genirq/irqdomain: Update irq_domain_ops.activate() signature

The irq_domain_ops.activate() callback has no return value and no way to
tell the function that the activation is early.

The upcoming changes to support a reservation scheme which allows to assign
interrupt vectors on x86 only when the interrupt is actually requested
requires:

  - A return value, so activation can fail at request_irq() time
  
  - Information that the activate invocation is early, i.e. before
    request_irq().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213152.848490816@linutronix.de

kernel/irq/irqdomain.c

@@ -1690,7 +1690,7 @@ static void __irq_domain_activate_irq(struct irq_data *irq_data)
 		if (irq_data->parent_data)
 			__irq_domain_activate_irq(irq_data->parent_data);
 		if (domain->ops->activate)
-			domain->ops->activate(domain, irq_data);
+			domain->ops->activate(domain, irq_data, false);
 	}
 }
 

kernel/irq/msi.c

@@ -102,13 +102,14 @@ int msi_domain_set_affinity(struct irq_data *irq_data,
 	return ret;
 }
 
-static void msi_domain_activate(struct irq_domain *domain,
-				struct irq_data *irq_data)
+static int msi_domain_activate(struct irq_domain *domain,
+			       struct irq_data *irq_data, bool early)
 {
 	struct msi_msg msg;
 
 	BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
 	irq_chip_write_msi_msg(irq_data, &msg);
+	return 0;
 }
 
 static void msi_domain_deactivate(struct irq_domain *domain,