Re: [PATCH 1/2] irq/irq_sim: make the irq_sim structure opaque
From: Jonathan Cameron
Date: Sun Aug 18 2019 - 15:38:44 EST
On Mon, 12 Aug 2019 14:52:55 +0200
Bartosz Golaszewski <brgl@xxxxxxxx> wrote:
> From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
>
> There's no good reason to export the interrupt simulator structure to
> users and have them provide memory for it. Let's make all the related
> data structures opaque and convert both users. This way we have a lot
> less APIs exposed in the header.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
I agree in principle, but there is the disadvantage that all drivers
that use it now need to bother with another allocation. I guess
it is still worthwhile though.
One comment inline.
Jonathan
> ---
> drivers/gpio/gpio-mockup.c | 12 ++---
> drivers/iio/dummy/iio_dummy_evgen.c | 18 +++----
> include/linux/irq_sim.h | 24 ++-------
> kernel/irq/irq_sim.c | 83 ++++++++++++++++++-----------
> 4 files changed, 70 insertions(+), 67 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
> index f1a9c0544e3f..9b28ffec5826 100644
> --- a/drivers/gpio/gpio-mockup.c
> +++ b/drivers/gpio/gpio-mockup.c
> @@ -53,7 +53,7 @@ struct gpio_mockup_line_status {
> struct gpio_mockup_chip {
> struct gpio_chip gc;
> struct gpio_mockup_line_status *lines;
> - struct irq_sim irqsim;
> + struct irq_sim *irqsim;
> struct dentry *dbg_dir;
> struct mutex lock;
> };
> @@ -186,7 +186,7 @@ static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
> {
> struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
>
> - return irq_sim_irqnum(&chip->irqsim, offset);
> + return irq_sim_irqnum(chip->irqsim, offset);
> }
>
> static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
> @@ -247,7 +247,7 @@ static ssize_t gpio_mockup_debugfs_write(struct file *file,
> chip = priv->chip;
> gc = &chip->gc;
> desc = &gc->gpiodev->descs[priv->offset];
> - sim = &chip->irqsim;
> + sim = chip->irqsim;
>
> mutex_lock(&chip->lock);
>
> @@ -431,9 +431,9 @@ static int gpio_mockup_probe(struct platform_device *pdev)
> return rv;
> }
>
> - rv = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio);
> - if (rv < 0)
> - return rv;
> + chip->irqsim = devm_irq_sim_new(dev, gc->ngpio);
> + if (IS_ERR(chip->irqsim))
> + return PTR_ERR(chip->irqsim);
>
> rv = devm_gpiochip_add_data(dev, &chip->gc, chip);
> if (rv)
> diff --git a/drivers/iio/dummy/iio_dummy_evgen.c b/drivers/iio/dummy/iio_dummy_evgen.c
> index a6edf30567aa..efbcd4a5609e 100644
> --- a/drivers/iio/dummy/iio_dummy_evgen.c
> +++ b/drivers/iio/dummy/iio_dummy_evgen.c
> @@ -37,7 +37,7 @@ struct iio_dummy_eventgen {
> struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
> struct mutex lock;
> bool inuse[IIO_EVENTGEN_NO];
> - struct irq_sim irq_sim;
> + struct irq_sim *irq_sim;
> int base;
> };
>
> @@ -46,19 +46,17 @@ static struct iio_dummy_eventgen *iio_evgen;
>
> static int iio_dummy_evgen_create(void)
> {
> - int ret;
> -
> iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
> if (!iio_evgen)
> return -ENOMEM;
>
> - ret = irq_sim_init(&iio_evgen->irq_sim, IIO_EVENTGEN_NO);
> - if (ret < 0) {
> + iio_evgen->irq_sim = irq_sim_new(IIO_EVENTGEN_NO);
> + if (IS_ERR(iio_evgen->irq_sim)) {
> kfree(iio_evgen);
> - return ret;
> + return PTR_ERR(iio_evgen->irq_sim);
> }
>
> - iio_evgen->base = irq_sim_irqnum(&iio_evgen->irq_sim, 0);
> + iio_evgen->base = irq_sim_irqnum(iio_evgen->irq_sim, 0);
> mutex_init(&iio_evgen->lock);
>
> return 0;
> @@ -80,7 +78,7 @@ int iio_dummy_evgen_get_irq(void)
> mutex_lock(&iio_evgen->lock);
> for (i = 0; i < IIO_EVENTGEN_NO; i++) {
> if (!iio_evgen->inuse[i]) {
> - ret = irq_sim_irqnum(&iio_evgen->irq_sim, i);
> + ret = irq_sim_irqnum(iio_evgen->irq_sim, i);
> iio_evgen->inuse[i] = true;
> break;
> }
> @@ -115,7 +113,7 @@ EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);
>
> static void iio_dummy_evgen_free(void)
> {
> - irq_sim_fini(&iio_evgen->irq_sim);
> + irq_sim_free(iio_evgen->irq_sim);
> kfree(iio_evgen);
> }
>
> @@ -140,7 +138,7 @@ static ssize_t iio_evgen_poke(struct device *dev,
> iio_evgen->regs[this_attr->address].reg_id = this_attr->address;
> iio_evgen->regs[this_attr->address].reg_data = event;
>
> - irq_sim_fire(&iio_evgen->irq_sim, this_attr->address);
> + irq_sim_fire(iio_evgen->irq_sim, this_attr->address);
>
> return len;
> }
> diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
> index 4500d453a63e..4bbf036145e2 100644
> --- a/include/linux/irq_sim.h
> +++ b/include/linux/irq_sim.h
> @@ -14,27 +14,11 @@
> * requested like normal irqs and enqueued from process context.
> */
>
> -struct irq_sim_work_ctx {
> - struct irq_work work;
> - unsigned long *pending;
> -};
> +struct irq_sim;
>
> -struct irq_sim_irq_ctx {
> - int irqnum;
> - bool enabled;
> -};
> -
> -struct irq_sim {
> - struct irq_sim_work_ctx work_ctx;
> - int irq_base;
> - unsigned int irq_count;
> - struct irq_sim_irq_ctx *irqs;
> -};
> -
> -int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs);
> -int devm_irq_sim_init(struct device *dev, struct irq_sim *sim,
> - unsigned int num_irqs);
> -void irq_sim_fini(struct irq_sim *sim);
> +struct irq_sim *irq_sim_new(unsigned int num_irqs);
> +struct irq_sim *devm_irq_sim_new(struct device *dev, unsigned int num_irqs);
> +void irq_sim_free(struct irq_sim *sim);
> void irq_sim_fire(struct irq_sim *sim, unsigned int offset);
> int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset);
>
> diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
> index b992f88c5613..79f0a6494b6c 100644
> --- a/kernel/irq/irq_sim.c
> +++ b/kernel/irq/irq_sim.c
> @@ -7,6 +7,23 @@
> #include <linux/irq_sim.h>
> #include <linux/irq.h>
>
> +struct irq_sim_work_ctx {
> + struct irq_work work;
> + unsigned long *pending;
> +};
> +
> +struct irq_sim_irq_ctx {
> + int irqnum;
> + bool enabled;
> +};
> +
> +struct irq_sim {
> + struct irq_sim_work_ctx work_ctx;
> + int irq_base;
> + unsigned int irq_count;
> + struct irq_sim_irq_ctx *irqs;
> +};
> +
> struct irq_sim_devres {
> struct irq_sim *sim;
> };
> @@ -63,34 +80,42 @@ static void irq_sim_handle_irq(struct irq_work *work)
> }
>
> /**
> - * irq_sim_init - Initialize the interrupt simulator: allocate a range of
> - * dummy interrupts.
> + * irq_sim_new - Create a new interrupt simulator: allocate a range of
> + * dummy interrupts.
> *
> - * @sim: The interrupt simulator object to initialize.
> * @num_irqs: Number of interrupts to allocate
> *
> - * On success: return the base of the allocated interrupt range.
> - * On failure: a negative errno.
> + * On success: return the new irq_sim object.
> + * On failure: a negative errno wrapped with ERR_PTR().
> */
> -int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs)
> +struct irq_sim *irq_sim_new(unsigned int num_irqs)
> {
> + struct irq_sim *sim;
> int i;
>
> + sim = kmalloc(sizeof(*sim), GFP_KERNEL);
> + if (!sim)
> + return ERR_PTR(-ENOMEM);
> +
> sim->irqs = kmalloc_array(num_irqs, sizeof(*sim->irqs), GFP_KERNEL);
> - if (!sim->irqs)
> - return -ENOMEM;
> + if (!sim->irqs) {
> + kfree(sim);
> + return ERR_PTR(-ENOMEM);
> + }
>
> sim->irq_base = irq_alloc_descs(-1, 0, num_irqs, 0);
> if (sim->irq_base < 0) {
> kfree(sim->irqs);
> - return sim->irq_base;
> + kfree(sim);
> + return ERR_PTR(sim->irq_base);
> }
>
> sim->work_ctx.pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
> if (!sim->work_ctx.pending) {
> kfree(sim->irqs);
> + kfree(sim);
This rather looks like a function that could benefit from some
unified error paths. That was true already, but adding another step
makes it an even better idea. Goto fun :)
> irq_free_descs(sim->irq_base, num_irqs);
> - return -ENOMEM;
> + return ERR_PTR(-ENOMEM);
> }
>
> for (i = 0; i < num_irqs; i++) {
> @@ -106,64 +131,60 @@ int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs)
> init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq);
> sim->irq_count = num_irqs;
>
> - return sim->irq_base;
> + return sim;
> }
> -EXPORT_SYMBOL_GPL(irq_sim_init);
> +EXPORT_SYMBOL_GPL(irq_sim_new);
>
> /**
> - * irq_sim_fini - Deinitialize the interrupt simulator: free the interrupt
> + * irq_sim_free - Deinitialize the interrupt simulator: free the interrupt
> * descriptors and allocated memory.
> *
> * @sim: The interrupt simulator to tear down.
> */
> -void irq_sim_fini(struct irq_sim *sim)
> +void irq_sim_free(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);
> + kfree(sim);
> }
> -EXPORT_SYMBOL_GPL(irq_sim_fini);
> +EXPORT_SYMBOL_GPL(irq_sim_free);
>
> static void devm_irq_sim_release(struct device *dev, void *res)
> {
> struct irq_sim_devres *this = res;
>
> - irq_sim_fini(this->sim);
> + irq_sim_free(this->sim);
> }
>
> /**
> - * irq_sim_init - Initialize the interrupt simulator for a managed device.
> + * devm_irq_sim_new - Create a new interrupt simulator for a managed device.
> *
> * @dev: Device to initialize the simulator object for.
> - * @sim: The interrupt simulator object to initialize.
> * @num_irqs: Number of interrupts to allocate
> *
> - * On success: return the base of the allocated interrupt range.
> - * On failure: a negative errno.
> + * On success: return a new irq_sim object.
> + * On failure: a negative errno wrapped with ERR_PTR().
> */
> -int devm_irq_sim_init(struct device *dev, struct irq_sim *sim,
> - unsigned int num_irqs)
> +struct irq_sim *devm_irq_sim_new(struct device *dev, unsigned int num_irqs)
> {
> struct irq_sim_devres *dr;
> - int rv;
>
> dr = devres_alloc(devm_irq_sim_release, sizeof(*dr), GFP_KERNEL);
> if (!dr)
> - return -ENOMEM;
> + return ERR_PTR(-ENOMEM);
>
> - rv = irq_sim_init(sim, num_irqs);
> - if (rv < 0) {
> + dr->sim = irq_sim_new(num_irqs);
> + if (IS_ERR(dr->sim)) {
> devres_free(dr);
> - return rv;
> + return dr->sim;
> }
>
> - dr->sim = sim;
> devres_add(dev, dr);
> -
> - return rv;
> + return dr->sim;
> }
> -EXPORT_SYMBOL_GPL(devm_irq_sim_init);
> +EXPORT_SYMBOL_GPL(devm_irq_sim_new);
>
> /**
> * irq_sim_fire - Enqueue an interrupt.