To get prepared to CPU offlining support we need co change the way how we
unbind clockevent devices. As one CPU may go online/offline multiple times
we need to bind it in hv_synic_init() and unbind it in hv_synic_cleanup().
The is an additional corner case: when we unload the module completely we
need to switch to some other clockevent mechanism before stopping VMBus or
we will hang. We can't call hv_synic_cleanup() before unloading VMBus as
we won't be able to send UNLOAD request and get a response so
hv_synic_clockevents_cleanup() has to live. Luckily, we can always call
clockevents_unbind_device(), even if it wasn't bound before and there is
no issue if we call it twice.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
drivers/hv/hv.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index a2567a4..c11393c 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -575,7 +575,7 @@ void hv_synic_clockevents_cleanup(void)
if (!(ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE))
return;
- for_each_online_cpu(cpu)
+ for_each_present_cpu(cpu)
clockevents_unbind_device(hv_context.clk_evt[cpu], cpu);
}
@@ -594,8 +594,10 @@ void hv_synic_cleanup(void *arg)
return;
/* Turn off clockevent device */
- if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)
+ if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE) {
+ clockevents_unbind_device(hv_context.clk_evt[cpu], cpu);
hv_ce_shutdown(hv_context.clk_evt[cpu]);
+ }
rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
--
2.7.4
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