From: Keir Fraser <keir.fraser@citrix.com>
Date: Wed, 21 Nov 2007 09:41:11 +0000 (+0000)
Subject: On pirq enable/disable we fully unregister/reregister with Xen. This
X-Git-Tag: xen-3.2.0~21^2^2~28^2^2~22^2^2~9^2
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=cccf45784472a8f53ad75a8a9b885ef1b6af3fee;p=xenclient%2Fkernel.git

On pirq enable/disable we fully unregister/reregister with Xen. This
causes the underlying IRQ to be properly masked/unmasked, thus
avoiding deadlock scenarios if the IRQ is not EOIed.
Based on a patch by Chris Lalancette <clalance@redhat.com>
Signed-off-by: Keir Fraser <keir.fraser@eu.citrix.com>
---

diff --git a/drivers/xen/core/evtchn.c b/drivers/xen/core/evtchn.c
index 6e83ca2d..1b777c56 100644
--- a/drivers/xen/core/evtchn.c
+++ b/drivers/xen/core/evtchn.c
@@ -782,20 +782,11 @@ static void shutdown_pirq(unsigned int irq)
 
 static void enable_pirq(unsigned int irq)
 {
-	int evtchn = evtchn_from_irq(irq);
-
-	if (VALID_EVTCHN(evtchn)) {
-		unmask_evtchn(evtchn);
-		pirq_unmask_notify(irq_to_pirq(irq));
-	}
+	startup_pirq(irq);
 }
 
 static void disable_pirq(unsigned int irq)
 {
-	int evtchn = evtchn_from_irq(irq);
-
-	if (VALID_EVTCHN(evtchn))
-		mask_evtchn(evtchn);
 }
 
 static void ack_pirq(unsigned int irq)
@@ -814,7 +805,10 @@ static void end_pirq(unsigned int irq)
 {
 	int evtchn = evtchn_from_irq(irq);
 
-	if (VALID_EVTCHN(evtchn) && !(irq_desc[irq].status & IRQ_DISABLED)) {
+	if ((irq_desc[irq].status & (IRQ_DISABLED|IRQ_PENDING)) ==
+	    (IRQ_DISABLED|IRQ_PENDING)) {
+		shutdown_pirq(irq);
+	} else if (VALID_EVTCHN(evtchn)) {
 		unmask_evtchn(evtchn);
 		pirq_unmask_notify(irq_to_pirq(irq));
 	}