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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 7FB20C64E75 for ; Sat, 21 Nov 2020 02:01:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47CCD2237B for ; Sat, 21 Nov 2020 02:01:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OWTrmrFh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726768AbgKUCBH (ORCPT ); Fri, 20 Nov 2020 21:01:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55022 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726417AbgKUCBG (ORCPT ); Fri, 20 Nov 2020 21:01:06 -0500 Received: from mail-yb1-xb43.google.com (mail-yb1-xb43.google.com [IPv6:2607:f8b0:4864:20::b43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E7F8C0613CF for ; Fri, 20 Nov 2020 18:01:06 -0800 (PST) Received: by mail-yb1-xb43.google.com with SMTP id l14so10369735ybq.3 for ; Fri, 20 Nov 2020 18:01:06 -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=K1DTYgzh1PTbt5Dy4OfYWtoZOqwKhfMyLvJRd1nKZqU=; b=OWTrmrFhgMKOD4nQ/pwBJ9g35AYS3uNk81qFnTGjAdORh6DQtZwbJDpzryS7hYSdfG ZfclUmgvHq2KAyNE3vPPPnAdFiTPZD++Ay29kDZZVVcFXH3HFKUq3hpP96QhSC4f3WUP tN7QyhbFxnOXMxQVXZJsWKrtjCr8QpsIfK4XUitTpDVkCCpLX8CmeKtE8uHLPzMzLzH8 nlcSAqn29YDGud9qmji88sgxJhdVQZIIHrFp5kaayrn+yLZmvJt0psTbeCzogFX50wth +zljqvHjn1XdsaDxtg2fm1zMp+iGxB8cqhRS9nWTigDeSpF3bM8AZ/UyNIcXTNV4GIZF cSNg== 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=K1DTYgzh1PTbt5Dy4OfYWtoZOqwKhfMyLvJRd1nKZqU=; b=rvMK8MT8TaSrB8Y5HfDPSzxAQNXbe1dyTp9CLEU8ouYDxHu9Bi+CNzfFhUP8tQdBtE BQkgEVt/ZMMh6V4LbpdmW0T0Cxw0j4ct71K1V7tHzvMm38KU02MXmu69bUVc3NS4RpQ7 lHSUsA4bkGYBvDk/7fSgfILEvvIToQGbi/KXjleXSDJWrVNRPiMFIGN5cB9MgwQ5nZeT qp6nrkQPQ0KCWeRXZZdzcsTVAFRZn7n0yIWLykY0BDJ+PRB2ifNEH1mr5qY9z36VCzi3 VZp8ZisHc04WHqEGGTmCHK9BQ3o51Z4hVxsqYWIpeq0HgtRZpGgFa8GWBNG5BDjrIOhd 3pbg== X-Gm-Message-State: AOAM532xuYh+MpUdeLkBvj6RXm8YrvSe98JHQPti9OtSZfW//3GvUtDg TAavU0cR3Yb37rz9a/5eh1Uyk93YZHwtL+mj9JdJ6w== X-Google-Smtp-Source: ABdhPJyaUd7orwxD63L9YPrdxfBc6vqRk8ovK/YWzUfH+pt8qh68rGG+nqHyaKxR4F41T+ZWt5vk0rTg+/kfNtg6Qxc= X-Received: by 2002:a25:b090:: with SMTP id f16mr25884519ybj.466.1605924065704; Fri, 20 Nov 2020 18:01:05 -0800 (PST) MIME-Version: 1.0 References: <20201104232356.4038506-1-saravanak@google.com> <20201104232356.4038506-15-saravanak@google.com> In-Reply-To: From: Saravana Kannan Date: Fri, 20 Nov 2020 18:00:30 -0800 Message-ID: Subject: Re: [PATCH v1 14/18] driver core: Use device's fwnode to check if it is waiting for suppliers To: "Rafael J. Wysocki" Cc: "Rafael J. Wysocki" , Len Brown , Greg Kroah-Hartman , Ard Biesheuvel , Rob Herring , Frank Rowand , Marc Zyngier , Thomas Gleixner , Tomi Valkeinen , Laurent Pinchart , Grygorii Strashko , "Cc: Android Kernel" , ACPI Devel Maling List , Linux Kernel Mailing List , linux-efi , "devicetree@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 16, 2020 at 8:34 AM Rafael J. Wysocki wrote: > > On Thu, Nov 5, 2020 at 12:24 AM Saravana Kannan wrote: > > > > To check if a device is still waiting for its supplier devices to be > > added, we used to check if the devices is in a global > > waiting_for_suppliers list. Since the global list will be deleted in > > subsequent patches, this patch stops using this check. > > My kind of educated guess is that you want to drop > waiting_for_suppliers and that's why you want to use supplier links > here. Yes, and a device would never be added waiting_for_suppliers list. > > > > Instead, this patch uses a more device specific check. It checks if the > > device's fwnode has any fwnode links that haven't been converted to > > device links yet. > > > > Signed-off-by: Saravana Kannan > > --- > > drivers/base/core.c | 18 ++++++++---------- > > 1 file changed, 8 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/base/core.c b/drivers/base/core.c > > index 4ae5f2885ac5..d51dd564add1 100644 > > --- a/drivers/base/core.c > > +++ b/drivers/base/core.c > > @@ -51,6 +51,7 @@ static DEFINE_MUTEX(wfs_lock); > > static LIST_HEAD(deferred_sync); > > static unsigned int defer_sync_state_count = 1; > > static DEFINE_MUTEX(fwnode_link_lock); > > +static bool fw_devlink_is_permissive(void); > > > > /** > > * fwnode_link_add - Create a link between two fwnode_handles. > > @@ -994,13 +995,13 @@ int device_links_check_suppliers(struct device *dev) > > * Device waiting for supplier to become available is not allowed to > > * probe. > > */ > > - mutex_lock(&wfs_lock); > > - if (!list_empty(&dev->links.needs_suppliers) && > > - dev->links.need_for_probe) { > > - mutex_unlock(&wfs_lock); > > + mutex_lock(&fwnode_link_lock); > > + if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) && > > + !fw_devlink_is_permissive()) { > > + mutex_unlock(&fwnode_link_lock); > > return -EPROBE_DEFER; > > } > > - mutex_unlock(&wfs_lock); > > + mutex_unlock(&fwnode_link_lock); > > > > device_links_write_lock(); > > > > @@ -1166,10 +1167,7 @@ static ssize_t waiting_for_supplier_show(struct device *dev, > > bool val; > > > > device_lock(dev); > > - mutex_lock(&wfs_lock); > > - val = !list_empty(&dev->links.needs_suppliers) > > - && dev->links.need_for_probe; > > - mutex_unlock(&wfs_lock); > > Why isn't the lock needed any more? > > Or maybe it wasn't needed previously too? Yeah, I sent a separate patch for dropping this lock [1]. But I didn't want to wait for that to land to write this series. The lock wasn't needed in the first place and it was causing a lockdep warning. > > > + val = !list_empty(&dev->fwnode->suppliers); > > device_unlock(dev); > > return sysfs_emit(buf, "%u\n", val); > > } > > @@ -2226,7 +2224,7 @@ static int device_add_attrs(struct device *dev) > > goto err_remove_dev_groups; > > } > > > > - if (fw_devlink_flags && !fw_devlink_is_permissive()) { > > + if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) { > > And why is this change needed? Because if a device doesn't have a fwnode, it can't ever be waiting on a supplier. Also, the "show" function dereferences dev->fwnode->suppliers. -Saravana [1] - https://lore.kernel.org/lkml/20201104205431.3795207-1-saravanak@google.com/ Ignore the 1/2 thing. There's only 1 relevant patch.