Index: sys/dev/nvme/nvme.c
===================================================================
--- sys/dev/nvme/nvme.c
+++ sys/dev/nvme/nvme.c
@@ -452,5 +452,6 @@
 	 */
 	memcpy(&status->cpl, cpl, sizeof(*cpl));
 	wmb();
-	status->done = TRUE;
+	if (status != NULL)
+		status->done = TRUE;
 }
Index: sys/dev/nvme/nvme_ns_cmd.c
===================================================================
--- sys/dev/nvme/nvme_ns_cmd.c
+++ sys/dev/nvme/nvme_ns_cmd.c
@@ -158,17 +158,25 @@
 int
 nvme_ns_dump(struct nvme_namespace *ns, void *virt, off_t offset, size_t len)
 {
-	struct nvme_completion_poll_status status;
+	struct nvme_completion_poll_status *status, cbarg;
 	struct nvme_request *req;
 	struct nvme_command *cmd;
 	uint64_t lba, lba_count;
 	int i;
 
-	status.done = FALSE;
-	req = nvme_allocate_request_vaddr(virt, len, nvme_completion_poll_cb,
-	    &status);
-	if (req == NULL)
-		return (ENOMEM);
+	if (len > 0) {
+		status = &cbarg;
+		status->done = FALSE;
+	} else
+		status = NULL;
+
+	for (i = 0; i < NVD_DUMP_TIMEOUT; i++) {
+		req = nvme_allocate_request_vaddr(virt, len,
+		    nvme_completion_poll_cb, &status);
+		if (req != NULL)
+			break;
+		nvme_qpair_process_completions(req->qpair);
+	}
 
 	cmd = &req->cmd;
 
@@ -183,13 +191,17 @@
 	if (req->qpair == NULL)
 		return (ENXIO);
 
-	i = 0;
-	while ((i++ < NVD_DUMP_TIMEOUT) && (status.done == FALSE)) {
+	if (len > 0)
+		return (0);
+
+	for (i = 0; i < NVD_DUMP_TIMEOUT; i++) {
 		DELAY(5);
 		nvme_qpair_process_completions(req->qpair);
+		if (status->done == TRUE)
+			break;
 	}
 
-	if (status.done == FALSE)
+	if (status->done == FALSE)
 		return (ETIMEDOUT);
 
 	return (0);