Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752681AbdLGJeU (ORCPT ); Thu, 7 Dec 2017 04:34:20 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:44915 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752640AbdLGJeO (ORCPT ); Thu, 7 Dec 2017 04:34:14 -0500 X-Google-Smtp-Source: AGs4zMbmecFBBR2hzkwSMm6C99Y+mO6oUnAcr3JANtri4vmiYBdb5bu6i72MLT+YUMrGir3e38Wx3Q== Subject: Re: [PATCH v2] firmware: qcom: scm: Fix incorrect of_node_put call in scm_init To: Jerome Forissier , Stephen Boyd Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, David Brown , Andy Gross , linux-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jerome Brunet , Jens Wiklander References: <1512555692-14439-1-git-send-email-lollivier@baylibre.com> <20171206200601.GH4283@codeaurora.org> <40113581-4b8c-defe-ba90-0aabc30a1b6d@linaro.org> From: Loys Ollivier Message-ID: Date: Thu, 7 Dec 2017 10:34:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <40113581-4b8c-defe-ba90-0aabc30a1b6d@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2015 Lines: 66 On 07/12/2017 09:42, Jerome Forissier wrote: > > > On 12/06/2017 09:06 PM, Stephen Boyd wrote: >> On 12/06, Loys Ollivier wrote: >>> When using other platform architectures, in the init of the qcom_scm >>> driver, of_node_put is called on /firmware if no qcom dt is found. >>> This results in a kernel error: Bad of_node_put() on /firmware. >>> >>> The call to of_node_put from the qcom_scm init is unnecessary as >>> of_find_matching_node is calling it automatically. >>> >>> Remove this of_node_put(). >>> >>> Fixes: d0f6fa7ba2d6 ("firmware: qcom: scm: Convert SCM to platform driver") >>> Signed-off-by: Loys Ollivier >>> --- >> >> This still looks wrong. Especially if of_find_matching_node() is >> going to look for siblings of the /firmware node for the >> compatible string for scm device. Why do we check at all? Can't >> we just delete this and let of_platform_populate() take care of >> it? BTW, OP-TEE driver seems to have a similar problem. > > https://lkml.org/lkml/2017/11/29/230 > Well, the patch I sent is a fix for a specific bug I am encountering. I tested the patch and it solves my problem. Stephen, your changes looks good but it's a change in the driver's behavior. Maybe it could be another patch ? It looks like OP-TEE had the same idea. >> >> ---8<---- >> >> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c >> index af4c75217ea6..440d8f796faa 100644 >> --- a/drivers/firmware/qcom_scm.c >> +++ b/drivers/firmware/qcom_scm.c >> @@ -626,23 +626,11 @@ static int __init qcom_scm_init(void) >> int ret; >> >> fw_np = of_find_node_by_name(NULL, "firmware"); >> - >> if (!fw_np) >> - return -ENODEV; >> - >> - np = of_find_matching_node(fw_np, qcom_scm_dt_match); >> - >> - if (!np) { >> - of_node_put(fw_np); >> - return -ENODEV; >> - } >> - >> - of_node_put(np); >> + return 0; >> >> ret = of_platform_populate(fw_np, qcom_scm_dt_match, NULL, NULL); >> - >> of_node_put(fw_np); >> - >> if (ret) >> return ret; >> >>