[RFC v3 04/11] vhost-vdpa: protect concurrent access to vhost device iotlb

[Xie Yongji <xieyongji@xxxxxxxxxxxxx>]

Introduce a mutex to protect vhost device iotlb from
concurrent access.

Fixes: 4c8cf318("vhost: introduce vDPA-based backend")
Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
---
 drivers/vhost/vdpa.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 448be7875b6d..4a241d380c40 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -49,6 +49,7 @@ struct vhost_vdpa {
 	struct eventfd_ctx *config_ctx;
 	int in_batch;
 	struct vdpa_iova_range range;
+	struct mutex mutex;
 };
 
 static DEFINE_IDA(vhost_vdpa_ida);
@@ -728,6 +729,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
 	if (r)
 		return r;
 
+	mutex_lock(&v->mutex);
 	switch (msg->type) {
 	case VHOST_IOTLB_UPDATE:
 		r = vhost_vdpa_process_iotlb_update(v, msg);
@@ -747,6 +749,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
 		r = -EINVAL;
 		break;
 	}
+	mutex_unlock(&v->mutex);
 
 	return r;
 }
@@ -1017,6 +1020,7 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
 		return minor;
 	}
 
+	mutex_init(&v->mutex);
 	atomic_set(&v->opened, 0);
 	v->minor = minor;
 	v->vdpa = vdpa;
-- 
2.11.0