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Subject[PATCH] irq/irq_sim: add locking
Date
Two threads can try to fire the irq_sim with different offsets and will
end up fighting for the irq_work asignment. To fix it: add a mutex and
lock it before firing.

Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
include/linux/irq_sim.h | 1 +
kernel/irq/irq_sim.c | 5 +++++
2 files changed, 6 insertions(+)

diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
index 630a57e55db6..676bfa0c12b9 100644
--- a/include/linux/irq_sim.h
+++ b/include/linux/irq_sim.h
@@ -29,6 +29,7 @@ struct irq_sim {
int irq_base;
unsigned int irq_count;
struct irq_sim_irq_ctx *irqs;
+ struct mutex lock;
};

int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs);
diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
index dd20d0d528d4..2f06c24b51a0 100644
--- a/kernel/irq/irq_sim.c
+++ b/kernel/irq/irq_sim.c
@@ -74,6 +74,7 @@ int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs)
}

init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq);
+ mutex_init(&sim->lock);
sim->irq_count = num_irqs;

return sim->irq_base;
@@ -142,10 +143,14 @@ EXPORT_SYMBOL_GPL(devm_irq_sim_init);
*/
void irq_sim_fire(struct irq_sim *sim, unsigned int offset)
{
+ mutex_lock(&sim->lock);
+
if (sim->irqs[offset].enabled) {
sim->work_ctx.irq = irq_sim_irqnum(sim, offset);
irq_work_queue(&sim->work_ctx.work);
}
+
+ mutex_unlock(&sim->lock);
}
EXPORT_SYMBOL_GPL(irq_sim_fire);

--
2.19.1
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