genirq: Separate activation and startup

Activation of an interrupt and startup are currently a combo
functionlity. That works so far, but upcoming changes require a strict
separation because the activation can fail in future.

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/20170913213152.754334077@linutronix.de

1 files changed, 16 insertions, 1 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 0e8b48315f3c..e667912d0e9c 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -519,7 +519,7 @@ void __enable_irq(struct irq_desc *desc)
                  * time. If it was already started up, then irq_startup()
                  * will invoke irq_enable() under the hood.
                  */
-                irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
+                irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
                 break;
         }
         default:
@@ -1325,6 +1325,21 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                                 goto out_unlock;
                 }
 
+                /*
+                 * Activate the interrupt. That activation must happen
+                 * independently of IRQ_NOAUTOEN. request_irq() can fail
+                 * and the callers are supposed to handle
+                 * that. enable_irq() of an interrupt requested with
+                 * IRQ_NOAUTOEN is not supposed to fail. The activation
+                 * keeps it in shutdown mode, it merily associates
+                 * resources if necessary and if that's not possible it
+                 * fails. Interrupts which are in managed shutdown mode
+                 * will simply ignore that activation request.
+                 */
+                ret = irq_activate(desc);
+                if (ret)
+                        goto out_unlock;
+
                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
                                   IRQS_ONESHOT | IRQS_WAITING);
                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);