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Subject[PATCH 4.19 04/49] Revert "ravb: Fixed to be able to unload modules"
Date
From: Geert Uytterhoeven <geert+renesas@glider.be>

commit 77972b55fb9d35d4a6b0abca99abffaa4ec6a85b upstream.

This reverts commit 1838d6c62f57836639bd3d83e7855e0ee4f6defc.

This commit moved the ravb_mdio_init() call (and thus the
of_mdiobus_register() call) from the ravb_probe() to the ravb_open()
call. This causes a regression during system resume (s2idle/s2ram), as
new PHY devices cannot be bound while suspended.

During boot, the Micrel PHY is detected like this:

Micrel KSZ9031 Gigabit PHY e6800000.ethernet-ffffffff:00: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=e6800000.ethernet-ffffffff:00, irq=228)
ravb e6800000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off

During system suspend, (A) defer_all_probes is set to true, and (B)
usermodehelper_disabled is set to UMH_DISABLED, to avoid drivers being
probed while suspended.

A. If CONFIG_MODULES=n, phy_device_register() calling device_add()
merely adds the device, but does not probe it yet, as
really_probe() returns early due to defer_all_probes being set:

dpm_resume+0x128/0x4f8
device_resume+0xcc/0x1b0
dpm_run_callback+0x74/0x340
ravb_resume+0x190/0x1b8
ravb_open+0x84/0x770
of_mdiobus_register+0x1e0/0x468
of_mdiobus_register_phy+0x1b8/0x250
of_mdiobus_phy_device_register+0x178/0x1e8
phy_device_register+0x114/0x1b8
device_add+0x3d4/0x798
bus_probe_device+0x98/0xa0
device_initial_probe+0x10/0x18
__device_attach+0xe4/0x140
bus_for_each_drv+0x64/0xc8
__device_attach_driver+0xb8/0xe0
driver_probe_device.part.11+0xc4/0xd8
really_probe+0x32c/0x3b8

Later, phy_attach_direct() notices no PHY driver has been bound,
and falls back to the Generic PHY, leading to degraded operation:

Generic PHY e6800000.ethernet-ffffffff:00: attached PHY driver [Generic PHY] (mii_bus:phy_addr=e6800000.ethernet-ffffffff:00, irq=POLL)
ravb e6800000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off

B. If CONFIG_MODULES=y, request_module() returns early with -EBUSY due
to UMH_DISABLED, and MDIO initialization fails completely:

mdio_bus e6800000.ethernet-ffffffff:00: error -16 loading PHY driver module for ID 0x00221622
ravb e6800000.ethernet eth0: failed to initialize MDIO
PM: dpm_run_callback(): ravb_resume+0x0/0x1b8 returns -16
PM: Device e6800000.ethernet failed to resume: error -16

Ignoring -EBUSY in phy_request_driver_module(), like was done for
-ENOENT in commit 21e194425abd65b5 ("net: phy: fix issue with loading
PHY driver w/o initramfs"), would makes it fall back to the Generic
PHY, like in the CONFIG_MODULES=n case.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: stable@vger.kernel.org
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/renesas/ravb_main.c | 110 +++++++++++++++----------------
1 file changed, 55 insertions(+), 55 deletions(-)

--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1337,51 +1337,6 @@ static inline int ravb_hook_irq(unsigned
return error;
}

-/* MDIO bus init function */
-static int ravb_mdio_init(struct ravb_private *priv)
-{
- struct platform_device *pdev = priv->pdev;
- struct device *dev = &pdev->dev;
- int error;
-
- /* Bitbang init */
- priv->mdiobb.ops = &bb_ops;
-
- /* MII controller setting */
- priv->mii_bus = alloc_mdio_bitbang(&priv->mdiobb);
- if (!priv->mii_bus)
- return -ENOMEM;
-
- /* Hook up MII support for ethtool */
- priv->mii_bus->name = "ravb_mii";
- priv->mii_bus->parent = dev;
- snprintf(priv->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x",
- pdev->name, pdev->id);
-
- /* Register MDIO bus */
- error = of_mdiobus_register(priv->mii_bus, dev->of_node);
- if (error)
- goto out_free_bus;
-
- return 0;
-
-out_free_bus:
- free_mdio_bitbang(priv->mii_bus);
- return error;
-}
-
-/* MDIO bus release function */
-static int ravb_mdio_release(struct ravb_private *priv)
-{
- /* Unregister mdio bus */
- mdiobus_unregister(priv->mii_bus);
-
- /* Free bitbang info */
- free_mdio_bitbang(priv->mii_bus);
-
- return 0;
-}
-
/* Network device open function for Ethernet AVB */
static int ravb_open(struct net_device *ndev)
{
@@ -1390,13 +1345,6 @@ static int ravb_open(struct net_device *
struct device *dev = &pdev->dev;
int error;

- /* MDIO bus init */
- error = ravb_mdio_init(priv);
- if (error) {
- netdev_err(ndev, "failed to initialize MDIO\n");
- return error;
- }
-
napi_enable(&priv->napi[RAVB_BE]);
napi_enable(&priv->napi[RAVB_NC]);

@@ -1474,7 +1422,6 @@ out_free_irq:
out_napi_off:
napi_disable(&priv->napi[RAVB_NC]);
napi_disable(&priv->napi[RAVB_BE]);
- ravb_mdio_release(priv);
return error;
}

@@ -1774,8 +1721,6 @@ static int ravb_close(struct net_device
ravb_ring_free(ndev, RAVB_BE);
ravb_ring_free(ndev, RAVB_NC);

- ravb_mdio_release(priv);
-
return 0;
}

@@ -1922,6 +1867,51 @@ static const struct net_device_ops ravb_
.ndo_set_features = ravb_set_features,
};

+/* MDIO bus init function */
+static int ravb_mdio_init(struct ravb_private *priv)
+{
+ struct platform_device *pdev = priv->pdev;
+ struct device *dev = &pdev->dev;
+ int error;
+
+ /* Bitbang init */
+ priv->mdiobb.ops = &bb_ops;
+
+ /* MII controller setting */
+ priv->mii_bus = alloc_mdio_bitbang(&priv->mdiobb);
+ if (!priv->mii_bus)
+ return -ENOMEM;
+
+ /* Hook up MII support for ethtool */
+ priv->mii_bus->name = "ravb_mii";
+ priv->mii_bus->parent = dev;
+ snprintf(priv->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x",
+ pdev->name, pdev->id);
+
+ /* Register MDIO bus */
+ error = of_mdiobus_register(priv->mii_bus, dev->of_node);
+ if (error)
+ goto out_free_bus;
+
+ return 0;
+
+out_free_bus:
+ free_mdio_bitbang(priv->mii_bus);
+ return error;
+}
+
+/* MDIO bus release function */
+static int ravb_mdio_release(struct ravb_private *priv)
+{
+ /* Unregister mdio bus */
+ mdiobus_unregister(priv->mii_bus);
+
+ /* Free bitbang info */
+ free_mdio_bitbang(priv->mii_bus);
+
+ return 0;
+}
+
static const struct of_device_id ravb_match_table[] = {
{ .compatible = "renesas,etheravb-r8a7790", .data = (void *)RCAR_GEN2 },
{ .compatible = "renesas,etheravb-r8a7794", .data = (void *)RCAR_GEN2 },
@@ -2148,6 +2138,13 @@ static int ravb_probe(struct platform_de
eth_hw_addr_random(ndev);
}

+ /* MDIO bus init */
+ error = ravb_mdio_init(priv);
+ if (error) {
+ dev_err(&pdev->dev, "failed to initialize MDIO\n");
+ goto out_dma_free;
+ }
+
netif_napi_add(ndev, &priv->napi[RAVB_BE], ravb_poll, 64);
netif_napi_add(ndev, &priv->napi[RAVB_NC], ravb_poll, 64);

@@ -2169,6 +2166,8 @@ static int ravb_probe(struct platform_de
out_napi_del:
netif_napi_del(&priv->napi[RAVB_NC]);
netif_napi_del(&priv->napi[RAVB_BE]);
+ ravb_mdio_release(priv);
+out_dma_free:
dma_free_coherent(ndev->dev.parent, priv->desc_bat_size, priv->desc_bat,
priv->desc_bat_dma);

@@ -2200,6 +2199,7 @@ static int ravb_remove(struct platform_d
unregister_netdev(ndev);
netif_napi_del(&priv->napi[RAVB_NC]);
netif_napi_del(&priv->napi[RAVB_BE]);
+ ravb_mdio_release(priv);
pm_runtime_disable(&pdev->dev);
free_netdev(ndev);
platform_set_drvdata(pdev, NULL);

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