[PATCH v4 00/19] irqdomain: fix mapping race and clean up locking

Johan Hovold
2023-01-16T13:51:02Z

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 v4
- add a comment to __irq_domain_add() as further documentation of the
domain lock and root pointer (19/19)
- add a comment documenting that the lockdep assertion in
irq_domain_set_mapping() also verifies that the domains in a
hierarchy point to the same root (19/19)

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)

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)

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 | 341 ++++++++++++++-----------
10 files changed, 233 insertions(+), 182 deletions(-)

--
2.38.2