From nobody Thu Apr 2 09:12:33 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 054A6330B27; Fri, 13 Feb 2026 09:31:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770975093; cv=none; b=lMuU3q2AyKp8k36+GrBMq6QPeZ2KzH5elRSW1SmgqI1idNsZ/TVMRA6N7arG3+IgUbIS8FNCv0dTtnWzaHHZJUKi+EOEgpEPxDuzOGGHY54E5Vi6KsLKMoV2e4didmCBrFhDISRp6b/XkzVGUiptaHdy+BTivOH5PDiFMMrgd+M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770975093; c=relaxed/simple; bh=sc68Y2yfU7vJPsAs/fppEoHXv0dQsgkbHlyNAxyY/KQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RLFvViXWw5NgbOZRh7Jva5EqYlTRe390bhOWO6p8qi06mPYWmlC7+Z0wd9cSTI21GOWdMgCT7l/JyRy8ZGNfXlhzBwB++WSnYrJX8zlfwPSpQWBb4/NyDXh1omHGpdIqJlJqtgFyHRSvWNY4KOCInFP/urJd70QFp1tZrb0dhZk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GMBJTlbQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GMBJTlbQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B14AC16AAE; Fri, 13 Feb 2026 09:31:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770975092; bh=sc68Y2yfU7vJPsAs/fppEoHXv0dQsgkbHlyNAxyY/KQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GMBJTlbQSoMbGuLvCNfO7N884adZYuIlKQDbzSiU0o0QVR9nSSFfFkPx3UCogq+Cn XfVQvFDnmcL7soAQnDHouOcYXVZj9vLWi6o/C5dPDbOkmAV8e1TEUeD6fV7Qj+7ZKg e6+Flw5JWGIplEsm/fjknKLfax9HvXiwosZgo9Lk+k3iWSciFPAac40Ft7F6TpuXxo fJXByL2vGxWf+nFpeCxRkw3FdSBOXcNgl40TdXxSobPLET9YD2sc5ls4X9cWBa0deF Nk/KvyZuCYE9fmkHfzEcxVC6KI0+IRN7DifOT/DZEB/Dro+wbdfO8iP/FXf0MiraVZ 27JpTACoiU5Og== From: Tzung-Bi Shih To: Bartosz Golaszewski , Linus Walleij Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Jonathan Corbet , Shuah Khan , Laurent Pinchart , Wolfram Sang , Jason Gunthorpe , Johan Hovold , "Paul E . McKenney" , Dan Williams , chrome-platform@lists.linux.dev, tzungbi@kernel.org, linux-gpio@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 10/11] gpio: Leverage revocable for accessing struct gpio_chip Date: Fri, 13 Feb 2026 09:29:57 +0000 Message-ID: <20260213092958.864411-11-tzungbi@kernel.org> X-Mailer: git-send-email 2.53.0.310.g728cabbaf7-goog In-Reply-To: <20260213092958.864411-1-tzungbi@kernel.org> References: <20260213092958.864411-1-tzungbi@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Struct gpio_device now provides a revocable provider to the underlying struct gpio_chip. Leverage revocable for accessing the struct gpio_chip. Signed-off-by: Tzung-Bi Shih --- v3: - Change revocable API usages accordingly. v2: https://lore.kernel.org/all/20260203061059.975605-11-tzungbi@kernel.org - Separate from v1(a) for excluding gpio_chip_guard and combine v1(b). v1(a): - https://lore.kernel.org/all/20260116081036.352286-23-tzungbi@kernel.org v1(b): - https://lore.kernel.org/all/20260116081036.352286-19-tzungbi@kernel.org drivers/gpio/gpiolib.c | 60 +++++++++++++----------------------------- 1 file changed, 18 insertions(+), 42 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 34f2665a9311..2ba78add3417 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -338,7 +338,10 @@ EXPORT_SYMBOL(gpio_device_get_label); */ struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev) { - return rcu_dereference_check(gdev->chip, 1); + struct gpio_chip *gc; + + revocable_try_access_with(gdev->chip_rp, gc); + return gc; } EXPORT_SYMBOL_GPL(gpio_device_get_chip); =20 @@ -556,9 +559,7 @@ static struct gpio_desc *gpio_name_to_desc(const char *= const name) =20 list_for_each_entry_srcu(gdev, &gpio_devices, list, srcu_read_lock_held(&gpio_devices_srcu)) { - guard(srcu)(&gdev->srcu); - - gc =3D srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, gc); if (!gc) continue; =20 @@ -972,9 +973,7 @@ static void gpiochip_setup_devs(void) =20 list_for_each_entry_srcu(gdev, &gpio_devices, list, srcu_read_lock_held(&gpio_devices_srcu)) { - guard(srcu)(&gdev->srcu); - - gc =3D srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, gc); if (!gc) { dev_err(&gdev->dev, "Underlying GPIO chip is gone\n"); continue; @@ -1378,11 +1377,11 @@ struct gpio_device *gpio_device_find(const void *da= ta, if (!device_is_registered(&gdev->dev)) continue; =20 - guard(srcu)(&gdev->srcu); - - gc =3D srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, gc); + if (!gc) + continue; =20 - if (gc && match(gc, data)) + if (match(gc, data)) return gpio_device_get(gdev); } =20 @@ -3310,18 +3309,10 @@ static int gpio_chip_get_value(struct gpio_chip *gc= , const struct gpio_desc *des =20 static int gpiod_get_raw_value_commit(const struct gpio_desc *desc) { - struct gpio_device *gdev; struct gpio_chip *gc; int value; =20 - /* FIXME Unable to use gpio_chip_guard due to const desc. */ - gdev =3D desc->gdev; - - guard(srcu)(&gdev->srcu); - - gc =3D srcu_dereference(gdev->chip, &gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(desc->gdev->chip_rp, gc); =20 value =3D gpio_chip_get_value(gc, desc); value =3D value < 0 ? value : !!value; @@ -3360,9 +3351,10 @@ static int gpio_chip_get_multiple(struct gpio_chip *= gc, /* The 'other' chip must be protected with its GPIO device's SRCU. */ static bool gpio_device_chip_cmp(struct gpio_device *gdev, struct gpio_chi= p *gc) { - guard(srcu)(&gdev->srcu); + struct gpio_chip *chip; =20 - return gc =3D=3D srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, chip); + return chip ? chip =3D=3D gc : false; } =20 int gpiod_get_array_value_complex(bool raw, bool can_sleep, @@ -3385,11 +3377,7 @@ int gpiod_get_array_value_complex(bool raw, bool can= _sleep, if (!can_sleep) WARN_ON(array_info->gdev->can_sleep); =20 - guard(srcu)(&array_info->gdev->srcu); - gc =3D srcu_dereference(array_info->gdev->chip, - &array_info->gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(array_info->gdev->chip_rp, gc); =20 ret =3D gpio_chip_get_multiple(gc, array_info->get_mask, value_bitmap); @@ -3726,11 +3714,7 @@ int gpiod_set_array_value_complex(bool raw, bool can= _sleep, return -EPERM; } =20 - guard(srcu)(&array_info->gdev->srcu); - gc =3D srcu_dereference(array_info->gdev->chip, - &array_info->gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(array_info->gdev->chip_rp, gc); =20 if (!raw && !bitmap_empty(array_info->invert_mask, array_size)) bitmap_xor(value_bitmap, value_bitmap, @@ -4024,7 +4008,6 @@ EXPORT_SYMBOL_GPL(gpiod_is_shared); */ int gpiod_to_irq(const struct gpio_desc *desc) { - struct gpio_device *gdev; struct gpio_chip *gc; int offset; int ret; @@ -4033,12 +4016,7 @@ int gpiod_to_irq(const struct gpio_desc *desc) if (ret <=3D 0) return -EINVAL; =20 - gdev =3D desc->gdev; - /* FIXME Cannot use gpio_chip_guard due to const desc. */ - guard(srcu)(&gdev->srcu); - gc =3D srcu_dereference(gdev->chip, &gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(desc->gdev->chip_rp, gc); =20 offset =3D gpiod_hwgpio(desc); if (gc->to_irq) { @@ -5413,9 +5391,7 @@ static int gpiolib_seq_show(struct seq_file *s, void = *v) if (priv->newline) seq_putc(s, '\n'); =20 - guard(srcu)(&gdev->srcu); - - gc =3D srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, gc); if (!gc) { seq_printf(s, "%s: (dangling chip)\n", dev_name(&gdev->dev)); return 0; --=20 2.53.0.310.g728cabbaf7-goog