queue might not be rewinded correctly in qdma_queue_add in case buffer too short

[hmaarrfk]

In the snippet below, an error message is passed to the user.
However, if they provide a buffer that is too small, the queue doesn't get rewound correctly.

dma_ip_drivers/QDMA/linux-kernel/libqdma/libqdma_export.c

Lines 994 to 1002 in 8b8c70b

	if (buf && buflen) {
	cur += snprintf(cur, end - cur,
	"qdma%05x no %s QP, %u.\n",
	xdev->conf.bdf,
	qconf->st ? "ST" : "MM", qdev->qmax);
	if (cur >= end)
	goto handle_truncation;
	}
	goto rewind_qcnt;

dma_ip_drivers/QDMA/linux-kernel/libqdma/libqdma_export.c

Lines 1110 to 1123 in 8b8c70b

	rewind_qcnt:
	spin_lock(&qdev->lock);
	if (qconf->c2h)
	qdev->c2h_qcnt--;
	else
	qdev->h2c_qcnt--;
	spin_unlock(&qdev->lock);
	return rv;
	handle_truncation:
	*buf = '\0';
	return rv;
	}

[sujathabanoth-xlnx]

Issue addressed in 2019.2 driver release, Hence closing it

[hmaarrfk]

hmm, ok. i'm not too sure it is done correctly even in the new version.

It seems that if the queue is added there may be some cases where the following is not called

			descq->q_state = Q_STATE_DISABLED;

before an error is raised...