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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AF70C433F5 for ; Tue, 5 Oct 2021 15:46:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E372661159 for ; Tue, 5 Oct 2021 15:46:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236244AbhJEPsB (ORCPT ); Tue, 5 Oct 2021 11:48:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:45280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236250AbhJEPsB (ORCPT ); Tue, 5 Oct 2021 11:48:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 720CF61131; Tue, 5 Oct 2021 15:46:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633448770; bh=Rj/0jHRMsB6F9MLOSYgfUq/M54kkJZlGAsxmV279FQ4=; h=Subject:To:From:Date:From; b=LxrM1HhQ4RaO3dewA7DbM8p5aFro7CKZnL8V7/0IfIEY83xjnyKheYYx7MMyE92dt t95z0UU5yJXIv4KW+SFFF+x2rODWV0DXqiC37ZKAKp9MXKut7nyjm2BQi6piQ/ru5g /FcIYUIRDitIONdoOuReUnb4mOjxFX5Ne/8hyWbE= Subject: patch "driver core: Reject pointless SYNC_STATE_ONLY device links" added to driver-core-linus To: saravanak@google.com, gregkh@linuxfoundation.org, rafael.j.wysocki@intel.com, stable@vger.kernel.org, ulf.hansson@linaro.org From: Date: Tue, 05 Oct 2021 17:46:08 +0200 Message-ID: <1633448768149175@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled driver core: Reject pointless SYNC_STATE_ONLY device links to my driver-core git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git in the driver-core-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From f729a592adb6760013c3e48622a5bf256b992452 Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Wed, 29 Sep 2021 12:05:49 -0700 Subject: driver core: Reject pointless SYNC_STATE_ONLY device links SYNC_STATE_ONLY device links intentionally allow cycles because cyclic sync_state() dependencies are valid and necessary. However a SYNC_STATE_ONLY device link where the consumer and the supplier are the same device is pointless because the device link would be deleted as soon as the device probes (because it's also the consumer) and won't affect when the sync_state() callback is called. It's a waste of CPU cycles and memory to create this device link. So reject any attempts to create such a device link. Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag") Cc: stable Reported-by: Ulf Hansson Reviewed-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20210929190549.860541-1-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 15986cc2fe5e..249da496581a 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -687,7 +687,8 @@ struct device_link *device_link_add(struct device *consumer, { struct device_link *link; - if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS || + if (!consumer || !supplier || consumer == supplier || + flags & ~DL_ADD_VALID_FLAGS || (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || (flags & DL_FLAG_SYNC_STATE_ONLY && (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) || -- 2.33.0