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=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 CFB6AC433E0 for ; Sun, 12 Jul 2020 04:13:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB24C20748 for ; Sun, 12 Jul 2020 04:13:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727946AbgGLENK (ORCPT ); Sun, 12 Jul 2020 00:13:10 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:37697 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726281AbgGLENJ (ORCPT ); Sun, 12 Jul 2020 00:13:09 -0400 Received: by mail-pg1-f193.google.com with SMTP id d4so4526967pgk.4 for ; Sat, 11 Jul 2020 21:13:09 -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=Q+Iuxj2tV4jqU+Jkl7CgmY/3MT6AJ7nvgpdZ/2MJldg=; b=R0F+yBGH8h/pHnuTC2srIWp09sjM729+xAmHh1mQb3IgR5Ui81SyFjV0X1fYLb4e9B j93v8vHA+0Fytn2B2QLb2j6U7aDvVZyYKb2zZ2F7jNX/Nrz92oRN61OYyhhJE8cnUXwP XicPMlCXuwveKVUiuIrNXC+AIWudob3ZG8uMMU26q8tZLjvSVPddCnDjHyCbBJJ1F+5V +JOorpYIKNoc2I4te+OIaugmqBFkbYiRJRocpFdKGbE6RJzt/lHaBhySiUrPou6DazLh V3sEFbVSAwSlgW8PkC47jjG+uXYYM7QhFAqMEq0soVqkW5PdmptErA6BaQRw3x9IzvQW MkeQ== X-Gm-Message-State: AOAM531iDomw6UUeueYNQ9BhDdxLoZp6y7QyF1qoJ9uzXWyJJ6xxEWyk LoCmEc7EGiq7qK45Msadcy4piRvR X-Google-Smtp-Source: ABdhPJyhW0VP5abOcT7EEhif0JSoYBIp1g4BJ8SDw1BKsFZyYVSPD8NCoq+JWZu5V1l9mlNyZwbMBQ== X-Received: by 2002:aa7:8391:: with SMTP id u17mr23928072pfm.156.1594527188617; Sat, 11 Jul 2020 21:13:08 -0700 (PDT) Received: from [192.168.50.147] (c-73-241-217-19.hsd1.ca.comcast.net. [73.241.217.19]) by smtp.gmail.com with ESMTPSA id y7sm10350718pjy.54.2020.07.11.21.13.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 11 Jul 2020 21:13:07 -0700 (PDT) Subject: Re: [PATCH] scsi: allow state transitions BLOCK -> BLOCK To: Hannes Reinecke , James Bottomley , "Martin K. Petersen" Cc: Christoph Hellwig , linux-scsi@vger.kernel.org References: <20200702142436.98336-1-hare@suse.de> <1593700443.9652.2.camel@HansenPartnership.com> <0c1ce7fc-98ba-0a14-d1a7-889bf1ce794f@suse.de> <2dd291ba-1e59-5e88-de96-5d3965f20317@acm.org> <819ce023-93c3-249d-2221-97438f229e03@suse.de> <97d4882d-2f26-de93-672a-6395e8fedf0c@suse.de> 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: Date: Sat, 11 Jul 2020 21:13:06 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <97d4882d-2f26-de93-672a-6395e8fedf0c@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 2020-07-05 23:22, Hannes Reinecke wrote: > That will still have a duplicate call as scsi_target_block() has been called already (cf scsi_target_block() in line 539 right at the start of srp_reconnect_rport()). > > (And I don't think we need the WARN_ON_ONCE() here; we are checking for rport->state == SRP_RPORT_BLOCKED just before that line...) How about the patch below? The approach implemented by that patch is only to call scsi_target_block() after a successful transition to the SRP_RPORT_BLOCKED state and to only call scsi_target_unblock() when leaving the SRP_RPORT_BLOCKED state. Thanks, Bart. diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c index d4d1104fac99..0334f86f0879 100644 --- a/drivers/scsi/scsi_transport_srp.c +++ b/drivers/scsi/scsi_transport_srp.c @@ -402,13 +402,9 @@ static void __rport_fail_io_fast(struct srp_rport *rport) lockdep_assert_held(&rport->mutex); + WARN_ON_ONCE(rport->state != SRP_RPORT_BLOCKED); if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST)) return; - /* - * Call scsi_target_block() to wait for ongoing shost->queuecommand() - * calls before invoking i->f->terminate_rport_io(). - */ - scsi_target_block(rport->dev.parent); scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE); /* Involve the LLD if possible to terminate all I/O on the rport. */ @@ -541,7 +537,8 @@ int srp_reconnect_rport(struct srp_rport *rport) res = mutex_lock_interruptible(&rport->mutex); if (res) goto out; - scsi_target_block(&shost->shost_gendev); + if (srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) + scsi_target_block(&shost->shost_gendev); res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV; pr_debug("%s (state %d): transport.reconnect() returned %d\n", dev_name(&shost->shost_gendev), rport->state, res); @@ -569,9 +566,9 @@ int srp_reconnect_rport(struct srp_rport *rport) * and dev_loss off. Mark the port as failed and start the TL * failure timers if these had not yet been started. */ + WARN_ON_ONCE(srp_rport_set_state(rport, SRP_RPORT_BLOCKED)); + scsi_target_block(rport->dev.parent); __rport_fail_io_fast(rport); - scsi_target_unblock(&shost->shost_gendev, - SDEV_TRANSPORT_OFFLINE); __srp_start_tl_fail_timers(rport); } else if (rport->state != SRP_RPORT_BLOCKED) { scsi_target_unblock(&shost->shost_gendev,