From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/hv/hv.c | 25 ++++++++++++++++++++++++-
drivers/hv/hyperv_vmbus.h | 2 ++
drivers/hv/vmbus_drv.c | 1 +
3 files changed, 27 insertions(+), 1 deletions(-)
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 39531dc..d3943bc 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -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;
@@ -470,6 +474,20 @@ void hv_synic_init(void *arg)
}
/*
+ * 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().
*/
void hv_synic_cleanup(void *arg)
@@ -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;
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 6cf2de9..b055e53 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -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.
*/
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index e7e35c6..da4333b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -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);
--
1.7.4.1
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