Messages in this thread | | | Subject | Re: [Linuxarm] Re: [PATCH for next v1 1/2] gpio: omap: Replace raw_spin_lock_irqsave with raw_spin_lock in omap_gpio_irq_handler() | From | Grygorii Strashko <> | Date | Fri, 12 Feb 2021 12:27:47 +0200 |
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Hi Arnd,
On 12/02/2021 11:45, Arnd Bergmann wrote: > On Fri, Feb 12, 2021 at 6:05 AM Song Bao Hua (Barry Song) > <song.bao.hua@hisilicon.com> wrote: >>> -----Original Message----- > >>> >>> Note. there is also generic_handle_irq() call inside. >> >> So generic_handle_irq() is not safe to run in thread thus requires >> an interrupt-disabled environment to run? If so, I'd rather this >> irqsave moved into generic_handle_irq() rather than asking everyone >> calling it to do irqsave. > > In a preempt-rt kernel, interrupts are run in task context, so they clearly > should not be called with interrupts disabled, that would defeat the > purpose of making them preemptible. > > generic_handle_irq() does need to run with in_irq()==true though, > but this should be set by the caller of the gpiochip's handler, and > it is not set by raw_spin_lock_irqsave().
It will produce warning from __handle_irq_event_percpu(), as this is IRQ dispatcher and generic_handle_irq() will call one of handle_level_irq or handle_edge_irq.
The history behind this is commit 450fa54cfd66 ("gpio: omap: convert to use generic irq handler").
The resent related discussion: https://lkml.org/lkml/2020/12/5/208
-- Best regards, grygorii
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