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hv: change clockevents unbind tactics

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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().
There 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@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vitaly Kuznetsov 2016-12-03 12:34:35 -08:00 committed by Greg Kroah-Hartman
parent abd1026da4
commit 6ffc4b8535
1 changed files with 4 additions and 2 deletions
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6
drivers/hv/hv.c
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@ -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);