>  				 nop_in->itt & ISCSI_NOP_IN_MSG_INDEX);
>  	if (task)
>  		__iscsi_put_task(task);
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  }
>  
>  /**
> @@ -1714,7 +1714,7 @@ static int bnx2i_process_nopin_mesg(struct iscsi_session *session,
>  
>  	nop_in = (struct bnx2i_nop_in_msg *)cqe;
>  
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	hdr = (struct iscsi_nopin *)&bnx2i_conn->gen_pdu.resp_hdr;
>  	memset(hdr, 0, sizeof(struct iscsi_hdr));
>  	hdr->opcode = nop_in->op_code;
> @@ -1740,7 +1740,7 @@ static int bnx2i_process_nopin_mesg(struct iscsi_session *session,
>  	}
>  done:
>  	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)hdr, NULL, 0);
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  
>  	return tgt_async_nop;
>  }
> @@ -1773,7 +1773,7 @@ static void bnx2i_process_async_mesg(struct iscsi_session *session,
>  		return;
>  	}
>  
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	resp_hdr = (struct iscsi_async *) &bnx2i_conn->gen_pdu.resp_hdr;
>  	memset(resp_hdr, 0, sizeof(struct iscsi_hdr));
>  	resp_hdr->opcode = async_cqe->op_code;
> @@ -1792,7 +1792,7 @@ static void bnx2i_process_async_mesg(struct iscsi_session *session,
>  
>  	__iscsi_complete_pdu(bnx2i_conn->cls_conn->dd_data,
>  			     (struct iscsi_hdr *)resp_hdr, NULL, 0);
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  }
>  
>  
> @@ -1819,7 +1819,7 @@ static void bnx2i_process_reject_mesg(struct iscsi_session *session,
>  	} else
>  		bnx2i_unsol_pdu_adjust_rq(bnx2i_conn);
>  
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	hdr = (struct iscsi_reject *) &bnx2i_conn->gen_pdu.resp_hdr;
>  	memset(hdr, 0, sizeof(struct iscsi_hdr));
>  	hdr->opcode = reject->op_code;
> @@ -1830,7 +1830,7 @@ static void bnx2i_process_reject_mesg(struct iscsi_session *session,
>  	hdr->ffffffff = cpu_to_be32(RESERVED_ITT);
>  	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)hdr, conn->data,
>  			     reject->data_length);
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  }
>  
>  /**
> @@ -1850,13 +1850,13 @@ static void bnx2i_process_cmd_cleanup_resp(struct iscsi_session *session,
>  	struct iscsi_task *task;
>  
>  	cmd_clean_rsp = (struct bnx2i_cleanup_response *)cqe;
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	task = iscsi_itt_to_task(conn,
>  			cmd_clean_rsp->itt & ISCSI_CLEANUP_RESPONSE_INDEX);
>  	if (!task)
>  		printk(KERN_ALERT "bnx2i: cmd clean ITT %x not active\n",
>  			cmd_clean_rsp->itt & ISCSI_CLEANUP_RESPONSE_INDEX);
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  	complete(&bnx2i_conn->cmd_cleanup_cmpl);
>  }
>  
> @@ -1923,11 +1923,11 @@ static int bnx2i_queue_scsi_cmd_resp(struct iscsi_session *session,
>  	int rc = 0;
>  	int cpu;
>  
> -	spin_lock(&session->back_lock);
> +	spin_lock(&session->lock);
>  	task = iscsi_itt_to_task(bnx2i_conn->cls_conn->dd_data,
>  				 cqe->itt & ISCSI_CMD_RESPONSE_INDEX);
>  	if (!task || !task->sc) {
> -		spin_unlock(&session->back_lock);
> +		spin_unlock(&session->lock);
>  		return -EINVAL;
>  	}
>  	sc = task->sc;
> @@ -1937,7 +1937,7 @@ static int bnx2i_queue_scsi_cmd_resp(struct iscsi_session *session,
>  	else
>  		cpu = sc->request->cpu;
>  
> -	spin_unlock(&session->back_lock);
> +	spin_unlock(&session->lock);
>  
>  	p = &per_cpu(bnx2i_percpu, cpu);
>  	spin_lock(&p->p_work_lock);
> diff --git a/drivers/scsi/bnx2i/bnx2i_iscsi.c b/drivers/scsi/bnx2i/bnx2i_iscsi.c
> index 7289437..1ef5bbb 100644
> --- a/drivers/scsi/bnx2i/bnx2i_iscsi.c
> +++ b/drivers/scsi/bnx2i/bnx2i_iscsi.c
> @@ -1172,12 +1172,10 @@ static void bnx2i_cleanup_task(struct iscsi_task *task)
>  	if (task->state == ISCSI_TASK_ABRT_TMF) {
>  		bnx2i_send_cmd_cleanup_req(hba, task->dd_data);
>  
> -		spin_unlock_bh(&conn->session->back_lock);
> -		spin_unlock_bh(&conn->session->frwd_lock);
> +		spin_unlock_bh(&conn->session->lock);
>  		wait_for_completion_timeout(&bnx2i_conn->cmd_cleanup_cmpl,
>  				msecs_to_jiffies(ISCSI_CMD_CLEANUP_TIMEOUT));
> -		spin_lock_bh(&conn->session->frwd_lock);
> -		spin_lock_bh(&conn->session->back_lock);
> +		spin_lock_bh(&conn->session->lock);
>  	}
>  	bnx2i_iscsi_unmap_sg_list(task->dd_data);
>  }
> @@ -2063,7 +2061,7 @@ int bnx2i_hw_ep_disconnect(struct bnx2i_endpoint *bnx2i_ep)
>  		goto out;
>  
>  	if (session) {
> -		spin_lock_bh(&session->frwd_lock);
> +		spin_lock_bh(&session->lock);
>  		if (bnx2i_ep->state != EP_STATE_TCP_FIN_RCVD) {
>  			if (session->state == ISCSI_STATE_LOGGING_OUT) {
>  				if (bnx2i_ep->state == EP_STATE_LOGOUT_SENT) {
> @@ -2079,7 +2077,7 @@ int bnx2i_hw_ep_disconnect(struct bnx2i_endpoint *bnx2i_ep)
>  		} else
>  			close = 1;
>  
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  	}
>  
>  	bnx2i_ep->state = EP_STATE_DISCONN_START;
> diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
> index 0b8af18..19be12f 100644
> --- a/drivers/scsi/iscsi_tcp.c
> +++ b/drivers/scsi/iscsi_tcp.c
> @@ -593,9 +593,9 @@ static void iscsi_sw_tcp_release_conn(struct iscsi_conn *conn)
>  	iscsi_sw_tcp_conn_restore_callbacks(conn);
>  	sock_put(sock->sk);
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	tcp_sw_conn->sock = NULL;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	sockfd_put(sock);
>  }
>  
> @@ -663,10 +663,10 @@ iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session,
>  	if (err)
>  		goto free_socket;
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	/* bind iSCSI connection and socket */
>  	tcp_sw_conn->sock = sock;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	/* setup Socket parameters */
>  	sk = sock->sk;
> @@ -727,9 +727,9 @@ static int iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
>  	case ISCSI_PARAM_CONN_PORT:
>  	case ISCSI_PARAM_CONN_ADDRESS:
>  	case ISCSI_PARAM_LOCAL_PORT:
> -		spin_lock_bh(&conn->session->frwd_lock);
> +		spin_lock_bh(&conn->session->lock);
>  		if (!tcp_sw_conn || !tcp_sw_conn->sock) {
> -			spin_unlock_bh(&conn->session->frwd_lock);
> +			spin_unlock_bh(&conn->session->lock);
>  			return -ENOTCONN;
>  		}
>  		if (param == ISCSI_PARAM_LOCAL_PORT)
> @@ -738,7 +738,7 @@ static int iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
>  		else
>  			rc = kernel_getpeername(tcp_sw_conn->sock,
>  						(struct sockaddr *)&addr, &len);
> -		spin_unlock_bh(&conn->session->frwd_lock);
> +		spin_unlock_bh(&conn->session->lock);
>  		if (rc)
>  			return rc;
>  
> @@ -767,23 +767,23 @@ static int iscsi_sw_tcp_host_get_param(struct Scsi_Host *shost,
>  		if (!session)
>  			return -ENOTCONN;
>  
> -		spin_lock_bh(&session->frwd_lock);
> +		spin_lock_bh(&session->lock);
>  		conn = session->leadconn;
>  		if (!conn) {
> -			spin_unlock_bh(&session->frwd_lock);
> +			spin_unlock_bh(&session->lock);
>  			return -ENOTCONN;
>  		}
>  		tcp_conn = conn->dd_data;
>  
>  		tcp_sw_conn = tcp_conn->dd_data;
>  		if (!tcp_sw_conn->sock) {
> -			spin_unlock_bh(&session->frwd_lock);
> +			spin_unlock_bh(&session->lock);
>  			return -ENOTCONN;
>  		}
>  
>  		rc = kernel_getsockname(tcp_sw_conn->sock,
>  					(struct sockaddr *)&addr, &len);
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		if (rc)
>  			return rc;
>  
> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
> index 98d9bb6..e519c2f 100644
> --- a/drivers/scsi/libiscsi.c
> +++ b/drivers/scsi/libiscsi.c
> @@ -477,7 +477,7 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
>   * iscsi_free_task - free a task
>   * @task: iscsi cmd task
>   *
> - * Must be called with session back_lock.
> + * Must be called with session lock.
>   * This function returns the scsi command to scsi-ml or cleans
>   * up mgmt tasks then returns the task to the pool.
>   */
> @@ -531,10 +531,9 @@ void iscsi_put_task(struct iscsi_task *task)
>  {
>  	struct iscsi_session *session = task->conn->session;
>  
> -	/* regular RX path uses back_lock */
> -	spin_lock_bh(&session->back_lock);
> +	spin_lock_bh(&session->lock);
>  	__iscsi_put_task(task);
> -	spin_unlock_bh(&session->back_lock);
> +	spin_unlock_bh(&session->lock);
>  }
>  EXPORT_SYMBOL_GPL(iscsi_put_task);
>  
> @@ -543,7 +542,7 @@ EXPORT_SYMBOL_GPL(iscsi_put_task);
>   * @task: iscsi cmd task
>   * @state: state to complete task with
>   *
> - * Must be called with session back_lock.
> + * Must be called with session lock.
>   */
>  static void iscsi_complete_task(struct iscsi_task *task, int state)
>  {
> @@ -582,7 +581,7 @@ static void iscsi_complete_task(struct iscsi_task *task, int state)
>   * This is used when drivers do not need or cannot perform
>   * lower level pdu processing.
>   *
> - * Called with session back_lock
> + * Called with session lock
>   */
>  void iscsi_complete_scsi_task(struct iscsi_task *task,
>  			      uint32_t exp_cmdsn, uint32_t max_cmdsn)
> @@ -599,7 +598,7 @@ EXPORT_SYMBOL_GPL(iscsi_complete_scsi_task);
>  
>  
>  /*
> - * session back_lock must be held and if not called for a task that is
> + * session lock must be held and if not called for a task that is
>   * still pending or from the xmit thread, then xmit thread must
>   * be suspended.
>   */
> @@ -639,10 +638,7 @@ static void fail_scsi_task(struct iscsi_task *task, int err)
>  		scsi_in(sc)->resid = scsi_in(sc)->length;
>  	}
>  
> -	/* regular RX path uses back_lock */
> -	spin_lock_bh(&conn->session->back_lock);
>  	iscsi_complete_task(task, state);
> -	spin_unlock_bh(&conn->session->back_lock);
>  }
>  
>  static int iscsi_prep_mgmt_task(struct iscsi_conn *conn,
> @@ -790,10 +786,7 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
>  	return task;
>  
>  free_task:
> -	/* regular RX path uses back_lock */
> -	spin_lock_bh(&session->back_lock);
>  	__iscsi_put_task(task);
> -	spin_unlock_bh(&session->back_lock);
>  	return NULL;
>  }
>  
> @@ -804,10 +797,10 @@ int iscsi_conn_send_pdu(struct iscsi_cls_conn *cls_conn, struct iscsi_hdr *hdr,
>  	struct iscsi_session *session = conn->session;
>  	int err = 0;
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (!__iscsi_conn_send_pdu(conn, hdr, data, data_size))
>  		err = -EPERM;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	return err;
>  }
>  EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);
> @@ -1071,19 +1064,14 @@ static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
>  		if (opcode != ISCSI_OP_NOOP_OUT)
>  			return 0;
>  
> -		 if (rejected_pdu.itt == cpu_to_be32(ISCSI_RESERVED_TAG)) {
> +		 if (rejected_pdu.itt == cpu_to_be32(ISCSI_RESERVED_TAG))
>  			/*
>  			 * nop-out in response to target's nop-out rejected.
>  			 * Just resend.
>  			 */
> -			/* In RX path we are under back lock */
> -			spin_unlock(&conn->session->back_lock);
> -			spin_lock(&conn->session->frwd_lock);
>  			iscsi_send_nopout(conn,
>  					  (struct iscsi_nopin*)&rejected_pdu);
> -			spin_unlock(&conn->session->frwd_lock);
> -			spin_lock(&conn->session->back_lock);
> -		} else {
> +		else {
>  			struct iscsi_task *task;
>  			/*
>  			 * Our nop as ping got dropped. We know the target
> @@ -1119,7 +1107,7 @@ static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
>   * This should be used for mgmt tasks like login and nops, or if
>   * the LDD's itt space does not include the session age.
>   *
> - * The session back_lock must be held.
> + * The session lock must be held.
>   */
>  struct iscsi_task *iscsi_itt_to_task(struct iscsi_conn *conn, itt_t itt)
>  {
> @@ -1148,7 +1136,7 @@ EXPORT_SYMBOL_GPL(iscsi_itt_to_task);
>   * @datalen: len of data buffer
>   *
>   * Completes pdu processing by freeing any resources allocated at
> - * queuecommand or send generic. session back_lock must be held and verify
> + * queuecommand or send generic. session lock must be held and verify
>   * itt must have been called.
>   */
>  int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
> @@ -1185,12 +1173,7 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
>  			if (hdr->ttt == cpu_to_be32(ISCSI_RESERVED_TAG))
>  				break;
>  
> -			/* In RX path we are under back lock */
> -			spin_unlock(&session->back_lock);
> -			spin_lock(&session->frwd_lock);
>  			iscsi_send_nopout(conn, (struct iscsi_nopin*)hdr);
> -			spin_unlock(&session->frwd_lock);
> -			spin_lock(&session->back_lock);
>  			break;
>  		case ISCSI_OP_REJECT:
>  			rc = iscsi_handle_reject(conn, hdr, data, datalen);
> @@ -1297,9 +1280,9 @@ int iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
>  {
>  	int rc;
>  
> -	spin_lock(&conn->session->back_lock);
> +	spin_lock(&conn->session->lock);
>  	rc = __iscsi_complete_pdu(conn, hdr, data, datalen);
> -	spin_unlock(&conn->session->back_lock);
> +	spin_unlock(&conn->session->lock);
>  	return rc;
>  }
>  EXPORT_SYMBOL_GPL(iscsi_complete_pdu);
> @@ -1343,7 +1326,7 @@ EXPORT_SYMBOL_GPL(iscsi_verify_itt);
>   *
>   * This should be used for cmd tasks.
>   *
> - * The session back_lock must be held.
> + * The session lock must be held.
>   */
>  struct iscsi_task *iscsi_itt_to_ctask(struct iscsi_conn *conn, itt_t itt)
>  {
> @@ -1373,15 +1356,15 @@ void iscsi_session_failure(struct iscsi_session *session,
>  	struct iscsi_conn *conn;
>  	struct device *dev;
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	conn = session->leadconn;
>  	if (session->state == ISCSI_STATE_TERMINATE || !conn) {
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		return;
>  	}
>  
>  	dev = get_device(&conn->cls_conn->dev);
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	if (!dev)
>  	        return;
>  	/*
> @@ -1401,15 +1384,15 @@ void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
>  {
>  	struct iscsi_session *session = conn->session;
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (session->state == ISCSI_STATE_FAILED) {
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		return;
>  	}
>  
>  	if (conn->stop_stage == 0)
>  		session->state = ISCSI_STATE_FAILED;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
>  	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
> @@ -1443,18 +1426,15 @@ static int iscsi_xmit_task(struct iscsi_conn *conn)
>  		return -ENODATA;
>  
>  	__iscsi_get_task(task);
> -	spin_unlock_bh(&conn->session->frwd_lock);
> +	spin_unlock_bh(&conn->session->lock);
>  	rc = conn->session->tt->xmit_task(task);
> -	spin_lock_bh(&conn->session->frwd_lock);
> +	spin_lock_bh(&conn->session->lock);
>  	if (!rc) {
>  		/* done with this task */
>  		task->last_xfer = jiffies;
>  		conn->task = NULL;
>  	}
> -	/* regular RX path uses back_lock */
> -	spin_lock(&conn->session->back_lock);
>  	__iscsi_put_task(task);
> -	spin_unlock(&conn->session->back_lock);
>  	return rc;
>  }
>  
> @@ -1463,7 +1443,7 @@ static int iscsi_xmit_task(struct iscsi_conn *conn)
>   * @task: task to requeue
>   *
>   * LLDs that need to run a task from the session workqueue should call
> - * this. The session frwd_lock must be held. This should only be called
> + * this. The session lock must be held. This should only be called
>   * by software drivers.
>   */
>  void iscsi_requeue_task(struct iscsi_task *task)
> @@ -1494,10 +1474,10 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
>  	struct iscsi_task *task;
>  	int rc = 0;
>  
> -	spin_lock_bh(&conn->session->frwd_lock);
> +	spin_lock_bh(&conn->session->lock);
>  	if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) {
>  		ISCSI_DBG_SESSION(conn->session, "Tx suspended!\n");
> -		spin_unlock_bh(&conn->session->frwd_lock);
> +		spin_unlock_bh(&conn->session->lock);
>  		return -ENODATA;
>  	}
>  
> @@ -1518,10 +1498,7 @@ check_mgmt:
>  					 struct iscsi_task, running);
>  		list_del_init(&conn->task->running);
>  		if (iscsi_prep_mgmt_task(conn, conn->task)) {
> -			/* regular RX path uses back_lock */
> -			spin_lock_bh(&conn->session->back_lock);
>  			__iscsi_put_task(conn->task);
> -			spin_unlock_bh(&conn->session->back_lock);
>  			conn->task = NULL;
>  			continue;
>  		}
> @@ -1583,11 +1560,11 @@ check_mgmt:
>  		if (!list_empty(&conn->mgmtqueue))
>  			goto check_mgmt;
>  	}
> -	spin_unlock_bh(&conn->session->frwd_lock);
> +	spin_unlock_bh(&conn->session->lock);
>  	return -ENODATA;
>  
>  done:
> -	spin_unlock_bh(&conn->session->frwd_lock);
> +	spin_unlock_bh(&conn->session->lock);
>  	return rc;
>  }
>  
> @@ -1657,7 +1634,7 @@ int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
>  
>  	cls_session = starget_to_session(scsi_target(sc->device));
>  	session = cls_session->dd_data;
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  
>  	reason = iscsi_session_chkready(cls_session);
>  	if (reason) {
> @@ -1743,13 +1720,13 @@ int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
>  	}
>  
>  	session->queued_cmdsn++;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	return 0;
>  
>  prepd_reject:
>  	iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ);
>  reject:
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	ISCSI_DBG_SESSION(session, "cmd 0x%x rejected (%d)\n",
>  			  sc->cmnd[0], reason);
>  	return SCSI_MLQUEUE_TARGET_BUSY;
> @@ -1757,7 +1734,7 @@ reject:
>  prepd_fault:
>  	iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ);
>  fault:
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n",
>  			  sc->cmnd[0], reason);
>  	if (!scsi_bidi_cmnd(sc))
> @@ -1786,14 +1763,14 @@ static void iscsi_tmf_timedout(unsigned long data)
>  	struct iscsi_conn *conn = (struct iscsi_conn *)data;
>  	struct iscsi_session *session = conn->session;
>  
> -	spin_lock(&session->frwd_lock);
> +	spin_lock(&session->lock);
>  	if (conn->tmf_state == TMF_QUEUED) {
>  		conn->tmf_state = TMF_TIMEDOUT;
>  		ISCSI_DBG_EH(session, "tmf timedout\n");
>  		/* unblock eh_abort() */
>  		wake_up(&conn->ehwait);
>  	}
> -	spin_unlock(&session->frwd_lock);
> +	spin_unlock(&session->lock);
>  }
>  
>  static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
> @@ -1806,10 +1783,10 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
>  	task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)hdr,
>  				      NULL, 0);
>  	if (!task) {
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		iscsi_conn_printk(KERN_ERR, conn, "Could not send TMF.\n");
>  		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
> -		spin_lock_bh(&session->frwd_lock);
> +		spin_lock_bh(&session->lock);
>  		return -EPERM;
>  	}
>  	conn->tmfcmd_pdus_cnt++;
> @@ -1819,7 +1796,7 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
>  	add_timer(&conn->tmf_timer);
>  	ISCSI_DBG_EH(session, "tmf set timeout\n");
>  
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	mutex_unlock(&session->eh_mutex);
>  
>  	/*
> @@ -1838,7 +1815,7 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
>  	del_timer_sync(&conn->tmf_timer);
>  
>  	mutex_lock(&session->eh_mutex);
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	/* if the session drops it will clean up the task */
>  	if (age != session->age ||
>  	    session->state != ISCSI_STATE_LOGGED_IN)
> @@ -1874,7 +1851,7 @@ static void fail_scsi_tasks(struct iscsi_conn *conn, u64 lun, int error)
>   * iscsi_suspend_queue - suspend iscsi_queuecommand
>   * @conn: iscsi conn to stop queueing IO on
>   *
> - * This grabs the session frwd_lock to make sure no one is in
> + * This grabs the session lock to make sure no one is in
>   * xmit_task/queuecommand, and then sets suspend to prevent
>   * new commands from being queued. This only needs to be called
>   * by offload drivers that need to sync a path like ep disconnect
> @@ -1883,9 +1860,9 @@ static void fail_scsi_tasks(struct iscsi_conn *conn, u64 lun, int error)
>   */
>  void iscsi_suspend_queue(struct iscsi_conn *conn)
>  {
> -	spin_lock_bh(&conn->session->frwd_lock);
> +	spin_lock_bh(&conn->session->lock);
>  	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
> -	spin_unlock_bh(&conn->session->frwd_lock);
> +	spin_unlock_bh(&conn->session->lock);
>  }
>  EXPORT_SYMBOL_GPL(iscsi_suspend_queue);
>  
> @@ -1944,7 +1921,7 @@ static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
>  
>  	ISCSI_DBG_EH(session, "scsi cmd %p timedout\n", sc);
>  
> -	spin_lock(&session->frwd_lock);
> +	spin_lock(&session->lock);
>  	task = (struct iscsi_task *)sc->SCp.ptr;
>  	if (!task) {
>  		/*
> @@ -2058,7 +2035,7 @@ static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
>  done:
>  	if (task)
>  		task->last_timeout = jiffies;
> -	spin_unlock(&session->frwd_lock);
> +	spin_unlock(&session->lock);
>  	ISCSI_DBG_EH(session, "return %s\n", rc == BLK_EH_RESET_TIMER ?
>  		     "timer reset" : "nh");
>  	return rc;
> @@ -2070,7 +2047,7 @@ static void iscsi_check_transport_timeouts(unsigned long data)
>  	struct iscsi_session *session = conn->session;
>  	unsigned long recv_timeout, next_timeout = 0, last_recv;
>  
> -	spin_lock(&session->frwd_lock);
> +	spin_lock(&session->lock);
>  	if (session->state != ISCSI_STATE_LOGGED_IN)
>  		goto done;
>  
> @@ -2087,7 +2064,7 @@ static void iscsi_check_transport_timeouts(unsigned long data)
>  				  "last ping %lu, now %lu\n",
>  				  conn->ping_timeout, conn->recv_timeout,
>  				  last_recv, conn->last_ping, jiffies);
> -		spin_unlock(&session->frwd_lock);
> +		spin_unlock(&session->lock);
>  		iscsi_conn_failure(conn, ISCSI_ERR_NOP_TIMEDOUT);
>  		return;
>  	}
> @@ -2103,7 +2080,7 @@ static void iscsi_check_transport_timeouts(unsigned long data)
>  	ISCSI_DBG_CONN(conn, "Setting next tmo %lu\n", next_timeout);
>  	mod_timer(&conn->transport_timer, next_timeout);
>  done:
> -	spin_unlock(&session->frwd_lock);
> +	spin_unlock(&session->lock);
>  }
>  
>  static void iscsi_prep_abort_task_pdu(struct iscsi_task *task,
> @@ -2133,7 +2110,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
>  	ISCSI_DBG_EH(session, "aborting sc %p\n", sc);
>  
>  	mutex_lock(&session->eh_mutex);
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	/*
>  	 * if session was ISCSI_STATE_IN_RECOVERY then we may not have
>  	 * got the command.
> @@ -2141,7 +2118,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
>  	if (!sc->SCp.ptr) {
>  		ISCSI_DBG_EH(session, "sc never reached iscsi layer or "
>  				      "it completed.\n");
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		mutex_unlock(&session->eh_mutex);
>  		return SUCCESS;
>  	}
> @@ -2152,7 +2129,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
>  	 */
>  	if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN ||
>  	    sc->SCp.phase != session->age) {
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		mutex_unlock(&session->eh_mutex);
>  		ISCSI_DBG_EH(session, "failing abort due to dropped "
>  				  "session.\n");
> @@ -2193,7 +2170,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
>  
>  	switch (conn->tmf_state) {
>  	case TMF_SUCCESS:
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		/*
>  		 * stop tx side incase the target had sent a abort rsp but
>  		 * the initiator was still writing out data.
> @@ -2204,15 +2181,15 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
>  		 * good and have never sent us a successful tmf response
>  		 * then sent more data for the cmd.
>  		 */
> -		spin_lock_bh(&session->frwd_lock);
> +		spin_lock_bh(&session->lock);
>  		fail_scsi_task(task, DID_ABORT);
>  		conn->tmf_state = TMF_INITIAL;
>  		memset(hdr, 0, sizeof(*hdr));
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		iscsi_start_tx(conn);
>  		goto success_unlocked;
>  	case TMF_TIMEDOUT:
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
>  		goto failed_unlocked;
>  	case TMF_NOT_FOUND:
> @@ -2231,7 +2208,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
>  	}
>  
>  success:
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  success_unlocked:
>  	ISCSI_DBG_EH(session, "abort success [sc %p itt 0x%x]\n",
>  		     sc, task->itt);
> @@ -2239,7 +2216,7 @@ success_unlocked:
>  	return SUCCESS;
>  
>  failed:
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  failed_unlocked:
>  	ISCSI_DBG_EH(session, "abort failed [sc %p itt 0x%x]\n", sc,
>  		     task ? task->itt : 0);
> @@ -2273,7 +2250,7 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc)
>  		     sc->device->lun);
>  
>  	mutex_lock(&session->eh_mutex);
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	/*
>  	 * Just check if we are not logged in. We cannot check for
>  	 * the phase because the reset could come from a ioctl.
> @@ -2300,7 +2277,7 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc)
>  	case TMF_SUCCESS:
>  		break;
>  	case TMF_TIMEDOUT:
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
>  		goto done;
>  	default:
> @@ -2309,21 +2286,21 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc)
>  	}
>  
>  	rc = SUCCESS;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	iscsi_suspend_tx(conn);
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	memset(hdr, 0, sizeof(*hdr));
>  	fail_scsi_tasks(conn, sc->device->lun, DID_ERROR);
>  	conn->tmf_state = TMF_INITIAL;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	iscsi_start_tx(conn);
>  	goto done;
>  
>  unlock:
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  done:
>  	ISCSI_DBG_EH(session, "dev reset result = %s\n",
>  		     rc == SUCCESS ? "SUCCESS" : "FAILED");
> @@ -2336,13 +2313,13 @@ void iscsi_session_recovery_timedout(struct iscsi_cls_session *cls_session)
>  {
>  	struct iscsi_session *session = cls_session->dd_data;
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (session->state != ISCSI_STATE_LOGGED_IN) {
>  		session->state = ISCSI_STATE_RECOVERY_FAILED;
>  		if (session->leadconn)
>  			wake_up(&session->leadconn->ehwait);
>  	}
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  }
>  EXPORT_SYMBOL_GPL(iscsi_session_recovery_timedout);
>  
> @@ -2364,19 +2341,19 @@ int iscsi_eh_session_reset(struct scsi_cmnd *sc)
>  	conn = session->leadconn;
>  
>  	mutex_lock(&session->eh_mutex);
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (session->state == ISCSI_STATE_TERMINATE) {
>  failed:
>  		ISCSI_DBG_EH(session,
>  			     "failing session reset: Could not log back into "
>  			     "%s, %s [age %d]\n", session->targetname,
>  			     conn->persistent_address, session->age);
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		mutex_unlock(&session->eh_mutex);
>  		return FAILED;
>  	}
>  
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	mutex_unlock(&session->eh_mutex);
>  	/*
>  	 * we drop the lock here but the leadconn cannot be destoyed while
> @@ -2393,14 +2370,14 @@ failed:
>  		flush_signals(current);
>  
>  	mutex_lock(&session->eh_mutex);
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (session->state == ISCSI_STATE_LOGGED_IN) {
>  		ISCSI_DBG_EH(session,
>  			     "session reset succeeded for %s,%s\n",
>  			     session->targetname, conn->persistent_address);
>  	} else
>  		goto failed;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	mutex_unlock(&session->eh_mutex);
>  	return SUCCESS;
>  }
> @@ -2436,7 +2413,7 @@ int iscsi_eh_target_reset(struct scsi_cmnd *sc)
>  		     session->targetname);
>  
>  	mutex_lock(&session->eh_mutex);
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	/*
>  	 * Just check if we are not logged in. We cannot check for
>  	 * the phase because the reset could come from a ioctl.
> @@ -2463,7 +2440,7 @@ int iscsi_eh_target_reset(struct scsi_cmnd *sc)
>  	case TMF_SUCCESS:
>  		break;
>  	case TMF_TIMEDOUT:
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
>  		goto done;
>  	default:
> @@ -2472,21 +2449,21 @@ int iscsi_eh_target_reset(struct scsi_cmnd *sc)
>  	}
>  
>  	rc = SUCCESS;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	iscsi_suspend_tx(conn);
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	memset(hdr, 0, sizeof(*hdr));
>  	fail_scsi_tasks(conn, -1, DID_ERROR);
>  	conn->tmf_state = TMF_INITIAL;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	iscsi_start_tx(conn);
>  	goto done;
>  
>  unlock:
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  done:
>  	ISCSI_DBG_EH(session, "tgt %s reset result = %s\n", session->targetname,
>  		     rc == SUCCESS ? "SUCCESS" : "FAILED");
> @@ -2784,10 +2761,8 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
>  	session->max_r2t = 1;
>  	session->tt = iscsit;
>  	session->dd_data = cls_session->dd_data + sizeof(*session);
> -
>  	mutex_init(&session->eh_mutex);
> -	spin_lock_init(&session->frwd_lock);
> -	spin_lock_init(&session->back_lock);
> +	spin_lock_init(&session->lock);
>  
>  	/* initialize SCSI PDU commands pool */
>  	if (iscsi_pool_init(&session->cmdpool, session->cmds_max,
> @@ -2901,14 +2876,14 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size,
>  	INIT_WORK(&conn->xmitwork, iscsi_xmitworker);
>  
>  	/* allocate login_task used for the login/text sequences */
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (!kfifo_out(&session->cmdpool.queue,
>                           (void*)&conn->login_task,
>  			 sizeof(void*))) {
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		goto login_task_alloc_fail;
>  	}
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	data = (char *) __get_free_pages(GFP_KERNEL,
>  					 get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
> @@ -2945,7 +2920,7 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
>  	del_timer_sync(&conn->transport_timer);
>  
>  	mutex_lock(&session->eh_mutex);
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
>  	if (session->leadconn == conn) {
>  		/*
> @@ -2954,24 +2929,21 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
>  		session->state = ISCSI_STATE_TERMINATE;
>  		wake_up(&conn->ehwait);
>  	}
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	/* flush queued up work because we free the connection below */
>  	iscsi_suspend_tx(conn);
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	free_pages((unsigned long) conn->data,
>  		   get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
>  	kfree(conn->persistent_address);
>  	kfree(conn->local_ipaddr);
> -	/* regular RX path uses back_lock */
> -	spin_lock_bh(&session->back_lock);
>  	kfifo_in(&session->cmdpool.queue, (void*)&conn->login_task,
>  		    sizeof(void*));
> -	spin_unlock_bh(&session->back_lock);
>  	if (session->leadconn == conn)
>  		session->leadconn = NULL;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	mutex_unlock(&session->eh_mutex);
>  
>  	iscsi_destroy_conn(cls_conn);
> @@ -3009,7 +2981,7 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
>  		conn->ping_timeout = 5;
>  	}
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	conn->c_stage = ISCSI_CONN_STARTED;
>  	session->state = ISCSI_STATE_LOGGED_IN;
>  	session->queued_cmdsn = session->cmdsn;
> @@ -3038,7 +3010,7 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
>  	default:
>  		break;
>  	}
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	iscsi_unblock_session(session->cls_session);
>  	wake_up(&conn->ehwait);
> @@ -3077,9 +3049,9 @@ static void iscsi_start_session_recovery(struct iscsi_session *session,
>  	int old_stop_stage;
>  
>  	mutex_lock(&session->eh_mutex);
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (conn->stop_stage == STOP_CONN_TERM) {
> -		spin_unlock_bh(&session->frwd_lock);
> +		spin_unlock_bh(&session->lock);
>  		mutex_unlock(&session->eh_mutex);
>  		return;
>  	}
> @@ -3096,14 +3068,14 @@ static void iscsi_start_session_recovery(struct iscsi_session *session,
>  
>  	old_stop_stage = conn->stop_stage;
>  	conn->stop_stage = flag;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	del_timer_sync(&conn->transport_timer);
>  	iscsi_suspend_tx(conn);
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	conn->c_stage = ISCSI_CONN_STOPPED;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	/*
>  	 * for connection level recovery we should not calculate
> @@ -3124,11 +3096,11 @@ static void iscsi_start_session_recovery(struct iscsi_session *session,
>  	/*
>  	 * flush queues.
>  	 */
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	fail_scsi_tasks(conn, -1, DID_TRANSPORT_DISRUPTED);
>  	fail_mgmt_tasks(session, conn);
>  	memset(&conn->tmhdr, 0, sizeof(conn->tmhdr));
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  	mutex_unlock(&session->eh_mutex);
>  }
>  
> @@ -3155,10 +3127,10 @@ int iscsi_conn_bind(struct iscsi_cls_session *cls_session,
>  	struct iscsi_session *session = cls_session->dd_data;
>  	struct iscsi_conn *conn = cls_conn->dd_data;
>  
> -	spin_lock_bh(&session->frwd_lock);
> +	spin_lock_bh(&session->lock);
>  	if (is_leading)
>  		session->leadconn = conn;
> -	spin_unlock_bh(&session->frwd_lock);
> +	spin_unlock_bh(&session->lock);
>  
>  	/*
>  	 * Unblock xmitworker(), Login Phase will pass through.
> diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
> index 60cb6dc..2f738dd 100644
> --- a/drivers/scsi/libiscsi_tcp.c
> +++ b/drivers/scsi/libiscsi_tcp.c
> @@ -446,7 +446,7 @@ iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
>   * iscsi_tcp_cleanup_task - free tcp_task resources
>   * @task: iscsi task
>   *
> - * must be called with session back_lock
> + * must be called with session lock
>   */
>  void iscsi_tcp_cleanup_task(struct iscsi_task *task)
>  {
> @@ -457,7 +457,6 @@ void iscsi_tcp_cleanup_task(struct iscsi_task *task)
>  	if (!task->sc)
>  		return;
>  
> -	spin_lock_bh(&tcp_task->queue2pool);
>  	/* flush task's r2t queues */
>  	while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
>  		kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
> @@ -471,7 +470,6 @@ void iscsi_tcp_cleanup_task(struct iscsi_task *task)
>  			    sizeof(void*));
>  		tcp_task->r2t = NULL;
>  	}
> -	spin_unlock_bh(&tcp_task->queue2pool);
>  }
>  EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
>  
> @@ -579,13 +577,11 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
>  		return ISCSI_ERR_DATALEN;
>  	}
>  
> -	spin_lock(&tcp_task->pool2queue);
>  	rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
>  	if (!rc) {
>  		iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
>  				  "Target has sent more R2Ts than it "
>  				  "negotiated for or driver has leaked.\n");
> -		spin_unlock(&tcp_task->pool2queue);
>  		return ISCSI_ERR_PROTO;
>  	}
>  
> @@ -600,7 +596,6 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
>  	tcp_task->exp_datasn = r2tsn + 1;
>  	kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
>  	conn->r2t_pdus_cnt++;
> -	spin_unlock(&tcp_task->pool2queue);
>  
>  	iscsi_requeue_task(task);
>  	return 0;
> @@ -673,14 +668,14 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
>  
>  	switch(opcode) {
>  	case ISCSI_OP_SCSI_DATA_IN:
> -		spin_lock(&conn->session->back_lock);
> +		spin_lock(&conn->session->lock);
>  		task = iscsi_itt_to_ctask(conn, hdr->itt);
>  		if (!task)
>  			rc = ISCSI_ERR_BAD_ITT;
>  		else
>  			rc = iscsi_tcp_data_in(conn, task);
>  		if (rc) {
> -			spin_unlock(&conn->session->back_lock);
> +			spin_unlock(&conn->session->lock);
>  			break;
>  		}
>  
> @@ -713,11 +708,11 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
>  						   tcp_conn->in.datalen,
>  						   iscsi_tcp_process_data_in,
>  						   rx_hash);
> -			spin_unlock(&conn->session->back_lock);
> +			spin_unlock(&conn->session->lock);
>  			return rc;
>  		}
>  		rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
> -		spin_unlock(&conn->session->back_lock);
> +		spin_unlock(&conn->session->lock);
>  		break;
>  	case ISCSI_OP_SCSI_CMD_RSP:
>  		if (tcp_conn->in.datalen) {
> @@ -727,20 +722,18 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
>  		rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
>  		break;
>  	case ISCSI_OP_R2T:
> -		spin_lock(&conn->session->back_lock);
> +		spin_lock(&conn->session->lock);
>  		task = iscsi_itt_to_ctask(conn, hdr->itt);
> -		spin_unlock(&conn->session->back_lock);
>  		if (!task)
>  			rc = ISCSI_ERR_BAD_ITT;
>  		else if (ahslen)
>  			rc = ISCSI_ERR_AHSLEN;
>  		else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
>  			task->last_xfer = jiffies;
> -			spin_lock(&conn->session->frwd_lock);
>  			rc = iscsi_tcp_r2t_rsp(conn, task);
> -			spin_unlock(&conn->session->frwd_lock);
>  		} else
>  			rc = ISCSI_ERR_PROTO;
> +		spin_unlock(&conn->session->lock);
>  		break;
>  	case ISCSI_OP_LOGIN_RSP:
>  	case ISCSI_OP_TEXT_RSP:
> @@ -988,13 +981,14 @@ EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
>  
>  static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
>  {
> +	struct iscsi_session *session = task->conn->session;
>  	struct iscsi_tcp_task *tcp_task = task->dd_data;
>  	struct iscsi_r2t_info *r2t = NULL;
>  
>  	if (iscsi_task_has_unsol_data(task))
>  		r2t = &task->unsol_r2t;
>  	else {
> -		spin_lock_bh(&tcp_task->queue2pool);
> +		spin_lock_bh(&session->lock);
>  		if (tcp_task->r2t) {
>  			r2t = tcp_task->r2t;
>  			/* Continue with this R2T? */
> @@ -1016,7 +1010,7 @@ static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
>  			else
>  				r2t = tcp_task->r2t;
>  		}
> -		spin_unlock_bh(&tcp_task->queue2pool);
> +		spin_unlock_bh(&session->lock);
>  	}
>  
>  	return r2t;
> @@ -1146,8 +1140,6 @@ int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
>  			iscsi_pool_free(&tcp_task->r2tpool);
>  			goto r2t_alloc_fail;
>  		}
> -		spin_lock_init(&tcp_task->pool2queue);
> -		spin_lock_init(&tcp_task->queue2pool);
>  	}
>  
>  	return 0;
> diff --git a/drivers/scsi/qla4xxx/ql4_isr.c b/drivers/scsi/qla4xxx/ql4_isr.c
> index 4f9c0f2..79b278b 100644
> --- a/drivers/scsi/qla4xxx/ql4_isr.c
> +++ b/drivers/scsi/qla4xxx/ql4_isr.c
> @@ -385,9 +385,9 @@ static void qla4xxx_passthru_status_entry(struct scsi_qla_host *ha,
>  
>  	cls_conn = ddb_entry->conn;
>  	conn = cls_conn->dd_data;
> -	spin_lock(&conn->session->back_lock);
> +	spin_lock(&conn->session->lock);
>  	task = iscsi_itt_to_task(conn, itt);
> -	spin_unlock(&conn->session->back_lock);
> +	spin_unlock(&conn->session->lock);
>  
>  	if (task == NULL) {
>  		ql4_printk(KERN_ERR, ha, "%s: Task is NULL\n", __func__);
> diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
> index 4d1c46a..52d858c 100644
> --- a/include/scsi/libiscsi.h
> +++ b/include/scsi/libiscsi.h
> @@ -331,19 +331,12 @@ struct iscsi_session {
>  	struct iscsi_transport	*tt;
>  	struct Scsi_Host	*host;
>  	struct iscsi_conn	*leadconn;	/* leading connection */
> -	/* Between the forward and the backward locks exists a strict locking
> -	 * hierarchy. The mutual exclusion zone protected by the forward lock
> -	 * can enclose the mutual exclusion zone protected by the backward lock
> -	 * but not vice versa.
> -	 */
> -	spinlock_t		frwd_lock;	/* protects session state, *
> -						 * cmdsn, queued_cmdsn     *
> +	spinlock_t		lock;		/* protects session state, *
> +						 * sequence numbers,       *
>  						 * session resources:      *
> -						 * - cmdpool kfifo_out ,   *
> -						 * - mgmtpool,		   */
> -	spinlock_t		back_lock;	/* protects cmdsn_exp      *
> -						 * cmdsn_max,              *
> -						 * cmdpool kfifo_in        */
> +						 * - cmdpool,		   *
> +						 * - mgmtpool,		   *
> +						 * - r2tpool		   */
>  	int			state;		/* session state           */
>  	int			age;		/* counts session re-opens */
>  
> diff --git a/include/scsi/libiscsi_tcp.h b/include/scsi/libiscsi_tcp.h
> index 2a7aa75..215469a 100644
> --- a/include/scsi/libiscsi_tcp.h
> +++ b/include/scsi/libiscsi_tcp.h
> @@ -83,8 +83,6 @@ struct iscsi_tcp_task {
>  	struct iscsi_pool	r2tpool;
>  	struct kfifo		r2tqueue;
>  	void			*dd_data;
> -	spinlock_t		pool2queue;
> -	spinlock_t		queue2pool;
>  };
>  
>  enum {
> -- 
> 1.9.1
> 
> 
> -- 
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team

Ack

-- 
Brad Figg brad.figg at canonical.com http://www.canonical.com




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