From a0a8bcf4670c2c696e6e83742539a5e0dd7a62d6 Mon Sep 17 00:00:00 2001 From: Grygorii Strashko Date: Mon, 17 Aug 2015 15:35:23 +0300 Subject: gpiolib: irqchip: use different lockdep class for each gpio irqchip Since IRQ chip helpers were introduced drivers lose ability to register separate lockdep classes for each registered GPIO IRQ chip and the gpiolib now is using shared lockdep class for all GPIO IRQ chips (gpiochip_irq_lock_class). As result, lockdep will produce warning when there are min two stacked GPIO chips and all of them are interrupt controllers. HW configuration which generates lockdep warning (TI dra7-evm): [SOC GPIO bankA.gpioX] <- irq - [pcf875x.gpioY] <- irq - DevZ.enable_irq_wake(pcf_gpioY_irq); The issue was reported in [1] and discussed [2]. ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc6-00013-g5d050ed-dirty #55 Not tainted --------------------------------------------- sh/63 is trying to acquire lock: (class){......}, at: [] __irq_get_desc_lock+0x50/0x94 but task is already holding lock: (class){......}, at: [] __irq_get_desc_lock+0x50/0x94 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(class); lock(class); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by sh/63: #0: (sb_writers#4){.+.+.+}, at: [] vfs_write+0x13c/0x164 #1: (&of->mutex){+.+.+.}, at: [] kernfs_fop_write+0x4c/0x1a0 #2: (s_active#36){.+.+.+}, at: [] kernfs_fop_write+0x54/0x1a0 #3: (pm_mutex){+.+.+.}, at: [] pm_suspend+0xec/0x4c4 #4: (&dev->mutex){......}, at: [] __device_suspend+0xd4/0x398 #5: (&gpio->lock){+.+.+.}, at: [] __irq_get_desc_lock+0x74/0x94 #6: (class){......}, at: [] __irq_get_desc_lock+0x50/0x94 stack backtrace: CPU: 0 PID: 63 Comm: sh Not tainted 4.2.0-rc6-00013-g5d050ed-dirty #55 Hardware name: Generic DRA74X (Flattened Device Tree) [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0x84/0x9c) [] (dump_stack) from [] (__lock_acquire+0x19c0/0x1e20) [] (__lock_acquire) from [] (lock_acquire+0xa8/0x128) [] (lock_acquire) from [] (_raw_spin_lock_irqsave+0x38/0x4c) [] (_raw_spin_lock_irqsave) from [] (__irq_get_desc_lock+0x50/0x94) [] (__irq_get_desc_lock) from [] (irq_set_irq_wake+0x20/0xfc) [] (irq_set_irq_wake) from [] (pcf857x_irq_set_wake+0x24/0x54) [] (pcf857x_irq_set_wake) from [] (irq_set_irq_wake+0x8c/0xfc) [] (irq_set_irq_wake) from [] (gpio_keys_suspend+0x70/0xd4) [] (gpio_keys_suspend) from [] (dpm_run_callback+0x50/0x124) [] (dpm_run_callback) from [] (__device_suspend+0x10c/0x398) [] (__device_suspend) from [] (dpm_suspend+0x134/0x2f4) [] (dpm_suspend) from [] (suspend_devices_and_enter+0xa8/0x728) [] (suspend_devices_and_enter) from [] (pm_suspend+0x32c/0x4c4) [] (pm_suspend) from [] (state_store+0x64/0xb8) [] (state_store) from [] (kernfs_fop_write+0xbc/0x1a0) [] (kernfs_fop_write) from [] (__vfs_write+0x20/0xd8) [] (__vfs_write) from [] (vfs_write+0x90/0x164) [] (vfs_write) from [] (SyS_write+0x44/0x9c) [] (SyS_write) from [] (ret_fast_syscall+0x0/0x54) Lets fix it by using separate lockdep class for each registered GPIO IRQ Chip. This is done by wrapping gpiochip_irqchip_add call into macros. The implementation of this patch inspired by solution done by Nicolas Boichat for regmap [3] [1] http://www.spinics.net/lists/linux-gpio/msg05844.html [2] http://www.spinics.net/lists/linux-gpio/msg06021.html [3] http://www.spinics.net/lists/arm-kernel/msg429834.html Cc: Geert Uytterhoeven Cc: Roger Quadros Reported-by: Roger Quadros Tested-by: Roger Quadros Signed-off-by: Grygorii Strashko Signed-off-by: Linus Walleij --- include/linux/gpio/driver.h | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) (limited to 'include/linux/gpio') diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index c8393cd4d44f..0c7004dab437 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -6,6 +6,7 @@ #include #include #include +#include #include struct device; @@ -126,6 +127,7 @@ struct gpio_chip { irq_flow_handler_t irq_handler; unsigned int irq_default_type; int irq_parent; + struct lock_class_key *lock_key; #endif #if defined(CONFIG_OF_GPIO) @@ -171,11 +173,25 @@ void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip, int parent_irq, irq_flow_handler_t parent_handler); -int gpiochip_irqchip_add(struct gpio_chip *gpiochip, - struct irq_chip *irqchip, - unsigned int first_irq, - irq_flow_handler_t handler, - unsigned int type); +int _gpiochip_irqchip_add(struct gpio_chip *gpiochip, + struct irq_chip *irqchip, + unsigned int first_irq, + irq_flow_handler_t handler, + unsigned int type, + struct lock_class_key *lock_key); + +#ifdef CONFIG_LOCKDEP +#define gpiochip_irqchip_add(...) \ +( \ + ({ \ + static struct lock_class_key _key; \ + _gpiochip_irqchip_add(__VA_ARGS__, &_key); \ + }) \ +) +#else +#define gpiochip_irqchip_add(...) \ + _gpiochip_irqchip_add(__VA_ARGS__, NULL) +#endif #endif /* CONFIG_GPIOLIB_IRQCHIP */ -- cgit v1.2.3