bdev/nvme: modify attach_controller rpc to also add multipath trids.

This allows us to avoid creating a separate rpc just for multipath TRIDs.

Signed-off-by: Seth Howell <seth.howell@intel.com>
Change-Id: I4e83167eaf16e50a72efbd513333a4d09c52be61
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/2884
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>

doc/jsonrpc.md

@@ -1771,7 +1771,10 @@ Example response:
 
 ## bdev_nvme_attach_controller {#rpc_bdev_nvme_attach_controller}
 
-Construct @ref bdev_config_nvme
+Construct @ref bdev_config_nvme. This RPC can also be used to add additional paths to an existing controller to enable
+multipathing. This is done by specifying the `name` parameter as an existing controller. When adding an additional
+path, the hostnqn, hostsvcid, hostaddr, prchk_reftag, and prchk_guard_arguments must not be specified and are assumed
+to have the same value as the existing path.
 
 ### Result
 

module/bdev/nvme/bdev_nvme.c

@@ -1686,7 +1686,7 @@ nvme_ctrlr_populate_namespaces_done(struct nvme_async_probe_ctx *ctx)
 	uint32_t		i, nsid;
 	size_t			j;
 
-	nvme_bdev_ctrlr = nvme_bdev_ctrlr_get(&ctx->trid);
+	nvme_bdev_ctrlr = nvme_bdev_ctrlr_get_by_name(ctx->base_name);
 	assert(nvme_bdev_ctrlr != NULL);
 
 	/*
@@ -1849,14 +1849,23 @@ bdev_nvme_create(struct spdk_nvme_transport_id *trid,
 {
 	struct nvme_probe_skip_entry	*entry, *tmp;
 	struct nvme_async_probe_ctx	*ctx;
+	struct nvme_bdev_ctrlr		*existing_ctrlr;
+	int				rc;
 
-	if (nvme_bdev_ctrlr_get(trid) != NULL) {
+	existing_ctrlr = nvme_bdev_ctrlr_get_by_name(base_name);
-		SPDK_ERRLOG("A controller with the provided trid (traddr: %s) already exists.\n", trid->traddr);
+	if (existing_ctrlr) {
+		if (trid->trtype == SPDK_NVME_TRANSPORT_PCIE) {
+			SPDK_ERRLOG("A controller with the provided name (name: %s) already exists with transport type PCIe. PCIe multipath is not supported.\n",
+				    base_name);
 			return -EEXIST;
 		}
-
+		rc = bdev_nvme_add_trid(existing_ctrlr->name, trid);
-	if (nvme_bdev_ctrlr_get_by_name(base_name)) {
+		if (rc) {
-		SPDK_ERRLOG("A controller with the provided name (%s) already exists.\n", base_name);
+			return rc;
+		}
+		/* TODO expand this check to include both the host and target TRIDs. Only if both are the same should we fail. */
+	} else if (nvme_bdev_ctrlr_get(trid) != NULL) {
+		SPDK_ERRLOG("A controller with the provided trid (traddr: %s) already exists.\n", trid->traddr);
 		return -EEXIST;
 	}
 
@@ -1882,6 +1891,11 @@ bdev_nvme_create(struct spdk_nvme_transport_id *trid,
 	ctx->prchk_flags = prchk_flags;
 	ctx->trid = *trid;
 
+	if (existing_ctrlr) {
+		nvme_ctrlr_populate_namespaces_done(ctx);
+		return 0;
+	}
+
 	spdk_nvme_ctrlr_get_default_ctrlr_opts(&ctx->opts, sizeof(ctx->opts));
 	ctx->opts.transport_retry_count = g_opts.retry_count;
 

module/bdev/nvme/bdev_nvme_rpc.c

@@ -257,6 +257,7 @@ rpc_bdev_nvme_attach_controller(struct spdk_jsonrpc_request *request,
 	struct spdk_nvme_transport_id trid = {};
 	struct spdk_nvme_host_id hostid = {};
 	uint32_t prchk_flags = 0;
+	struct nvme_bdev_ctrlr *ctrlr = NULL;
 	int rc;
 
 	ctx = calloc(1, sizeof(*ctx));
@@ -287,6 +288,8 @@ rpc_bdev_nvme_attach_controller(struct spdk_jsonrpc_request *request,
 	rc = spdk_nvme_transport_id_parse_trtype(&trid.trtype, ctx->req.trtype);
 	assert(rc == 0);
 
+	ctrlr = nvme_bdev_ctrlr_get_by_name(ctx->req.name);
+
 	/* Parse traddr */
 	snprintf(trid.traddr, sizeof(trid.traddr), "%s", ctx->req.traddr);
 
@@ -316,6 +319,11 @@ rpc_bdev_nvme_attach_controller(struct spdk_jsonrpc_request *request,
 		snprintf(trid.subnqn, sizeof(trid.subnqn), "%s", ctx->req.subnqn);
 	}
 
+	if (ctrlr && (ctx->req.hostaddr || ctx->req.hostnqn || ctx->req.hostsvcid || ctx->req.prchk_guard ||
+		      ctx->req.prchk_reftag)) {
+		goto conflicting_arguments;
+	}
+
 	if (ctx->req.hostaddr) {
 		snprintf(hostid.hostaddr, sizeof(hostid.hostaddr), "%s", ctx->req.hostaddr);
 	}
@@ -343,6 +351,9 @@ rpc_bdev_nvme_attach_controller(struct spdk_jsonrpc_request *request,
 
 	return;
 
+conflicting_arguments:
+	spdk_jsonrpc_send_error_response_fmt(request, -EINVAL,
+					     "Invalid agrgument list. Existing controller name cannot be combined with host information or PI options.\n");
 cleanup:
 	free_rpc_bdev_nvme_attach_controller(&ctx->req);
 	free(ctx);