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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 644D4C433E6 for ; Thu, 18 Feb 2021 19:18:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1244364E79 for ; Thu, 18 Feb 2021 19:18:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232963AbhBRTSR (ORCPT ); Thu, 18 Feb 2021 14:18:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234919AbhBRR7h (ORCPT ); Thu, 18 Feb 2021 12:59:37 -0500 Received: from mail-yb1-xb2d.google.com (mail-yb1-xb2d.google.com [IPv6:2607:f8b0:4864:20::b2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72336C061756 for ; Thu, 18 Feb 2021 09:58:52 -0800 (PST) Received: by mail-yb1-xb2d.google.com with SMTP id p193so3014408yba.4 for ; Thu, 18 Feb 2021 09:58:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pqlO7T1aKbV39Ityo1M+jjwnDIJxvPvVDTyYS8zw2v0=; b=qnQYXKdiKQ5FvOO3MyXT5JsAkK8ez6GEtDjfDcyF8JR5Rg6xfgyNRvJ3l+azbNq9t5 cC/d8aiOZpBNav7rlbnyqPdyra89p3gk2Pn0tdl7E/f7K3uxvvea9SAq0dXkHYWaDaCo 5Cz5Fv5NxEMo1r1azbBQG/7/XiQZ+Xzvs0KGdnDttvRYF77OyYYqISZMAE7sH/pSjTOw QFZ8cJEl54GP0ASAw0xX1pc1XlAa+8tnr472Q6utpdrpxqy8GlY37Jjby7x0yQHW/8mg +aWPGocoImDXKAwXc6XgvWa5N/+XXvIt/aVZK6EqN/3K3/Qwc5hrfWapojXik6edNNCU 8j9Q== 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=pqlO7T1aKbV39Ityo1M+jjwnDIJxvPvVDTyYS8zw2v0=; b=Y0yl06/L5GmNYzOj15DBmTifZ5SNnaaE7x/U3k0gpYvGv3smRnck0Lke9U2YEjD6Wv irwdlQJD1q1fqTvas38ARjI7erZlxbd0zI/gZ+tDdBVB9VgzDqrEDNGUO3ZHu67+WxsJ ZiKXHAO7IEBS/c+4lD02WOag3pzUxIySt7rgBemny0DFuwO6eyjgqMkpXUV0JdSEBTAy RdwMOgaSGGITpQr2QwfyzuC9h+ACBGKFmTZfL+d3Wpy+P0UeVmlYpUTD8vTEiWpUPmgH s+bm2Qgkaq8OdBd1Sl0uhyWBgTGmhP35THZddtZNBH7zANjKVU3y4kMtnQK/HTZzixth /H3w== X-Gm-Message-State: AOAM533wnQEhMNcJ0UONlEDhV1t1rp/mZrHUyOt8zXg40QbFV3iXDjtW ybZ0QKQH/BZgnI6O/6Rw9S9u4c2vuyJipWuJHOpl9w== X-Google-Smtp-Source: ABdhPJzAjk84jCvAO1GGNwAjQhjA5NVJMJvEMdoeXmwQYafmLhasQs8GjvNUFQwXo45Q/t3+YPCB+oVDMVYNP42Ehuw= X-Received: by 2002:a25:3345:: with SMTP id z66mr8110740ybz.466.1613671131587; Thu, 18 Feb 2021 09:58:51 -0800 (PST) MIME-Version: 1.0 References: <20210217235130.1744843-1-saravanak@google.com> In-Reply-To: From: Saravana Kannan Date: Thu, 18 Feb 2021 09:58:15 -0800 Message-ID: Subject: Re: [PATCH] driver core: Avoid pointless deferred probe attempts To: "Rafael J. Wysocki" Cc: Greg Kroah-Hartman , Geert Uytterhoeven , "Cc: Android Kernel" , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 18, 2021 at 9:24 AM Saravana Kannan wrote: > > On Thu, Feb 18, 2021 at 9:18 AM Rafael J. Wysocki wrote: > > > > On Thu, Feb 18, 2021 at 12:51 AM Saravana Kannan wrote: > > > > > > There's no point in adding a device to the deferred probe list if we > > > know for sure that it doesn't have a matching driver. So, check if a > > > device can match with a driver before adding it to the deferred probe > > > list. > > > > What if a matching driver module loads in the meantime? > > Driver registration always triggers a match attempt and this flag will > get set at that point. Yes, the user can disable autoprobe, but > that'll block deferred probes too. > Btw, this can wait for 5.13. Doesn't need to go into 5.12-rcX. > > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > > index 9179825ff646..f18963f42e21 100644 > > > --- a/drivers/base/dd.c > > > +++ b/drivers/base/dd.c > > > @@ -123,6 +123,9 @@ static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); > > > > > > void driver_deferred_probe_add(struct device *dev) > > > { > > > + if (!dev->can_match) > > > + return; > > > + Also, if you are worried about this check, for now, I can move it inside device_links_driver_bound() which is the only place that currently adds a device to the deferred probe list before the driver is present. But it seemed like a good check in general to have in driver_deferred_probe_add(), so I put it there. -Saravana