Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull vhost fixes from Michael Tsirkin:
 "Fixes all over the place, most notably vhost scsi IO error fixes"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost scsi: Add support for LUN resets.
  vhost scsi: add lun parser helper
  vhost scsi: fix cmd completion race
  vhost scsi: alloc cmds per vq instead of session
  vhost: add helper to check if a vq has been setup
  vdpasim: fix "mac_pton" undefined error
  swiotlb: using SIZE_MAX needs limits.h included

4 files changed, 288 insertions, 117 deletions

diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
index d7d32b656102..358f6048dd3c 100644
--- a/drivers/vdpa/Kconfig
+++ b/drivers/vdpa/Kconfig
@@ -13,6 +13,7 @@ config VDPA_SIM
 	depends on RUNTIME_TESTING_MENU && HAS_DMA
 	select DMA_OPS
 	select VHOST_RING
+	select GENERIC_NET_UTILS
 	default n
 	help
 	  vDPA networking device simulator which loop TX traffic back
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index b22adf03f584..f22fce549862 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -52,7 +52,6 @@
 #define VHOST_SCSI_VERSION  "v0.1"
 #define VHOST_SCSI_NAMELEN 256
 #define VHOST_SCSI_MAX_CDB_SIZE 32
-#define VHOST_SCSI_DEFAULT_TAGS 256
 #define VHOST_SCSI_PREALLOC_SGLS 2048
 #define VHOST_SCSI_PREALLOC_UPAGES 2048
 #define VHOST_SCSI_PREALLOC_PROT_SGLS 2048
@@ -140,6 +139,7 @@ struct vhost_scsi_tpg {
 	struct se_portal_group se_tpg;
 	/* Pointer back to vhost_scsi, protected by tv_tpg_mutex */
 	struct vhost_scsi *vhost_scsi;
+	struct list_head tmf_queue;
 };
 
 struct vhost_scsi_tport {
@@ -189,6 +189,9 @@ struct vhost_scsi_virtqueue {
 	 * Writers must also take dev mutex and flush under it.
 	 */
 	int inflight_idx;
+	struct vhost_scsi_cmd *scsi_cmds;
+	struct sbitmap scsi_tags;
+	int max_cmds;
 };
 
 struct vhost_scsi {
@@ -209,6 +212,20 @@ struct vhost_scsi {
 	int vs_events_nr; /* num of pending events, protected by vq->mutex */
 };
 
+struct vhost_scsi_tmf {
+	struct vhost_work vwork;
+	struct vhost_scsi_tpg *tpg;
+	struct vhost_scsi *vhost;
+	struct vhost_scsi_virtqueue *svq;
+	struct list_head queue_entry;
+
+	struct se_cmd se_cmd;
+	struct vhost_scsi_inflight *inflight;
+	struct iovec resp_iov;
+	int in_iovs;
+	int vq_desc;
+};
+
 /*
  * Context for processing request and control queue operations.
  */
@@ -320,11 +337,13 @@ static u32 vhost_scsi_tpg_get_inst_index(struct se_portal_group *se_tpg)
 	return 1;
 }
 
-static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)
+static void vhost_scsi_release_cmd_res(struct se_cmd *se_cmd)
 {
 	struct vhost_scsi_cmd *tv_cmd = container_of(se_cmd,
 				struct vhost_scsi_cmd, tvc_se_cmd);
-	struct se_session *se_sess = tv_cmd->tvc_nexus->tvn_se_sess;
+	struct vhost_scsi_virtqueue *svq = container_of(tv_cmd->tvc_vq,
+				struct vhost_scsi_virtqueue, vq);
+	struct vhost_scsi_inflight *inflight = tv_cmd->inflight;
 	int i;
 
 	if (tv_cmd->tvc_sgl_count) {
@@ -336,8 +355,36 @@ static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)
 			put_page(sg_page(&tv_cmd->tvc_prot_sgl[i]));
 	}
 
-	vhost_scsi_put_inflight(tv_cmd->inflight);
-	target_free_tag(se_sess, se_cmd);
+	sbitmap_clear_bit(&svq->scsi_tags, se_cmd->map_tag);
+	vhost_scsi_put_inflight(inflight);
+}
+
+static void vhost_scsi_release_tmf_res(struct vhost_scsi_tmf *tmf)
+{
+	struct vhost_scsi_tpg *tpg = tmf->tpg;
+	struct vhost_scsi_inflight *inflight = tmf->inflight;
+
+	mutex_lock(&tpg->tv_tpg_mutex);
+	list_add_tail(&tpg->tmf_queue, &tmf->queue_entry);
+	mutex_unlock(&tpg->tv_tpg_mutex);
+	vhost_scsi_put_inflight(inflight);
+}
+
+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);
+
+		vhost_work_queue(&tmf->vhost->dev, &tmf->vwork);
+	} else {
+		struct vhost_scsi_cmd *cmd = container_of(se_cmd,
+					struct vhost_scsi_cmd, tvc_se_cmd);
+		struct vhost_scsi *vs = cmd->tvc_vhost;
+
+		llist_add(&cmd->tvc_completion_list, &vs->vs_completion_list);
+		vhost_work_queue(&vs->dev, &vs->vs_completion_work);
+	}
 }
 
 static u32 vhost_scsi_sess_get_index(struct se_session *se_sess)
@@ -362,34 +409,24 @@ static int vhost_scsi_get_cmd_state(struct se_cmd *se_cmd)
 	return 0;
 }
 
-static void vhost_scsi_complete_cmd(struct vhost_scsi_cmd *cmd)
-{
-	struct vhost_scsi *vs = cmd->tvc_vhost;
-
-	llist_add(&cmd->tvc_completion_list, &vs->vs_completion_list);
-
-	vhost_work_queue(&vs->dev, &vs->vs_completion_work);
-}
-
 static int vhost_scsi_queue_data_in(struct se_cmd *se_cmd)
 {
-	struct vhost_scsi_cmd *cmd = container_of(se_cmd,
-				struct vhost_scsi_cmd, tvc_se_cmd);
-	vhost_scsi_complete_cmd(cmd);
+	transport_generic_free_cmd(se_cmd, 0);
 	return 0;
 }
 
 static int vhost_scsi_queue_status(struct se_cmd *se_cmd)
 {
-	struct vhost_scsi_cmd *cmd = container_of(se_cmd,
-				struct vhost_scsi_cmd, tvc_se_cmd);
-	vhost_scsi_complete_cmd(cmd);
+	transport_generic_free_cmd(se_cmd, 0);
 	return 0;
 }
 
 static void vhost_scsi_queue_tm_rsp(struct se_cmd *se_cmd)
 {
-	return;
+	struct vhost_scsi_tmf *tmf = container_of(se_cmd, struct vhost_scsi_tmf,
+						  se_cmd);
+
+	transport_generic_free_cmd(&tmf->se_cmd, 0);
 }
 
 static void vhost_scsi_aborted_task(struct se_cmd *se_cmd)
@@ -429,15 +466,6 @@ vhost_scsi_allocate_evt(struct vhost_scsi *vs,
 	return evt;
 }
 
-static void vhost_scsi_free_cmd(struct vhost_scsi_cmd *cmd)
-{
-	struct se_cmd *se_cmd = &cmd->tvc_se_cmd;
-
-	/* TODO locking against target/backend threads? */
-	transport_generic_free_cmd(se_cmd, 0);
-
-}
-
 static int vhost_scsi_check_stop_free(struct se_cmd *se_cmd)
 {
 	return target_put_sess_cmd(se_cmd);
@@ -556,7 +584,7 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
 		} else
 			pr_err("Faulted on virtio_scsi_cmd_resp\n");
 
-		vhost_scsi_free_cmd(cmd);
+		vhost_scsi_release_cmd_res(se_cmd);
 	}
 
 	vq = -1;
@@ -566,31 +594,31 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
 }
 
 static struct vhost_scsi_cmd *
-vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
+vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
 		   unsigned char *cdb, u64 scsi_tag, u16 lun, u8 task_attr,
 		   u32 exp_data_len, int data_direction)
 {
+	struct vhost_scsi_virtqueue *svq = container_of(vq,
+					struct vhost_scsi_virtqueue, vq);
 	struct vhost_scsi_cmd *cmd;
 	struct vhost_scsi_nexus *tv_nexus;
-	struct se_session *se_sess;
 	struct scatterlist *sg, *prot_sg;
 	struct page **pages;
-	int tag, cpu;
+	int tag;
 
 	tv_nexus = tpg->tpg_nexus;
 	if (!tv_nexus) {
 		pr_err("Unable to locate active struct vhost_scsi_nexus\n");
 		return ERR_PTR(-EIO);
 	}
-	se_sess = tv_nexus->tvn_se_sess;
 
-	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
+	tag = sbitmap_get(&svq->scsi_tags, 0, false);
 	if (tag < 0) {
 		pr_err("Unable to obtain tag for vhost_scsi_cmd\n");
 		return ERR_PTR(-ENOMEM);
 	}
 
-	cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[tag];
+	cmd = &svq->scsi_cmds[tag];
 	sg = cmd->tvc_sgl;
 	prot_sg = cmd->tvc_prot_sgl;
 	pages = cmd->tvc_upages;
@@ -599,7 +627,6 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
 	cmd->tvc_prot_sgl = prot_sg;
 	cmd->tvc_upages = pages;
 	cmd->tvc_se_cmd.map_tag = tag;
-	cmd->tvc_se_cmd.map_cpu = cpu;
 	cmd->tvc_tag = scsi_tag;
 	cmd->tvc_lun = lun;
 	cmd->tvc_task_attr = task_attr;
@@ -907,6 +934,11 @@ vhost_scsi_get_req(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc,
 	return ret;
 }
 
+static u16 vhost_buf_to_lun(u8 *lun_buf)
+{
+	return ((lun_buf[2] << 8) | lun_buf[3]) & 0x3FFF;
+}
+
 static void
 vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 {
@@ -1045,12 +1077,12 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 			tag = vhost64_to_cpu(vq, v_req_pi.tag);
 			task_attr = v_req_pi.task_attr;
 			cdb = &v_req_pi.cdb[0];
-			lun = ((v_req_pi.lun[2] << 8) | v_req_pi.lun[3]) & 0x3FFF;
+			lun = vhost_buf_to_lun(v_req_pi.lun);
 		} else {
 			tag = vhost64_to_cpu(vq, v_req.tag);
 			task_attr = v_req.task_attr;
 			cdb = &v_req.cdb[0];
-			lun = ((v_req.lun[2] << 8) | v_req.lun[3]) & 0x3FFF;
+			lun = vhost_buf_to_lun(v_req.lun);
 		}
 		/*
 		 * Check that the received CDB size does not exceeded our
@@ -1065,11 +1097,11 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 				scsi_command_size(cdb), VHOST_SCSI_MAX_CDB_SIZE);
 				goto err;
 		}
-		cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
+		cmd = vhost_scsi_get_cmd(vq, tpg, cdb, tag, lun, task_attr,
 					 exp_data_len + prot_bytes,
 					 data_direction);
 		if (IS_ERR(cmd)) {
-			vq_err(vq, "vhost_scsi_get_tag failed %ld\n",
+			vq_err(vq, "vhost_scsi_get_cmd failed %ld\n",
 			       PTR_ERR(cmd));
 			goto err;
 		}
@@ -1088,7 +1120,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 						      &prot_iter, exp_data_len,
 						      &data_iter))) {
 				vq_err(vq, "Failed to map iov to sgl\n");
-				vhost_scsi_release_cmd(&cmd->tvc_se_cmd);
+				vhost_scsi_release_cmd_res(&cmd->tvc_se_cmd);
 				goto err;
 			}
 		}
@@ -1124,9 +1156,9 @@ out:
 }
 
 static void
-vhost_scsi_send_tmf_reject(struct vhost_scsi *vs,
-			   struct vhost_virtqueue *vq,
-			   struct vhost_scsi_ctx *vc)
+vhost_scsi_send_tmf_resp(struct vhost_scsi *vs, struct vhost_virtqueue *vq,
+			 int in_iovs, int vq_desc, struct iovec *resp_iov,
+			 int tmf_resp_code)
 {
 	struct virtio_scsi_ctrl_tmf_resp rsp;
 	struct iov_iter iov_iter;
@@ -1134,17 +1166,87 @@ vhost_scsi_send_tmf_reject(struct vhost_scsi *vs,
 
 	pr_debug("%s\n", __func__);
 	memset(&rsp, 0, sizeof(rsp));
-	rsp.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
+	rsp.response = tmf_resp_code;
 
-	iov_iter_init(&iov_iter, READ, &vq->iov[vc->out], vc->in, sizeof(rsp));
+	iov_iter_init(&iov_iter, READ, resp_iov, in_iovs, sizeof(rsp));
 
 	ret = copy_to_iter(&rsp, sizeof(rsp), &iov_iter);
 	if (likely(ret == sizeof(rsp)))
-		vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0);
+		vhost_add_used_and_signal(&vs->dev, vq, vq_desc, 0);
 	else
 		pr_err("Faulted on virtio_scsi_ctrl_tmf_resp\n");
 }
 
+static void vhost_scsi_tmf_resp_work(struct vhost_work *work)
+{
+	struct vhost_scsi_tmf *tmf = container_of(work, struct vhost_scsi_tmf,
+						  vwork);
+	int resp_code;
+
+	if (tmf->se_cmd.se_tmr_req->response == TMR_FUNCTION_COMPLETE)
+		resp_code = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
+	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_handle_tmf(struct vhost_scsi *vs, struct vhost_scsi_tpg *tpg,
+		      struct vhost_virtqueue *vq,
+		      struct virtio_scsi_ctrl_tmf_req *vtmf,
+		      struct vhost_scsi_ctx *vc)
+{
+	struct vhost_scsi_virtqueue *svq = container_of(vq,
+					struct vhost_scsi_virtqueue, vq);
+	struct vhost_scsi_tmf *tmf;
+
+	if (vhost32_to_cpu(vq, vtmf->subtype) !=
+	    VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET)
+		goto send_reject;
+
+	if (!tpg->tpg_nexus || !tpg->tpg_nexus->tvn_se_sess) {
+		pr_err("Unable to locate active struct vhost_scsi_nexus for LUN RESET.\n");
+		goto send_reject;
+	}
+
+	mutex_lock(&tpg->tv_tpg_mutex);
+	if (list_empty(&tpg->tmf_queue)) {
+		pr_err("Missing reserve TMF. Could not handle LUN RESET.\n");
+		mutex_unlock(&tpg->tv_tpg_mutex);
+		goto send_reject;
+	}
+
+	tmf = list_first_entry(&tpg->tmf_queue, struct vhost_scsi_tmf,
+			       queue_entry);
+	list_del_init(&tmf->queue_entry);
+	mutex_unlock(&tpg->tv_tpg_mutex);
+
+	tmf->tpg = tpg;
+	tmf->vhost = vs;
+	tmf->svq = svq;
+	tmf->resp_iov = vq->iov[vc->out];
+	tmf->vq_desc = vc->head;
+	tmf->in_iovs = vc->in;
+	tmf->inflight = vhost_scsi_get_inflight(vq);
+
+	if (target_submit_tmr(&tmf->se_cmd, tpg->tpg_nexus->tvn_se_sess, NULL,
+			      vhost_buf_to_lun(vtmf->lun), NULL,
+			      TMR_LUN_RESET, GFP_KERNEL, 0,
+			      TARGET_SCF_ACK_KREF) < 0) {
+		vhost_scsi_release_tmf_res(tmf);
+		goto send_reject;
+	}
+
+	return;
+
+send_reject:
+	vhost_scsi_send_tmf_resp(vs, vq, vc->in, vc->head, &vq->iov[vc->out],
+				 VIRTIO_SCSI_S_FUNCTION_REJECTED);
+}
+
 static void
 vhost_scsi_send_an_resp(struct vhost_scsi *vs,
 			struct vhost_virtqueue *vq,
@@ -1170,6 +1272,7 @@ vhost_scsi_send_an_resp(struct vhost_scsi *vs,
 static void
 vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 {
+	struct vhost_scsi_tpg *tpg;
 	union {
 		__virtio32 type;
 		struct virtio_scsi_ctrl_an_req an;
@@ -1251,12 +1354,12 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 		vc.req += typ_size;
 		vc.req_size -= typ_size;
 
-		ret = vhost_scsi_get_req(vq, &vc, NULL);
+		ret = vhost_scsi_get_req(vq, &vc, &tpg);
 		if (ret)
 			goto err;
 
 		if (v_req.type == VIRTIO_SCSI_T_TMF)
-			vhost_scsi_send_tmf_reject(vs, vq, &vc);
+			vhost_scsi_handle_tmf(vs, tpg, vq, &v_req.tmf, &vc);
 		else
 			vhost_scsi_send_an_resp(vs, vq, &vc);
 err:
@@ -1373,6 +1476,83 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)
 		wait_for_completion(&old_inflight[i]->comp);
 }
 
+static void vhost_scsi_destroy_vq_cmds(struct vhost_virtqueue *vq)
+{
+	struct vhost_scsi_virtqueue *svq = container_of(vq,
+					struct vhost_scsi_virtqueue, vq);
+	struct vhost_scsi_cmd *tv_cmd;
+	unsigned int i;
+
+	if (!svq->scsi_cmds)
+		return;
+
+	for (i = 0; i < svq->max_cmds; i++) {
+		tv_cmd = &svq->scsi_cmds[i];
+
+		kfree(tv_cmd->tvc_sgl);
+		kfree(tv_cmd->tvc_prot_sgl);
+		kfree(tv_cmd->tvc_upages);
+	}
+
+	sbitmap_free(&svq->scsi_tags);
+	kfree(svq->scsi_cmds);
+	svq->scsi_cmds = NULL;
+}
+
+static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds)
+{
+	struct vhost_scsi_virtqueue *svq = container_of(vq,
+					struct vhost_scsi_virtqueue, vq);
+	struct vhost_scsi_cmd *tv_cmd;
+	unsigned int i;
+
+	if (svq->scsi_cmds)
+		return 0;
+
+	if (sbitmap_init_node(&svq->scsi_tags, max_cmds, -1, GFP_KERNEL,
+			      NUMA_NO_NODE))
+		return -ENOMEM;
+	svq->max_cmds = max_cmds;
+
+	svq->scsi_cmds = kcalloc(max_cmds, sizeof(*tv_cmd), GFP_KERNEL);
+	if (!svq->scsi_cmds) {
+		sbitmap_free(&svq->scsi_tags);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < max_cmds; i++) {
+		tv_cmd = &svq->scsi_cmds[i];
+
+		tv_cmd->tvc_sgl = kcalloc(VHOST_SCSI_PREALLOC_SGLS,
+					  sizeof(struct scatterlist),
+					  GFP_KERNEL);
+		if (!tv_cmd->tvc_sgl) {
+			pr_err("Unable to allocate tv_cmd->tvc_sgl\n");
+			goto out;
+		}
+
+		tv_cmd->tvc_upages = kcalloc(VHOST_SCSI_PREALLOC_UPAGES,
+					     sizeof(struct page *),
+					     GFP_KERNEL);
+		if (!tv_cmd->tvc_upages) {
+			pr_err("Unable to allocate tv_cmd->tvc_upages\n");
+			goto out;
+		}
+
+		tv_cmd->tvc_prot_sgl = kcalloc(VHOST_SCSI_PREALLOC_PROT_SGLS,
+					       sizeof(struct scatterlist),
+					       GFP_KERNEL);
+		if (!tv_cmd->tvc_prot_sgl) {
+			pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");
+			goto out;
+		}
+	}
+	return 0;
+out:
+	vhost_scsi_destroy_vq_cmds(vq);
+	return -ENOMEM;
+}
+
 /*
  * Called from vhost_scsi_ioctl() context to walk the list of available
  * vhost_scsi_tpg with an active struct vhost_scsi_nexus
@@ -1427,10 +1607,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
 
 		if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) {
 			if (vs->vs_tpg && vs->vs_tpg[tpg->tport_tpgt]) {
-				kfree(vs_tpg);
 				mutex_unlock(&tpg->tv_tpg_mutex);
 				ret = -EEXIST;
-				goto out;
+				goto undepend;
 			}
 			/*
 			 * In order to ensure individual vhost-scsi configfs
@@ -1442,9 +1621,8 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
 			ret = target_depend_item(&se_tpg->tpg_group.cg_item);
 			if (ret) {
 				pr_warn("target_depend_item() failed: %d\n", ret);
-				kfree(vs_tpg);
 				mutex_unlock(&tpg->tv_tpg_mutex);
-				goto out;
+				goto undepend;
 			}
 			tpg->tv_tpg_vhost_count++;
 			tpg->vhost_scsi = vs;
@@ -1457,6 +1635,16 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
 	if (match) {
 		memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn,
 		       sizeof(vs->vs_vhost_wwpn));
+
+		for (i = VHOST_SCSI_VQ_IO; i < VHOST_SCSI_MAX_VQ; i++) {
+			vq = &vs->vqs[i].vq;
+			if (!vhost_vq_is_setup(vq))
+				continue;
+
+			if (vhost_scsi_setup_vq_cmds(vq, vq->num))
+				goto destroy_vq_cmds;
+		}
+
 		for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) {
 			vq = &vs->vqs[i].vq;
 			mutex_lock(&vq->mutex);
@@ -1476,7 +1664,22 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
 	vhost_scsi_flush(vs);
 	kfree(vs->vs_tpg);
 	vs->vs_tpg = vs_tpg;
+	goto out;
 
+destroy_vq_cmds:
+	for (i--; i >= VHOST_SCSI_VQ_IO; i--) {
+		if (!vhost_vq_get_backend(&vs->vqs[i].vq))
+			vhost_scsi_destroy_vq_cmds(&vs->vqs[i].vq);
+	}
+undepend:
+	for (i = 0; i < VHOST_SCSI_MAX_TARGET; i++) {
+		tpg = vs_tpg[i];
+		if (tpg) {
+			tpg->tv_tpg_vhost_count--;
+			target_undepend_item(&tpg->se_tpg.tpg_group.cg_item);
+		}
+	}
+	kfree(vs_tpg);
 out:
 	mutex_unlock(&vs->dev.mutex);
 	mutex_unlock(&vhost_scsi_mutex);
@@ -1549,6 +1752,12 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs,
 			mutex_lock(&vq->mutex);
 			vhost_vq_set_backend(vq, NULL);
 			mutex_unlock(&vq->mutex);
+			/*
+			 * Make sure cmds are not running before tearing them
+			 * down.
+			 */
+			vhost_scsi_flush(vs);
+			vhost_scsi_destroy_vq_cmds(vq);
 		}
 	}
 	/*
@@ -1811,11 +2020,19 @@ static int vhost_scsi_port_link(struct se_portal_group *se_tpg,
 {
 	struct vhost_scsi_tpg *tpg = container_of(se_tpg,
 				struct vhost_scsi_tpg, se_tpg);
+	struct vhost_scsi_tmf *tmf;
+
+	tmf = kzalloc(sizeof(*tmf), GFP_KERNEL);
+	if (!tmf)
+		return -ENOMEM;
+	INIT_LIST_HEAD(&tmf->queue_entry);
+	vhost_work_init(&tmf->vwork, vhost_scsi_tmf_resp_work);
 
 	mutex_lock(&vhost_scsi_mutex);
 
 	mutex_lock(&tpg->tv_tpg_mutex);
 	tpg->tv_tpg_port_count++;
+	list_add_tail(&tmf->queue_entry, &tpg->tmf_queue);
 	mutex_unlock(&tpg->tv_tpg_mutex);
 
 	vhost_scsi_hotplug(tpg, lun);
@@ -1830,11 +2047,16 @@ static void vhost_scsi_port_unlink(struct se_portal_group *se_tpg,
 {
 	struct vhost_scsi_tpg *tpg = container_of(se_tpg,
 				struct vhost_scsi_tpg, se_tpg);
+	struct vhost_scsi_tmf *tmf;
 
 	mutex_lock(&vhost_scsi_mutex);
 
 	mutex_lock(&tpg->tv_tpg_mutex);
 	tpg->tv_tpg_port_count--;
+	tmf = list_first_entry(&tpg->tmf_queue, struct vhost_scsi_tmf,
+			       queue_entry);
+	list_del(&tmf->queue_entry);
+	kfree(tmf);
 	mutex_unlock(&tpg->tv_tpg_mutex);
 
 	vhost_scsi_hotunplug(tpg, lun);
@@ -1842,23 +2064,6 @@ static void vhost_scsi_port_unlink(struct se_portal_group *se_tpg,
 	mutex_unlock(&vhost_scsi_mutex);
 }
 
-static void vhost_scsi_free_cmd_map_res(struct se_session *se_sess)
-{
-	struct vhost_scsi_cmd *tv_cmd;
-	unsigned int i;
-
-	if (!se_sess->sess_cmd_map)
-		return;
-
-	for (i = 0; i < VHOST_SCSI_DEFAULT_TAGS; i++) {
-		tv_cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[i];
-
-		kfree(tv_cmd->tvc_sgl);
-		kfree(tv_cmd->tvc_prot_sgl);
-		kfree(tv_cmd->tvc_upages);
-	}
-}
-
 static ssize_t vhost_scsi_tpg_attrib_fabric_prot_type_store(
 		struct config_item *item, const char *page, size_t count)
 {
@@ -1898,45 +2103,6 @@ static struct configfs_attribute *vhost_scsi_tpg_attrib_attrs[] = {
 	NULL,
 };
 
-static int vhost_scsi_nexus_cb(struct se_portal_group *se_tpg,
-			       struct se_session *se_sess, void *p)
-{
-	struct vhost_scsi_cmd *tv_cmd;
-	unsigned int i;
-
-	for (i = 0; i < VHOST_SCSI_DEFAULT_TAGS; i++) {
-		tv_cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[i];
-
-		tv_cmd->tvc_sgl = kcalloc(VHOST_SCSI_PREALLOC_SGLS,
-					  sizeof(struct scatterlist),
-					  GFP_KERNEL);
-		if (!tv_cmd->tvc_sgl) {
-			pr_err("Unable to allocate tv_cmd->tvc_sgl\n");
-			goto out;
-		}
-
-		tv_cmd->tvc_upages = kcalloc(VHOST_SCSI_PREALLOC_UPAGES,
-					     sizeof(struct page *),
-					     GFP_KERNEL);
-		if (!tv_cmd->tvc_upages) {
-			pr_err("Unable to allocate tv_cmd->tvc_upages\n");
-			goto out;
-		}
-
-		tv_cmd->tvc_prot_sgl = kcalloc(VHOST_SCSI_PREALLOC_PROT_SGLS,
-					       sizeof(struct scatterlist),
-					       GFP_KERNEL);
-		if (!tv_cmd->tvc_prot_sgl) {
-			pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");
-			goto out;
-		}
-	}
-	return 0;
-out:
-	vhost_scsi_free_cmd_map_res(se_sess);
-	return -ENOMEM;
-}
-
 static int vhost_scsi_make_nexus(struct vhost_scsi_tpg *tpg,
 				const char *name)
 {
@@ -1960,12 +2126,9 @@ static int vhost_scsi_make_nexus(struct vhost_scsi_tpg *tpg,
 	 * struct se_node_acl for the vhost_scsi struct se_portal_group with
 	 * the SCSI Initiator port name of the passed configfs group 'name'.
 	 */
-	tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
-					VHOST_SCSI_DEFAULT_TAGS,
-					sizeof(struct vhost_scsi_cmd),
+	tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg, 0, 0,
 					TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS,
-					(unsigned char *)name, tv_nexus,
-					vhost_scsi_nexus_cb);
+					(unsigned char *)name, tv_nexus, NULL);
 	if (IS_ERR(tv_nexus->tvn_se_sess)) {
 		mutex_unlock(&tpg->tv_tpg_mutex);
 		kfree(tv_nexus);
@@ -2015,7 +2178,6 @@ static int vhost_scsi_drop_nexus(struct vhost_scsi_tpg *tpg)
 		" %s Initiator Port: %s\n", vhost_scsi_dump_proto_id(tpg->tport),
 		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
 
-	vhost_scsi_free_cmd_map_res(se_sess);
 	/*
 	 * Release the SCSI I_T Nexus to the emulated vhost Target Port
 	 */
@@ -2155,6 +2317,7 @@ vhost_scsi_make_tpg(struct se_wwn *wwn, const char *name)
 	}
 	mutex_init(&tpg->tv_tpg_mutex);
 	INIT_LIST_HEAD(&tpg->tv_tpg_list);
+	INIT_LIST_HEAD(&tpg->tmf_queue);
 	tpg->tport = tport;
 	tpg->tport_tpgt = tpgt;
 
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 5c835a292783..a262e12c6dc2 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -304,6 +304,12 @@ static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
 	memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
 }
 
+bool vhost_vq_is_setup(struct vhost_virtqueue *vq)
+{
+	return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq);
+}
+EXPORT_SYMBOL_GPL(vhost_vq_is_setup);
+
 static void vhost_vq_reset(struct vhost_dev *dev,
 			   struct vhost_virtqueue *vq)
 {
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index e016cd3fa02f..b063324c7669 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -190,6 +190,7 @@ 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);
 
+bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
 int vhost_vq_init_access(struct vhost_virtqueue *);
 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,