From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754216AbaLDNfi (ORCPT ); Thu, 4 Dec 2014 08:35:38 -0500 Received: from mail-lb0-f180.google.com ([209.85.217.180]:49000 "EHLO mail-lb0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753732AbaLDNfg (ORCPT ); Thu, 4 Dec 2014 08:35:36 -0500 Message-ID: <54806325.4060306@cogentembedded.com> Date: Thu, 04 Dec 2014 16:35:33 +0300 From: Sergei Shtylyov User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Thierry Reding CC: Felipe Balbi , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: phy: Restore deferred probing path References: <1417694767-18848-1-git-send-email-thierry.reding@gmail.com> <5480522A.5010900@cogentembedded.com> <20141204132200.GC7262@ulmo.nvidia.com> In-Reply-To: <20141204132200.GC7262@ulmo.nvidia.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/4/2014 4:22 PM, Thierry Reding wrote: >>> From: Thierry Reding >>> Commit 1290a958d48e ("usb: phy: propagate __of_usb_find_phy()'s error on >>> failure") broke platforms that rely on deferred probing to order probing >>> of PHY and host controller drivers. The reason is that the commit simply >>> propagates errors from __of_usb_find_phy(), which returns -ENODEV if no >>> PHY has been registered yet for a given device tree node. The only case >>> in which -EPROBE_DEFER would now be returned is if try_module_get() did >>> fail, which does not make sense. >>> The correct thing to do is to return -EPROBE_DEFER if a PHY hasn't been >>> registered yet. The only condition under which it makes sense to return >>> -ENODEV is if the device tree node representing the PHY has been >>> disabled (via the status property) because in that case the PHY will >>> never be registered. >>> This patch addresses the problem by making __of_usb_find_phy() return an >>> appropriate error code while keeping in line with the above-mentioned >>> commit to propagate error codes rather than overwriting them. At the >>> same time the check for a valid PHY is decoupled from the check for the >>> try_module_get() call and a separate error code is returned if the >>> latter fails. >>> Signed-off-by: Thierry Reding >>> --- >>> drivers/usb/phy/phy.c | 14 ++++++++++---- >>> 1 file changed, 10 insertions(+), 4 deletions(-) >>> diff --git a/drivers/usb/phy/phy.c b/drivers/usb/phy/phy.c >>> index b4066a001ba0..2f9735b35338 100644 >>> --- a/drivers/usb/phy/phy.c >>> +++ b/drivers/usb/phy/phy.c >> [...] >>> @@ -190,10 +193,13 @@ struct usb_phy *devm_usb_get_phy_by_phandle(struct device *dev, >>> spin_lock_irqsave(&phy_lock, flags); >>> >>> phy = __of_usb_find_phy(node); >>> - if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) { >>> - if (!IS_ERR(phy)) >>> - phy = ERR_PTR(-EPROBE_DEFER); >>> + if (IS_ERR(phy)) { >>> + devres_free(ptr); >>> + goto err1; >>> + } >>> >>> + if (!try_module_get(phy->dev->driver->owner)) { >>> + phy = ERR_PTR(-ENODEV); >>> devres_free(ptr); >>> goto err1; >>> } >> I think devres_free() should now be called in one place, under the new >> 'err2' label. > That'd make things very confusing, though. devres_free() should only be > called on error, whereas both err1 and err0 are shared with the success > case as well. If we were to do what you suggest we'd end up with > something like this: [...] > That's pretty spaghetti-like. Oh, sorry, I wasn't looking attentively enough. :-/ > Thierry WBR, Sergei