From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756053Ab3E0Rha (ORCPT ); Mon, 27 May 2013 13:37:30 -0400 Received: from mail.free-electrons.com ([94.23.35.102]:53139 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755645Ab3E0Rh3 (ORCPT ); Mon, 27 May 2013 13:37:29 -0400 Message-ID: <51A399D6.8030000@free-electrons.com> Date: Mon, 27 May 2013 19:37:26 +0200 From: Alexandre Belloni Organization: Free Electrons User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 MIME-Version: 1.0 To: Sascha Hauer CC: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Russell King , Shawn Guo , Sascha Hauer Subject: Re: [PATCH 1/3] net: phy: prevent linking breakage References: <1369671524-14797-1-git-send-email-alexandre.belloni@free-electrons.com> <1369671524-14797-2-git-send-email-alexandre.belloni@free-electrons.com> <20130527163913.GO32299@pengutronix.de> In-Reply-To: <20130527163913.GO32299@pengutronix.de> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/05/2013 18:39, Sascha Hauer wrote: > On Mon, May 27, 2013 at 06:18:42PM +0200, Alexandre Belloni wrote: >> phy_register_fixup{,_for_uid,_for_id} are called from arch/, quite >> often, there is no protection to check whether CONFIG_PHYLIB=y which is >> the only case where this would work. Having phylib as a module or not >> compiled at all will result in that kind of linking failure: >> >> arch/arm/mach-at91/built-in.o: In function `ksz9021rn_phy_fixup': >> :(.text+0x1174): undefined reference to `mdiobus_write' >> :(.text+0x1188): undefined reference to `mdiobus_write' >> :(.text+0x119c): undefined reference to `mdiobus_write' >> :(.text+0x11b0): undefined reference to `mdiobus_write' >> arch/arm/mach-at91/built-in.o: In function `sama5_dt_device_init': >> :(.init.text+0x1e34): undefined reference to `phy_register_fixup_for_uid' >> >> Signed-off-by: Alexandre Belloni >> --- >> drivers/net/phy/phy_device.c | 6 ++++++ >> include/linux/phy.h | 12 ++++++++++++ >> 2 files changed, 18 insertions(+) >> >> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c >> index 3657b4a..df36367 100644 >> --- a/drivers/net/phy/phy_device.c >> +++ b/drivers/net/phy/phy_device.c >> @@ -64,6 +64,11 @@ static int phy_attach_direct(struct net_device *dev, struct phy_device *phydev, >> u32 flags, phy_interface_t interface); >> >> /* >> + * phy_register_fixup{,_for_uid,_for_id} are called from arch/ so this won't >> + * work unless phylib is compiled in the kernel. >> + */ >> +#ifdef CONFIG_PHYLIB >> +/* >> * Creates a new phy_fixup and adds it to the list >> * @bus_id: A string which matches phydev->dev.bus_id (or PHY_ANY_ID) >> * @phy_uid: Used to match against phydev->phy_id (the UID of the PHY) >> @@ -109,6 +114,7 @@ int phy_register_fixup_for_id(const char *bus_id, >> return phy_register_fixup(bus_id, PHY_ANY_UID, 0xffffffff, run); >> } >> EXPORT_SYMBOL(phy_register_fixup_for_id); >> +#endif /* CONFIG_PHYLIB */ >> >> /* >> * Returns 1 if fixup matches phydev in bus_id and phy_uid. >> diff --git a/include/linux/phy.h b/include/linux/phy.h >> index 9e11039..3f998a6 100644 >> --- a/include/linux/phy.h >> +++ b/include/linux/phy.h >> @@ -556,12 +556,24 @@ int phy_start_interrupts(struct phy_device *phydev); >> void phy_print_status(struct phy_device *phydev); >> void phy_device_free(struct phy_device *phydev); >> >> +/* >> + * phy_register_fixup{,_for_uid,_for_id} are called from arch/ so this won't >> + * work unless phylib is compiled in the kernel. >> + * Defining stubs allows to prevent linking errors. >> + */ >> +#ifdef CONFIG_PHYLIB >> int phy_register_fixup(const char *bus_id, u32 phy_uid, u32 phy_uid_mask, >> int (*run)(struct phy_device *)); >> int phy_register_fixup_for_id(const char *bus_id, >> int (*run)(struct phy_device *)); >> int phy_register_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask, >> int (*run)(struct phy_device *)); >> +#else >> +#define phy_register_fixup(a, b, c, d) do { } while (0) >> +#define phy_register_fixup_for_id(a, b) do { } while (0) >> +#define phy_register_fixup_for_uid(a, b, c) do { } while (0) > Use static inline functions here. This breaks if someone does result > checking on the functions which then expands to ret = do {} while (0); > Also we still have type safety for !CONFIG_PHYLIB. Right, I tried that first but forgot static so I had issues with redefinition of the functions. I even played with __weak at some point... I'll wait a bit for comments before sending v2. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com