From patchwork Fri Sep 15 15:03:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bartosz Golaszewski X-Patchwork-Id: 140571 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:172:b0:3f2:4152:657d with SMTP id h50csp1210777vqi; Fri, 15 Sep 2023 10:32:36 -0700 (PDT) X-Google-Smtp-Source: AGHT+IG9Cr+KVoU49lYjJvHc0FUa4+WcTaB2GD7PdhBWgT3a5TkmrdxZT6RN06s/wQJ1wZiX4zHQ X-Received: by 2002:a05:6a00:21d5:b0:690:2ecd:a597 with SMTP id t21-20020a056a0021d500b006902ecda597mr2577872pfj.21.1694799156531; Fri, 15 Sep 2023 10:32:36 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1694799156; cv=none; d=google.com; s=arc-20160816; b=vGk6H+YfF8xfu4yGPgeLY5dMpIOuQx6su8VPn9xkldtG5XHLUKDane3SHGSH95x/m0 086aQ7kP542YEqf/r+JpRlW7yzULJcRX/qe04CK+vMHO79Qpw7rbohCgYHgGnZdboyZY 8SPwbaWm2A1u5X1EIglZPD2qim1NrqDSqMIP728EDZ54FWS7ZCs8nNPriNLtWrvL790H X7evDeqNfDfNJERSLeMbpiWs+3jzTJB1ho7WBsLzj4lRDl52w8M/FzLLshzyHxXXAMjU RvvHbfIwAugwmCtgdi6k5Kbt75KN67XySZCOJPnsuzGfCcH51SwNb4bM5CcmIfKNvQVV 635w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=AG+MBGFlKyeqAoI+zBkkhuwZdyh02KZ6W2Oat6+x/rc=; fh=sKfwLbYyGsqFA9J5964tfV31zxizqPhzkdLiyF/udjc=; b=C6RA+YM77tzng+gshljulmC+UUdfp3uqsLp/s9TD9x2iVDQEHEUvz0r3jsjUtOIvWM X9fQTX3d77FuL2xggUevM1EMiniO/APP+VGqzaCzHjiqPTm8ROMvJCL6iOdu/+A8XeC1 HsFqmH5+cuaZYQLBfflG5IssfC54O/53Cwn1pnc520MzWr7b/N/XGTsCRKJSkDI2+GaE Oh+pW+6jod7UbiUHVdA2+Qfd4ZRAcloLaFXhEq2JRANNer8xhJMSwPZtVBn+Y5VbU6Jc RrX7D9jfKKqASFLsHQfpKHcoHflQhvlYTbnIX/fWl7LFvef7gv4UPqRkAS2A9SrN13e9 SB2w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@bgdev-pl.20230601.gappssmtp.com header.s=20230601 header.b="lo08M29/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from howler.vger.email (howler.vger.email. [23.128.96.34]) by mx.google.com with ESMTPS id x40-20020a056a0018a800b0068fe810e8a1si3661654pfh.193.2023.09.15.10.32.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Sep 2023 10:32:36 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) client-ip=23.128.96.34; Authentication-Results: mx.google.com; dkim=pass header.i=@bgdev-pl.20230601.gappssmtp.com header.s=20230601 header.b="lo08M29/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by howler.vger.email (Postfix) with ESMTP id D9208808206C; Fri, 15 Sep 2023 08:04:01 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at howler.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235733AbjIOPED (ORCPT + 31 others); Fri, 15 Sep 2023 11:04:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235732AbjIOPDn (ORCPT ); Fri, 15 Sep 2023 11:03:43 -0400 Received: from mail-wm1-x32a.google.com (mail-wm1-x32a.google.com [IPv6:2a00:1450:4864:20::32a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 710032703 for ; Fri, 15 Sep 2023 08:03:35 -0700 (PDT) Received: by mail-wm1-x32a.google.com with SMTP id 5b1f17b1804b1-403004a96eeso24334085e9.3 for ; Fri, 15 Sep 2023 08:03:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20230601.gappssmtp.com; s=20230601; t=1694790214; x=1695395014; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=AG+MBGFlKyeqAoI+zBkkhuwZdyh02KZ6W2Oat6+x/rc=; b=lo08M29/S8Ch6GA1Fi7eCGWgf9Ni+B+3SGHBw/M+1NwJ8x8Dry5xj9ByPK+WA0lcRr FEpQYv6zoyLLniYO9UvF/oQtW0QvH/rZahNI6oQbgYax6h4CVsOz1bKOYbjXKhjPaJiU LbYFCgN/ol63Dezd2kNVpQ0j+ah3WEl7YQV2gkcJTj+ZqXsHZEdtF16Rugz5OTMA5Vln Fn+zfcDQZ/qU1gtYM5aL1oW0f9a6EENQTruSA+6zRwe3j3AuuMU9ggmD0jQMrt4qmApb OMqG9W5gyz6qu+5tPJrvsOww5U5Lz/U2Ur4XGiXeOkFVRkSwQFMiksCTR3zjY8zQW31X ExBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694790214; x=1695395014; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=AG+MBGFlKyeqAoI+zBkkhuwZdyh02KZ6W2Oat6+x/rc=; b=CNQTR/VuDYAo+C7Ow4cj+9XRKOyJzbHj4ITt46v0XwGAfwkvF037Xb7B37Fhc3Eotj Azmfurju5/dKNlS8J2gV0CTUBLc6y+hdRNi2b3/Xj51R1N3nU8sR4YD6A4Erc5JSEl8Z V5Xm80MXSZlZ//b5MIJdDi5hZ3WUpM3Nw0utpHX6gjN2n1OAmWqKmALZR60D0v+JjCoq K8Rwd//xp7CnUrjY2RwndUkMSCCHYPNkvlxpH/jFSc5RLIlbVF0HqQCK0jyRGn1GRd0u g5w+ZsVTOTuQTOt69YWXMmqH+V/Jel9tFoyH3opXzReZoHzbvoz9lBZQGd+VRYX1VY1a pvVA== X-Gm-Message-State: AOJu0Yyn9Ms7OEMh7cgcYTsFAyhq6hoLL4uWa4bUp6gUisZ23ZRxngDo 3/qRlg57ei4zn2vEDJPEiQffcQ== X-Received: by 2002:a05:600c:378f:b0:401:d258:ad26 with SMTP id o15-20020a05600c378f00b00401d258ad26mr1690953wmr.19.1694790213635; Fri, 15 Sep 2023 08:03:33 -0700 (PDT) Received: from brgl-uxlite.home ([2a01:cb1d:334:ac00:aa19:4569:aeeb:c0d3]) by smtp.gmail.com with ESMTPSA id hn40-20020a05600ca3a800b003fef19bb55csm4853369wmb.34.2023.09.15.08.03.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Sep 2023 08:03:33 -0700 (PDT) From: Bartosz Golaszewski To: Linus Walleij , Andy Shevchenko , Mika Westerberg Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v3 03/11] gpiolib: provide gpio_device_find() Date: Fri, 15 Sep 2023 17:03:18 +0200 Message-Id: <20230915150327.81918-4-brgl@bgdev.pl> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230915150327.81918-1-brgl@bgdev.pl> References: <20230915150327.81918-1-brgl@bgdev.pl> MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Fri, 15 Sep 2023 08:04:02 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777125720060292599 X-GMAIL-MSGID: 1777125720060292599 From: Bartosz Golaszewski gpiochip_find() is wrong and its kernel doc is misleading as the function doesn't return a reference to the gpio_chip but just a raw pointer. The chip itself is not guaranteed to stay alive, in fact it can be deleted at any point. Also: other than GPIO drivers themselves, nobody else has any business accessing gpio_chip structs. Provide a new gpio_device_find() function that returns a real reference to the opaque gpio_device structure that is guaranteed to stay alive for as long as there are active users of it. Signed-off-by: Bartosz Golaszewski Reviewed-by: Linus Walleij --- drivers/gpio/gpiolib.c | 71 +++++++++++++++++++++++++++---------- include/linux/gpio/driver.h | 3 ++ 2 files changed, 56 insertions(+), 18 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index f84ad54d8dbd..0371d23f0a46 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1014,16 +1014,10 @@ void gpiochip_remove(struct gpio_chip *gc) } EXPORT_SYMBOL_GPL(gpiochip_remove); -/** - * gpiochip_find() - iterator for locating a specific gpio_chip - * @data: data to pass to match function - * @match: Callback function to check gpio_chip +/* + * FIXME: This will be removed soon. * - * Similar to bus_find_device. It returns a reference to a gpio_chip as - * determined by a user supplied @match callback. The callback should return - * 0 if the device doesn't match and non-zero if it does. If the callback is - * non-zero, this function will return to the caller and not iterate over any - * more gpio_chips. + * This function is depracated, don't use. */ struct gpio_chip *gpiochip_find(void *data, int (*match)(struct gpio_chip *gc, @@ -1031,21 +1025,62 @@ struct gpio_chip *gpiochip_find(void *data, { struct gpio_device *gdev; struct gpio_chip *gc = NULL; - unsigned long flags; - spin_lock_irqsave(&gpio_lock, flags); - list_for_each_entry(gdev, &gpio_devices, list) - if (gdev->chip && match(gdev->chip, data)) { - gc = gdev->chip; - break; - } - - spin_unlock_irqrestore(&gpio_lock, flags); + gdev = gpio_device_find(data, match); + if (gdev) { + gc = gdev->chip; + gpio_device_put(gdev); + } return gc; } EXPORT_SYMBOL_GPL(gpiochip_find); +/** + * gpio_device_find() - find a specific GPIO device + * @data: data to pass to match function + * @match: Callback function to check gpio_chip + * + * Returns: + * New reference to struct gpio_device. + * + * Similar to bus_find_device(). It returns a reference to a gpio_device as + * determined by a user supplied @match callback. The callback should return + * 0 if the device doesn't match and non-zero if it does. If the callback + * returns non-zero, this function will return to the caller and not iterate + * over any more gpio_devices. + * + * The callback takes the GPIO chip structure as argument. During the execution + * of the callback function the chip is protected from being freed. TODO: This + * actually has yet to be implemented. + * + * If the function returns non-NULL, the returned reference must be freed by + * the caller using gpio_device_put(). + */ +struct gpio_device *gpio_device_find(void *data, + int (*match)(struct gpio_chip *gc, + void *data)) +{ + struct gpio_device *gdev; + + /* + * Not yet but in the future the spinlock below will become a mutex. + * Annotate this function before anyone tries to use it in interrupt + * context like it happened with gpiochip_find(). + */ + might_sleep(); + + guard(spinlock_irqsave)(&gpio_lock); + + list_for_each_entry(gdev, &gpio_devices, list) { + if (gdev->chip && match(gdev->chip, data)) + return gpio_device_get(gdev); + } + + return NULL; +} +EXPORT_SYMBOL_GPL(gpio_device_find); + static int gpiochip_match_name(struct gpio_chip *gc, void *data) { const char *name = data; diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 1cedbc3d3200..6ad1f1a8ef2e 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -608,6 +608,9 @@ int devm_gpiochip_add_data_with_key(struct device *dev, struct gpio_chip *gc, struct gpio_chip *gpiochip_find(void *data, int (*match)(struct gpio_chip *gc, void *data)); +struct gpio_device *gpio_device_find(void *data, + int (*match)(struct gpio_chip *gc, void *data)); + struct gpio_device *gpio_device_get(struct gpio_device *gdev); void gpio_device_put(struct gpio_device *gdev);