From patchwork Tue Jul 5 13:45:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Abel Vesa X-Patchwork-Id: 12906613 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 BCD10C433EF for ; Tue, 5 Jul 2022 14:01:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232496AbiGEOBK (ORCPT ); Tue, 5 Jul 2022 10:01:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232591AbiGEOAw (ORCPT ); Tue, 5 Jul 2022 10:00:52 -0400 Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9343C20BDF for ; Tue, 5 Jul 2022 06:45:22 -0700 (PDT) Received: by mail-wr1-x434.google.com with SMTP id v16so6200436wrd.13 for ; Tue, 05 Jul 2022 06:45:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=7WU85wt75maZ/AzK5oGTPi4CFNSsHv61sFJKv4WZ1Y0=; b=RxiXpcrkgknD4jjo++ZfyQAgggitaIk+6jlabkqZstpElMQaJlj7WCB9WZGrPXSU1e vhknTdnPzCBAtCskAii1CkeT6i/u6wIns5IreDXa/KhP2WaFY4HZ2ZcUbPc8CkU5NsZD 0EfAsTQcWIEhC7uKrNPg9YcGlSt5WHanF/aKbjnhZ5TdsyaUM1/abNR7m2AfEI8QLOky 9oRdyCCA9rY4LEzCv59/h9RjLM3Nb5Z4iVxynwZIxUmFOeGjO6Wfehyw4yA8XKnik2nc /N+R7EXvR9+o4LZS4QqTzr8N9Q/bpQh0ch7rFmRugndYg21hGQqIyBhnWzHM3L81kco+ c0Gw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=7WU85wt75maZ/AzK5oGTPi4CFNSsHv61sFJKv4WZ1Y0=; b=W4HyvxlTzQ55NjCyJTUaBVtPqVCrgo3i1lg8Df2yO3b2BxqBvSl7KiBRj7pWptX/i8 sIL7KvfDjQY7ng+6fojaYIL3l28g2o4/NQCjkw3wm1XaRAyfEmC327msGMltmpYSvtme zCB3g2Ttchwvpg3SYaAMqiB3FJ0W9MNghaYwKHMIInN207MqQKvvjdRnB5sNB2ptdHbu tZY3WbwfkuhbDda2ri+wKsA4aGuFhXbET6o3GPnvUEVVSBPhHsFQ8ORnxT4l+Bo78PBx BaOfMH6fuY18jAX1gfpEVPb2YRLXmcp0SiV6PkcvG9CMHapP/n1kBXDZ6dGc23KONZcB j94A== X-Gm-Message-State: AJIora/+5q79jMO1UVNLMCiv47Do9llXvtntQXARI7DTfAEyO+c2Uldj VpodODLYkdy5LDLqXUhUn8h6Cy+IH8Br3A== X-Google-Smtp-Source: AGRyM1vHf9aHnIcGqMkM0n4kILpbEuJpe3onES5N1d//akuurbopz8QkeZRhLlGJZdsG/KloV4uXZA== X-Received: by 2002:a5d:4c8d:0:b0:21d:75cd:5ae4 with SMTP id z13-20020a5d4c8d000000b0021d75cd5ae4mr2523540wrs.510.1657028721155; Tue, 05 Jul 2022 06:45:21 -0700 (PDT) Received: from localhost.localdomain ([94.52.112.99]) by smtp.gmail.com with ESMTPSA id v11-20020adfe28b000000b0021d6ef34b2asm3047860wri.51.2022.07.05.06.45.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jul 2022 06:45:20 -0700 (PDT) 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, Abel Vesa Subject: [RFC] driver core: Fix repeated device_is_dependent check for same link Date: Tue, 5 Jul 2022 16:45:02 +0300 Message-Id: <20220705134502.2603795-1-abel.vesa@linaro.org> X-Mailer: git-send-email 2.34.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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(-) -- 2.34.3 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; + 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.