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Commit e0726407 authored by Mike Christie's avatar Mike Christie Committed by James Bottomley
Browse files

[SCSI] libiscsi: fix cmd seqeunce number checking 



We should not be checking the cmd windown for just handling r2t responses.
And if the window closes in on us, always have scsi-ml requeue the command
from our queuecommand function.

Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent 7974392c

drivers/scsi/libiscsi.c

+25 −21
Original line number Diff line number Diff line
@@ -596,10 +596,17 @@ static void iscsi_prep_mtask(struct iscsi_conn *conn, 
	nop->cmdsn = cpu_to_be32(session->cmdsn);

	if (hdr->itt != RESERVED_ITT) {

		hdr->itt = build_itt(mtask->itt, conn->id, 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))

		    !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {

			session->queued_cmdsn++;

			session->cmdsn++;

		}

	}



	if (session->tt->init_mgmt_task)

		session->tt->init_mgmt_task(conn, mtask);
@@ -641,9 +648,11 @@ static int iscsi_check_cmdsn_window_closed(struct iscsi_conn *conn) 
	/*

	 * Check for iSCSI window and take care of CmdSN wrap-around

	 */

	if (!iscsi_sna_lte(session->cmdsn, session->max_cmdsn)) {

		debug_scsi("iSCSI CmdSN closed. MaxCmdSN %u CmdSN %u\n",

			   session->max_cmdsn, session->cmdsn);

	if (!iscsi_sna_lte(session->queued_cmdsn, session->max_cmdsn)) {

		debug_scsi("iSCSI CmdSN closed. ExpCmdSn %u MaxCmdSN %u "

			   "CmdSN %u/%u\n", session->exp_cmdsn,

			   session->max_cmdsn, session->cmdsn,

			   session->queued_cmdsn);

		return -ENOSPC;

	}

	return 0;
@@ -722,11 +731,6 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 


	/* process command queue */

	while (!list_empty(&conn->xmitqueue)) {

		rc = iscsi_check_cmdsn_window_closed(conn);

		if (rc) {

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

			return rc;

		}

		/*

		 * iscsi tcp may readd the task to the xmitqueue to send

		 * write data
@@ -834,12 +838,6 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *)) 
		goto fault;

	}



	/*

	 * We check this here and in data xmit, because if we get to the point

	 * that this check is hitting the window then we have enough IO in

	 * flight and enough IO waiting to be transmitted it is better

	 * to let the scsi/block layer queue up.

	 */

	if (iscsi_check_cmdsn_window_closed(conn)) {

		reason = FAILURE_WINDOW_CLOSED;

		goto reject;
@@ -850,6 +848,8 @@ 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;
@@ -1140,7 +1140,13 @@ static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask, 
	if (!sc)

		return;



	if (ctask->state != ISCSI_TASK_PENDING)

	if (ctask->state == ISCSI_TASK_PENDING)

		/*

		 * cmd never made it to the xmit thread, so we should not count

		 * the cmd in the sequencing

		 */

		conn->session->queued_cmdsn--;

	else

		conn->session->tt->cleanup_cmd_task(conn, ctask);

	iscsi_ctask_mtask_cleanup(ctask);
@@ -1392,7 +1398,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, 
	session->state = ISCSI_STATE_FREE;

	session->mgmtpool_max = ISCSI_MGMT_CMDS_MAX;

	session->cmds_max = cmds_max;

	session->cmdsn = initial_cmdsn;

	session->queued_cmdsn = session->cmdsn = initial_cmdsn;

	session->exp_cmdsn = initial_cmdsn + 1;

	session->max_cmdsn = initial_cmdsn + 1;

	session->max_r2t = 1;
@@ -1616,11 +1622,8 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn) 
	kfree(conn->persistent_address);

	__kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,

		    sizeof(void*));

	if (session->leadconn == conn) {

	if (session->leadconn == conn)

		session->leadconn = NULL;

		/* no connections exits.. reset sequencing */

		session->cmdsn = session->max_cmdsn = session->exp_cmdsn = 1;

	}

	spin_unlock_bh(&session->lock);



	kfifo_free(conn->mgmtqueue);
@@ -1650,6 +1653,7 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn) 
	spin_lock_bh(&session->lock);

	conn->c_stage = ISCSI_CONN_STARTED;

	session->state = ISCSI_STATE_LOGGED_IN;

	session->queued_cmdsn = session->cmdsn;



	switch(conn->stop_stage) {

	case STOP_CONN_RECOVER:

include/scsi/libiscsi.h

+3 −0
Original line number Diff line number Diff line
@@ -210,6 +210,9 @@ struct iscsi_session { 
	uint32_t		exp_cmdsn;

	uint32_t		max_cmdsn;



	/* This tracks the reqs queued into the initiator */

	uint32_t		queued_cmdsn;



	/* configuration */

	int			initial_r2t_en;

	unsigned		max_r2t;