From patchwork Tue Jun 15 13:35:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 12321705 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 830D9C48BDF for ; Tue, 15 Jun 2021 13:37:40 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 44A2161439 for ; Tue, 15 Jun 2021 13:37:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 44A2161439 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F085D6E30D; Tue, 15 Jun 2021 13:37:39 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by gabe.freedesktop.org (Postfix) with ESMTPS id 013276E30D; Tue, 15 Jun 2021 13:37:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=NvKrTegNJt6p9ts7Wx4ZCH5HpolsdcaWLfUZKxp8Ym0=; b=MGKJ4afA3hE7QZbybSgt+x3RSf SHGz+JwWUFKMROwY6XxNd/ClwtFZw+BkvFoKanLLyWcyPTYUMWpVU4vnOQF+wy7e1HySXzciQpNxj YgpqE4bz7K4myBaxQnFETcDTCdcbm2BPG/MPzKfCL+2oIX6SIdu5okPGuGf3oKa7EGhuFxSFw9827 hO2LX34nZ7Ku4Z58qjH1URziQbGAlBBQlEl2sudXryKDuLu9EKbWYRvz//eLyaFvs/h6tJQkgWWGN K+h5hhel73haPEmX3OuHhxRjswvnqCXQ4OClqfTBXsumpaIa6AnttuhINCpHBY7chvTbUljVfDlxj Dh9SoIGA==; Received: from [2001:4bb8:19b:fdce:9045:1e63:20f0:ca9] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1lt9Ep-006p1g-W0; Tue, 15 Jun 2021 13:36:34 +0000 From: Christoph Hellwig To: Greg Kroah-Hartman , Jason Gunthorpe , Alex Williamson , Kirti Wankhede Date: Tue, 15 Jun 2021 15:35:10 +0200 Message-Id: <20210615133519.754763-2-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210615133519.754763-1-hch@lst.de> References: <20210615133519.754763-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Subject: [Intel-gfx] [PATCH 01/10] driver core: Pull required checks into driver_probe_device() X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tony Krowiak , Jason Herne , kvm@vger.kernel.org, Vasily Gorbik , Jonathan Corbet , David Airlie , linux-s390@vger.kernel.org, Heiko Carstens , Cornelia Huck , linux-doc@vger.kernel.org, dri-devel@lists.freedesktop.org, Halil Pasic , Christian Borntraeger , "Rafael J. Wysocki" , intel-gfx@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" From: Jason Gunthorpe Checking if the dev is dead or if the dev is already bound is a required precondition to invoking driver_probe_device(). All the call chains leading here duplicate these checks. Add it directly to driver_probe_device() so the precondition is clear and remove the checks from device_driver_attach() and __driver_attach_async_helper(). The other call chain going through __device_attach_driver() does have these same checks but they are inlined into logic higher up the call stack and can't be removed. The sysfs uAPI call chain starting at bind_store() is a bit confused because it reads dev->driver unlocked and returns -ENODEV if it is !NULL, otherwise it reads it again under lock and returns 0 if it is !NULL. Fix this to always return -EBUSY and always read dev->driver under its lock. Done in preparation for the next patches which will add additional callers to driver_probe_device() and will need these checks as well. Signed-off-by: Jason Gunthorpe [hch: drop the extra checks in device_driver_attach and bind_store] Signed-off-by: Christoph Hellwig Reviewed-by: Greg Kroah-Hartman Reviewed-by: Cornelia Huck --- drivers/base/bus.c | 2 +- drivers/base/dd.c | 32 ++++++++++---------------------- 2 files changed, 11 insertions(+), 23 deletions(-) diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 36d0c654ea61..7de13302e8c8 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -210,7 +210,7 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, int err = -ENODEV; dev = bus_find_device_by_name(bus, NULL, buf); - if (dev && dev->driver == NULL && driver_match_device(drv, dev)) { + if (dev && driver_match_device(drv, dev)) { err = device_driver_attach(drv, dev); if (err > 0) { diff --git a/drivers/base/dd.c b/drivers/base/dd.c index ecd7cf848daf..7477d3322b3a 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -733,8 +733,9 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe); * @drv: driver to bind a device to * @dev: device to try to bind to the driver * - * This function returns -ENODEV if the device is not registered, - * 1 if the device is bound successfully and 0 otherwise. + * This function returns -ENODEV if the device is not registered, -EBUSY if it + * already has a driver, and 1 if the device is bound successfully and 0 + * otherwise. * * This function must be called with @dev lock held. When called for a * USB interface, @dev->parent lock must be held as well. @@ -745,8 +746,10 @@ static int driver_probe_device(struct device_driver *drv, struct device *dev) { int ret = 0; - if (!device_is_registered(dev)) + if (dev->p->dead || !device_is_registered(dev)) return -ENODEV; + if (dev->driver) + return -EBUSY; dev->can_match = true; pr_debug("bus: '%s': %s: matched device %s with driver %s\n", @@ -1027,17 +1030,10 @@ static void __device_driver_unlock(struct device *dev, struct device *parent) */ int device_driver_attach(struct device_driver *drv, struct device *dev) { - int ret = 0; + int ret; __device_driver_lock(dev, dev->parent); - - /* - * If device has been removed or someone has already successfully - * bound a driver before us just skip the driver probe call. - */ - if (!dev->p->dead && !dev->driver) - ret = driver_probe_device(drv, dev); - + ret = driver_probe_device(drv, dev); __device_driver_unlock(dev, dev->parent); return ret; @@ -1047,19 +1043,11 @@ static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie) { struct device *dev = _dev; struct device_driver *drv; - int ret = 0; + int ret; __device_driver_lock(dev, dev->parent); - drv = dev->p->async_driver; - - /* - * If device has been removed or someone has already successfully - * bound a driver before us just skip the driver probe call. - */ - if (!dev->p->dead && !dev->driver) - ret = driver_probe_device(drv, dev); - + ret = driver_probe_device(drv, dev); __device_driver_unlock(dev, dev->parent); dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);