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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 27C8DC433DF for ; Fri, 22 May 2020 15:23:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2D3E2065F for ; Fri, 22 May 2020 15:23:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qdbCWZlw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730528AbgEVPXG (ORCPT ); Fri, 22 May 2020 11:23:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729931AbgEVPXD (ORCPT ); Fri, 22 May 2020 11:23:03 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60F66C061A0E; Fri, 22 May 2020 08:23:03 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id p30so5124168pgl.11; Fri, 22 May 2020 08:23:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=+6TOThcfrCoo/dB//49POAXWHMbH0VtQ+5JMYE00jS4=; b=qdbCWZlw8zITa3fBX/i9UHBrOQJnVY0QHCf6vjJjBy8gsiQ4glBScKebyHCTVKSPTQ BjKzfdIr6Pbo7tFcBa8Matdv7z1sALCJkArYfZ1H4/271Xc58MYM2pjDVf715TMfKfWN bSO4C3n2JoUbtgDeZT638utqfz5CJ+vP1fL/nwFM7nGfdgiV59uVdG2qhAKhknGndnmH taTlsu+TDfPOdYr49/d70o3Tm0kMw9DtUvJsLXg/VjZjdKUninYV616rrJXAQIa8ZM7G jKgN+r35pTkcIIIhDDs1a52zGzGukmjPDwJquuSKF0r8YwoCBn+bjy/s+KcxoeJwc7HF haIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=+6TOThcfrCoo/dB//49POAXWHMbH0VtQ+5JMYE00jS4=; b=kGCMPDSRE/VDwxkLwNrcL4wyZd6FeDqvPApPQL/efUrVRJGM3zEhrXlvFr9EHi0RcI x0MM1LPT+L5tGKi/tkLujl9/fGg8o9tylhBoI/OZ24+XCXUueJdbkAG+4zkAFj6V2EgE eSS1BaAfIQBpI6r7uG+LaGjS0H+4MxMFsxSjrjmFyEtsU35e45Xp7N/lKD/ywOGJGcpl g8vxw/JztUekbY2GjoaITYRVWlFyIJ2QIF8AOYMCaFIygL6bOQnrvkumlVE61xdmeHA3 XBUE9OaQKfdcKgOC3hiE5COEQmWEcW9ahqcOc5IagegmZENOwxSnCNQs5QNEC7qDX+qn pcCA== X-Gm-Message-State: AOAM530wPQiraiA6tW3SpvY7iot93JRUmz24qM8xw/qLmaGp7SvRIzt9 U6Wa4F8OHL6eRKoJofd1fwPG2/+AeNlzZfsBf8k= X-Google-Smtp-Source: ABdhPJxEGo6ljrna1zI7Tc0KBf/r5xRQMfrE2gMH/mp9Uh3KNMV6dDc6OlHXiuYyLoc6qbYYaTsUf3VHiGl22xH/W2A= X-Received: by 2002:a62:5ec7:: with SMTP id s190mr4243873pfb.130.1590160982872; Fri, 22 May 2020 08:23:02 -0700 (PDT) MIME-Version: 1.0 References: <20200521074946.21799-1-dinghao.liu@zju.edu.cn> <5a8a6e7b.bef25.1723b588c7f.Coremail.dinghao.liu@zju.edu.cn> In-Reply-To: From: Andy Shevchenko Date: Fri, 22 May 2020 18:22:51 +0300 Message-ID: Subject: Re: Re: [PATCH] spi: tegra20-slink: Fix runtime PM imbalance on error To: Dinghao Liu Cc: Kangjie Lu , Laxman Dewangan , Mark Brown , Thierry Reding , Jonathan Hunter , linux-spi , linux-tegra@vger.kernel.org, Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 22, 2020 at 6:20 PM Andy Shevchenko wrote: > On Fri, May 22, 2020 at 10:46 AM wrote: ... > Moreover, consider below case > > CPU1: ...somewhere in the code... > pm_runtime_get() // with success! > ...see below... > pm_runtime_put() > > CPU2: ...on parallel thread... > ret = pm_runtime_get_sync() // failed! > if (ret) > pm_runtime_put() // oi vei, we put device into sleep > > So, there is a potential issue. ...and even if it's impossible (no bugs in runtime PM core, etc) the code with put() looks suspicious. -- With Best Regards, Andy Shevchenko