vhost-scsi: Always access vq->private_data under vq mutex

Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 4264840ef7dcde2b0ed3fa15f4f5611e085fee62..45365396dbbcf2b3c07ffc1933873cbcb0b04cbd 100644 (file)
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -896,19 +896,15 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
        int head, ret;
        u8 target;
 
+       mutex_lock(&vq->mutex);
        /*
         * 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
         */
-       vs_tpg = rcu_dereference_check(vq->private_data, 1);
+       vs_tpg = vq->private_data;
        if (!vs_tpg)
-               return;
+               goto out;
 
-       mutex_lock(&vq->mutex);
        vhost_disable_notify(&vs->dev, vq);
 
        for (;;) {
@@ -1058,6 +1054,7 @@ err_free:
        vhost_scsi_free_cmd(cmd);
 err_cmd:
        vhost_scsi_send_bad_target(vs, vq, head, out);
+out:
        mutex_unlock(&vq->mutex);
 }