[PATCH 14/18] x86: Replace setup_irq() by request_irq()

afzal mohammed
2020-02-12T08:05:20Z

request_irq() is preferred over setup_irq(). Existing callers of
setup_irq() reached mostly via 'init_IRQ()' & 'time_init()', while
memory allocators are ready by 'mm_init()'.

Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.

Hence replace setup_irq() by request_irq().

Seldom remove_irq() usage has been observed coupled with setup_irq(),
wherever that has been found, it too has been replaced by free_irq().

[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
---

Since cc'ing cover letter to all maintainers/reviewers would be too
many, refer for cover letter,
https://lkml.kernel.org/r/cover.1581478323.git.afzal.mohd.ma@gmail.com

arch/x86/kernel/irqinit.c | 18 +++++++-----------
arch/x86/kernel/time.c | 10 +++-------
2 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index 16919a9671fa..8147075238bf 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -44,15 +44,6 @@
* (these are usually mapped into the 0x30-0xff vector range)
*/

-/*
- * IRQ2 is cascade interrupt to second interrupt controller
- */
-static struct irqaction irq2 = {
- .handler = no_action,
- .name = "cascade",
- .flags = IRQF_NO_THREAD,
-};
-
DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
[0 ... NR_VECTORS - 1] = VECTOR_UNUSED,
};
@@ -104,6 +95,11 @@ void __init native_init_IRQ(void)
idt_setup_apic_and_irq_gates();
lapic_assign_system_vectors();

- if (!acpi_ioapic && !of_ioapic && nr_legacy_irqs())
- setup_irq(2, &irq2);
+ if (!acpi_ioapic && !of_ioapic && nr_legacy_irqs()) {
+ /*
+ * IRQ2 is cascade interrupt to second interrupt controller
+ */
+ if (request_irq(2, no_action, IRQF_NO_THREAD, "cascade", NULL))
+ pr_err("request_irq() on %s failed\n", "cascade");
+ }
}
diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c
index d8673d8a779b..0f9cb386d71f 100644
--- a/arch/x86/kernel/time.c
+++ b/arch/x86/kernel/time.c
@@ -62,19 +62,15 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}

-static struct irqaction irq0 = {
- .handler = timer_interrupt,
- .flags = IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
- .name = "timer"
-};
-
static void __init setup_default_timer_irq(void)
{
/*
* Unconditionally register the legacy timer; even without legacy
* PIC/PIT we need this for the HPET0 in legacy replacement mode.
*/
- if (setup_irq(0, &irq0))
+ if (request_irq(0, timer_interrupt,
+ IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER, "timer",
+ NULL))
pr_info("Failed to register legacy timer interrupt\n");
}

--
2.24.1