Commit 5d12c05e authored by Mike Christie's avatar Mike Christie Committed by James Bottomley
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[SCSI] libiscsi: Check TMF state before sending PDU 



Patch and mail from both MikeC and HannesR:

Before we're trying to send a PDU we have to check whether a TMF
is active. If so and if the PDU will be affected by the TMF
we should allow only Data-out PDUs to be sent.

If fast_abort is set, no Data-out PDUs will be sent while
a LUN reset is being processed for a affected LUN.

fast_abort is now ingored during a ABORT TASK tmf. We will not
send any Data-outs for a task if the task is being aborted.

Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent 4f704dc0

drivers/scsi/libiscsi.c

+101 −12
Original line number Diff line number Diff line
@@ -265,6 +265,88 @@ static int iscsi_prep_bidi_ahs(struct iscsi_task *task) 
	return 0;

}



/**

 * iscsi_check_tmf_restrictions - check if a task is affected by TMF

 * @task: iscsi task

 * @opcode: opcode to check for

 *

 * During TMF a task has to be checked if it's affected.

 * All unrelated I/O can be passed through, but I/O to the

 * affected LUN should be restricted.

 * If 'fast_abort' is set we won't be sending any I/O to the

 * affected LUN.

 * Otherwise the target is waiting for all TTTs to be completed,

 * so we have to send all outstanding Data-Out PDUs to the target.

 */

static int iscsi_check_tmf_restrictions(struct iscsi_task *task, int opcode)

{

	struct iscsi_conn *conn = task->conn;

	struct iscsi_tm *tmf = &conn->tmhdr;

	unsigned int hdr_lun;



	if (conn->tmf_state == TMF_INITIAL)

		return 0;



	if ((tmf->opcode & ISCSI_OPCODE_MASK) != ISCSI_OP_SCSI_TMFUNC)

		return 0;



	switch (ISCSI_TM_FUNC_VALUE(tmf)) {

	case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:

		/*

		 * Allow PDUs for unrelated LUNs

		 */

		hdr_lun = scsilun_to_int((struct scsi_lun *)tmf->lun);

		if (hdr_lun != task->sc->device->lun)

			return 0;



		/*

		 * Fail all SCSI cmd PDUs

		 */

		if (opcode != ISCSI_OP_SCSI_DATA_OUT) {

			iscsi_conn_printk(KERN_INFO, conn,

					  "task [op %x/%x itt "

					  "0x%x/0x%x lun %u] "

					  "rejected.\n",

					  task->hdr->opcode, opcode,

					  task->itt, task->hdr_itt, hdr_lun);

			return -EACCES;

		}

		/*

		 * And also all data-out PDUs in response to R2T

		 * if fast_abort is set.

		 */

		if (conn->session->fast_abort) {

			iscsi_conn_printk(KERN_INFO, conn,

					  "task [op %x/%x itt "

					  "0x%x/0x%x lun %u] "

					  "fast abort.\n",

					  task->hdr->opcode, opcode,

					  task->itt, task->hdr_itt, hdr_lun);

			return -EACCES;

		}

		break;

	case ISCSI_TM_FUNC_ABORT_TASK:

		/*

		 * the caller has already checked if the task

		 * they want to abort was in the pending queue so if

		 * we are here the cmd pdu has gone out already, and

		 * we will only hit this for data-outs

		 */

		if (opcode == ISCSI_OP_SCSI_DATA_OUT &&

		    task->hdr_itt == tmf->rtt) {

			ISCSI_DBG_SESSION(conn->session,

					  "Preventing task %x/%x from sending "

					  "data-out due to abort task in "

					  "progress\n", task->itt,

					  task->hdr_itt);

			return -EACCES;

		}

		break;

	}



	return 0;

}



/**

 * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu

 * @task: iscsi task
@@ -282,6 +364,10 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task) 
	itt_t itt;

	int rc;



	rc = iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_CMD);

	if (rc)

		return rc;



	if (conn->session->tt->alloc_pdu) {

		rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_CMD);

		if (rc)
@@ -1366,6 +1452,7 @@ EXPORT_SYMBOL_GPL(iscsi_requeue_task); 
 **/

static int iscsi_data_xmit(struct iscsi_conn *conn)

{

	struct iscsi_task *task;

	int rc = 0;



	spin_lock_bh(&conn->session->lock);
@@ -1403,11 +1490,8 @@ check_mgmt: 


	/* process pending command queue */

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

		if (conn->tmf_state == TMF_QUEUED)

			break;



		conn->task = list_entry(conn->cmdqueue.next,

					 struct iscsi_task, running);

		conn->task = list_entry(conn->cmdqueue.next, struct iscsi_task,

					running);

		list_del_init(&conn->task->running);

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

			fail_scsi_task(conn->task, DID_IMM_RETRY);
@@ -1415,7 +1499,7 @@ check_mgmt: 
		}

		rc = iscsi_prep_scsi_cmd_pdu(conn->task);

		if (rc) {

			if (rc == -ENOMEM) {

			if (rc == -ENOMEM || rc == -EACCES) {

				list_add_tail(&conn->task->running,

					      &conn->cmdqueue);

				conn->task = NULL;
@@ -1437,17 +1521,18 @@ check_mgmt: 
	}



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

		if (conn->session->fast_abort && conn->tmf_state != TMF_INITIAL)

			break;



		/*

		 * we always do fastlogout - conn stop code will clean up.

		 */

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

			break;



		conn->task = list_entry(conn->requeue.next,

					 struct iscsi_task, running);

		task = list_entry(conn->requeue.next, struct iscsi_task,

				  running);

		if (iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_DATA_OUT))

			break;



		conn->task = task;

		list_del_init(&conn->task->running);

		conn->task->state = ISCSI_TASK_RUNNING;

		rc = iscsi_xmit_task(conn);
@@ -1600,7 +1685,7 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *)) 
	if (!ihost->workq) {

		reason = iscsi_prep_scsi_cmd_pdu(task);

		if (reason) {

			if (reason == -ENOMEM) {

			if (reason == -ENOMEM ||  reason == -EACCES) {

				reason = FAILURE_OOM;

				goto prepd_reject;

			} else {
@@ -2120,6 +2205,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) 
		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->lock);

		iscsi_start_tx(conn);

		goto success_unlocked;
@@ -2130,6 +2216,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) 
	case TMF_NOT_FOUND:

		if (!sc->SCp.ptr) {

			conn->tmf_state = TMF_INITIAL;

			memset(hdr, 0, sizeof(*hdr));

			/* task completed before tmf abort response */

			ISCSI_DBG_EH(session, "sc completed while abort	in "

					      "progress\n");
@@ -2224,6 +2311,7 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc) 
	iscsi_suspend_tx(conn);



	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->lock);
@@ -2868,6 +2956,7 @@ static void iscsi_start_session_recovery(struct iscsi_session *session, 
	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->lock);

	mutex_unlock(&session->eh_mutex);

}

include/scsi/iscsi_proto.h

+2 −0
Original line number Diff line number Diff line
@@ -279,6 +279,8 @@ struct iscsi_tm { 
#define ISCSI_TM_FUNC_TARGET_COLD_RESET		7

#define ISCSI_TM_FUNC_TASK_REASSIGN		8



#define ISCSI_TM_FUNC_VALUE(hdr) ((hdr)->flags & ISCSI_FLAG_TM_FUNC_MASK)



/* SCSI Task Management Response Header */

struct iscsi_tm_rsp {

	uint8_t opcode;

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