Messages in this thread Patch in this message | | | From | Valentin Schneider <> | Subject | [RFC PATCH v2 06/10] genirq: Don't mask IRQ within flow handler if IRQ is flow-masked | Date | Tue, 25 May 2021 18:32:51 +0100 |
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mask_irq() lets an IRQ with IRQD_IRQ_FLOW_MASKED set be further masked via chip->irq_mask(). This is necessary for unhandled IRQs as we want to keep them masked beyond eoi_irq() (which clears IRQD_IRQ_FLOW_MASKED).
This is however not necessary in paths that do end up handling the IRQ and are bounded by a final eoi_irq() - this is the case for chips with IRQCHIP_AUTOMASKS_FLOW and IRQCHIP_EOI_THREADED.
Make handle_strict_flow_irq() leverage IRQCHIP_AUTOMASKS_FLOW and issue an ack_irq() rather than a mask_ack_irq() when possible.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> --- kernel/irq/chip.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 699e70b51aae..c2ca6b748987 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -896,6 +896,12 @@ void handle_edge_eoi_irq(struct irq_desc *desc) } #endif +/* + * AUTOMASKS_FLOW tells us ack/eoi handle the masking, EOI_THREADED tells us + * that masking will persist until irq_finalize_oneshot() + */ +#define ONESHOT_AUTOMASK_FLAGS (IRQCHIP_AUTOMASKS_FLOW | IRQCHIP_EOI_THREADED) + /** * handle_strict_flow_irq - irq handler for strict controllers * @desc: the interrupt description structure for this irq @@ -909,10 +915,9 @@ void handle_strict_flow_irq(struct irq_desc *desc) struct irq_chip *chip = desc->irq_data.chip; raw_spin_lock(&desc->lock); - mask_ack_irq(desc); if (!irq_may_run(desc)) - goto out; + goto out_mask; desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING); @@ -922,10 +927,20 @@ void handle_strict_flow_irq(struct irq_desc *desc) */ if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) { desc->istate |= IRQS_PENDING; - goto out; + goto out_mask; } kstat_incr_irqs_this_cpu(desc); + /* + * Masking is required if IRQ is ONESHOT and we can't rely on the + * flow-masking persisting down to irq_finalize_oneshot() + * (in the IRQ thread). + */ + if ((desc->istate & IRQS_ONESHOT) && + ((chip->flags & ONESHOT_AUTOMASK_FLAGS) != ONESHOT_AUTOMASK_FLAGS)) + mask_ack_irq(desc); + else + ack_irq(desc); handle_irq_event(desc); @@ -933,7 +948,8 @@ void handle_strict_flow_irq(struct irq_desc *desc) raw_spin_unlock(&desc->lock); return; -out: +out_mask: + mask_ack_irq(desc); /* * XXX: this is where IRQCHIP_EOI_IF_HANDLED would be checked, but * it's conceptually incompatible with this handler (it breaks the -- 2.25.1
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