From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pandora.arm.linux.org.uk (pandora.arm.linux.org.uk [IPv6:2001:4d48:ad52:3201:214:fdff:fe10:1be6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 87B1E1A04FA for ; Fri, 25 Sep 2015 05:37:23 +1000 (AEST) In-Reply-To: <20150922161710.GA21084@n2100.arm.linux.org.uk> References: <20150922161710.GA21084@n2100.arm.linux.org.uk> From: Russell King To: Florian Fainelli , David Miller Cc: devicetree@vger.kernel.org, Frank Rowand , Grant Likely , Iyappan Subramanian , Keyur Chudgar , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Li Yang , Michal Simek , netdev@vger.kernel.org, Robert Richter , Rob Herring , "Soren Brinkmann" , Sunil Goutham , Thomas Petazzoni , linux-kernel@vger.kernel.org Subject: [PATCH RESEND v3 5/9] of_mdio: fix MDIO phy device refcounting MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Message-Id: Sender: Russell King Date: Thu, 24 Sep 2015 20:36:13 +0100 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , bus_find_device() is defined as: * This is similar to the bus_for_each_dev() function above, but it * returns a reference to a device that is 'found' for later use, as * determined by the @match callback. and it does indeed return a reference-counted pointer to the device: while ((dev = next_device(&i))) if (match(dev, data) && get_device(dev)) ^^^^^^^^^^^^^^^ break; klist_iter_exit(&i); return dev; What that means is that when we're done with the struct device, we must drop that reference. Neither of_phy_connect() nor of_phy_attach() did this when phy_connect_direct() or phy_attach_direct() failed. With our previous patch, phy_connect_direct() and phy_attach_direct() take a new refcount on the phy device when successful, so we can drop our local reference immediatley after these functions, whether or not they succeeded. Signed-off-by: Russell King --- drivers/of/of_mdio.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c index 1350fa25cdb0..a87a868fed64 100644 --- a/drivers/of/of_mdio.c +++ b/drivers/of/of_mdio.c @@ -197,7 +197,8 @@ static int of_phy_match(struct device *dev, void *phy_np) * of_phy_find_device - Give a PHY node, find the phy_device * @phy_np: Pointer to the phy's device tree node * - * Returns a pointer to the phy_device. + * If successful, returns a pointer to the phy_device with the embedded + * struct device refcount incremented by one, or NULL on failure. */ struct phy_device *of_phy_find_device(struct device_node *phy_np) { @@ -217,7 +218,9 @@ EXPORT_SYMBOL(of_phy_find_device); * @hndlr: Link state callback for the network device * @iface: PHY data interface type * - * Returns a pointer to the phy_device if successful. NULL otherwise + * If successful, returns a pointer to the phy_device with the embedded + * struct device refcount incremented by one, or NULL on failure. The + * refcount must be dropped by calling phy_disconnect() or phy_detach(). */ struct phy_device *of_phy_connect(struct net_device *dev, struct device_node *phy_np, @@ -225,13 +228,19 @@ struct phy_device *of_phy_connect(struct net_device *dev, phy_interface_t iface) { struct phy_device *phy = of_phy_find_device(phy_np); + int ret; if (!phy) return NULL; phy->dev_flags = flags; - return phy_connect_direct(dev, phy, hndlr, iface) ? NULL : phy; + ret = phy_connect_direct(dev, phy, hndlr, iface); + + /* refcount is held by phy_connect_direct() on success */ + put_device(&phy->dev); + + return ret ? NULL : phy; } EXPORT_SYMBOL(of_phy_connect); @@ -241,17 +250,27 @@ EXPORT_SYMBOL(of_phy_connect); * @phy_np: Node pointer for the PHY * @flags: flags to pass to the PHY * @iface: PHY data interface type + * + * If successful, returns a pointer to the phy_device with the embedded + * struct device refcount incremented by one, or NULL on failure. The + * refcount must be dropped by calling phy_disconnect() or phy_detach(). */ struct phy_device *of_phy_attach(struct net_device *dev, struct device_node *phy_np, u32 flags, phy_interface_t iface) { struct phy_device *phy = of_phy_find_device(phy_np); + int ret; if (!phy) return NULL; - return phy_attach_direct(dev, phy, flags, iface) ? NULL : phy; + ret = phy_attach_direct(dev, phy, flags, iface); + + /* refcount is held by phy_attach_direct() on success */ + put_device(&phy->dev); + + return ret ? NULL : phy; } EXPORT_SYMBOL(of_phy_attach); -- 2.1.0