vhost/scsi: Fix incorrect early vhost_scsi_handle_vq failures

This patch fixes vhost_scsi_handle_vq() failure cases that result in BUG_ON()
getting triggered when vhost_scsi_free_cmd() is called, and ->tvc_se_cmd has
not been initialized by target_submit_cmd_map_sgls().

It changes tcm_vhost_release_cmd() to use tcm_vhost_cmd->tvc_nexus for obtaining
se_session pointer reference.  Also, avoid calling put_page() on NULL sg->page
entries in vhost_scsi_map_to_sgl() failure path.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 29dfdf66bbc520cca8f14f3c7bcbd34e2ff955e4..62de820ae2f4fc72244ad85b04fbd5ce99fbba75 100644 (file)
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -462,7 +462,7 @@ static void tcm_vhost_release_cmd(struct se_cmd *se_cmd)
 {
        struct tcm_vhost_cmd *tv_cmd = container_of(se_cmd,
                                struct tcm_vhost_cmd, tvc_se_cmd);
-       struct se_session *se_sess = se_cmd->se_sess;
+       struct se_session *se_sess = tv_cmd->tvc_nexus->tvn_se_sess;
        int i;
 
        if (tv_cmd->tvc_sgl_count) {
@@ -864,9 +864,11 @@ vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *cmd,
                ret = vhost_scsi_map_to_sgl(cmd, sg, sgl_count, &iov[i],
                                            cmd->tvc_upages, write);
                if (ret < 0) {
-                       for (i = 0; i < cmd->tvc_sgl_count; i++)
-                               put_page(sg_page(&cmd->tvc_sgl[i]));
-
+                       for (i = 0; i < cmd->tvc_sgl_count; i++) {
+                               struct page *page = sg_page(&cmd->tvc_sgl[i]);
+                               if (page)
+                                       put_page(page);
+                       }
                        cmd->tvc_sgl_count = 0;
                        return ret;
                }
@@ -905,9 +907,11 @@ vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd,
                ret = vhost_scsi_map_to_sgl(cmd, prot_sg, prot_sgl_count, &iov[i],
                                            cmd->tvc_upages, write);
                if (ret < 0) {
-                       for (i = 0; i < cmd->tvc_prot_sgl_count; i++)
-                               put_page(sg_page(&cmd->tvc_prot_sgl[i]));
-
+                       for (i = 0; i < cmd->tvc_prot_sgl_count; i++) {
+                               struct page *page = sg_page(&cmd->tvc_prot_sgl[i]);
+                               if (page)
+                                       put_page(page);
+                       }
                        cmd->tvc_prot_sgl_count = 0;
                        return ret;
                }
@@ -1065,12 +1069,14 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                if (unlikely(vq->iov[0].iov_len < req_size)) {
                        pr_err("Expecting virtio-scsi header: %zu, got %zu\n",
                               req_size, vq->iov[0].iov_len);
-                       break;
+                       vhost_scsi_send_bad_target(vs, vq, head, out);
+                       continue;
                }
                ret = memcpy_fromiovecend(req, &vq->iov[0], 0, req_size);
                if (unlikely(ret)) {
                        vq_err(vq, "Faulted on virtio_scsi_cmd_req\n");
-                       break;
+                       vhost_scsi_send_bad_target(vs, vq, head, out);
+                       continue;
                }
 
                /* virtio-scsi spec requires byte 0 of the lun to be 1 */
@@ -1101,14 +1107,16 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                                if (data_direction != DMA_TO_DEVICE) {
                                        vq_err(vq, "Received non zero do_pi_niov"
                                                ", but wrong data_direction\n");
-                                       goto err_cmd;
+                                       vhost_scsi_send_bad_target(vs, vq, head, out);
+                                       continue;
                                }
                                prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesout);
                        } else if (v_req_pi.pi_bytesin) {
                                if (data_direction != DMA_FROM_DEVICE) {
                                        vq_err(vq, "Received non zero di_pi_niov"
                                                ", but wrong data_direction\n");
-                                       goto err_cmd;
+                                       vhost_scsi_send_bad_target(vs, vq, head, out);
+                                       continue;
                                }
                                prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesin);
                        }
@@ -1148,7 +1156,8 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                        vq_err(vq, "Received SCSI CDB with command_size: %d that"
                                " exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
                                scsi_command_size(cdb), TCM_VHOST_MAX_CDB_SIZE);
-                       goto err_cmd;
+                       vhost_scsi_send_bad_target(vs, vq, head, out);
+                       continue;
                }
 
                cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
@@ -1157,7 +1166,8 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                if (IS_ERR(cmd)) {
                        vq_err(vq, "vhost_scsi_get_tag failed %ld\n",
                                        PTR_ERR(cmd));
-                       goto err_cmd;
+                       vhost_scsi_send_bad_target(vs, vq, head, out);
+                       continue;
                }
 
                pr_debug("Allocated tv_cmd: %p exp_data_len: %d, data_direction"
@@ -1178,7 +1188,9 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                        if (unlikely(ret)) {
                                vq_err(vq, "Failed to map iov to"
                                        " prot_sgl\n");
-                               goto err_free;
+                               tcm_vhost_release_cmd(&cmd->tvc_se_cmd);
+                               vhost_scsi_send_bad_target(vs, vq, head, out);
+                               continue;
                        }
                }
                if (data_direction != DMA_NONE) {
@@ -1187,7 +1199,9 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                                        data_direction == DMA_FROM_DEVICE);
                        if (unlikely(ret)) {
                                vq_err(vq, "Failed to map iov to sgl\n");
-                               goto err_free;
+                               tcm_vhost_release_cmd(&cmd->tvc_se_cmd);
+                               vhost_scsi_send_bad_target(vs, vq, head, out);
+                               continue;
                        }
                }
                /*
@@ -1205,14 +1219,6 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
                INIT_WORK(&cmd->work, tcm_vhost_submission_work);
                queue_work(tcm_vhost_workqueue, &cmd->work);
        }
-
-       mutex_unlock(&vq->mutex);
-       return;
-
-err_free:
-       vhost_scsi_free_cmd(cmd);
-err_cmd:
-       vhost_scsi_send_bad_target(vs, vq, head, out);
 out:
        mutex_unlock(&vq->mutex);
 }