On Tue, Jan 11, 2011 at 05:20:15PM +0000, Ian Campbell wrote:
> This is neater than open-coded calls to irq_alloc_desc_at and
> irq_free_desc.
>
> No intended behavioural change.
>
> Note that we previously were not checking the return value of
> irq_alloc_desc_at which would be failing for GSI<NR_IRQS_LEGACY
> because the core architecture code has already allocated those for
> us. Hence the additional check against NR_IRQS_LEGACY in
> xen_allocate_irq_gsi.
>
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
> ---
> drivers/xen/events.c | 53
> +++++++++++++++++++++++++++++++++-----------------
> 1 files changed, 35 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index ae8d45d..74fb216 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -384,7 +384,7 @@ static int get_nr_hw_irqs(void)
> return ret;
> }
>
> -static int find_unbound_irq(void)
> +static int xen_allocate_irq_dynamic(void)
> {
> struct irq_data *data;
> int irq, res;
> @@ -442,6 +442,30 @@ static bool identity_mapped_irq(unsigned irq)
> return irq < get_nr_hw_irqs();
> }
>
> +static int xen_allocate_irq_gsi(unsigned gsi)
> +{
> + int irq;
> +
> + if (!identity_mapped_irq(gsi) &&
> + (xen_initial_domain() || !xen_pv_domain()))
Perhaps 'xen_hvm_domain()' would sound better? That way there
are less _not_ expressions to think through?
> + return xen_allocate_irq_dynamic();
Ok, so this ends up allocating an IRQ for all non-physical
IRQs, such as the spinlock, call IPI, and so on, correct?
> +
> + /* Legacy IRQ descriptors are already allocated by the arch. */
> + if (gsi < NR_IRQS_LEGACY)
> + return gsi;
> +
> + irq = irq_alloc_desc_at(gsi, -1);
> + if (irq < 0)
> + panic("Unable to allocate to IRQ%d (%d)\n", gsi, irq);
> +
> + return irq;
> +}
> +
> +static void xen_free_irq(unsigned irq)
> +{
> + irq_free_desc(irq);
This is still OK even if the IRQ is < NR_IRQS_LEGACY? You mention
"Legacy IRQ descriptors are already allocated by the arch" so I would
think that the arch would take care of de-allocating those?
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