| Message ID | 1439477919-24356-1-git-send-email-grygorii.strashko@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 13/08/15 17:58, Grygorii Strashko wrote: > 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: [<c009b91c>] __irq_get_desc_lock+0x50/0x94 > > but task is already holding lock: > (class){......}, at: [<c009b91c>] __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: [<c016bbb8>] vfs_write+0x13c/0x164 > #1: (&of->mutex){+.+.+.}, at: [<c01debf4>] kernfs_fop_write+0x4c/0x1a0 > #2: (s_active#36){.+.+.+}, at: [<c01debfc>] kernfs_fop_write+0x54/0x1a0 > #3: (pm_mutex){+.+.+.}, at: [<c009758c>] pm_suspend+0xec/0x4c4 > #4: (&dev->mutex){......}, at: [<c03f77f8>] __device_suspend+0xd4/0x398 > #5: (&gpio->lock){+.+.+.}, at: [<c009b940>] __irq_get_desc_lock+0x74/0x94 > #6: (class){......}, at: [<c009b91c>] __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) > [<c0016e24>] (unwind_backtrace) from [<c0013338>] (show_stack+0x10/0x14) > [<c0013338>] (show_stack) from [<c05f6b24>] (dump_stack+0x84/0x9c) > [<c05f6b24>] (dump_stack) from [<c00903f4>] (__lock_acquire+0x19c0/0x1e20) > [<c00903f4>] (__lock_acquire) from [<c0091098>] (lock_acquire+0xa8/0x128) > [<c0091098>] (lock_acquire) from [<c05fd61c>] (_raw_spin_lock_irqsave+0x38/0x4c) > [<c05fd61c>] (_raw_spin_lock_irqsave) from [<c009b91c>] (__irq_get_desc_lock+0x50/0x94) > [<c009b91c>] (__irq_get_desc_lock) from [<c009c4f4>] (irq_set_irq_wake+0x20/0xfc) > [<c009c4f4>] (irq_set_irq_wake) from [<c0393ac4>] (pcf857x_irq_set_wake+0x24/0x54) > [<c0393ac4>] (pcf857x_irq_set_wake) from [<c009c560>] (irq_set_irq_wake+0x8c/0xfc) > [<c009c560>] (irq_set_irq_wake) from [<c04a02ac>] (gpio_keys_suspend+0x70/0xd4) > [<c04a02ac>] (gpio_keys_suspend) from [<c03f6a00>] (dpm_run_callback+0x50/0x124) > [<c03f6a00>] (dpm_run_callback) from [<c03f7830>] (__device_suspend+0x10c/0x398) > [<c03f7830>] (__device_suspend) from [<c03f90f0>] (dpm_suspend+0x134/0x2f4) > [<c03f90f0>] (dpm_suspend) from [<c0096e20>] (suspend_devices_and_enter+0xa8/0x728) > [<c0096e20>] (suspend_devices_and_enter) from [<c00977cc>] (pm_suspend+0x32c/0x4c4) > [<c00977cc>] (pm_suspend) from [<c0096060>] (state_store+0x64/0xb8) > [<c0096060>] (state_store) from [<c01dec64>] (kernfs_fop_write+0xbc/0x1a0) > [<c01dec64>] (kernfs_fop_write) from [<c016b280>] (__vfs_write+0x20/0xd8) > [<c016b280>] (__vfs_write) from [<c016bb0c>] (vfs_write+0x90/0x164) > [<c016bb0c>] (vfs_write) from [<c016c330>] (SyS_write+0x44/0x9c) > [<c016c330>] (SyS_write) from [<c000f500>] (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 <geert@linux-m68k.org> > Cc: Roger Quadros <rogerq@ti.com> > Reported-by: Roger Quadros <rogerq@ti.com> > Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Nice !! :) Tested-by: Roger Quadros <rogerq@ti.com> cheers, -roger > --- > drivers/gpio/gpiolib.c | 27 ++++++++++++++------------- > include/linux/gpio/driver.h | 27 ++++++++++++++++++++++----- > 2 files changed, 36 insertions(+), 18 deletions(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index bf4bd1d..75dddc1 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -456,12 +456,6 @@ void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip, > } > EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip); > > -/* > - * This lock class tells lockdep that GPIO irqs are in a different > - * category than their parents, so it won't report false recursion. > - */ > -static struct lock_class_key gpiochip_irq_lock_class; > - > /** > * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip > * @d: the irqdomain used by this irqchip > @@ -478,7 +472,11 @@ static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, > struct gpio_chip *chip = d->host_data; > > irq_set_chip_data(irq, chip); > - irq_set_lockdep_class(irq, &gpiochip_irq_lock_class); > + /* > + * This lock class tells lockdep that GPIO irqs are in a different > + * category than their parents, so it won't report false recursion. > + */ > + irq_set_lockdep_class(irq, chip->lock_key); > irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler); > /* Chips that can sleep need nested thread handlers */ > if (chip->can_sleep && !chip->irq_not_threaded) > @@ -584,6 +582,7 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) > * @handler: the irq handler to use (often a predefined irq core function) > * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE > * to have the core avoid setting up any default type in the hardware. > + * @lock_key: lockdep class > * > * This function closely associates a certain irqchip with a certain > * gpiochip, providing an irq domain to translate the local IRQs to > @@ -599,11 +598,12 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) > * the pins on the gpiochip can generate a unique IRQ. Everything else > * need to be open coded. > */ > -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) > { > struct device_node *of_node; > unsigned int offset; > @@ -629,6 +629,7 @@ int gpiochip_irqchip_add(struct gpio_chip *gpiochip, > gpiochip->irq_handler = handler; > gpiochip->irq_default_type = type; > gpiochip->to_irq = gpiochip_to_irq; > + gpiochip->lock_key = lock_key; > gpiochip->irqdomain = irq_domain_add_simple(of_node, > gpiochip->ngpio, first_irq, > &gpiochip_domain_ops, gpiochip); > @@ -658,7 +659,7 @@ int gpiochip_irqchip_add(struct gpio_chip *gpiochip, > > return 0; > } > -EXPORT_SYMBOL_GPL(gpiochip_irqchip_add); > +EXPORT_SYMBOL_GPL(_gpiochip_irqchip_add); > > #else /* CONFIG_GPIOLIB_IRQCHIP */ > > diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h > index c8393cd..dd1dfbb 100644 > --- a/include/linux/gpio/driver.h > +++ b/include/linux/gpio/driver.h > @@ -6,6 +6,7 @@ > #include <linux/irq.h> > #include <linux/irqchip/chained_irq.h> > #include <linux/irqdomain.h> > +#include <linux/lockdep.h> > #include <linux/pinctrl/pinctrl.h> > > struct device; > @@ -62,6 +63,7 @@ struct seq_file; > * implies that if the chip supports IRQs, these IRQs need to be threaded > * as the chip access may sleep when e.g. reading out the IRQ status > * registers. > + * @exported: flags if the gpiochip is exported for use from sysfs. Private. > * @irq_not_threaded: flag must be set if @can_sleep is set but the > * IRQs don't need to be threaded > * > @@ -126,6 +128,7 @@ 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 +174,25 @@ 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 */ > > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Aug 13, 2015 at 4:58 PM, Grygorii Strashko <grygorii.strashko@ti.com> wrote: > 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): (...) > > Cc: Geert Uytterhoeven <geert@linux-m68k.org> > Cc: Roger Quadros <rogerq@ti.com> > Reported-by: Roger Quadros <rogerq@ti.com> > Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Ah, I see... > * implies that if the chip supports IRQs, these IRQs need to be threaded > * as the chip access may sleep when e.g. reading out the IRQ status > * registers. > + * @exported: flags if the gpiochip is exported for use from sysfs. Private. > * @irq_not_threaded: flag must be set if @can_sleep is set but the > * IRQs don't need to be threaded > * > @@ -126,6 +128,7 @@ struct gpio_chip { > irq_flow_handler_t irq_handler; > unsigned int irq_default_type; > int irq_parent; > + struct lock_class_key *lock_key; There is something weird with the kerneldoc. It is documenting something else but not documenting the new member. Anyway, so here: > +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 Every chip will get their own lock class on the heap. But I think it is a bit kludgy. Is it not possible to have the lock key in struct gpio_chip be a real member instead of a pointer and get a per-chip lock that way? (...) struct lock_class_key lock_key; instead of: struct lock_class_key *lock_key; -> problem solved, without kludgy header defines? Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/14/2015 02:34 PM, Linus Walleij wrote: [...] > Every chip will get their own lock class on the heap. > > But I think it is a bit kludgy. > > Is it not possible to have the lock key in struct gpio_chip > be a real member instead of a pointer and get a per-chip > lock that way? > > (...) > struct lock_class_key lock_key; > > instead of: > > struct lock_class_key *lock_key; > > -> problem solved, without kludgy header defines? Lock keys need to be in persistent memory since they have a unlimited life time. Once registered it is expected to exist until the system is reset. We recently fixed the same issue of nested locks in regmap. For reference the discussion with had a look at different ways to solve this can be found here[1] and the final patch series that went in here[2]. - Lars [1] https://lkml.org/lkml/2015/6/25/144 [2] https://lkml.org/lkml/2015/7/8/43 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/14/2015 03:40 PM, Lars-Peter Clausen wrote: > On 08/14/2015 02:34 PM, Linus Walleij wrote: > [...] >> Every chip will get their own lock class on the heap. >> >> But I think it is a bit kludgy. >> >> Is it not possible to have the lock key in struct gpio_chip >> be a real member instead of a pointer and get a per-chip >> lock that way? >> >> (...) >> struct lock_class_key lock_key; >> >> instead of: >> >> struct lock_class_key *lock_key; >> >> -> problem solved, without kludgy header defines? > > > Lock keys need to be in persistent memory since they have a unlimited life > time. Once registered it is expected to exist until the system is reset. > > We recently fixed the same issue of nested locks in regmap. For reference > the discussion with had a look at different ways to solve this can be found > here[1] and the final patch series that went in here[2]. > > - Lars > > [1] https://lkml.org/lkml/2015/6/25/144 > [2] https://lkml.org/lkml/2015/7/8/43 I've actually followed [2], but without deep digging in Lock keys anatomy :) (as mentioned in commit message)
On Fri, Aug 14, 2015 at 2:40 PM, Lars-Peter Clausen <lars@metafoo.de> wrote: > On 08/14/2015 02:34 PM, Linus Walleij wrote: > [...] >> Every chip will get their own lock class on the heap. >> >> But I think it is a bit kludgy. >> >> Is it not possible to have the lock key in struct gpio_chip >> be a real member instead of a pointer and get a per-chip >> lock that way? >> >> (...) >> struct lock_class_key lock_key; >> >> instead of: >> >> struct lock_class_key *lock_key; >> >> -> problem solved, without kludgy header defines? > > > Lock keys need to be in persistent memory since they have a unlimited life > time. Once registered it is expected to exist until the system is reset. Aha I see. OK if we fix the documentation comment I guess we can go with this, even if it makes the header file somewhat hard to read. I have a bit of problem with it, because lockdep instrumentation is supposed to make development easier, not harder, now it helps in one end with lock validation and screws up in another end by creating API headers that are hopeless to read :( Linus -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/14/2015 03:34 PM, Linus Walleij wrote: > On Thu, Aug 13, 2015 at 4:58 PM, Grygorii Strashko > <grygorii.strashko@ti.com> wrote: > >> 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): > (...) >> >> Cc: Geert Uytterhoeven <geert@linux-m68k.org> >> Cc: Roger Quadros <rogerq@ti.com> >> Reported-by: Roger Quadros <rogerq@ti.com> >> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> > > Ah, I see... > > >> * implies that if the chip supports IRQs, these IRQs need to be threaded >> * as the chip access may sleep when e.g. reading out the IRQ status >> * registers. >> + * @exported: flags if the gpiochip is exported for use from sysfs. Private. >> * @irq_not_threaded: flag must be set if @can_sleep is set but the >> * IRQs don't need to be threaded >> * >> @@ -126,6 +128,7 @@ struct gpio_chip { >> irq_flow_handler_t irq_handler; >> unsigned int irq_default_type; >> int irq_parent; >> + struct lock_class_key *lock_key; > > There is something weird with the kerneldoc. It is documenting something > else but not documenting the new member. > Sorry, for that. There are no kerneldocs for any of GPIO IRQ chip's specific fields, Do you prefer me to add doc for "lock_key" or all of them?
============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc6-00013-g5d050ed-dirty #55 Not tainted --------------------------------------------- sh/63 is trying to acquire lock: (class){......}, at: [<c009b91c>] __irq_get_desc_lock+0x50/0x94 but task is already holding lock: (class){......}, at: [<c009b91c>] __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: [<c016bbb8>] vfs_write+0x13c/0x164 #1: (&of->mutex){+.+.+.}, at: [<c01debf4>] kernfs_fop_write+0x4c/0x1a0 #2: (s_active#36){.+.+.+}, at: [<c01debfc>] kernfs_fop_write+0x54/0x1a0 #3: (pm_mutex){+.+.+.}, at: [<c009758c>] pm_suspend+0xec/0x4c4 #4: (&dev->mutex){......}, at: [<c03f77f8>] __device_suspend+0xd4/0x398 #5: (&gpio->lock){+.+.+.}, at: [<c009b940>] __irq_get_desc_lock+0x74/0x94 #6: (class){......}, at: [<c009b91c>] __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) [<c0016e24>] (unwind_backtrace) from [<c0013338>] (show_stack+0x10/0x14) [<c0013338>] (show_stack) from [<c05f6b24>] (dump_stack+0x84/0x9c) [<c05f6b24>] (dump_stack) from [<c00903f4>] (__lock_acquire+0x19c0/0x1e20) [<c00903f4>] (__lock_acquire) from [<c0091098>] (lock_acquire+0xa8/0x128) [<c0091098>] (lock_acquire) from [<c05fd61c>] (_raw_spin_lock_irqsave+0x38/0x4c) [<c05fd61c>] (_raw_spin_lock_irqsave) from [<c009b91c>] (__irq_get_desc_lock+0x50/0x94) [<c009b91c>] (__irq_get_desc_lock) from [<c009c4f4>] (irq_set_irq_wake+0x20/0xfc) [<c009c4f4>] (irq_set_irq_wake) from [<c0393ac4>] (pcf857x_irq_set_wake+0x24/0x54) [<c0393ac4>] (pcf857x_irq_set_wake) from [<c009c560>] (irq_set_irq_wake+0x8c/0xfc) [<c009c560>] (irq_set_irq_wake) from [<c04a02ac>] (gpio_keys_suspend+0x70/0xd4) [<c04a02ac>] (gpio_keys_suspend) from [<c03f6a00>] (dpm_run_callback+0x50/0x124) [<c03f6a00>] (dpm_run_callback) from [<c03f7830>] (__device_suspend+0x10c/0x398) [<c03f7830>] (__device_suspend) from [<c03f90f0>] (dpm_suspend+0x134/0x2f4) [<c03f90f0>] (dpm_suspend) from [<c0096e20>] (suspend_devices_and_enter+0xa8/0x728) [<c0096e20>] (suspend_devices_and_enter) from [<c00977cc>] (pm_suspend+0x32c/0x4c4) [<c00977cc>] (pm_suspend) from [<c0096060>] (state_store+0x64/0xb8) [<c0096060>] (state_store) from [<c01dec64>] (kernfs_fop_write+0xbc/0x1a0) [<c01dec64>] (kernfs_fop_write) from [<c016b280>] (__vfs_write+0x20/0xd8) [<c016b280>] (__vfs_write) from [<c016bb0c>] (vfs_write+0x90/0x164) [<c016bb0c>] (vfs_write) from [<c016c330>] (SyS_write+0x44/0x9c) [<c016c330>] (SyS_write) from [<c000f500>] (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 <geert@linux-m68k.org> Cc: Roger Quadros <rogerq@ti.com> Reported-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> --- drivers/gpio/gpiolib.c | 27 ++++++++++++++------------- include/linux/gpio/driver.h | 27 ++++++++++++++++++++++----- 2 files changed, 36 insertions(+), 18 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index bf4bd1d..75dddc1 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -456,12 +456,6 @@ void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip, } EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip); -/* - * This lock class tells lockdep that GPIO irqs are in a different - * category than their parents, so it won't report false recursion. - */ -static struct lock_class_key gpiochip_irq_lock_class; - /** * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip * @d: the irqdomain used by this irqchip @@ -478,7 +472,11 @@ static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, struct gpio_chip *chip = d->host_data; irq_set_chip_data(irq, chip); - irq_set_lockdep_class(irq, &gpiochip_irq_lock_class); + /* + * This lock class tells lockdep that GPIO irqs are in a different + * category than their parents, so it won't report false recursion. + */ + irq_set_lockdep_class(irq, chip->lock_key); irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler); /* Chips that can sleep need nested thread handlers */ if (chip->can_sleep && !chip->irq_not_threaded) @@ -584,6 +582,7 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) * @handler: the irq handler to use (often a predefined irq core function) * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE * to have the core avoid setting up any default type in the hardware. + * @lock_key: lockdep class * * This function closely associates a certain irqchip with a certain * gpiochip, providing an irq domain to translate the local IRQs to @@ -599,11 +598,12 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) * the pins on the gpiochip can generate a unique IRQ. Everything else * need to be open coded. */ -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) { struct device_node *of_node; unsigned int offset; @@ -629,6 +629,7 @@ int gpiochip_irqchip_add(struct gpio_chip *gpiochip, gpiochip->irq_handler = handler; gpiochip->irq_default_type = type; gpiochip->to_irq = gpiochip_to_irq; + gpiochip->lock_key = lock_key; gpiochip->irqdomain = irq_domain_add_simple(of_node, gpiochip->ngpio, first_irq, &gpiochip_domain_ops, gpiochip); @@ -658,7 +659,7 @@ int gpiochip_irqchip_add(struct gpio_chip *gpiochip, return 0; } -EXPORT_SYMBOL_GPL(gpiochip_irqchip_add); +EXPORT_SYMBOL_GPL(_gpiochip_irqchip_add); #else /* CONFIG_GPIOLIB_IRQCHIP */ diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index c8393cd..dd1dfbb 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -6,6 +6,7 @@ #include <linux/irq.h> #include <linux/irqchip/chained_irq.h> #include <linux/irqdomain.h> +#include <linux/lockdep.h> #include <linux/pinctrl/pinctrl.h> struct device; @@ -62,6 +63,7 @@ struct seq_file; * implies that if the chip supports IRQs, these IRQs need to be threaded * as the chip access may sleep when e.g. reading out the IRQ status * registers. + * @exported: flags if the gpiochip is exported for use from sysfs. Private. * @irq_not_threaded: flag must be set if @can_sleep is set but the * IRQs don't need to be threaded * @@ -126,6 +128,7 @@ 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 +174,25 @@ 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 */
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].