From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56C73C7EE22 for ; Sun, 14 May 2023 04:17:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231501AbjENERM (ORCPT ); Sun, 14 May 2023 00:17:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229462AbjENERH (ORCPT ); Sun, 14 May 2023 00:17:07 -0400 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7E1D1702; Sat, 13 May 2023 21:17:06 -0700 (PDT) Received: from pps.filterd (m0279871.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 34E47Rfs008754; Sun, 14 May 2023 04:16:34 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=co4vRrnTivwIzFDIwnV3dMAsjHlQ/SjpLfqX2dsGaik=; b=k23QVqg5w4yinxoAw3dYRHeFAfYqVk2BHZuL5zYY0M97waJIKEWDT06DiieWgBqvNeZY FRNQOzA2k9E5t54eO7UkDZYK+iWF23574W2dF2VZrrJics6p9ZxH8XqoAX8yiOOzwY0y Q+5s0UhOvyne4hgbMdT9BiL6wBtOx/4b1uGz8iptAyUMnwnYAm3LYKM7FyM8++tNRnQN STWj4jAMymLRs8peHQ71irPwwpvY/GKG6uW4hTP7FxXfI4FqbT9lABiLp8LocbV5YNpC V2WGE/E/F7djmrtVewkuVL6EGbmZkpPaUmYa+BevAkNgmUBhGjRkvsixTUyyazTXUIMD Bw== Received: from nasanppmta03.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3qj257sc73-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 14 May 2023 04:16:34 +0000 Received: from nasanex01a.na.qualcomm.com (nasanex01a.na.qualcomm.com [10.52.223.231]) by NASANPPMTA03.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 34E4GXxC003508 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 14 May 2023 04:16:33 GMT Received: from [10.110.80.184] (10.80.80.8) by nasanex01a.na.qualcomm.com (10.52.223.231) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.42; Sat, 13 May 2023 21:16:32 -0700 Message-ID: Date: Sat, 13 May 2023 21:16:31 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH v3 04/18] soc: qcom: Add Qualcomm minidump kernel driver Content-Language: en-US To: Mukesh Ojha , Krzysztof Kozlowski , , , , , , , , , , , , , , CC: , , , , , References: <1683133352-10046-1-git-send-email-quic_mojha@quicinc.com> <1683133352-10046-5-git-send-email-quic_mojha@quicinc.com> <23b493f4-1a01-8d03-fc12-d588b2c6fd74@quicinc.com> <575a422d-6224-06b7-628c-8487b47882e9@linaro.org> <500e5abc-fb71-8468-a6b0-3ced2676b57c@linaro.org> From: Trilok Soni In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nasanex01a.na.qualcomm.com (10.52.223.231) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: 0Zr-_av0jVj5LIrEzqJPzDiF31cnJxEQ X-Proofpoint-GUID: 0Zr-_av0jVj5LIrEzqJPzDiF31cnJxEQ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-05-14_02,2023-05-05_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 bulkscore=0 impostorscore=0 mlxlogscore=999 lowpriorityscore=0 clxscore=1011 spamscore=0 mlxscore=0 priorityscore=1501 suspectscore=0 adultscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2304280000 definitions=main-2305140036 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/8/2023 12:10 AM, Mukesh Ojha wrote: > > > On 5/4/2023 10:04 PM, Krzysztof Kozlowski wrote: >> On 04/05/2023 17:21, Krzysztof Kozlowski wrote: >>>>> >>>>>> +    ret = qcom_minidump_init_apss_subsystem(md); >>>>>> +    if (ret) { >>>>>> +        dev_err(&pdev->dev, "apss minidump initialization failed: >>>>>> %d\n", ret); >>>>>> +        goto unlock; >>>>>> +    } >>>>>> + >>>>>> +    __md = md; >>>>> >>>>> No. This is a platform device, so it can have multiple instances. >>>> >>>> It can have only one instance that is created from SMEM driver probe. >>> >>> Anyone can instantiate more of them.... how did you solve it? >> >> To clarify - sprinkling more of singletons makes everything tightly >> coupled, difficult to debug and non-portable. You cannot have two >> instances, you have to control concurrent initialization by yourself in >> each of such singletons. >> >> I understand sometimes they are unavoidable, for example when this does >> not map to hardware property. However here you have the parent - smem - >> which can return you valid instance. Thus you avoid entire problem of >> file-scope variables. > > I get your point, why one's should avoid file scope variables. > > > This is infrastructure driver and will not have multiple instances and > even if it happens could be avoided with with the help of global mutex > and protect below function which i am already doing at the moment and > fail the other probe if it is already initialized with proper logging..e.g Another way to think here is what if you have chiplets? Two SOCs looks like one as a product? How does your driver will behave in those cases? ---Trilok Soni