genirq: Use hlist for managing resend handlers

The current implementation utilizes a bitmap for managing interrupt resend
handlers, which is allocated based on the SPARSE_IRQ/NR_IRQS macros.
However, this method may not efficiently utilize memory during runtime,
particularly when IRQ_BITMAP_BITS is large.

Address this issue by using an hlist to manage interrupt resend handlers
instead of relying on a static bitmap memory allocation. Additionally, a
new function, clear_irq_resend(), is introduced and called from
irq_shutdown to ensure a graceful teardown of the interrupt.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230519134902.1495562-2-sdonthineni@nvidia.com

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 5fdc0b557579..51fc8c497c22 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -113,6 +113,8 @@ irqreturn_t handle_irq_event(struct irq_desc *desc);
 
 /* Resending of interrupts :*/
 int check_irq_resend(struct irq_desc *desc, bool inject);
+void clear_irq_resend(struct irq_desc *desc);
+void irq_resend_init(struct irq_desc *desc);
 bool irq_wait_for_poll(struct irq_desc *desc);
 void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action);