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 X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6F3EC433E1 for ; Thu, 13 Aug 2020 03:22:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3EE720675 for ; Thu, 13 Aug 2020 03:22:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726596AbgHMDWx (ORCPT ); Wed, 12 Aug 2020 23:22:53 -0400 Received: from mail-pj1-f66.google.com ([209.85.216.66]:40896 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726131AbgHMDWx (ORCPT ); Wed, 12 Aug 2020 23:22:53 -0400 Received: by mail-pj1-f66.google.com with SMTP id d4so2094859pjx.5; Wed, 12 Aug 2020 20:22:52 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=gOeWB/fFQX8TFgcsqSgEvvRAYNi8MuzmPzQBJ7DPQtM=; b=atGvLhvb8+pb6ts7fJk8/5M+d5zYXf0xSnsClWDsA+84HEnhTGWkS5oZuErOUR+FAT GkCtsIXIbdQ/G03fGabhn2PrliLbvvpkUT43IzbKPUNrDMNIbUbnuGMsuNdFDwVibBbf R7DzjqfTsuTEZ4ZPksDtWiA1/6tvS1OOx+rziS/K6P9ookrinNgZUBuS+EIJ/2yXzRCT lujZh/ZqzECXL75fVbxhiMhALY2fgBFlbOHSQgs1b0dACvAquIr+SK/lMJBXrzeecu54 zKXOHwjSBbtMpMRhRDhWclZRPlh9mxIC7ljLGRU34zRU9iGhYfV6J2KIMB3r1xCKA/SQ VrLg== X-Gm-Message-State: AOAM532swuwwn79XvHfzdxf3Xt1kwgjOwCNXAWwrEgK64FBz0tBF8MKu 7hLh0qR5NgDpH+fVdfXKglk= X-Google-Smtp-Source: ABdhPJw0Vet94i2VnEo4BrDlHg25TtG0an+p9xK5Pb7L/vDiGeB0J9UbTAbtkPdJsX73UwDwQIJvHQ== X-Received: by 2002:a17:90b:138a:: with SMTP id hr10mr2918610pjb.161.1597288971581; Wed, 12 Aug 2020 20:22:51 -0700 (PDT) Received: from [192.168.3.217] (c-73-241-217-19.hsd1.ca.comcast.net. [73.241.217.19]) by smtp.gmail.com with ESMTPSA id h18sm3900116pfo.21.2020.08.12.20.22.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 12 Aug 2020 20:22:50 -0700 (PDT) Subject: Re: [PATCH v8 2/4] scsi: ufs: Introduce HPB feature To: daejun7.park@samsung.com, "avri.altman@wdc.com" , "jejb@linux.ibm.com" , "martin.petersen@oracle.com" , "asutoshd@codeaurora.org" , "beanhuo@micron.com" , "stanley.chu@mediatek.com" , "cang@codeaurora.org" , "tomas.winkler@intel.com" , ALIM AKHTAR Cc: "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Sang-yoon Oh , Sung-Jun Park , yongmyung lee , Jinyoung CHOI , Adel Choi , BoRam Shin References: <2154d9c6-4b29-7d24-0261-26d2aa05caef@acm.org> <231786897.01596705001840.JavaMail.epsvc@epcpadp1> <231786897.01596704281715.JavaMail.epsvc@epcpadp2> <231786897.01596705302142.JavaMail.epsvc@epcpadp1> <231786897.01597287781957.JavaMail.epsvc@epcpadp2> From: Bart Van Assche Autocrypt: addr=bvanassche@acm.org; prefer-encrypt=mutual; keydata= mQENBFSOu4oBCADcRWxVUvkkvRmmwTwIjIJvZOu6wNm+dz5AF4z0FHW2KNZL3oheO3P8UZWr LQOrCfRcK8e/sIs2Y2D3Lg/SL7qqbMehGEYcJptu6mKkywBfoYbtBkVoJ/jQsi2H0vBiiCOy fmxMHIPcYxaJdXxrOG2UO4B60Y/BzE6OrPDT44w4cZA9DH5xialliWU447Bts8TJNa3lZKS1 AvW1ZklbvJfAJJAwzDih35LxU2fcWbmhPa7EO2DCv/LM1B10GBB/oQB5kvlq4aA2PSIWkqz4 3SI5kCPSsygD6wKnbRsvNn2mIACva6VHdm62A7xel5dJRfpQjXj2snd1F/YNoNc66UUTABEB AAG0JEJhcnQgVmFuIEFzc2NoZSA8YnZhbmFzc2NoZUBhY20ub3JnPokBOQQTAQIAIwUCVI67 igIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEHFcPTXFzhAJ8QkH/1AdXblKL65M Y1Zk1bYKnkAb4a98LxCPm/pJBilvci6boefwlBDZ2NZuuYWYgyrehMB5H+q+Kq4P0IBbTqTa jTPAANn62A6jwJ0FnCn6YaM9TZQjM1F7LoDX3v+oAkaoXuq0dQ4hnxQNu792bi6QyVdZUvKc macVFVgfK9n04mL7RzjO3f+X4midKt/s+G+IPr4DGlrq+WH27eDbpUR3aYRk8EgbgGKvQFdD CEBFJi+5ZKOArmJVBSk21RHDpqyz6Vit3rjep7c1SN8s7NhVi9cjkKmMDM7KYhXkWc10lKx2 RTkFI30rkDm4U+JpdAd2+tP3tjGf9AyGGinpzE2XY1K5AQ0EVI67igEIAKiSyd0nECrgz+H5 PcFDGYQpGDMTl8MOPCKw/F3diXPuj2eql4xSbAdbUCJzk2ETif5s3twT2ER8cUTEVOaCEUY3 eOiaFgQ+nGLx4BXqqGewikPJCe+UBjFnH1m2/IFn4T9jPZkV8xlkKmDUqMK5EV9n3eQLkn5g lco+FepTtmbkSCCjd91EfThVbNYpVQ5ZjdBCXN66CKyJDMJ85HVr5rmXG/nqriTh6cv1l1Js T7AFvvPjUPknS6d+BETMhTkbGzoyS+sywEsQAgA+BMCxBH4LvUmHYhpS+W6CiZ3ZMxjO8Hgc ++w1mLeRUvda3i4/U8wDT3SWuHcB3DWlcppECLkAEQEAAYkBHwQYAQIACQUCVI67igIbDAAK CRBxXD01xc4QCZ4dB/0QrnEasxjM0PGeXK5hcZMT9Eo998alUfn5XU0RQDYdwp6/kMEXMdmT oH0F0xB3SQ8WVSXA9rrc4EBvZruWQ+5/zjVrhhfUAx12CzL4oQ9Ro2k45daYaonKTANYG22y //x8dLe2Fv1By4SKGhmzwH87uXxbTJAUxiWIi1np0z3/RDnoVyfmfbbL1DY7zf2hYXLLzsJR mSsED/1nlJ9Oq5fALdNEPgDyPUerqHxcmIub+pF0AzJoYHK5punqpqfGmqPbjxrJLPJfHVKy goMj5DlBMoYqEgpbwdUYkH6QdizJJCur4icy8GUNbisFYABeoJ91pnD4IGei3MTdvINSZI5e Message-ID: <842c51c6-320f-a096-d9ea-b9d411ac6e3a@acm.org> Date: Wed, 12 Aug 2020 20:22:48 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <231786897.01597287781957.JavaMail.epsvc@epcpadp2> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-08-12 20:00, Daejun Park wrote: > On 2020-08-06 02:11, Daejun Park wrote: >>> +static int ufshpb_create_sysfs(struct ufs_hba *hba, struct ufshpb_lu *hpb) >>> +{ >>> + int ret; >>> + >>> + ufshpb_stat_init(hpb); >>> + >>> + kobject_init(&hpb->kobj, &ufshpb_ktype); >>> + mutex_init(&hpb->sysfs_lock); >>> + >>> + ret = kobject_add(&hpb->kobj, kobject_get(&hba->dev->kobj), >>> + "ufshpb_lu%d", hpb->lun); >>> + >>> + if (ret) >>> + return ret; >>> + >>> + ret = sysfs_create_group(&hpb->kobj, &ufshpb_sysfs_group); >>> + >>> + if (ret) { >>> + dev_err(hba->dev, "ufshpb_lu%d create file error\n", hpb->lun); >>> + return ret; >>> + } >>> + >>> + dev_info(hba->dev, "ufshpb_lu%d sysfs adds uevent", hpb->lun); >>> + kobject_uevent(&hpb->kobj, KOBJ_ADD); >>> + >>> + return 0; >>> +} >> >> Please attach these sysfs attributes to /sys/class/scsi_device/*/device >> instead of creating a new kobject. Consider using the following >> scsi_host_template member to define LUN sysfs attributes: > > I am not rejecting your comment. But I added kobject for distinguishing > between other attributes and attributes related to HPB feature. > If you think it's pointless, I'll fix it. Hi Daejun, I see two reasons to add these sysfs attributes under /sys/class/scsi_device/*/device: - This makes the behavior of the UFS driver similar to that of other Linux SCSI LLD drivers. - This makes it easier for people who want to write udev rules that read from these attributes. Since ufshpb_lu%d is attached to the UFS controller it is not clear to me which attributes will appear first in sysfs - the SCSI device attributes or the ufshpb_lu%d attributes. If there are only SCSI device attributes there is no such ambiguity and hence authors of udev rules won't have to worry about this race condition. >>> +void ufshpb_remove(struct ufs_hba *hba) >>> +{ >>> + struct ufshpb_lu *hpb, *n_hpb; >>> + struct ufsf_feature_info *ufsf; >>> + struct scsi_device *sdev; >>> + >>> + ufsf = &hba->ufsf; >>> + >>> + list_for_each_entry_safe(hpb, n_hpb, &lh_hpb_lu, list_hpb_lu) { >>> + ufshpb_set_state(hpb, HPB_FAILED); >>> + >>> + sdev = hpb->sdev_ufs_lu; >>> + sdev->hostdata = NULL; >>> + >>> + ufshpb_destroy_region_tbl(hpb); >>> + >>> + list_del_init(&hpb->list_hpb_lu); >>> + ufshpb_remove_sysfs(hpb); >>> + >>> + kfree(hpb); >>> + } >>> + >>> + dev_info(hba->dev, "ufshpb: remove success\n"); >>> +} >> >> Should the code in the body of the above loop perhaps be called from inside >> ufshcd_slave_destroy()? > > Moving other stuffs in the loop is good idea, but removing attributes is problem. > To avoid adding new kobject, I will try to use sysfs_merge_group() > for adding attributes. To delete merged attributes, sysfs_unmerge_group() > should be called. But sysfs_remove_groups() is called before calling ufshcd_slave_destroy(). Hmm ... I don't see why the sdev_groups host template attribute can't be used? Please don't use sysfs_merge_group() and sysfs_unmerge_group() because that would create a race condition against udev rules if these functions are called after the device core has emitted a KOBJ_ADD event. Thanks, Bart.