From: Bartosz Golaszewski <brgl@bgdev.pl>
To: "Thomas Gleixner" <tglx@linutronix.de>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Marc Zyngier" <marc.zyngier@arm.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] irq/irq_sim: store multiple interrupt offsets in a bitmap
Date: Tue, 11 Dec 2018 15:02:48 +0100 [thread overview]
Message-ID: <CAMRc=MeY_CbdQDF7UOai5MW3OLF1u+a04AAyq5bsux8_Fv5DVQ@mail.gmail.com> (raw)
In-Reply-To: <20181109172132.30939-1-brgl@bgdev.pl>
pt., 9 lis 2018 o 18:21 Bartosz Golaszewski <brgl@bgdev.pl> napisał(a):
>
> 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 <tglx@linutronix.de>
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---
> include/linux/irq_sim.h | 2 +-
> kernel/irq/irq_sim.c | 23 +++++++++++++++++++++--
> 2 files changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
> index 630a57e55db6..4500d453a63e 100644
> --- a/include/linux/irq_sim.h
> +++ b/include/linux/irq_sim.h
> @@ -16,7 +16,7 @@
>
> struct irq_sim_work_ctx {
> struct irq_work work;
> - int irq;
> + unsigned long *pending;
> };
>
> struct irq_sim_irq_ctx {
> 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);
> }
> }
> --
> 2.19.1
>
Ping and Cc'ing Marc Zyngier. Any chance of getting this in for 4.21?
Bart
next prev parent reply other threads:[~2018-12-11 14:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-09 17:21 [PATCH] irq/irq_sim: store multiple interrupt offsets in a bitmap Bartosz Golaszewski
2018-12-11 14:02 ` Bartosz Golaszewski [this message]
2018-12-11 14:41 ` Marc Zyngier
2018-12-11 15:39 ` Bartosz Golaszewski
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