net: dsa: microchip: Fix symetry in ksz_ptp_msg_irq_{setup/free}()

The IRQ numbers created through irq_create_mapping() are only assigned
to ptpmsg_irq[n].num at the end of the IRQ setup. So if an error occurs
between their creation and their assignment (for instance during the
request_threaded_irq() step), we enter the error path and fail to
release the newly created virtual IRQs because they aren't yet assigned
to ptpmsg_irq[n].num.

Move the mapping creation to ksz_ptp_msg_irq_setup() to ensure symetry
with what's released by ksz_ptp_msg_irq_free().
In the error path, move the irq_dispose_mapping to the out_ptp_msg label
so it will be called only on created IRQs.

Cc: [e-mail]
Fixes: cc13ab18b201 ("net: dsa: microchip: ptp: enable interrupt for timestamping")
Reviewed-by: Andrew Lunn <[e-mail]>
Signed-off-by: Bastien Curutchet (Schneider Electric) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Paolo Abeni <[e-mail]>

drivers/net/dsa/microchip/ksz_ptp.c

···
 	static const char * const name[] = {"pdresp-msg", "xdreq-msg",
 					    "sync-msg"};
 	const struct ksz_dev_ops *ops = port->ksz_dev->dev_ops;
+	struct ksz_irq *ptpirq = &port->ptpirq;
 	struct ksz_ptp_irq *ptpmsg_irq;
 
 	ptpmsg_irq = &port->ptpmsg_irq[n];
+	ptpmsg_irq->num = irq_create_mapping(ptpirq->domain, n);
+	if (!ptpmsg_irq->num)
+		return -EINVAL;
 
 	ptpmsg_irq->port = port;
 	ptpmsg_irq->ts_reg = ops->get_port_addr(port->num, ts_reg[n]);
 
 	strscpy(ptpmsg_irq->name, name[n]);
-
-	ptpmsg_irq->num = irq_find_mapping(port->ptpirq.domain, n);
-	if (ptpmsg_irq->num < 0)
-		return ptpmsg_irq->num;
 
 	return request_threaded_irq(ptpmsg_irq->num, NULL,
 				    ksz_ptp_msg_thread_fn, IRQF_ONESHOT,
···
 	if (!ptpirq->domain)
 		return -ENOMEM;
 
-	for (irq = 0; irq < ptpirq->nirqs; irq++)
-		irq_create_mapping(ptpirq->domain, irq);
-
 	ptpirq->irq_num = irq_find_mapping(port->pirq.domain, PORT_SRC_PTP_INT);
 	if (!ptpirq->irq_num) {
 		ret = -EINVAL;
···
 
 out_ptp_msg:
 	free_irq(ptpirq->irq_num, ptpirq);
-	while (irq--)
+	while (irq--) {
 		free_irq(port->ptpmsg_irq[irq].num, &port->ptpmsg_irq[irq]);
-out:
-	for (irq = 0; irq < ptpirq->nirqs; irq++)
 		irq_dispose_mapping(port->ptpmsg_irq[irq].num);
-
+	}
+out:
 	irq_domain_remove(ptpirq->domain);
 
 	return ret;