[PATCH v7 2/3] tcm_vhost: Add helper to check if endpoint is setup

[Asias He <asias@redhat.com>]

Signed-off-by: Asias He <asias@redhat.com>
---
 drivers/vhost/tcm_vhost.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 88ebb79..8f05528 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -111,6 +111,24 @@ static bool tcm_vhost_check_feature(struct vhost_scsi *vs, int feature)
 	return ret;
 }
 
+static bool tcm_vhost_check_endpoint(struct vhost_virtqueue *vq)
+{
+	bool ret = false;
+
+	/*
+	* We can handle the vq only after the endpoint is setup by calling the
+	* VHOST_SCSI_SET_ENDPOINT ioctl.
+	*
+	* TODO: Check that we are running from vhost_worker which acts
+	* as read-side critical section for vhost kind of RCU.
+	* See the comments in struct vhost_virtqueue in drivers/vhost/vhost.h
+	*/
+	if (rcu_dereference_check(vq->private_data, 1))
+		ret = true;
+
+	return ret;
+}
+
 static int tcm_vhost_check_true(struct se_portal_group *se_tpg)
 {
 	return 1;
-- 
1.8.1.4