[PATCH 06/40] Staging: hv: vmbus: Introduce a lock to protect the ext field in hv_device

[K. Y. Srinivasan]

The current mechanism for handling references in broken. 
Introduce a lock to protect the ext field in hv_device.

Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Signed-off-by: Abhishek Kane <v-abkane@xxxxxxxxxxxxx>
Signed-off-by: Hank Janssen <hjanssen@xxxxxxxxxxxxx>
---
 drivers/staging/hv/hyperv.h    |    3 +++
 drivers/staging/hv/vmbus_drv.c |    1 +
 2 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/staging/hv/hyperv.h b/drivers/staging/hv/hyperv.h
index 370b096..ff3c69d 100644
--- a/drivers/staging/hv/hyperv.h
+++ b/drivers/staging/hv/hyperv.h
@@ -830,6 +830,9 @@ struct hv_device {
 
 	struct vmbus_channel *channel;
 
+	/* This lock protects the device extension field */
+	spinlock_t ext_lock;
+
 	/* Device extension; */
 	void *ext;
 };
diff --git a/drivers/staging/hv/vmbus_drv.c b/drivers/staging/hv/vmbus_drv.c
index 2e6bfc1..903362e 100644
--- a/drivers/staging/hv/vmbus_drv.c
+++ b/drivers/staging/hv/vmbus_drv.c
@@ -557,6 +557,7 @@ struct hv_device *vmbus_child_device_create(struct hv_guid *type,
 		return NULL;
 	}
 
+	spin_lock_init(&child_device_obj->ext_lock);
 	child_device_obj->channel = channel;
 	/*
 	 * Get the human readable device type name and stash it away.
-- 
1.7.4.1

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