genirq/irqdomain: Add force reactivation flag to irq domains

Allow irqdomains to tell the core code, that after early activation the
interrupt needs to be reactivated at request_irq() time.

This allows reservation of vectors at early activation time and actual
vector assignment at request_irq() time.

Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Juergen Gross <[email protected]>
Tested-by: Yu Chen <[email protected]>
Acked-by: Juergen Gross <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Alok Kataria <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Rui Zhang <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Len Brown <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: KAGA-KOKO

include/linux/msi.h

@@ -283,6 +283,11 @@ enum {
 	MSI_FLAG_PCI_MSIX		= (1 << 3),
 	/* Needs early activate, required for PCI */
 	MSI_FLAG_ACTIVATE_EARLY		= (1 << 4),
+	/*
+	 * Must reactivate when irq is started even when
+	 * MSI_FLAG_ACTIVATE_EARLY has been set.
+	 */
+	MSI_FLAG_MUST_REACTIVATE	= (1 << 5),
 };
 
 int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,

kernel/irq/msi.c

@@ -404,6 +404,8 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 			ret = irq_domain_activate_irq(irq_data, true);
 			if (ret)
 				goto cleanup;
+			if (info->flags & MSI_FLAG_MUST_REACTIVATE)
+				irqd_clr_activated(irq_data);
 		}
 	}
 	return 0;