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    Subject[PATCH 09/12] irqdomain: Reserve IRQs for legacy domain
    It is really important to make sure irqs used by the legacy domain are
    still reserved in the irq_desc subsystem so they don't get allocated
    for some other purpose. Without SPARSE_IRQ, this generally isn't a
    problem because it is assumed that all irqs have static assignments
    (which isn't actually true, and is part of the reason why SPARSE_IRQ
    should really be turned on these days). However, when SPARSE_IRQs is
    turned on, the irq range passed to irq_domain_add_legacy() is not
    guaranteed to be reserved.

    This patch fixes the problem by unconditionally reserving any irqs
    passed into irq_domain_add_legacy(). The irqs may have already been
    reserved, so the return code on irq_reserve_irqs() may report a
    failure, but it should still be safe.

    Signed-off-by: Grant Likely <>
    kernel/irq/irqdomain.c | 7 +++++++
    1 file changed, 7 insertions(+)

    diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
    index d6d0de0..c0a00de 100644
    --- a/kernel/irq/irqdomain.c
    +++ b/kernel/irq/irqdomain.c
    @@ -151,6 +151,13 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
    if (!domain)
    return NULL;

    + /*
    + * Do our best to reserve the irq descs; but this overlaps with the nr_irqs setting
    + * from the platform code
    + */
    + if (irq_reserve_irqs(first_irq, size))
    + pr_info("IRQs %i..%i already reserved, overlapping with nr_irqs?\n",
    + first_irq, first_irq + size - 1);
    WARN_ON(irq_domain_associate_many(domain, first_irq, first_hwirq, size));

    return domain;

     \ /
      Last update: 2012-06-16 07:41    [W:0.024 / U:39.360 seconds]
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