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authorRoss Lagerwall <ross.lagerwall@citrix.com>2015-06-19 17:15:57 +0200
committerDavid Vrabel <david.vrabel@citrix.com>2015-12-02 14:23:25 +0100
commit3de88d622fd68bd4dbee0f80168218b23f798fd0 (patch)
tree9c9b1fc13b007b604e04405fb8f2bc29643bc299 /drivers/xen/events
parentxen/evtchn: dynamically grow pending event channel ring (diff)
downloadlinux-3de88d622fd68bd4dbee0f80168218b23f798fd0.tar.xz
linux-3de88d622fd68bd4dbee0f80168218b23f798fd0.zip
xen/events/fifo: Consume unprocessed events when a CPU dies
When a CPU is offlined, there may be unprocessed events on a port for that CPU. If the port is subsequently reused on a different CPU, it could be in an unexpected state with the link bit set, resulting in interrupts being missed. Fix this by consuming any unprocessed events for a particular CPU when that CPU dies. Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Cc: <stable@vger.kernel.org> # 3.14+ Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'drivers/xen/events')
-rw-r--r--drivers/xen/events/events_fifo.c23
1 files changed, 18 insertions, 5 deletions
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index e3e9e3d46d1b..96a1b8da5371 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -281,7 +281,8 @@ static void handle_irq_for_port(unsigned port)
static void consume_one_event(unsigned cpu,
struct evtchn_fifo_control_block *control_block,
- unsigned priority, unsigned long *ready)
+ unsigned priority, unsigned long *ready,
+ bool drop)
{
struct evtchn_fifo_queue *q = &per_cpu(cpu_queue, cpu);
uint32_t head;
@@ -313,13 +314,17 @@ static void consume_one_event(unsigned cpu,
if (head == 0)
clear_bit(priority, ready);
- if (evtchn_fifo_is_pending(port) && !evtchn_fifo_is_masked(port))
- handle_irq_for_port(port);
+ if (evtchn_fifo_is_pending(port) && !evtchn_fifo_is_masked(port)) {
+ if (unlikely(drop))
+ pr_warn("Dropping pending event for port %u\n", port);
+ else
+ handle_irq_for_port(port);
+ }
q->head[priority] = head;
}
-static void evtchn_fifo_handle_events(unsigned cpu)
+static void __evtchn_fifo_handle_events(unsigned cpu, bool drop)
{
struct evtchn_fifo_control_block *control_block;
unsigned long ready;
@@ -331,11 +336,16 @@ static void evtchn_fifo_handle_events(unsigned cpu)
while (ready) {
q = find_first_bit(&ready, EVTCHN_FIFO_MAX_QUEUES);
- consume_one_event(cpu, control_block, q, &ready);
+ consume_one_event(cpu, control_block, q, &ready, drop);
ready |= xchg(&control_block->ready, 0);
}
}
+static void evtchn_fifo_handle_events(unsigned cpu)
+{
+ __evtchn_fifo_handle_events(cpu, false);
+}
+
static void evtchn_fifo_resume(void)
{
unsigned cpu;
@@ -420,6 +430,9 @@ static int evtchn_fifo_cpu_notification(struct notifier_block *self,
if (!per_cpu(cpu_control_block, cpu))
ret = evtchn_fifo_alloc_control_block(cpu);
break;
+ case CPU_DEAD:
+ __evtchn_fifo_handle_events(cpu, true);
+ break;
default:
break;
}