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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 EF9DCC433E0 for ; Wed, 20 May 2020 09:13:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE06F206C3 for ; Wed, 20 May 2020 09:13:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589965997; bh=uXpehXfQAXLtA1Bk4iTWrCyHj87VS/F/DgihMsGHERE=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=Cl/6PW3YIptd+R8dPUnacYazMi93SjsuEZ+62ColcKtipAVCrYRASBJCLhERu5RPZ /JkE7sqvsdZYJpV0K72rPtgkV7HSnZX2UgCcQf6W/DqfLHheFqzrzo8j7ERktYHDmM BIJb10oxqIQhYtKnbbMWJGT9Rwml01r57NJsPDvo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726691AbgETJNR (ORCPT ); Wed, 20 May 2020 05:13:17 -0400 Received: from mail-ot1-f68.google.com ([209.85.210.68]:42839 "EHLO mail-ot1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726224AbgETJNQ (ORCPT ); Wed, 20 May 2020 05:13:16 -0400 Received: by mail-ot1-f68.google.com with SMTP id z3so1878127otp.9 for ; Wed, 20 May 2020 02:13:14 -0700 (PDT) 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=xoitxofxdcZF88ApsFuFoZL7BHUanT6st1VxSuWkKL0=; b=VFVoCW6IJLcdy7EbZ/HNQKfrogt3fGtybVP4DZMmBmhoaJGTwml92MDN3KNl5kTiUT gTSXUdjcvPe9AZPF0oVoXbyi944+0dTFYJC78GjSIgcQA4nsUaiT3AfOx4RDWDq1x/6m x/ETcV4aOW7cn9u3ETouR98QLEzsI3YCBtabZmz9wUHMXShuGy73cmTgIIk+OFxcgro1 2rgz0Slg6jeu2duTrKKAxOC4pjWWZ+WWYjv5exn7xf7JMerhTDx0P8G/whzCwMLVS/gm 0lUJIMN3pLCrO608Tnx3tQL+QMidaSz3M1AUG/zHF63sK1BvIvc/AypQPoriLkC5I3ND FNTQ== X-Gm-Message-State: AOAM530qEz2+h5p/hiyi0hAaxjWlHGXOmxU/WSn7WV1STS51dMDCIkpZ CSlYu2N5MNdM3DH4s7UXwQm5KgQJdcgv5Wfk99w= X-Google-Smtp-Source: ABdhPJxvoAXt54eunVMvuRpdJq87YT21H8CqKDI5O6EsnR6CKJSkxxpmzBKh8V6YHgmFI2Bdps53BzlZFKbNhdSLwMs= X-Received: by 2002:a9d:3d05:: with SMTP id a5mr2495693otc.262.1589965994552; Wed, 20 May 2020 02:13:14 -0700 (PDT) MIME-Version: 1.0 References: <20200520043626.181820-1-saravanak@google.com> In-Reply-To: <20200520043626.181820-1-saravanak@google.com> From: "Rafael J. Wysocki" Date: Wed, 20 May 2020 11:13:03 +0200 Message-ID: Subject: Re: [PATCH v1] driver core: Fix handling of SYNC_STATE_ONLY + STATELESS device links To: Saravana Kannan Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , "Cc: Android Kernel" , "Rafael J. Wysocki" , 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 Wed, May 20, 2020 at 6:36 AM Saravana Kannan wrote: > > Commit 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link > implementation") didn't completely fix STATELESS + SYNC_STATE_ONLY > handling. > > What looks like an optimization in that commit is actually a bug that > causes an if condition to always take the else path. This prevents > reordering of devices in the dpm_list when a DL_FLAG_STATELESS device > link is create on top of an existing DL_FLAG_SYNC_STATE_ONLY device > link. > > Fixes: 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link implementation") > Signed-off-by: Saravana Kannan > --- > Sigh... device links are tricky and hard! Sorry about the endless fixes :( > Also, how was this not caught by the compiler as a warning? Well, I haven't spotted this either ... Reviewed-by: Rafael J. Wysocki > drivers/base/core.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index 83a3e0b62ce3..dfd4e94ef790 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -543,12 +543,14 @@ struct device_link *device_link_add(struct device *consumer, > > if (flags & DL_FLAG_STATELESS) { > kref_get(&link->kref); > - link->flags |= DL_FLAG_STATELESS; > if (link->flags & DL_FLAG_SYNC_STATE_ONLY && > - !(link->flags & DL_FLAG_STATELESS)) > + !(link->flags & DL_FLAG_STATELESS)) { > + link->flags |= DL_FLAG_STATELESS; > goto reorder; > - else > + } else { > + link->flags |= DL_FLAG_STATELESS; > goto out; > + } > } > > /* > -- > 2.26.2.761.g0e0b3e54be-goog >