From mboxrd@z Thu Jan 1 00:00:00 1970 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 5BDE7337BB5; Fri, 8 May 2026 10:55:44 +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=1778237744; cv=none; b=BPg8S7zUlL++wwla/arYLa9YhI7IcVktLh1DykOt+aAc535FqRXIwT3zC8i3MsD6dmPS/vo9OAMdpmtzI90hG6pRhoSO46fUfkJv+3xKajm8N2Vx3FVI4+9iRrTXxmKSPlLTWSvNhKgSL8OZEY5lUqxoA6QKh2oNQk80vcSGoZM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778237744; c=relaxed/simple; bh=e7scW9mci2GzMCZUWCGmaXC5WgiFPb07UflccUab+fI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=o/8DBTMIuJ/cD9uOknNEgXr1z+9USXCy9cvxFAMwYUtGeKIraxrmzAI7ngVTZPbM950cNGh5UksX9G63gKKXULPWEczSO+5az0AaAY9Y+HbYtfPC+m4A+X+K8CA2tXjvNwEqWtR4WVCFutOq7HTQazj91OZmYPGCmJxe61E2YPE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jIv/ghbr; 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="jIv/ghbr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E227C2BCB0; Fri, 8 May 2026 10:55:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778237743; bh=e7scW9mci2GzMCZUWCGmaXC5WgiFPb07UflccUab+fI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jIv/ghbr/fvXlD6p2N1u2jHqlygChItLff4aSG5FiezI6OmU533z73pUW+8jGqImy RTIFgbNeRpIvuwUvPfHDKdvlh2KiAVhHPFrH9kPp1wYWsgzE//++eH4/7PD7AdewmC XpwUoykO96VlaeYbYr6XeOgAEwcJm4c59M4Dl8Q5BgAnoTJ9HanEMtyrLhzf9x9x+i jhEJLtjrDfTQ7ajwMqBd/q7X+p/K6zHPZ5+KMl7pGKJkTUbS/jSa4PjZir7JdHFOn+ +V+GDiNiYN+9NKzJtc1A+GyGJIR3Ow6EHkUVOu93jCFhmXdpAPL5IHgzo5wnsS++hd Wlf+ed9X27Fqw== From: Tzung-Bi Shih To: Arnd Bergmann , Greg Kroah-Hartman , Bartosz Golaszewski , Linus Walleij Cc: Benson Leung , tzungbi@kernel.org, linux-kernel@vger.kernel.org, chrome-platform@lists.linux.dev, driver-core@lists.linux.dev, linux-doc@vger.kernel.org, linux-gpio@vger.kernel.org, "Rafael J. Wysocki" , Danilo Krummrich , Jonathan Corbet , Shuah Khan , Laurent Pinchart , Wolfram Sang , Jason Gunthorpe , Johan Hovold , "Paul E . McKenney" Subject: [PATCH v10 6/9] gpio: Leverage revocable for accessing struct gpio_chip Date: Fri, 8 May 2026 18:54:45 +0800 Message-ID: <20260508105448.31799-7-tzungbi@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260508105448.31799-1-tzungbi@kernel.org> References: <20260508105448.31799-1-tzungbi@kernel.org> Precedence: bulk X-Mailing-List: driver-core@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- v10: - No changes. v9: https://lore.kernel.org/all/20260427135841.96266-7-tzungbi@kernel.org - New to the series. - Rename "chip_rp" -> "chip_rev". v4 - v8: - Doesn't exist. v3: https://lore.kernel.org/all/20260213092958.864411-11-tzungbi@kernel.org - 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 0389d5f55282..d2d9807da98d 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -335,7 +335,10 @@ 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_rev, gc); + return gc; } EXPORT_SYMBOL_GPL(gpio_device_get_chip); @@ -561,9 +564,7 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name) list_for_each_entry_srcu(gdev, &gpio_devices, list, srcu_read_lock_held(&gpio_devices_srcu)) { - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(&gdev->chip_rev, gc); if (!gc) continue; @@ -1050,9 +1051,7 @@ static void gpiochip_setup_devs(void) list_for_each_entry_srcu(gdev, &gpio_devices, list, srcu_read_lock_held(&gpio_devices_srcu)) { - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(&gdev->chip_rev, gc); if (!gc) { dev_err(&gdev->dev, "Underlying GPIO chip is gone\n"); continue; @@ -1457,11 +1456,11 @@ struct gpio_device *gpio_device_find(const void *data, if (!device_is_registered(&gdev->dev)) continue; - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(&gdev->chip_rev, gc); + if (!gc) + continue; - if (gc && match(gc, data)) + if (match(gc, data)) return gpio_device_get(gdev); } @@ -3404,18 +3403,10 @@ static int gpio_chip_get_value(struct gpio_chip *gc, const struct gpio_desc *des static int gpiod_get_raw_value_commit(const struct gpio_desc *desc) { - struct gpio_device *gdev; struct gpio_chip *gc; int value; - /* FIXME Unable to use gpio_chip_guard due to const desc. */ - gdev = desc->gdev; - - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(&desc->gdev->chip_rev, gc); value = gpio_chip_get_value(gc, desc); value = value < 0 ? value : !!value; @@ -3454,9 +3445,10 @@ 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_chip *gc) { - guard(srcu)(&gdev->srcu); + struct gpio_chip *chip; - return gc == srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(&gdev->chip_rev, chip); + return chip ? chip == gc : false; } int gpiod_get_array_value_complex(bool raw, bool can_sleep, @@ -3479,11 +3471,7 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep, if (!can_sleep) WARN_ON(array_info->gdev->can_sleep); - guard(srcu)(&array_info->gdev->srcu); - gc = srcu_dereference(array_info->gdev->chip, - &array_info->gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(&array_info->gdev->chip_rev, gc); ret = gpio_chip_get_multiple(gc, array_info->get_mask, value_bitmap); @@ -3820,11 +3808,7 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep, return -EPERM; } - guard(srcu)(&array_info->gdev->srcu); - gc = srcu_dereference(array_info->gdev->chip, - &array_info->gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(&array_info->gdev->chip_rev, gc); if (!raw && !bitmap_empty(array_info->invert_mask, array_size)) bitmap_xor(value_bitmap, value_bitmap, @@ -4119,7 +4103,6 @@ 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; @@ -4128,12 +4111,7 @@ int gpiod_to_irq(const struct gpio_desc *desc) if (ret <= 0) return -EINVAL; - gdev = desc->gdev; - /* FIXME Cannot use gpio_chip_guard due to const desc. */ - guard(srcu)(&gdev->srcu); - gc = srcu_dereference(gdev->chip, &gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(&desc->gdev->chip_rev, gc); offset = gpiod_hwgpio(desc); if (gc->to_irq) { @@ -5472,9 +5450,7 @@ static int gpiolib_seq_show(struct seq_file *s, void *v) if (priv->newline) seq_putc(s, '\n'); - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(&gdev->chip_rev, gc); if (!gc) { seq_printf(s, "%s: (dangling chip)\n", dev_name(&gdev->dev)); return 0; -- 2.51.0