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McKenney" , Andy Shevchenko , Wolfram Sang Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v3 04/24] gpio: provide and use gpiod_get_label() Date: Thu, 8 Feb 2024 10:59:00 +0100 Message-Id: <20240208095920.8035-5-brgl@bgdev.pl> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240208095920.8035-1-brgl@bgdev.pl> References: <20240208095920.8035-1-brgl@bgdev.pl> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Bartosz Golaszewski We will soon serialize access to the descriptor label using SRCU. The write-side of the protection will require calling synchronize_srcu() which must not be called from atomic context. We have two irq helpers: gpiochip_lock_as_irq() and gpiochip_unlock_as_irq() that set the label if the GPIO is not requested but is being used as interrupt. They are called with a spinlock held from the interrupt subsystem. They must not do it if we are to use SRCU so instead let's move the special corner case to a dedicated getter. First: let's implement and use the getter where it's applicable. Signed-off-by: Bartosz Golaszewski Reviewed-by: Linus Walleij --- drivers/gpio/gpiolib-cdev.c | 4 ++-- drivers/gpio/gpiolib.c | 9 +++++++-- drivers/gpio/gpiolib.h | 1 + 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 34d6712fa07c..2c0a0700762d 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -2305,8 +2305,8 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, if (desc->name) strscpy(info->name, desc->name, sizeof(info->name)); - if (desc->label) - strscpy(info->consumer, desc->label, + if (gpiod_get_label(desc)) + strscpy(info->consumer, gpiod_get_label(desc), sizeof(info->consumer)); dflags = READ_ONCE(desc->flags); diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 8ca9aebfa81f..8331fdbb6faa 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -105,6 +105,11 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc); static bool gpiolib_initialized; +const char *gpiod_get_label(struct gpio_desc *desc) +{ + return desc->label; +} + static inline void desc_set_label(struct gpio_desc *d, const char *label) { d->label = label; @@ -2391,7 +2396,7 @@ char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset) * * Until this happens, this allocation needs to be atomic. */ - label = kstrdup(desc->label, GFP_ATOMIC); + label = kstrdup(gpiod_get_label(desc), GFP_ATOMIC); if (!label) return ERR_PTR(-ENOMEM); @@ -4732,7 +4737,7 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev) is_irq = test_bit(FLAG_USED_AS_IRQ, &desc->flags); active_low = test_bit(FLAG_ACTIVE_LOW, &desc->flags); seq_printf(s, " gpio-%-3d (%-20.20s|%-20.20s) %s %s %s%s\n", - gpio, desc->name ?: "", desc->label, + gpio, desc->name ?: "", gpiod_get_label(desc), is_out ? "out" : "in ", value >= 0 ? (value ? "hi" : "lo") : "? ", is_irq ? "IRQ " : "", diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index c3ae5bfa3f2e..1058f326fe2b 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -208,6 +208,7 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce); int gpiod_hog(struct gpio_desc *desc, const char *name, unsigned long lflags, enum gpiod_flags dflags); int gpiochip_get_ngpios(struct gpio_chip *gc, struct device *dev); +const char *gpiod_get_label(struct gpio_desc *desc); /* * Return the GPIO number of the passed descriptor relative to its chip