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authorJeremy Fitzhardinge <jeremy@goop.org>2008-08-20 17:02:18 -0700
committerIngo Molnar <mingo@elte.hu>2008-08-21 13:52:57 +0200
commit168d2f464ab9860f0d1e66cf1f9684973222f1c6 (patch)
treec3a4199cf2aa4c6322b7860c431fd5bfdc4220ef /include/xen/events.h
parent7708ad64a24a674f7905aa7a5099a50f055debec (diff)
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xen: save previous spinlock when blocking
A spinlock can be interrupted while spinning, so make sure we preserve the previous lock of interest if we're taking a lock from within an interrupt handler. We also need to deal with the case where the blocking path gets interrupted between testing to see if the lock is free and actually blocking. If we get interrupted there and end up in the state where the lock is free but the irq isn't pending, then we'll block indefinitely in the hypervisor. This fix is to make sure that any nested lock-takers will always leave the irq pending if there's any chance the outer lock became free. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/xen/events.h')
-rw-r--r--include/xen/events.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/xen/events.h b/include/xen/events.h
index 4680ff3fbc9..0d5f1adc036 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -46,6 +46,8 @@ extern void xen_irq_resume(void);
/* Clear an irq's pending state, in preparation for polling on it */
void xen_clear_irq_pending(int irq);
+void xen_set_irq_pending(int irq);
+bool xen_test_irq_pending(int irq);
/* Poll waiting for an irq to become pending. In the usual case, the
irq will be disabled so it won't deliver an interrupt. */