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Commit f159b3c7 authored by Quinn Tran's avatar Quinn Tran Committed by Nicholas Bellinger
Browse files

qla2xxx: Fix sess_lock & hardware_lock lock order problem. 



The main lock that needs to be held for CMD or TMR submission
to upper layer is the sess_lock. The sess_lock is used to
serialize cmd submission and session deletion. The addition
of hardware_lock being held is not necessary. This patch removes
hardware_lock dependency from CMD/TMR submission.

Use hardware_lock only for error response in this case.

Path1
       CPU0                    CPU1
       ----                    ----
  lock(&(&ha->tgt.sess_lock)->rlock);
                               lock(&(&ha->hardware_lock)->rlock);
                               lock(&(&ha->tgt.sess_lock)->rlock);
  lock(&(&ha->hardware_lock)->rlock);

Path2/deadlock
*** DEADLOCK ***
Call Trace:
dump_stack+0x85/0xc2
print_circular_bug+0x1e3/0x250
__lock_acquire+0x1425/0x1620
lock_acquire+0xbf/0x210
_raw_spin_lock_irqsave+0x53/0x70
qlt_sess_work_fn+0x21d/0x480 [qla2xxx]
process_one_work+0x1f4/0x6e0

Cc: <stable@vger.kernel.org>
Cc: Bart Van Assche <Bart.VanAssche@sandisk.com>
Reported-by: default avatarBart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: default avatarQuinn Tran <quinn.tran@cavium.com>
Signed-off-by: default avatarHimanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 8f6fc8d4

drivers/scsi/qla2xxx/qla_target.c

+18 −23
Original line number Diff line number Diff line
@@ -5727,30 +5727,23 @@ static void qlt_abort_work(struct qla_tgt *tgt, 
		}

	}



	spin_lock_irqsave(&ha->hardware_lock, flags);



	if (tgt->tgt_stop)

		goto out_term;



	rc = __qlt_24xx_handle_abts(vha, &prm->abts, sess);

	if (rc != 0)

		goto out_term;

	spin_unlock_irqrestore(&ha->hardware_lock, flags);

	if (sess)

	ha->tgt.tgt_ops->put_sess(sess);

	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags2);



	if (rc != 0)

		goto out_term;

	return;



out_term2:

	spin_lock_irqsave(&ha->hardware_lock, flags);

	if (sess)

		ha->tgt.tgt_ops->put_sess(sess);

	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags2);



out_term:

	spin_lock_irqsave(&ha->hardware_lock, flags);

	qlt_24xx_send_abts_resp(vha, &prm->abts, FCP_TMF_REJECTED, false);

	spin_unlock_irqrestore(&ha->hardware_lock, flags);



	if (sess)

		ha->tgt.tgt_ops->put_sess(sess);

	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags2);

}



static void qlt_tmr_work(struct qla_tgt *tgt,
@@ -5770,7 +5763,7 @@ static void qlt_tmr_work(struct qla_tgt *tgt, 
	spin_lock_irqsave(&ha->tgt.sess_lock, flags);



	if (tgt->tgt_stop)

		goto out_term;

		goto out_term2;



	s_id = prm->tm_iocb2.u.isp24.fcp_hdr.s_id;

	sess = ha->tgt.tgt_ops->find_sess_by_s_id(vha, s_id);
@@ -5782,11 +5775,11 @@ static void qlt_tmr_work(struct qla_tgt *tgt, 


		spin_lock_irqsave(&ha->tgt.sess_lock, flags);

		if (!sess)

			goto out_term;

			goto out_term2;

	} else {

		if (sess->deleted) {

			sess = NULL;

			goto out_term;

			goto out_term2;

		}



		if (!kref_get_unless_zero(&sess->sess_kref)) {
@@ -5794,7 +5787,7 @@ static void qlt_tmr_work(struct qla_tgt *tgt, 
			    "%s: kref_get fail %8phC\n",

			     __func__, sess->port_name);

			sess = NULL;

			goto out_term;

			goto out_term2;

		}

	}
@@ -5804,17 +5797,19 @@ static void qlt_tmr_work(struct qla_tgt *tgt, 
	unpacked_lun = scsilun_to_int((struct scsi_lun *)&lun);



	rc = qlt_issue_task_mgmt(sess, unpacked_lun, fn, iocb, 0);

	ha->tgt.tgt_ops->put_sess(sess);

	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);



	if (rc != 0)

		goto out_term;

	return;



out_term2:

	if (sess)

		ha->tgt.tgt_ops->put_sess(sess);

	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);

	return;



out_term:

	qlt_send_term_exchange(vha, NULL, &prm->tm_iocb2, 1, 0);

	ha->tgt.tgt_ops->put_sess(sess);

	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);

}



static void qlt_sess_work_fn(struct work_struct *work)