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authorDexuan Cui <decui@microsoft.com>2019-09-05 23:01:21 +0000
committerSasha Levin <sashal@kernel.org>2019-09-06 14:52:44 -0400
commitb307b38962eb0f22d1aa6dcf53cb7d3c2ed5eec7 (patch)
tree38f55d99f6960a7738cb8af94ce4837de60b2444 /drivers/hv/channel_mgmt.c
parent1f48dcf180e5422b1a633b24680dd0f5c3f540f5 (diff)
downloadlinux-b307b38962eb0f22d1aa6dcf53cb7d3c2ed5eec7.tar.bz2
Drivers: hv: vmbus: Suspend after cleaning up hv_sock and sub channels
Before suspend, Linux must make sure all the hv_sock channels have been properly cleaned up, because a hv_sock connection can not persist across hibernation, and the user-space app must be properly notified of the state change of the connection. Before suspend, Linux also must make sure all the sub-channels have been destroyed, i.e. the related channel structs of the sub-channels must be properly removed, otherwise they would cause a conflict when the sub-channels are recreated upon resume. Add a counter to track such channels, and vmbus_bus_suspend() should wait for the counter to drop to zero. Signed-off-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hv/channel_mgmt.c')
-rw-r--r--drivers/hv/channel_mgmt.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 44b92fa1b7fa..5518d031f62a 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -545,6 +545,10 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
mutex_lock(&vmbus_connection.channel_mutex);
+ /* Remember the channels that should be cleaned up upon suspend. */
+ if (is_hvsock_channel(newchannel) || is_sub_channel(newchannel))
+ atomic_inc(&vmbus_connection.nr_chan_close_on_suspend);
+
/*
* Now that we have acquired the channel_mutex,
* we can release the potentially racing rescind thread.
@@ -944,6 +948,16 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
vmbus_process_offer(newchannel);
}
+static void check_ready_for_suspend_event(void)
+{
+ /*
+ * If all the sub-channels or hv_sock channels have been cleaned up,
+ * then it's safe to suspend.
+ */
+ if (atomic_dec_and_test(&vmbus_connection.nr_chan_close_on_suspend))
+ complete(&vmbus_connection.ready_for_suspend_event);
+}
+
/*
* vmbus_onoffer_rescind - Rescind offer handler.
*
@@ -954,6 +968,7 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
struct vmbus_channel_rescind_offer *rescind;
struct vmbus_channel *channel;
struct device *dev;
+ bool clean_up_chan_for_suspend;
rescind = (struct vmbus_channel_rescind_offer *)hdr;
@@ -993,6 +1008,8 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
return;
}
+ clean_up_chan_for_suspend = is_hvsock_channel(channel) ||
+ is_sub_channel(channel);
/*
* Before setting channel->rescind in vmbus_rescind_cleanup(), we
* should make sure the channel callback is not running any more.
@@ -1018,6 +1035,10 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
if (channel->device_obj) {
if (channel->chn_rescind_callback) {
channel->chn_rescind_callback(channel);
+
+ if (clean_up_chan_for_suspend)
+ check_ready_for_suspend_event();
+
return;
}
/*
@@ -1050,6 +1071,11 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
}
mutex_unlock(&vmbus_connection.channel_mutex);
}
+
+ /* The "channel" may have been freed. Do not access it any longer. */
+
+ if (clean_up_chan_for_suspend)
+ check_ready_for_suspend_event();
}
void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)