From aded190312379b6752ba748153d87ffd9f1d970b Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Mon, 25 Apr 2022 11:07:54 +0200 Subject: [PATCH] Revert "Revert "gpio: Restrict usage of GPIO chip irq members before initialization"" This reverts commit 34c16f1a20733de8aff7657cdf29a04266993ccd. It is no longer needed as we are able to update the abi at this point in time. Signed-off-by: Greg Kroah-Hartman Change-Id: I2654f99101dc95994cb5cc3328f288401dfe389f --- drivers/gpio/gpiolib.c | 19 +++++++++++++++++++ include/linux/gpio/driver.h | 9 +++++++++ 2 files changed, 28 insertions(+) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 358f0ad9d0f8..91628edad2c6 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1368,6 +1368,16 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset) { struct irq_domain *domain = gc->irq.domain; +#ifdef CONFIG_GPIOLIB_IRQCHIP + /* + * Avoid race condition with other code, which tries to lookup + * an IRQ before the irqchip has been properly registered, + * i.e. while gpiochip is still being brought up. + */ + if (!gc->irq.initialized) + return -EPROBE_DEFER; +#endif + if (!gpiochip_irqchip_irq_valid(gc, offset)) return -ENXIO; @@ -1552,6 +1562,15 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc, acpi_gpiochip_request_interrupts(gc); + /* + * Using barrier() here to prevent compiler from reordering + * gc->irq.initialized before initialization of above + * GPIO chip irq members. + */ + barrier(); + + gc->irq.initialized = true; + return 0; } diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index a0f9901dcae6..e3c29d2e6826 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -224,6 +224,15 @@ struct gpio_irq_chip { unsigned long *valid_mask, unsigned int ngpios); + /** + * @initialized: + * + * Flag to track GPIO chip irq member's initialization. + * This flag will make sure GPIO chip irq members are not used + * before they are initialized. + */ + bool initialized; + /** * @valid_mask: *