crossbar_domain_free(9)

💖 NAME 💖

okay so this is crossbar_domain_free(9), straight from the Kernel API Manual, and it’s literally the “unmap/free a crossbar<->irq connection” girlie. Bestie, this is the cleanup-core function you call when that connection needs to go bye-bye. 💅

✨ SYNOPSIS ✨

void crossbar_domain_free (struct irq_domain *domain , unsigned int virq , unsigned int nr_irqs );

🎀 ARGUMENTS 🎀

• domain — the domain of the irq you’re unmapping, bestie.
• virq — the virq number. iconic lil identifier.
• nr_irqs — the number of irqs to free. yes ma’am, count them.

🦋 DESCRIPTION 🦋

okay so real talk: we do not maintain a use count of the total number of map/unmap calls for a particular irq, so there’s no counter to check and find out if an irq can really be unmapped. not me explaining the whole vibe 😭

Why? Because unmap is called during irq_dispose_mapping(irq), and after that the irq is anyways unusable. So an explicit map has to be called after that. periodt. 🔥

fr fr, this is the “after irq_dispose_mapping(irq) it’s unusable, so map again explicitly” situation. no cap.

🌸 SEE ALSO 🌸

• Kernel file ./drivers/irqchip/irq-crossbar.c
• struct crossbar_device(9)

mwah 💋 this cutie comes from ./drivers/irqchip, dated October 2026. drink water, bestie 🫶