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References: <20221209140150.1453-1-johan+linaro@kernel.org>
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From:   Hsin-Yi Wang <hsinyi@chromium.org>
Date:   Thu, 15 Dec 2022 17:31:24 +0800
Message-ID: <CAJMQK-ht8_dvdCOQXfUMGGa6ZcPJSXf_AjDd0OLi79WF43NYGA@mail.gmail.com>
Subject: Re: [PATCH v3 00/19] irqdomain: fix mapping race and clean up locking
To:     Johan Hovold <johan+linaro@kernel.org>
Cc:     Marc Zyngier <maz@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, x86@kernel.org,
        platform-driver-x86@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Thu, Dec 15, 2022 at 5:22 PM Johan Hovold <johan+linaro@kernel.org> wrote:
>
> Parallel probing (e.g. due to asynchronous probing) of devices that
> share interrupts can currently result in two mappings for the same
> hardware interrupt to be created.
>
> This series fixes this mapping race and clean up the irqdomain locking
> so that in the end the global irq_domain_mutex is only used for managing
> the likewise global irq_domain_list, while domain operations (e.g.
> IRQ allocations) use per-domain (hierarchy) locking.
>
> Johan
>
>
> Changes in v2
>  - split out redundant-lookup cleanup (1/4)
>  - use a per-domain mutex to address mapping race (2/4)
>  - move kernel-doc to exported function (2/4)
>  - fix association race (3/4, new)
>  - use per-domain mutex for associations (4/4, new)
>
> Changes in v3
>  - drop dead and bogus code (1--3/19, new)
>  - fix racy mapcount accesses (5/19, new)
>  - drop revmap mutex (6/19, new)
>  - use irq_domain_mutex to address mapping race (9/19)
>  - clean up irq_domain_push/pop_irq() (10/19, new)
>  - use irq_domain_create_hierarchy() to construct hierarchies
>    (11--18/19, new)
>  - switch to per-domain locking (19/19, new)
>
>
> Johan Hovold (19):
>   irqdomain: Drop bogus fwspec-mapping error handling
>   irqdomain: Drop dead domain-name assignment
>   irqdomain: Drop leftover brackets
>   irqdomain: Fix association race
>   irqdomain: Fix disassociation race
>   irqdomain: Drop revmap mutex
>   irqdomain: Look for existing mapping only once
>   irqdomain: Refactor __irq_domain_alloc_irqs()
>   irqdomain: Fix mapping-creation race
>   irqdomain: Clean up irq_domain_push/pop_irq()
>   x86/ioapic: Use irq_domain_create_hierarchy()
>   x86/apic: Use irq_domain_create_hierarchy()
>   irqchip/alpine-msi: Use irq_domain_add_hierarchy()
>   irqchip/gic-v2m: Use irq_domain_create_hierarchy()
>   irqchip/gic-v3-its: Use irq_domain_create_hierarchy()
>   irqchip/gic-v3-mbi: Use irq_domain_create_hierarchy()
>   irqchip/loongson-pch-msi: Use irq_domain_create_hierarchy()
>   irqchip/mvebu-odmi: Use irq_domain_create_hierarchy()
>   irqdomain: Switch to per-domain locking
>
>  arch/x86/kernel/apic/io_apic.c         |   8 +-
>  arch/x86/platform/uv/uv_irq.c          |   7 +-
>  drivers/irqchip/irq-alpine-msi.c       |   8 +-
>  drivers/irqchip/irq-gic-v2m.c          |   5 +-
>  drivers/irqchip/irq-gic-v3-its.c       |  13 +-
>  drivers/irqchip/irq-gic-v3-mbi.c       |   5 +-
>  drivers/irqchip/irq-loongson-pch-msi.c |   9 +-
>  drivers/irqchip/irq-mvebu-odmi.c       |  13 +-
>  include/linux/irqdomain.h              |   6 +-
>  kernel/irq/irqdomain.c                 | 328 ++++++++++++++-----------
>  10 files changed, 220 insertions(+), 182 deletions(-)
>
> --

Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>

The series solves a race issue when having non-populated 2nd source
components that share the same irq on ARM devices:
Previously we would see
[    0.476357] irq: type mismatch, failed to map hwirq-11 for pinctrl@10005000!
and the component failed to probe.


> 2.37.4
>