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 C8161C433EF for ; Tue, 5 Jul 2022 14:08:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232877AbiGEOIe (ORCPT ); Tue, 5 Jul 2022 10:08:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232607AbiGEOIV (ORCPT ); Tue, 5 Jul 2022 10:08:21 -0400 Received: from mail-wm1-x332.google.com (mail-wm1-x332.google.com [IPv6:2a00:1450:4864:20::332]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A14F2408D for ; Tue, 5 Jul 2022 06:57:01 -0700 (PDT) Received: by mail-wm1-x332.google.com with SMTP id f190so7083096wma.5 for ; Tue, 05 Jul 2022 06:57:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=BjBLo3BZc3i/RrsqwYepC98EZoOUEWdJFyaQ2Y5SkP0=; b=HVTwtZciptDZ08KFzuykH2G4uvbG1AF9IUbGC6tPbew+VkkEep2biH9kqSb2g2WudP k3SAShqWQEBii7o3dGcbIl77ShsFOqF2GBIBbr+934nuyV77fVbDoBzI2EWMySR6qkKA EAomRNCay5OQGrRSiLPGF2kIcHCn9DtJQAYUUDlgYK0WfUUURvvrXitCCYwVBcxpXxJC Ywfj7RmFSvikjNUHDME3fb2Jti/pd3k6cDcPf+AZh2GRCqK56E/69h5fZ/GWWW/QpVQD 0oS4VtrmruMf/9nENMSS7m4auTm1KBfEbFCg5Yd8a4tq8Xx97eDhxtRXS84fslUSA+zj 9ksA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=BjBLo3BZc3i/RrsqwYepC98EZoOUEWdJFyaQ2Y5SkP0=; b=qedn6KYZ3V/h09WzonaGikMUE5PctVURwtcLEVGGe0HvjfjyTM/IrJjCL1mgU6bQ/C ghUC0MPoXHsRqlHE1pW1sR/gDhrt0KYFCt6szIslw+ItfnP6XbmeSkywiui5/aufZzet uSU3/2YMrAiiphH+pehuTB1bMLfSUpjjD3LhdJ6+RRc3zB/XSwiD23unXeldsAgAHwgW h2hJmx/PPPv1J2tfoeOa4jqmrlLGjWJxJw8pVXb9TUBSCTFuTBS0wldttal36Edxi+W6 JQGWf9jtew3GWLpukuIeQZs8RwK6bErqwfZx9kUN0zzxcN7++jrg1+xdWXH0tGuQeLQn biOg== X-Gm-Message-State: AJIora+JBIXTgy0k2g9V8UEuq9/SYx02Tk1+pSCtx+iCGQQ/v6VDd5ei V24AiZftItzj2lw99dVH4TkWdw== X-Google-Smtp-Source: AGRyM1ta/onHiJ4mcOXFofWIPIfNC6d8zHYsI6fzj5uesjQthvz30oMnsL4Ne07JK1olvzUJKW0PgA== X-Received: by 2002:a05:600c:a42:b0:39c:9166:5a55 with SMTP id c2-20020a05600c0a4200b0039c91665a55mr36560873wmq.141.1657029420036; Tue, 05 Jul 2022 06:57:00 -0700 (PDT) Received: from linaro.org ([94.52.112.99]) by smtp.gmail.com with ESMTPSA id q4-20020a1ce904000000b003a2b433c738sm4799348wmc.26.2022.07.05.06.56.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jul 2022 06:56:59 -0700 (PDT) Date: Tue, 5 Jul 2022 16:56:58 +0300 From: Abel Vesa To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Saravana Kannan , Thomas Gleixner Cc: Linux Kernel Mailing List , linux-arm-msm@vger.kernel.org Subject: Re: [RFC] driver core: Fix repeated device_is_dependent check for same link Message-ID: References: <20220705134502.2603795-1-abel.vesa@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220705134502.2603795-1-abel.vesa@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 22-07-05 16:45:02, Abel Vesa wrote: > In case of a cyclic dependency, if the supplier is not yet available, > the parent of the supplier is checked for dependency. But if there are > more than one suppliers with the same parent, the first check returns > true while the next checks skip that specific link entirely. So add a > flag that marks the link for future checks and bail early if it is > already marked with that flag. > > Signed-off-by: Abel Vesa > --- > > For more details about this issue, have a look at this thread: > https://lore.kernel.org/all/CAGETcx8F0wP+RA0KpjOJeZfc=DVG-MbM_=SkRHD4UhD2ReL7Kw@mail.gmail.com/ > > drivers/base/core.c | 14 +++++++++++--- > include/linux/device.h | 2 ++ > 2 files changed, 13 insertions(+), 3 deletions(-) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index ccdd5b4295de..38cb478ae400 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -297,12 +297,18 @@ int device_is_dependent(struct device *dev, void *target) > return ret; > > list_for_each_entry(link, &dev->links.consumers, s_node) { > + /* if already marked before as dependent, bail early */ > + if (link->flags & DL_FLAG_DEVICE_IS_DEPENDENT) > + return 1; On a second thought, this is wrong since it might be a different consumer link. > + > if ((link->flags & ~DL_FLAG_INFERRED) == > (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) > continue; > > - if (link->consumer == target) > + if (link->consumer == target) { > + link->flags |= DL_FLAG_DEVICE_IS_DEPENDENT; > return 1; > + } > > ret = device_is_dependent(link->consumer, target); > if (ret) > @@ -1660,11 +1666,13 @@ static void fw_devlink_relax_link(struct device_link *link) > if (!(link->flags & DL_FLAG_INFERRED)) > return; > > - if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE)) > + if ((link->flags & (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE)) == > + (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE)) > return; > > pm_runtime_drop_link(link); > - link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE; > + link->flags &= DL_FLAG_DEVICE_IS_DEPENDENT; > + link->flags |= DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE; > dev_dbg(link->consumer, "Relaxing link with %s\n", > dev_name(link->supplier)); > } > diff --git a/include/linux/device.h b/include/linux/device.h > index 424b55df0272..3b0c4b777a60 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -317,6 +317,7 @@ enum device_link_state { > * MANAGED: The core tracks presence of supplier/consumer drivers (internal). > * SYNC_STATE_ONLY: Link only affects sync_state() behavior. > * INFERRED: Inferred from data (eg: firmware) and not from driver actions. > + * DEVICE_IS_DEPENDENT: The consumer is dependent on the supplier > */ > #define DL_FLAG_STATELESS BIT(0) > #define DL_FLAG_AUTOREMOVE_CONSUMER BIT(1) > @@ -327,6 +328,7 @@ enum device_link_state { > #define DL_FLAG_MANAGED BIT(6) > #define DL_FLAG_SYNC_STATE_ONLY BIT(7) > #define DL_FLAG_INFERRED BIT(8) > +#define DL_FLAG_DEVICE_IS_DEPENDENT BIT(9) > > /** > * enum dl_dev_state - Device driver presence tracking information. > -- > 2.34.3 >