The following commit has been merged into the irq/core branch of tip: Commit-ID: cbe16f35bee6880becca6f20d2ebf6b457148552 Gitweb: https://git.kernel.org/tip/cbe16f35bee6880becca6f20d2ebf6b457148552 Author: Barry Song <song.bao....@hisilicon.com> AuthorDate: Wed, 03 Mar 2021 11:49:15 +13:00 Committer: Ingo Molnar <mi...@kernel.org> CommitterDate: Sat, 06 Mar 2021 12:48:00 +01:00
genirq: Add IRQF_NO_AUTOEN for request_irq/nmi() Many drivers don't want interrupts enabled automatically via request_irq(). So they are handling this issue by either way of the below two: (1) irq_set_status_flags(irq, IRQ_NOAUTOEN); request_irq(dev, irq...); (2) request_irq(dev, irq...); disable_irq(irq); The code in the second way is silly and unsafe. In the small time gap between request_irq() and disable_irq(), interrupts can still come. The code in the first way is safe though it's subobtimal. Add a new IRQF_NO_AUTOEN flag which can be handed in by drivers to request_irq() and request_nmi(). It prevents the automatic enabling of the requested interrupt/nmi in the same safe way as #1 above. With that the various usage sites of #1 and #2 above can be simplified and corrected. Signed-off-by: Barry Song <song.bao....@hisilicon.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Signed-off-by: Ingo Molnar <mi...@kernel.org> Cc: dmitry.torok...@gmail.com Link: https://lore.kernel.org/r/20210302224916.13980-2-song.bao....@hisilicon.com --- include/linux/interrupt.h | 4 ++++ kernel/irq/manage.c | 11 +++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 967e257..76f1161 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -61,6 +61,9 @@ * interrupt handler after suspending interrupts. For system * wakeup devices users need to implement wakeup detection in * their interrupt handlers. + * IRQF_NO_AUTOEN - Don't enable IRQ or NMI automatically when users request it. + * Users will enable it explicitly by enable_irq() or enable_nmi() + * later. */ #define IRQF_SHARED 0x00000080 #define IRQF_PROBE_SHARED 0x00000100 @@ -74,6 +77,7 @@ #define IRQF_NO_THREAD 0x00010000 #define IRQF_EARLY_RESUME 0x00020000 #define IRQF_COND_SUSPEND 0x00040000 +#define IRQF_NO_AUTOEN 0x00080000 #define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index dec3f73..97c231a 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1693,7 +1693,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) irqd_set(&desc->irq_data, IRQD_NO_BALANCING); } - if (irq_settings_can_autoenable(desc)) { + if (!(new->flags & IRQF_NO_AUTOEN) && + irq_settings_can_autoenable(desc)) { irq_startup(desc, IRQ_RESEND, IRQ_START_COND); } else { /* @@ -2086,10 +2087,15 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler, * which interrupt is which (messes up the interrupt freeing * logic etc). * + * Also shared interrupts do not go well with disabling auto enable. + * The sharing interrupt might request it while it's still disabled + * and then wait for interrupts forever. + * * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and * it cannot be set along with IRQF_NO_SUSPEND. */ if (((irqflags & IRQF_SHARED) && !dev_id) || + ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) || (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) || ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND))) return -EINVAL; @@ -2245,7 +2251,8 @@ int request_nmi(unsigned int irq, irq_handler_t handler, desc = irq_to_desc(irq); - if (!desc || irq_settings_can_autoenable(desc) || + if (!desc || (irq_settings_can_autoenable(desc) && + !(irqflags & IRQF_NO_AUTOEN)) || !irq_settings_can_request(desc) || WARN_ON(irq_settings_is_per_cpu_devid(desc)) || !irq_supports_nmi(desc))
