[PATCH 2/5] 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>
---
 drivers/vhost/tcm_vhost.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index b3e50d7..fdbf986 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -91,6 +91,20 @@ 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, u64 feature)
+{
+	u64 acked_features;
+	bool ret = false;
+
+	mutex_lock(&vs->dev.mutex);
+	acked_features = vs->dev.acked_features;
+	if (acked_features & 1ULL << feature)
+		ret = true;
+	mutex_unlock(&vs->dev.mutex);
+
+	return ret;
+}
+
 static int tcm_vhost_check_true(struct se_portal_group *se_tpg)
 {
 	return 1;
-- 
1.8.1.4