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| author | Ross Lagerwall <ross.lagerwall@citrix.com> | 2015-06-19 17:15:57 +0200 |
|---|---|---|
| committer | David Vrabel <david.vrabel@citrix.com> | 2015-12-02 14:23:25 +0100 |
| commit | 3de88d622fd68bd4dbee0f80168218b23f798fd0 (patch) | |
| tree | 9c9b1fc13b007b604e04405fb8f2bc29643bc299 /drivers/xen | |
| parent | xen/evtchn: dynamically grow pending event channel ring (diff) | |
| download | linux-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')
| -rw-r--r-- | drivers/xen/events/events_fifo.c | 23 |
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; } |