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Commit 052d0144 authored by Mike Christie's avatar Mike Christie Committed by James Bottomley
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[SCSI] libiscsi: modify libiscsi so it supports offloaded data paths 



This patch modifies libiscsi, so drivers like bnx2i and iser can execute
a command from queuecommand/send_pdu instead of having to be queued to
be run in a workq.

Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent 0af967f5

drivers/scsi/libiscsi.c

+104 −75
Original line number Diff line number Diff line
@@ -79,11 +79,13 @@ iscsi_update_cmdsn(struct iscsi_session *session, struct iscsi_nopin *hdr) 
		 * xmit thread

		 */

		if (!list_empty(&session->leadconn->xmitqueue) ||

		    !list_empty(&session->leadconn->mgmtqueue))

		    !list_empty(&session->leadconn->mgmtqueue)) {

			if (!(session->tt->caps & CAP_DATA_PATH_OFFLOAD))

				scsi_queue_work(session->host,

						&session->leadconn->xmitwork);

		}

	}

}

EXPORT_SYMBOL_GPL(iscsi_update_cmdsn);



void iscsi_prep_unsolicit_data_pdu(struct iscsi_cmd_task *ctask,
@@ -298,8 +300,12 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask) 
	WARN_ON(hdrlength >= 256);

	hdr->hlength = hdrlength & 0xFF;



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

		return EIO;

	if (conn->session->tt->init_cmd_task &&

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

		return -EIO;



	ctask->state = ISCSI_TASK_RUNNING;

	list_move_tail(&ctask->running, &conn->run_list);



	conn->scsicmd_pdus_cnt++;

	debug_scsi("iscsi prep [%s cid %d sc %p cdb 0x%x itt 0x%x "
@@ -334,6 +340,8 @@ static void iscsi_complete_command(struct iscsi_cmd_task *ctask) 
		conn->ctask = NULL;

	list_del_init(&ctask->running);

	__kfifo_put(session->cmdpool.queue, (void*)&ctask, sizeof(void*));



	if (sc->scsi_done)

		sc->scsi_done(sc);

}
@@ -403,6 +411,50 @@ void iscsi_free_mgmt_task(struct iscsi_conn *conn, 
}

EXPORT_SYMBOL_GPL(iscsi_free_mgmt_task);



static int iscsi_prep_mtask(struct iscsi_conn *conn,

			    struct iscsi_mgmt_task *mtask)

{

	struct iscsi_session *session = conn->session;

	struct iscsi_hdr *hdr = mtask->hdr;

	struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;



	if (conn->session->state == ISCSI_STATE_LOGGING_OUT)

		return -ENOTCONN;



	if (hdr->opcode != (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) &&

	    hdr->opcode != (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))

		nop->exp_statsn = cpu_to_be32(conn->exp_statsn);

	/*

	 * pre-format CmdSN for outgoing PDU.

	 */

	nop->cmdsn = cpu_to_be32(session->cmdsn);

	if (hdr->itt != RESERVED_ITT) {

		hdr->itt = build_itt(mtask->itt, session->age);

		/*

		 * TODO: We always use immediate, so we never hit this.

		 * If we start to send tmfs or nops as non-immediate then

		 * we should start checking the cmdsn numbers for mgmt tasks.

		 */

		if (conn->c_stage == ISCSI_CONN_STARTED &&

		    !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {

			session->queued_cmdsn++;

			session->cmdsn++;

		}

	}



	if (session->tt->init_mgmt_task)

		session->tt->init_mgmt_task(conn, mtask);



	if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT)

		session->state = ISCSI_STATE_LOGGING_OUT;



	list_move_tail(&mtask->running, &conn->mgmt_run_list);

	debug_scsi("mgmtpdu [op 0x%x hdr->itt 0x%x datalen %d]\n",

		   hdr->opcode & ISCSI_OPCODE_MASK, hdr->itt,

		   mtask->data_count);

	return 0;

}



static struct iscsi_mgmt_task *

__iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,

		      char *data, uint32_t data_size)
@@ -429,6 +481,12 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr, 
		if (!__kfifo_get(session->mgmtpool.queue,

				 (void*)&mtask, sizeof(void*)))

			return NULL;



		if ((hdr->opcode == (ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE)) &&

		     hdr->ttt == RESERVED_ITT) {

			conn->ping_mtask = mtask;

			conn->last_ping = jiffies;

		}

	}



	if (data_size) {
@@ -440,6 +498,19 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr, 
	memcpy(mtask->hdr, hdr, sizeof(struct iscsi_hdr));

	INIT_LIST_HEAD(&mtask->running);

	list_add_tail(&mtask->running, &conn->mgmtqueue);



	if (session->tt->caps & CAP_DATA_PATH_OFFLOAD) {

		if (iscsi_prep_mtask(conn, mtask)) {

			iscsi_free_mgmt_task(conn, mtask);

			return NULL;

		}



		if (session->tt->xmit_mgmt_task(conn, mtask))

			mtask = NULL;



	} else

		scsi_queue_work(conn->session->host, &conn->xmitwork);



	return mtask;

}
@@ -454,7 +525,6 @@ int iscsi_conn_send_pdu(struct iscsi_cls_conn *cls_conn, struct iscsi_hdr *hdr, 
	if (!__iscsi_conn_send_pdu(conn, hdr, data, data_size))

		err = -EPERM;

	spin_unlock_bh(&session->lock);

	scsi_queue_work(session->host, &conn->xmitwork);

	return err;

}

EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);
@@ -581,17 +651,8 @@ static void iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr) 
		hdr.ttt = RESERVED_ITT;



	mtask = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);

	if (!mtask) {

	if (!mtask)

		iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");

		return;

	}



	/* only track our nops */

	if (!rhdr) {

		conn->ping_mtask = mtask;

		conn->last_ping = jiffies;

	}

	scsi_queue_work(conn->session->host, &conn->xmitwork);

}



static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
@@ -868,56 +929,15 @@ void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err) 
}

EXPORT_SYMBOL_GPL(iscsi_conn_failure);



static void iscsi_prep_mtask(struct iscsi_conn *conn,

			     struct iscsi_mgmt_task *mtask)

{

	struct iscsi_session *session = conn->session;

	struct iscsi_hdr *hdr = mtask->hdr;

	struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;



	if (hdr->opcode != (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) &&

	    hdr->opcode != (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))

		nop->exp_statsn = cpu_to_be32(conn->exp_statsn);

	/*

	 * pre-format CmdSN for outgoing PDU.

	 */

	nop->cmdsn = cpu_to_be32(session->cmdsn);

	if (hdr->itt != RESERVED_ITT) {

		hdr->itt = build_itt(mtask->itt, session->age);

		/*

		 * TODO: We always use immediate, so we never hit this.

		 * If we start to send tmfs or nops as non-immediate then

		 * we should start checking the cmdsn numbers for mgmt tasks.

		 */

		if (conn->c_stage == ISCSI_CONN_STARTED &&

		    !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {

			session->queued_cmdsn++;

			session->cmdsn++;

		}

	}



	if (session->tt->init_mgmt_task)

		session->tt->init_mgmt_task(conn, mtask);



	debug_scsi("mgmtpdu [op 0x%x hdr->itt 0x%x datalen %d]\n",

		   hdr->opcode & ISCSI_OPCODE_MASK, hdr->itt,

		   mtask->data_count);

}



static int iscsi_xmit_mtask(struct iscsi_conn *conn)

{

	struct iscsi_hdr *hdr = conn->mtask->hdr;

	int rc;



	if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT)

		conn->session->state = ISCSI_STATE_LOGGING_OUT;

	spin_unlock_bh(&conn->session->lock);



	rc = conn->session->tt->xmit_mgmt_task(conn, conn->mtask);

	spin_lock_bh(&conn->session->lock);

	if (rc)

		return rc;



	/* done with this in-progress mtask */

	conn->mtask = NULL;

	return 0;
@@ -961,7 +981,8 @@ static int iscsi_xmit_ctask(struct iscsi_conn *conn) 
 * @ctask: ctask to requeue

 *

 * LLDs that need to run a ctask from the session workqueue should call

 * this. The session lock must be held.

 * this. The session lock must be held. This should only be called

 * by software drivers.

 */

void iscsi_requeue_ctask(struct iscsi_cmd_task *ctask)

{
@@ -1013,14 +1034,11 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 
	while (!list_empty(&conn->mgmtqueue)) {

		conn->mtask = list_entry(conn->mgmtqueue.next,

					 struct iscsi_mgmt_task, running);

		if (conn->session->state == ISCSI_STATE_LOGGING_OUT) {

		if (iscsi_prep_mtask(conn, conn->mtask)) {

			iscsi_free_mgmt_task(conn, conn->mtask);

			conn->mtask = NULL;

			continue;

		}



		iscsi_prep_mtask(conn, conn->mtask);

		list_move_tail(conn->mgmtqueue.next, &conn->mgmt_run_list);

		rc = iscsi_xmit_mtask(conn);

		if (rc)

			goto again;
@@ -1041,9 +1059,6 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 
			fail_command(conn, conn->ctask, DID_ABORT << 16);

			continue;

		}



		conn->ctask->state = ISCSI_TASK_RUNNING;

		list_move_tail(conn->xmitqueue.next, &conn->run_list);

		rc = iscsi_xmit_ctask(conn);

		if (rc)

			goto again;
@@ -1192,8 +1207,6 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *)) 
		reason = FAILURE_OOM;

		goto reject;

	}

	session->queued_cmdsn++;



	sc->SCp.phase = session->age;

	sc->SCp.ptr = (char *)ctask;
@@ -1202,11 +1215,26 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *)) 
	ctask->conn = conn;

	ctask->sc = sc;

	INIT_LIST_HEAD(&ctask->running);



	list_add_tail(&ctask->running, &conn->xmitqueue);

	spin_unlock(&session->lock);



	scsi_queue_work(host, &conn->xmitwork);

	if (session->tt->caps & CAP_DATA_PATH_OFFLOAD) {

		if (iscsi_prep_scsi_cmd_pdu(ctask)) {

			sc->result = DID_ABORT << 16;

			sc->scsi_done = NULL;

			iscsi_complete_command(ctask);

			goto fault;

		}

		if (session->tt->xmit_cmd_task(conn, ctask)) {

			sc->scsi_done = NULL;

			iscsi_complete_command(ctask);

			reason = FAILURE_SESSION_NOT_READY;

			goto reject;

		}

	} else

		scsi_queue_work(session->host, &conn->xmitwork);



	session->queued_cmdsn++;

	spin_unlock(&session->lock);

	spin_lock(host->host_lock);

	return 0;
@@ -1225,7 +1253,7 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *)) 
		scsi_out(sc)->resid = scsi_out(sc)->length;

		scsi_in(sc)->resid = scsi_in(sc)->length;

	}

	sc->scsi_done(sc);

	done(sc);

	spin_lock(host->host_lock);

	return 0;

}
@@ -1344,7 +1372,6 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn, 


	spin_unlock_bh(&session->lock);

	mutex_unlock(&session->eh_mutex);

	scsi_queue_work(session->host, &conn->xmitwork);



	/*

	 * block eh thread until:
@@ -1412,6 +1439,7 @@ static void fail_all_commands(struct iscsi_conn *conn, unsigned lun, 
void iscsi_suspend_tx(struct iscsi_conn *conn)

{

	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);

	if (!(conn->session->tt->caps & CAP_DATA_PATH_OFFLOAD))

		scsi_flush_work(conn->session->host);

}

EXPORT_SYMBOL_GPL(iscsi_suspend_tx);
@@ -1419,6 +1447,7 @@ EXPORT_SYMBOL_GPL(iscsi_suspend_tx); 
static void iscsi_start_tx(struct iscsi_conn *conn)

{

	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);

	if (!(conn->session->tt->caps & CAP_DATA_PATH_OFFLOAD))

		scsi_queue_work(conn->session->host, &conn->xmitwork);

}