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From:   Vladimir Oltean <vladimir.oltean@nxp.com>
To:     netdev@vger.kernel.org
Cc:     Ioana Ciornei <ioana.ciornei@nxp.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Russell King <linux@armlinux.org.uk>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH net-next 09/12] net: dpaa2-eth: connect to MAC before requesting the "endpoint changed" IRQ
Date:   Tue, 29 Nov 2022 16:12:18 +0200
Message-Id: <20221129141221.872653-10-vladimir.oltean@nxp.com>
In-Reply-To: <20221129141221.872653-1-vladimir.oltean@nxp.com>
References: <20221129141221.872653-1-vladimir.oltean@nxp.com>
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dpaa2_eth_connect_mac() is called both from dpaa2_eth_probe() and from
dpni_irq0_handler_thread().

It could happen that the DPNI gets connected to a DPMAC on the fsl-mc
bus exactly during probe, as soon as the "endpoint change" interrupt is
requested in dpaa2_eth_setup_irqs(). This will cause the
dpni_irq0_handler_thread() to register a phylink instance for that DPMAC.

Then, the probing function will also try to register a phylink instance
for the same DPMAC, operation which should fail (and this will fail the
probing of the driver).

Reorder dpaa2_eth_setup_irqs() and dpaa2_eth_connect_mac(), such that
dpni_irq0_handler_thread() never races with the DPMAC-related portion of
the probing path.

Also reorder dpaa2_eth_disconnect_mac() to be in the mirror position of
dpaa2_eth_connect_mac() in the teardown path.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 .../net/ethernet/freescale/dpaa2/dpaa2-eth.c   | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index 4dbf8a1651cd..b77d292cd960 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -4899,6 +4899,10 @@ static int dpaa2_eth_probe(struct fsl_mc_device *dpni_dev)
 	}
 #endif
 
+	err = dpaa2_eth_connect_mac(priv);
+	if (err)
+		goto err_connect_mac;
+
 	err = dpaa2_eth_setup_irqs(dpni_dev);
 	if (err) {
 		netdev_warn(net_dev, "Failed to set link interrupt, fall back to polling\n");
@@ -4911,10 +4915,6 @@ static int dpaa2_eth_probe(struct fsl_mc_device *dpni_dev)
 		priv->do_link_poll = true;
 	}
 
-	err = dpaa2_eth_connect_mac(priv);
-	if (err)
-		goto err_connect_mac;
-
 	err = dpaa2_eth_dl_alloc(priv);
 	if (err)
 		goto err_dl_register;
@@ -4948,13 +4948,13 @@ static int dpaa2_eth_probe(struct fsl_mc_device *dpni_dev)
 err_dl_trap_register:
 	dpaa2_eth_dl_free(priv);
 err_dl_register:
-	dpaa2_eth_disconnect_mac(priv);
-err_connect_mac:
 	if (priv->do_link_poll)
 		kthread_stop(priv->poll_thread);
 	else
 		fsl_mc_free_irqs(dpni_dev);
 err_poll_thread:
+	dpaa2_eth_disconnect_mac(priv);
+err_connect_mac:
 	dpaa2_eth_free_rings(priv);
 err_alloc_rings:
 err_csum:
@@ -5002,9 +5002,6 @@ static int dpaa2_eth_remove(struct fsl_mc_device *ls_dev)
 #endif
 
 	unregister_netdev(net_dev);
-	rtnl_lock();
-	dpaa2_eth_disconnect_mac(priv);
-	rtnl_unlock();
 
 	dpaa2_eth_dl_port_del(priv);
 	dpaa2_eth_dl_traps_unregister(priv);
@@ -5015,6 +5012,9 @@ static int dpaa2_eth_remove(struct fsl_mc_device *ls_dev)
 	else
 		fsl_mc_free_irqs(ls_dev);
 
+	rtnl_lock();
+	dpaa2_eth_disconnect_mac(priv);
+	rtnl_unlock();
 	dpaa2_eth_free_rings(priv);
 	free_percpu(priv->fd);
 	free_percpu(priv->sgt_cache);
-- 
2.34.1