From 06459901d55ee2f690b8e1fe084fb03061d617cf Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Fri, 9 Nov 2018 18:21:32 +0100 Subject: 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: Thomas Gleixner Signed-off-by: Bartosz Golaszewski Signed-off-by: Marc Zyngier --- kernel/irq/irq_sim.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) (limited to 'kernel/irq') diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c index dd20d0d528d4..98a20e1594ce 100644 --- a/kernel/irq/irq_sim.c +++ b/kernel/irq/irq_sim.c @@ -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); } } -- cgit