[RFC PATCH 06/10] genirq: Don't mask IRQ within flow handler if IRQ is flow-masked
From: Valentin Schneider <hidden>
Date: 2021-04-08 15:44:18
Also in:
lkml
Subsystem:
irq subsystem, the rest · Maintainers:
Thomas Gleixner, Linus Torvalds
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 <redacted> --- kernel/irq/chip.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 6c033b0044cb..1add0b4f0662 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c@@ -909,10 +909,9 @@ 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 +921,21 @@ 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 & IRQCHIP_AUTOMASKS_FLOW) || + !(chip->flags & IRQCHIP_EOI_THREADED))) + mask_ack_irq(desc); + else + ack_irq(desc); handle_irq_event(desc);
@@ -933,7 +943,8 @@ 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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