[PATCH v1] vhost-scsi: do not validate vrings during endpoint teardown

[Yuho Choi <oss.patchbox@gmail.com>]

vhost_scsi_clear_endpoint() checks every virtqueue with
vhost_vq_access_ok() before disabling the backends and waiting for
in-flight SCSI commands.  If that check fails, endpoint teardown is
skipped.

vhost_scsi_release() ignores the error and frees the vhost-scsi state.
vhost_dev_stop() drains vhost work, but it does not wait for commands
owned by the target core.  A later command or TMF completion can therefore
dereference its saved virtqueue pointer after the virtqueue has been freed.

Vring access is not a prerequisite for tearing an endpoint down.  Remove
the check so teardown always disables the backends and waits for in-flight
commands before releasing their state.

Fixes: 057cbf49a1f0 ("tcm_vhost: Initial merge for vhost level target fabric driver")
Signed-off-by: Yuho Choi <oss.patchbox@gmail.com>
---
 drivers/vhost/scsi.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index e44044449cef..f0966f25b09a 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -2194,17 +2194,10 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs,
 	struct vhost_scsi_tpg *tpg;
 	struct vhost_virtqueue *vq;
 	bool match = false;
-	int index, ret, i;
+	int ret, i;
 	u8 target;
 
 	mutex_lock(&vs->dev.mutex);
-	/* Verify that ring has been setup correctly. */
-	for (index = 0; index < vs->dev.nvqs; ++index) {
-		if (!vhost_vq_access_ok(&vs->vqs[index].vq)) {
-			ret = -EFAULT;
-			goto err_dev;
-		}
-	}
 
 	if (!vs->vs_tpg) {
 		ret = 0;
-- 
2.43.0