From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ezequiel Garcia Subject: [PATCH 2/2] net: phy: Ensure the MDIO bus module is held Date: Tue, 22 Jul 2014 21:16:10 -0300 Message-ID: <1406074570-13246-3-git-send-email-ezequiel.garcia@free-electrons.com> References: <1406074570-13246-1-git-send-email-ezequiel.garcia@free-electrons.com> Cc: David Miller , Florian Fainelli , Thomas Petazzoni , Gregory Clement , Ezequiel Garcia To: Return-path: Received: from top.free-electrons.com ([176.31.233.9]:37436 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757301AbaGWAR0 (ORCPT ); Tue, 22 Jul 2014 20:17:26 -0400 In-Reply-To: <1406074570-13246-1-git-send-email-ezequiel.garcia@free-electrons.com> Sender: netdev-owner@vger.kernel.org List-ID: This commit adds proper module_{get,put} to prevent the MDIO bus module from being unloaded while the phydev is connected. By doing so, we fix a kernel panic produced when a MDIO driver is removed, but the phydev that relies on it is attached and running. Signed-off-by: Ezequiel Garcia --- drivers/net/phy/phy_device.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 35d753d..a10dc47 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -575,6 +575,7 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev, u32 flags, phy_interface_t interface) { struct device *d = &phydev->dev; + struct module *bus_module; int err; /* Assume that if there is no driver, that it doesn't @@ -599,6 +600,14 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev, return -EBUSY; } + /* Increment the bus module reference count */ + bus_module = phydev->bus->dev.driver ? + phydev->bus->dev.driver->owner : NULL; + if (!try_module_get(bus_module)) { + dev_err(&dev->dev, "failed to get the bus module\n"); + return -EIO; + } + phydev->attached_dev = dev; dev->phydev = phydev; @@ -614,10 +623,14 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev, */ err = phy_init_hw(phydev); if (err) - phy_detach(phydev); - else - phy_resume(phydev); + goto err_module_put; + phy_resume(phydev); + return err; + +err_module_put: + module_put(bus_module); + phy_detach(phydev); return err; } EXPORT_SYMBOL(phy_attach_direct); @@ -664,6 +677,10 @@ EXPORT_SYMBOL(phy_attach); void phy_detach(struct phy_device *phydev) { int i; + + if (phydev->bus->dev.driver) + module_put(phydev->bus->dev.driver->owner); + phydev->attached_dev->phydev = NULL; phydev->attached_dev = NULL; phy_suspend(phydev); -- 2.0.1