From patchwork Tue Jun 15 13:35:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 12321663 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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 5E6F5C48BE8 for ; Tue, 15 Jun 2021 13:39:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F60C61474 for ; Tue, 15 Jun 2021 13:39:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231784AbhFONlk (ORCPT ); Tue, 15 Jun 2021 09:41:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231761AbhFONlM (ORCPT ); Tue, 15 Jun 2021 09:41:12 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C57E8C0611C0; Tue, 15 Jun 2021 06:38:53 -0700 (PDT) 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=5WVkKfD7lYvSciXI8AQt4/QZBYbZAS/m8pwsS80NMu0=; b=sUEdoXdiUpK0/tvBAqbiEsw8I8 cZ8odIRFIFUZHhFLVQKxXbFeQlVtQ6IYOIQ1iDvZJWtRP+aqNDkIUYFXFJFcxevj1m1phE9dllCJ3 5Tq797f7OkDPPy5b4+KRJEm/A19n97OkREB0JNIJ46HzSsNkPRiLh6FrK/XBG1cxrNGo/UNPOAShK X3BZZQ87bPaVkUx7HcemZDzyALj5VTAyfLuPspV2/bQJWVWJtMzBevxQIkdK9xYpoHqK6n+3YwQmR e+p0QS6rLR5jJ5eUMc6taYdXAC7ojf+I8UimCNapNuyfkZvdiiSX9Dz/U94Brkz7d5Y04v4MYaSwb BgPYdbPw==; 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 1lt9G6-006p9a-Tx; Tue, 15 Jun 2021 13:37:50 +0000 From: Christoph Hellwig To: Greg Kroah-Hartman , Jason Gunthorpe , Alex Williamson , Kirti Wankhede Cc: David Airlie , Tony Krowiak , Christian Borntraeger , Cornelia Huck , Jonathan Corbet , Daniel Vetter , dri-devel@lists.freedesktop.org, Vasily Gorbik , Heiko Carstens , intel-gfx@lists.freedesktop.org, Jani Nikula , Jason Herne , Joonas Lahtinen , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-s390@vger.kernel.org, Halil Pasic , "Rafael J. Wysocki" , Rodrigo Vivi Subject: [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Date: Tue, 15 Jun 2021 15:35:12 +0200 Message-Id: <20210615133519.754763-4-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 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Currently really_probe() returns 1 on success and 0 if the probe() call fails. This return code arrangement is designed to be useful for __device_attach_driver() which is walking the device list and trying every driver. 0 means to keep trying. However, it is not useful for the other places that call through to really_probe() that do actually want to see the probe() return code. For instance bind_store() would be better to return the actual error code from the driver's probe method, not discarding it and returning -ENODEV. Reorganize things so that really_probe() returns the error code from ->probe as a (inverted) positive number, and 0 for successful attach. With this, __device_attach_driver can ignore the (positive) probe errors, return 1 to exit the loop for a successful binding and pass on the other negative errors, while device_driver_attach simplify inverts the positive errors and returns all errors to the sysfs code. Signed-off-by: Christoph Hellwig Reviewed-by: Greg Kroah-Hartman Reviewed-by: Cornelia Huck --- drivers/base/bus.c | 6 +----- drivers/base/dd.c | 29 ++++++++++++++++++++--------- 2 files changed, 21 insertions(+), 14 deletions(-) diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 7de13302e8c8..1f6b4bd61056 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -212,13 +212,9 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, dev = bus_find_device_by_name(bus, NULL, buf); if (dev && driver_match_device(drv, dev)) { err = device_driver_attach(drv, dev); - - if (err > 0) { + if (!err) { /* success */ err = count; - } else if (err == 0) { - /* driver didn't accept device */ - err = -ENODEV; } } put_device(dev); diff --git a/drivers/base/dd.c b/drivers/base/dd.c index fd83817240e6..25341f52198c 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -607,10 +607,10 @@ static int really_probe(struct device *dev, struct device_driver *drv) probe_ret = call_driver_probe(dev, drv); if (probe_ret) { /* - * Ignore errors returned by ->probe so that the next driver can - * try its luck. + * Return probe errors as positive values so that the callers + * can distinguish them from other errors. */ - ret = 0; + ret = -probe_ret; goto probe_failed; } @@ -653,7 +653,6 @@ static int really_probe(struct device *dev, struct device_driver *drv) dev->pm_domain->sync(dev); driver_bound(dev); - ret = 1; pr_debug("bus: '%s': %s: bound device %s to driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); goto done; @@ -746,8 +745,8 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe); * @dev: device to try to bind to the driver * * 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. + * already has a driver, 0 if the device is bound successfully and a positive + * (inverted) error code for failures from the ->probe method. * * This function must be called with @dev lock held. When called for a * USB interface, @dev->parent lock must be held as well. @@ -882,7 +881,14 @@ static int __device_attach_driver(struct device_driver *drv, void *_data) if (data->check_async && async_allowed != data->want_async) return 0; - return driver_probe_device(drv, dev); + /* + * Ignore errors returned by ->probe so that the next driver can try + * its luck. + */ + ret = driver_probe_device(drv, dev); + if (ret < 0) + return ret; + return ret == 0; } static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) @@ -1038,7 +1044,7 @@ static void __device_driver_unlock(struct device *dev, struct device *parent) * @dev: Device to attach it to * * Manually attach driver to a device. Will acquire both @dev lock and - * @dev->parent lock if needed. + * @dev->parent lock if needed. Returns 0 on success, -ERR on failure. */ int device_driver_attach(struct device_driver *drv, struct device *dev) { @@ -1048,6 +1054,9 @@ int device_driver_attach(struct device_driver *drv, struct device *dev) ret = driver_probe_device(drv, dev); __device_driver_unlock(dev, dev->parent); + /* also return probe errors as normal negative errnos */ + if (ret > 0) + ret = -ret; return ret; } @@ -1114,7 +1123,9 @@ static int __driver_attach(struct device *dev, void *data) return 0; } - device_driver_attach(drv, dev); + __device_driver_lock(dev, dev->parent); + driver_probe_device(drv, dev); + __device_driver_unlock(dev, dev->parent); return 0; }