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Drivers: hv: vmbus: Teardown clockevent devices on module unload

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Newly introduced clockevent devices made it impossible to unload hv_vmbus
module as clockevents_config_and_register() takes additional reverence to
the module. To make it possible again we do the following:
- avoid setting dev->owner for clockevent devices;
- implement hv_synic_clockevents_cleanup() doing clockevents_unbind_device();
- call it from vmbus_exit().

In theory hv_synic_clockevents_cleanup() can be merged with hv_synic_cleanup(),
however, we call hv_synic_cleanup() from smp_call_function_single() and this
doesn't work for clockevents_unbind_device() as it does such call on its own. I
opted for a separate function.

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 2015-02-27 11:25:57 -08:00 committed by Greg Kroah-Hartman
parent 32a158325a
commit e086748c65
3 changed files with 27 additions and 1 deletions
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25
drivers/hv/hv.c
View File

@ -312,7 +312,11 @@ static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu)
dev->features = CLOCK_EVT_FEAT_ONESHOT;
dev->cpumask = cpumask_of(cpu);
dev->rating = 1000;
dev->owner = THIS_MODULE;
/*
* Avoid settint dev->owner = THIS_MODULE deliberately as doing so will
* result in clockevents_config_and_register() taking additional
* references to the hv_vmbus module making it impossible to unload.
*/
dev->set_mode = hv_ce_setmode;
dev->set_next_event = hv_ce_set_next_event;
@ -469,6 +473,20 @@ void hv_synic_init(void *arg)
return;
}
/*
* hv_synic_clockevents_cleanup - Cleanup clockevent devices
*/
void hv_synic_clockevents_cleanup(void)
{
int cpu;
if (!(ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE))
return;
for_each_online_cpu(cpu)
clockevents_unbind_device(hv_context.clk_evt[cpu], cpu);
}
/*
* hv_synic_cleanup - Cleanup routine for hv_synic_init().
*/
@ -483,6 +501,11 @@ void hv_synic_cleanup(void *arg)
if (!hv_context.synic_initialized)
return;
/* Turn off clockevent device */
if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)
hv_ce_setmode(CLOCK_EVT_MODE_SHUTDOWN,
hv_context.clk_evt[cpu]);
rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
shared_sint.masked = 1;

2
drivers/hv/hyperv_vmbus.h
View File

@ -572,6 +572,8 @@ extern void hv_synic_init(void *irqarg);
extern void hv_synic_cleanup(void *arg);
extern void hv_synic_clockevents_cleanup(void);
/*
* Host version information.
*/

1
drivers/hv/vmbus_drv.c
View File

@ -1032,6 +1032,7 @@ static void __exit vmbus_exit(void)
int cpu;
vmbus_connection.conn_state = DISCONNECTED;
hv_synic_clockevents_cleanup();
hv_remove_vmbus_irq();
vmbus_free_channels();
bus_unregister(&hv_bus);