linux-kernel - [PATCH v2 06/11] gpiolib: reluctantly provide gpio_device_get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230912100727.23197-7-brgl@bgdev.pl>
Date:   Tue, 12 Sep 2023 12:07:22 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-acpi@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH v2 06/11] gpiolib: reluctantly provide gpio_device_get_chip()

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

The process of converting all unauthorized users of struct gpio_chip to
using dedicated struct gpio_device function will be long so in the
meantime we must provide a way of retrieving the pointer to struct
gpio_chip from a GPIO device.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
---
 drivers/gpio/gpiolib.c      | 21 +++++++++++++++++++++
 include/linux/gpio/driver.h |  2 ++
 2 files changed, 23 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e413136d1566..224e0d330009 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -219,6 +219,27 @@ struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 }
 EXPORT_SYMBOL_GPL(gpiod_to_chip);
 
+/**
+ * gpio_device_get_chip() - Get the gpio_chip implementation of this GPIO device
+ * @gdev: GPIO device
+ *
+ * Returns:
+ * Address of the GPIO chip backing this device.
+ *
+ * Until we can get rid of all non-driver users of struct gpio_chip, we must
+ * provide a way of retrieving the pointer to it from struct gpio_device. This
+ * is *NOT* safe as the GPIO API is considered to be hot-unpluggable and the
+ * chip can dissapear at any moment (unlike reference-counted struct
+ * gpio_device).
+ *
+ * Use at your own risk.
+ */
+struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev)
+{
+	return gdev->chip;
+}
+EXPORT_SYMBOL_GPL(gpio_device_get_chip);
+
 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
 static int gpiochip_find_base(int ngpio)
 {
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 5c0f2ccfd51b..a583e539263e 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -770,6 +770,8 @@ struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum);
 struct gpio_desc *
 gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum);
 
+struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev);
+
 #ifdef CONFIG_GPIOLIB
 
 /* lock/unlock as IRQ */
-- 
2.39.2