[PATCH V4 1/2] tcm_vhost: Introduce tcm_vhost_check_feature()

[Asias He <asias@redhat.com>]

This helper is useful to check if a feature is supported.

Signed-off-by: Asias He <asias@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 drivers/vhost/tcm_vhost.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 0524267..d81e3a9 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -90,6 +90,18 @@ static int iov_num_pages(struct iovec *iov)
 	       ((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT;
 }
 
+static bool tcm_vhost_check_feature(struct vhost_scsi *vs, int feature)
+{
+	bool ret = false;
+
+	mutex_lock(&vs->dev.mutex);
+	if (vhost_has_feature(&vs->dev, feature))
+		ret = true;
+	mutex_unlock(&vs->dev.mutex);
+
+	return ret;
+}
+
 static bool tcm_vhost_check_endpoint(struct vhost_virtqueue *vq)
 {
 	bool ret = false;
-- 
1.8.1.4