4 files changed, 140 insertions, 65 deletions

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 282aac45c690..006ffacf1c56 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -210,6 +210,7 @@ struct vhost_scsi {
 
 struct vhost_scsi_tmf {
 	struct vhost_work vwork;
+	struct work_struct flush_work;
 	struct vhost_scsi *vhost;
 	struct vhost_scsi_virtqueue *svq;
 
@@ -358,14 +359,23 @@ static void vhost_scsi_release_tmf_res(struct vhost_scsi_tmf *tmf)
 	vhost_scsi_put_inflight(inflight);
 }
 
+static void vhost_scsi_drop_cmds(struct vhost_scsi_virtqueue *svq)
+{
+	struct vhost_scsi_cmd *cmd, *t;
+	struct llist_node *llnode;
+
+	llnode = llist_del_all(&svq->completion_list);
+	llist_for_each_entry_safe(cmd, t, llnode, tvc_completion_list)
+		vhost_scsi_release_cmd_res(&cmd->tvc_se_cmd);
+}
+
 static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)
 {
 	if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB) {
 		struct vhost_scsi_tmf *tmf = container_of(se_cmd,
 					struct vhost_scsi_tmf, se_cmd);
-		struct vhost_virtqueue *vq = &tmf->svq->vq;
 
-		vhost_vq_work_queue(vq, &tmf->vwork);
+		schedule_work(&tmf->flush_work);
 	} else {
 		struct vhost_scsi_cmd *cmd = container_of(se_cmd,
 					struct vhost_scsi_cmd, tvc_se_cmd);
@@ -373,7 +383,8 @@ static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)
 					struct vhost_scsi_virtqueue, vq);
 
 		llist_add(&cmd->tvc_completion_list, &svq->completion_list);
-		vhost_vq_work_queue(&svq->vq, &svq->completion_work);
+		if (!vhost_vq_work_queue(&svq->vq, &svq->completion_work))
+			vhost_scsi_drop_cmds(svq);
 	}
 }
 
@@ -497,10 +508,8 @@ again:
 		vq_err(vq, "Faulted on vhost_scsi_send_event\n");
 }
 
-static void vhost_scsi_evt_work(struct vhost_work *work)
+static void vhost_scsi_complete_events(struct vhost_scsi *vs, bool drop)
 {
-	struct vhost_scsi *vs = container_of(work, struct vhost_scsi,
-					vs_event_work);
 	struct vhost_virtqueue *vq = &vs->vqs[VHOST_SCSI_VQ_EVT].vq;
 	struct vhost_scsi_evt *evt, *t;
 	struct llist_node *llnode;
@@ -508,12 +517,20 @@ static void vhost_scsi_evt_work(struct vhost_work *work)
 	mutex_lock(&vq->mutex);
 	llnode = llist_del_all(&vs->vs_event_list);
 	llist_for_each_entry_safe(evt, t, llnode, list) {
-		vhost_scsi_do_evt_work(vs, evt);
+		if (!drop)
+			vhost_scsi_do_evt_work(vs, evt);
 		vhost_scsi_free_evt(vs, evt);
 	}
 	mutex_unlock(&vq->mutex);
 }
 
+static void vhost_scsi_evt_work(struct vhost_work *work)
+{
+	struct vhost_scsi *vs = container_of(work, struct vhost_scsi,
+					     vs_event_work);
+	vhost_scsi_complete_events(vs, false);
+}
+
 static int vhost_scsi_copy_sgl_to_iov(struct vhost_scsi_cmd *cmd)
 {
 	struct iov_iter *iter = &cmd->saved_iter;
@@ -1270,33 +1287,32 @@ static void vhost_scsi_tmf_resp_work(struct vhost_work *work)
 {
 	struct vhost_scsi_tmf *tmf = container_of(work, struct vhost_scsi_tmf,
 						  vwork);
-	struct vhost_virtqueue *ctl_vq, *vq;
-	int resp_code, i;
-
-	if (tmf->scsi_resp == TMR_FUNCTION_COMPLETE) {
-		/*
-		 * Flush IO vqs that don't share a worker with the ctl to make
-		 * sure they have sent their responses before us.
-		 */
-		ctl_vq = &tmf->vhost->vqs[VHOST_SCSI_VQ_CTL].vq;
-		for (i = VHOST_SCSI_VQ_IO; i < tmf->vhost->dev.nvqs; i++) {
-			vq = &tmf->vhost->vqs[i].vq;
-
-			if (vhost_vq_is_setup(vq) &&
-			    vq->worker != ctl_vq->worker)
-				vhost_vq_flush(vq);
-		}
+	int resp_code;
 
+	if (tmf->scsi_resp == TMR_FUNCTION_COMPLETE)
 		resp_code = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
-	} else {
+	else
 		resp_code = VIRTIO_SCSI_S_FUNCTION_REJECTED;
-	}
 
 	vhost_scsi_send_tmf_resp(tmf->vhost, &tmf->svq->vq, tmf->in_iovs,
 				 tmf->vq_desc, &tmf->resp_iov, resp_code);
 	vhost_scsi_release_tmf_res(tmf);
 }
 
+static void vhost_scsi_tmf_flush_work(struct work_struct *work)
+{
+	struct vhost_scsi_tmf *tmf = container_of(work, struct vhost_scsi_tmf,
+						 flush_work);
+	struct vhost_virtqueue *vq = &tmf->svq->vq;
+	/*
+	 * Make sure we have sent responses for other commands before we
+	 * send our response.
+	 */
+	vhost_dev_flush(vq->dev);
+	if (!vhost_vq_work_queue(vq, &tmf->vwork))
+		vhost_scsi_release_tmf_res(tmf);
+}
+
 static void
 vhost_scsi_handle_tmf(struct vhost_scsi *vs, struct vhost_scsi_tpg *tpg,
 		      struct vhost_virtqueue *vq,
@@ -1320,6 +1336,7 @@ vhost_scsi_handle_tmf(struct vhost_scsi *vs, struct vhost_scsi_tpg *tpg,
 	if (!tmf)
 		goto send_reject;
 
+	INIT_WORK(&tmf->flush_work, vhost_scsi_tmf_flush_work);
 	vhost_work_init(&tmf->vwork, vhost_scsi_tmf_resp_work);
 	tmf->vhost = vs;
 	tmf->svq = svq;
@@ -1509,7 +1526,8 @@ vhost_scsi_send_evt(struct vhost_scsi *vs, struct vhost_virtqueue *vq,
 	}
 
 	llist_add(&evt->list, &vs->vs_event_list);
-	vhost_vq_work_queue(vq, &vs->vs_event_work);
+	if (!vhost_vq_work_queue(vq, &vs->vs_event_work))
+		vhost_scsi_complete_events(vs, true);
 }
 
 static void vhost_scsi_evt_handle_kick(struct vhost_work *work)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index ba52d128aeb7..63a53680a85c 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -1548,7 +1548,7 @@ static void vhost_vdpa_release_dev(struct device *device)
 	struct vhost_vdpa *v =
 	       container_of(device, struct vhost_vdpa, dev);
 
-	ida_simple_remove(&vhost_vdpa_ida, v->minor);
+	ida_free(&vhost_vdpa_ida, v->minor);
 	kfree(v->vqs);
 	kfree(v);
 }
@@ -1571,8 +1571,8 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
 	if (!v)
 		return -ENOMEM;
 
-	minor = ida_simple_get(&vhost_vdpa_ida, 0,
-			       VHOST_VDPA_DEV_MAX, GFP_KERNEL);
+	minor = ida_alloc_max(&vhost_vdpa_ida, VHOST_VDPA_DEV_MAX - 1,
+			      GFP_KERNEL);
 	if (minor < 0) {
 		kfree(v);
 		return minor;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 8995730ce0bf..b60955682474 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -263,34 +263,37 @@ bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work)
 }
 EXPORT_SYMBOL_GPL(vhost_vq_work_queue);
 
-void vhost_vq_flush(struct vhost_virtqueue *vq)
-{
-	struct vhost_flush_struct flush;
-
-	init_completion(&flush.wait_event);
-	vhost_work_init(&flush.work, vhost_flush_work);
-
-	if (vhost_vq_work_queue(vq, &flush.work))
-		wait_for_completion(&flush.wait_event);
-}
-EXPORT_SYMBOL_GPL(vhost_vq_flush);
-
 /**
- * vhost_worker_flush - flush a worker
+ * __vhost_worker_flush - flush a worker
  * @worker: worker to flush
  *
- * This does not use RCU to protect the worker, so the device or worker
- * mutex must be held.
+ * The worker's flush_mutex must be held.
  */
-static void vhost_worker_flush(struct vhost_worker *worker)
+static void __vhost_worker_flush(struct vhost_worker *worker)
 {
 	struct vhost_flush_struct flush;
 
+	if (!worker->attachment_cnt || worker->killed)
+		return;
+
 	init_completion(&flush.wait_event);
 	vhost_work_init(&flush.work, vhost_flush_work);
 
 	vhost_worker_queue(worker, &flush.work);
+	/*
+	 * Drop mutex in case our worker is killed and it needs to take the
+	 * mutex to force cleanup.
+	 */
+	mutex_unlock(&worker->mutex);
 	wait_for_completion(&flush.wait_event);
+	mutex_lock(&worker->mutex);
+}
+
+static void vhost_worker_flush(struct vhost_worker *worker)
+{
+	mutex_lock(&worker->mutex);
+	__vhost_worker_flush(worker);
+	mutex_unlock(&worker->mutex);
 }
 
 void vhost_dev_flush(struct vhost_dev *dev)
@@ -298,15 +301,8 @@ void vhost_dev_flush(struct vhost_dev *dev)
 	struct vhost_worker *worker;
 	unsigned long i;
 
-	xa_for_each(&dev->worker_xa, i, worker) {
-		mutex_lock(&worker->mutex);
-		if (!worker->attachment_cnt) {
-			mutex_unlock(&worker->mutex);
-			continue;
-		}
+	xa_for_each(&dev->worker_xa, i, worker)
 		vhost_worker_flush(worker);
-		mutex_unlock(&worker->mutex);
-	}
 }
 EXPORT_SYMBOL_GPL(vhost_dev_flush);
 
@@ -392,7 +388,7 @@ static void vhost_vq_reset(struct vhost_dev *dev,
 	__vhost_vq_meta_reset(vq);
 }
 
-static bool vhost_worker(void *data)
+static bool vhost_run_work_list(void *data)
 {
 	struct vhost_worker *worker = data;
 	struct vhost_work *work, *work_next;
@@ -417,6 +413,40 @@ static bool vhost_worker(void *data)
 	return !!node;
 }
 
+static void vhost_worker_killed(void *data)
+{
+	struct vhost_worker *worker = data;
+	struct vhost_dev *dev = worker->dev;
+	struct vhost_virtqueue *vq;
+	int i, attach_cnt = 0;
+
+	mutex_lock(&worker->mutex);
+	worker->killed = true;
+
+	for (i = 0; i < dev->nvqs; i++) {
+		vq = dev->vqs[i];
+
+		mutex_lock(&vq->mutex);
+		if (worker ==
+		    rcu_dereference_check(vq->worker,
+					  lockdep_is_held(&vq->mutex))) {
+			rcu_assign_pointer(vq->worker, NULL);
+			attach_cnt++;
+		}
+		mutex_unlock(&vq->mutex);
+	}
+
+	worker->attachment_cnt -= attach_cnt;
+	if (attach_cnt)
+		synchronize_rcu();
+	/*
+	 * Finish vhost_worker_flush calls and any other works that snuck in
+	 * before the synchronize_rcu.
+	 */
+	vhost_run_work_list(worker);
+	mutex_unlock(&worker->mutex);
+}
+
 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
 {
 	kfree(vq->indirect);
@@ -631,9 +661,11 @@ static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
 	if (!worker)
 		return NULL;
 
+	worker->dev = dev;
 	snprintf(name, sizeof(name), "vhost-%d", current->pid);
 
-	vtsk = vhost_task_create(vhost_worker, worker, name);
+	vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
+				 worker, name);
 	if (!vtsk)
 		goto free_worker;
 
@@ -664,22 +696,37 @@ static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq,
 {
 	struct vhost_worker *old_worker;
 
-	old_worker = rcu_dereference_check(vq->worker,
-					   lockdep_is_held(&vq->dev->mutex));
-
 	mutex_lock(&worker->mutex);
-	worker->attachment_cnt++;
-	mutex_unlock(&worker->mutex);
+	if (worker->killed) {
+		mutex_unlock(&worker->mutex);
+		return;
+	}
+
+	mutex_lock(&vq->mutex);
+
+	old_worker = rcu_dereference_check(vq->worker,
+					   lockdep_is_held(&vq->mutex));
 	rcu_assign_pointer(vq->worker, worker);
+	worker->attachment_cnt++;
 
-	if (!old_worker)
+	if (!old_worker) {
+		mutex_unlock(&vq->mutex);
+		mutex_unlock(&worker->mutex);
 		return;
+	}
+	mutex_unlock(&vq->mutex);
+	mutex_unlock(&worker->mutex);
+
 	/*
 	 * Take the worker mutex to make sure we see the work queued from
 	 * device wide flushes which doesn't use RCU for execution.
 	 */
 	mutex_lock(&old_worker->mutex);
-	old_worker->attachment_cnt--;
+	if (old_worker->killed) {
+		mutex_unlock(&old_worker->mutex);
+		return;
+	}
+
 	/*
 	 * We don't want to call synchronize_rcu for every vq during setup
 	 * because it will slow down VM startup. If we haven't done
@@ -690,6 +737,8 @@ static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq,
 	mutex_lock(&vq->mutex);
 	if (!vhost_vq_get_backend(vq) && !vq->kick) {
 		mutex_unlock(&vq->mutex);
+
+		old_worker->attachment_cnt--;
 		mutex_unlock(&old_worker->mutex);
 		/*
 		 * vsock can queue anytime after VHOST_VSOCK_SET_GUEST_CID.
@@ -705,7 +754,8 @@ static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq,
 	/* Make sure new vq queue/flush/poll calls see the new worker */
 	synchronize_rcu();
 	/* Make sure whatever was queued gets run */
-	vhost_worker_flush(old_worker);
+	__vhost_worker_flush(old_worker);
+	old_worker->attachment_cnt--;
 	mutex_unlock(&old_worker->mutex);
 }
 
@@ -754,10 +804,16 @@ static int vhost_free_worker(struct vhost_dev *dev,
 		return -ENODEV;
 
 	mutex_lock(&worker->mutex);
-	if (worker->attachment_cnt) {
+	if (worker->attachment_cnt || worker->killed) {
 		mutex_unlock(&worker->mutex);
 		return -EBUSY;
 	}
+	/*
+	 * A flush might have raced and snuck in before attachment_cnt was set
+	 * to zero. Make sure flushes are flushed from the queue before
+	 * freeing.
+	 */
+	__vhost_worker_flush(worker);
 	mutex_unlock(&worker->mutex);
 
 	vhost_worker_destroy(dev, worker);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 9e942fcda5c3..bb75a292d50c 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -28,12 +28,14 @@ struct vhost_work {
 
 struct vhost_worker {
 	struct vhost_task	*vtsk;
+	struct vhost_dev	*dev;
 	/* Used to serialize device wide flushing with worker swapping. */
 	struct mutex		mutex;
 	struct llist_head	work_list;
 	u64			kcov_handle;
 	u32			id;
 	int			attachment_cnt;
+	bool			killed;
 };
 
 /* Poll a file (eventfd or socket) */
@@ -205,7 +207,6 @@ int vhost_get_vq_desc(struct vhost_virtqueue *,
 		      struct vhost_log *log, unsigned int *log_num);
 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 
-void vhost_vq_flush(struct vhost_virtqueue *vq);
 bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work);
 bool vhost_vq_has_work(struct vhost_virtqueue *vq);
 bool vhost_vq_is_setup(struct vhost_virtqueue *vq);