Commit 06459901 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Marc Zyngier
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irq/irq_sim: Store multiple interrupt offsets in a bitmap 



Two threads can try to fire the irq_sim with different offsets and will
end up fighting for the irq_work asignment. Thomas Gleixner suggested a
solution based on a bitfield where we set a bit for every offset
associated with an interrupt that should be fired and then iterate over
all set bits in the interrupt handler.

This is a slightly modified solution using a bitmap so that we don't
impose a limit on the number of interrupts one can allocate with
irq_sim.

Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 81b1e6e6

include/linux/irq_sim.h

+1 −1
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 


struct irq_sim_work_ctx {

	struct irq_work		work;

	int			irq;

	unsigned long		*pending;

};



struct irq_sim_irq_ctx {

kernel/irq/irq_sim.c

+21 −2
Original line number Diff line number Diff line
@@ -34,9 +34,20 @@ static struct irq_chip irq_sim_irqchip = { 
static void irq_sim_handle_irq(struct irq_work *work)

{

	struct irq_sim_work_ctx *work_ctx;

	unsigned int offset = 0;

	struct irq_sim *sim;

	int irqnum;



	work_ctx = container_of(work, struct irq_sim_work_ctx, work);

	handle_simple_irq(irq_to_desc(work_ctx->irq));

	sim = container_of(work_ctx, struct irq_sim, work_ctx);



	while (!bitmap_empty(work_ctx->pending, sim->irq_count)) {

		offset = find_next_bit(work_ctx->pending,

				       sim->irq_count, offset);

		clear_bit(offset, work_ctx->pending);

		irqnum = irq_sim_irqnum(sim, offset);

		handle_simple_irq(irq_to_desc(irqnum));

	}

}



/**
@@ -63,6 +74,13 @@ int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs) 
		return sim->irq_base;

	}



	sim->work_ctx.pending = bitmap_zalloc(num_irqs, GFP_KERNEL);

	if (!sim->work_ctx.pending) {

		kfree(sim->irqs);

		irq_free_descs(sim->irq_base, num_irqs);

		return -ENOMEM;

	}



	for (i = 0; i < num_irqs; i++) {

		sim->irqs[i].irqnum = sim->irq_base + i;

		sim->irqs[i].enabled = false;
@@ -89,6 +107,7 @@ EXPORT_SYMBOL_GPL(irq_sim_init); 
void irq_sim_fini(struct irq_sim *sim)

{

	irq_work_sync(&sim->work_ctx.work);

	bitmap_free(sim->work_ctx.pending);

	irq_free_descs(sim->irq_base, sim->irq_count);

	kfree(sim->irqs);

}
@@ -143,7 +162,7 @@ EXPORT_SYMBOL_GPL(devm_irq_sim_init); 
void irq_sim_fire(struct irq_sim *sim, unsigned int offset)

{

	if (sim->irqs[offset].enabled) {

		sim->work_ctx.irq = irq_sim_irqnum(sim, offset);

		set_bit(offset, sim->work_ctx.pending);

		irq_work_queue(&sim->work_ctx.work);

	}

}

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