[PATCH v6 00/20] irqdomain: fix mapping race and rework locking

[Johan Hovold]

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 reworks 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 v6
 - use common exit path in irq_create_fwspec_mapping() (6/20)
 - fix domain registration race (7/20, new)
 - fix x86/uv commit prefix (13/20)
 - use &domain->root->mutex also for non-hierarchichal domains (20/20)
 - fix kernel doc typo (20/20)

Changes in v5
 - reorder patches (since we do care about stable after all)
 - tweak commit messages and add stable tags
 - use '__locked' suffix for new helper functions
 - drop a line break from an argument list (11/19)

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: Fix association race
  irqdomain: Fix disassociation race
  irqdomain: Drop bogus fwspec-mapping error handling
  irqdomain: Look for existing mapping only once
  irqdomain: Refactor __irq_domain_alloc_irqs()
  irqdomain: Fix mapping-creation race
  irqdomain: Drop revmap mutex
  irqdomain: Drop dead domain-name assignment
  irqdomain: Drop leftover brackets
  irqdomain: Clean up irq_domain_push/pop_irq()
  x86/ioapic: Use irq_domain_create_hierarchy()
  x86/uv: 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

Marc Zyngier (1):
  irqdomain: Fix domain registration race

 arch/x86/kernel/apic/io_apic.c         |   7 +-
 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                 | 408 +++++++++++++++----------
 10 files changed, 279 insertions(+), 202 deletions(-)

-- 
2.39.1