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Date: Wed, 9 Dec 2015 18:59:19 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Sinan Kaya <okaya@...eaurora.org>
Cc: "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
Timur Tabi <timur@...eaurora.org>, cov@...eaurora.org,
jcm@...hat.com, helgaas@...nel.org,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V9 1/2] ACPI, PCI, irq: remove interrupt count restriction
On Wed, Dec 9, 2015 at 6:18 PM, Sinan Kaya <okaya@...eaurora.org> wrote:
> Code currently supports 256 maximum interrupts at this moment. The patch is
> reconfiguring the penalty array as a dynamic list to remove this
> limitation.
>
> A new penalty linklist has been added for all other interrupts greater than
> 16. If an IRQ is not found in the link list, an IRQ info structure will be
> dynamically allocated on the first access and will be placed on the list
> for further reuse. The list will grow by the number of supported interrupts
> in the ACPI table rather than having a 256 hard limitation.
>
> Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
> Signed-off-by: Sinan Kaya <okaya@...eaurora.org>
Few nitpicks, though if Bjorn is okay with this one, you may ignore below.
> ---
> drivers/acpi/pci_link.c | 136 ++++++++++++++++++++++++++++++++++++------------
> 1 file changed, 102 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
> index 7c8408b..0286f17 100644
> --- a/drivers/acpi/pci_link.c
> +++ b/drivers/acpi/pci_link.c
> @@ -4,6 +4,7 @@
> * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@...el.com>
> * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@...el.com>
> * Copyright (C) 2002 Dominik Brodowski <devel@...do.de>
> + * Copyright (c) 2015, The Linux Foundation. All rights reserved.
> *
> * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> *
> @@ -437,7 +438,6 @@ static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
> * enabled system.
> */
>
> -#define ACPI_MAX_IRQS 256
> #define ACPI_MAX_ISA_IRQ 16
>
> #define PIRQ_PENALTY_PCI_AVAILABLE (0)
> @@ -447,7 +447,7 @@ static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
> #define PIRQ_PENALTY_ISA_USED (16*16*16*16*16)
> #define PIRQ_PENALTY_ISA_ALWAYS (16*16*16*16*16*16)
>
> -static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
> +static int acpi_irq_isa_penalty[ACPI_MAX_ISA_IRQ] = {
> PIRQ_PENALTY_ISA_ALWAYS, /* IRQ0 timer */
> PIRQ_PENALTY_ISA_ALWAYS, /* IRQ1 keyboard */
> PIRQ_PENALTY_ISA_ALWAYS, /* IRQ2 cascade */
> @@ -464,9 +464,68 @@ static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
> PIRQ_PENALTY_ISA_USED, /* IRQ13 fpe, sometimes */
> PIRQ_PENALTY_ISA_USED, /* IRQ14 ide0 */
> PIRQ_PENALTY_ISA_USED, /* IRQ15 ide1 */
> - /* >IRQ15 */
> };
>
> +struct irq_penalty_info {
> + int irq;
> + int penalty;
> + struct list_head node;
> +};
> +
> +static LIST_HEAD(acpi_irq_penalty_list);
> +
> +static int acpi_irq_get_penalty(int irq)
> +{
> + struct irq_penalty_info *irq_info;
> +
> + if (irq < ACPI_MAX_ISA_IRQ)
> + return acpi_irq_isa_penalty[irq];
> +
> + list_for_each_entry(irq_info, &acpi_irq_penalty_list, node) {
> + if (irq_info->irq == irq)
> + return irq_info->penalty;
> + }
> +
> + return 0;
> +}
> +
> +static int acpi_irq_set_penalty(int irq, int new_penalty)
> +{
> + struct irq_penalty_info *irq_info;
> +
> + /* see if this is a ISA IRQ */
> + if (irq < ACPI_MAX_ISA_IRQ) {
> + acpi_irq_isa_penalty[irq] = new_penalty;
> + return 0;
> + }
> +
> + /* next, try to locate from the dynamic list */
> + list_for_each_entry(irq_info, &acpi_irq_penalty_list, node) {
> + if (irq_info->irq == irq) {
> + irq_info->penalty = new_penalty;
> + return 0;
> + }
> + }
> +
> + /* nope, let's allocate a slot for this IRQ */
> + irq_info = kzalloc(sizeof(*irq_info), GFP_KERNEL);
Maybe a comment to explain why we don't have a symmetric free() option.
> + if (!irq_info)
> + return -ENOMEM;
> +
> + irq_info->irq = irq;
> + irq_info->penalty = new_penalty;
> + list_add_tail(&irq_info->node, &acpi_irq_penalty_list);
> +
> + return 0;
> +}
> +
> +static void acpi_irq_add_penalty(int irq, int penalty)
> +{
> + int curpen = acpi_irq_get_penalty(irq);
> +
> + acpi_irq_set_penalty(irq, curpen + penalty);
Can it be one line?
> +}
> +
> int __init acpi_irq_penalty_init(void)
> {
> struct acpi_pci_link *link;
> @@ -487,15 +546,16 @@ int __init acpi_irq_penalty_init(void)
> link->irq.possible_count;
>
> for (i = 0; i < link->irq.possible_count; i++) {
> - if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
> - acpi_irq_penalty[link->irq.
> - possible[i]] +=
> - penalty;
> + if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ) {
> + int irqpos = link->irq.possible[i];
> +
> + acpi_irq_add_penalty(irqpos, penalty);
> + }
> }
>
> } else if (link->irq.active) {
> - acpi_irq_penalty[link->irq.active] +=
> - PIRQ_PENALTY_PCI_POSSIBLE;
> + acpi_irq_add_penalty(link->irq.active,
> + PIRQ_PENALTY_PCI_POSSIBLE);
> }
> }
>
> @@ -547,12 +607,12 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
> * the use of IRQs 9, 10, 11, and >15.
> */
> for (i = (link->irq.possible_count - 1); i >= 0; i--) {
> - if (acpi_irq_penalty[irq] >
> - acpi_irq_penalty[link->irq.possible[i]])
> + if (acpi_irq_get_penalty(irq) >
> + acpi_irq_get_penalty(link->irq.possible[i]))
> irq = link->irq.possible[i];
> }
> }
> - if (acpi_irq_penalty[irq] >= PIRQ_PENALTY_ISA_ALWAYS) {
> + if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
> printk(KERN_ERR PREFIX "No IRQ available for %s [%s]. "
> "Try pci=noacpi or acpi=off\n",
> acpi_device_name(link->device),
> @@ -568,7 +628,8 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
> acpi_device_bid(link->device));
> return -ENODEV;
> } else {
> - acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
> + acpi_irq_add_penalty(link->irq.active, PIRQ_PENALTY_PCI_USING);
> +
> printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
> acpi_device_name(link->device),
> acpi_device_bid(link->device), link->irq.active);
> @@ -778,7 +839,7 @@ static void acpi_pci_link_remove(struct acpi_device *device)
> }
>
> /*
> - * modify acpi_irq_penalty[] from cmdline
> + * modify penalty from cmdline
> */
> static int __init acpi_irq_penalty_update(char *str, int used)
> {
> @@ -796,13 +857,10 @@ static int __init acpi_irq_penalty_update(char *str, int used)
> if (irq < 0)
> continue;
>
> - if (irq >= ARRAY_SIZE(acpi_irq_penalty))
> - continue;
> -
> if (used)
> - acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
> + acpi_irq_add_penalty(irq, PIRQ_PENALTY_ISA_USED);
> else
> - acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
> + acpi_irq_set_penalty(irq, PIRQ_PENALTY_PCI_AVAILABLE);
>
> if (retval != 2) /* no next number */
> break;
> @@ -819,18 +877,23 @@ static int __init acpi_irq_penalty_update(char *str, int used)
> */
> void acpi_penalize_isa_irq(int irq, int active)
> {
> - if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
> - if (active)
> - acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
> - else
> - acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
> - }
> + int penalty;
> +
> + if (irq < 0)
> + return;
> +
> + if (active)
> + penalty = PIRQ_PENALTY_ISA_USED;
> + else
> + penalty = PIRQ_PENALTY_PCI_USING;
> +
> + acpi_irq_add_penalty(irq, penalty);
Same as below
> }
>
> bool acpi_isa_irq_available(int irq)
> {
> - return irq >= 0 && (irq >= ARRAY_SIZE(acpi_irq_penalty) ||
> - acpi_irq_penalty[irq] < PIRQ_PENALTY_ISA_ALWAYS);
> + return irq >= 0 &&
> + (acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
> }
>
> /*
> @@ -840,13 +903,18 @@ bool acpi_isa_irq_available(int irq)
> */
> void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
> {
> - if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
> - if (trigger != ACPI_MADT_TRIGGER_LEVEL ||
> - polarity != ACPI_MADT_POLARITY_ACTIVE_LOW)
> - acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_ALWAYS;
> - else
> - acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
> - }
> + int penalty;
> +
> + if (irq < 0)
> + return;
> +
> + if (trigger != ACPI_MADT_TRIGGER_LEVEL ||
> + polarity != ACPI_MADT_POLARITY_ACTIVE_LOW)
> + penalty = PIRQ_PENALTY_ISA_ALWAYS;
> + else
> + penalty = PIRQ_PENALTY_PCI_USING;
> +
> + acpi_irq_add_penalty(irq, penalty);
Why not to change in place? I think a common sense rule is not to
change something existing if it doesn't add any significant value.
- acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
+ acpi_irq_add_penalty(irq, PIRQ_PENALTY_PCI_USING);
> }
--
With Best Regards,
Andy Shevchenko
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