[PATCH v2 6/8] um: irqs: allow invoking time-travel handler multiple times

From: Johannes Berg
Date: Mon Mar 01 2021 - 10:11:13 EST


From: Johannes Berg <johannes.berg@xxxxxxxxx>

If we happen to get multiple messages while IRQS are already
suspended, we still need to handle them, since otherwise the
simulation blocks.

Remove the "prevent nesting" part, time_travel_add_irq_event()
will deal with being called multiple times just fine.

Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
arch/um/kernel/irq.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index ccf5e4d27202..2ee0a368aa59 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -101,10 +101,12 @@ static bool irq_do_timetravel_handler(struct irq_entry *entry,
if (!reg->timetravel_handler)
return false;

- /* prevent nesting - we'll get it again later when we SIGIO ourselves */
- if (reg->pending_on_resume)
- return true;
-
+ /*
+ * Handle all messages - we might get multiple even while
+ * interrupts are already suspended, due to suspend order
+ * etc. Note that time_travel_add_irq_event() will not add
+ * an event twice, if it's pending already "first wins".
+ */
reg->timetravel_handler(reg->irq, entry->fd, reg->id, &reg->event);

if (!reg->event.pending)
--
2.26.2