ublk: add ublk to export block device

ublk could export a backend device as ublk block device (/dev/ublkb*).
A rpc method is used to add ublk device and it should be done
after creating ublk target. Corresponding, ublk_del_dev is
used to delete the specified ublk device.

Signed-off-by: Yifan Bian <yifan.bian@intel.com>
Co-authored-by: Xiaodong Liu <xiaodong.liu@intel.com>
Change-Id: I3a4ba8d8dc5f5ad241511ccbc9d3336b582a6dc5
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/15976
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Xiaodong Liu <xiaodong.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Paul Luse <paul.e.luse@intel.com>

doc/jsonrpc.md

@@ -10749,6 +10749,88 @@ Example response:
 }
 ~~~
 
+### ublk_start_disk {#rpc_ublk_start_disk}
+
+Start to export one SPDK bdev as a UBLK device
+
+#### Parameters
+
+Name                    | Optional | Type        | Description
+----------------------- | -------- | ----------- | -----------
+bdev_name               | Required | string      | Bdev name to export
+ublk_id                 | Required | int         | Device id
+queue_depth             | Optional | int         | Device queue depth
+num_queues              | Optional | int         | Total number of device queues
+
+#### Response
+
+UBLK device ID
+
+#### Example
+
+Example request:
+
+~~~json
+{
+ "params": {
+    "ublk_id": "1",
+    "bdev_name": "Malloc1"
+  },
+  "jsonrpc": "2.0",
+  "method": "ublk_start_disk",
+  "id": 1
+}
+~~~
+
+Example response:
+
+~~~json
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": 1
+}
+~~~
+
+### ublk_stop_disk {#rpc_ublk_stop_disk}
+
+Delete a UBLK device
+
+#### Parameters
+
+Name                    | Optional | Type        | Description
+----------------------- | -------- | ----------- | -----------
+ublk_id                 | Required | int         | Device id to delete
+
+#### Response
+
+True if UBLK device is deleted successfully; False if failed.
+
+#### Example
+
+Example request:
+
+~~~json
+{
+ "params": {
+    "ublk_id": "1",
+  },
+  "jsonrpc": "2.0",
+  "method": "ublk_stop_disk",
+  "id": 1
+}
+~~~
+
+Example response:
+
+~~~json
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": true
+}
+~~~
+
 ## Linux Network Block Device (NBD) {#jsonrpc_components_nbd}
 
 SPDK supports exporting bdevs through Linux nbd. These devices then appear as standard Linux kernel block devices

lib/ublk/ublk_internal.h

@@ -10,12 +10,22 @@
 
 #include "spdk/ublk.h"
 
+#define UBLK_DEV_QUEUE_DEPTH	128
+#define UBLK_DEV_NUM_QUEUE	1
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+typedef void (*ublk_del_cb)(void *cb_arg);
+
 int ublk_create_target(const char *cpumask_str);
 int ublk_destroy_target(spdk_ublk_fini_cb cb_fn, void *cb_arg);
+int ublk_start_disk(const char *bdev_name, uint32_t ublk_id,
+		    uint32_t num_queues, uint32_t queue_depth);
+int ublk_stop_disk(uint32_t ublk_id, ublk_del_cb del_cb, void *cb_arg);
+struct spdk_ublk_dev *ublk_dev_find_by_id(uint32_t ublk_id);
+const char *ublk_dev_get_bdev_name(struct spdk_ublk_dev *ublk);
 
 #ifdef __cplusplus
 }

lib/ublk/ublk_rpc.c

@@ -75,3 +75,115 @@ rpc_ublk_destroy_target(struct spdk_jsonrpc_request *request, const struct spdk_
 	}
 }
 SPDK_RPC_REGISTER("ublk_destroy_target", rpc_ublk_destroy_target, SPDK_RPC_RUNTIME)
+
+struct rpc_ublk_start_disk {
+	char		*bdev_name;
+	uint32_t	ublk_id;
+	uint32_t	num_queues;
+	uint32_t	queue_depth;
+};
+
+static const struct spdk_json_object_decoder rpc_ublk_start_disk_decoders[] = {
+	{"bdev_name", offsetof(struct rpc_ublk_start_disk, bdev_name), spdk_json_decode_string},
+	{"ublk_id", offsetof(struct rpc_ublk_start_disk, ublk_id), spdk_json_decode_uint32},
+	{"num_queues", offsetof(struct rpc_ublk_start_disk, num_queues), spdk_json_decode_uint32, true},
+	{"queue_depth", offsetof(struct rpc_ublk_start_disk, queue_depth), spdk_json_decode_uint32, true},
+};
+
+static void
+rpc_ublk_start_disk(struct spdk_jsonrpc_request *request,
+		    const struct spdk_json_val *params)
+{
+	struct spdk_json_write_ctx *w;
+	struct rpc_ublk_start_disk req = {};
+	int rc;
+
+	req.queue_depth = UBLK_DEV_QUEUE_DEPTH;
+	req.num_queues = UBLK_DEV_NUM_QUEUE;
+
+	if (spdk_json_decode_object(params, rpc_ublk_start_disk_decoders,
+				    SPDK_COUNTOF(rpc_ublk_start_disk_decoders),
+				    &req)) {
+		SPDK_ERRLOG("spdk_json_decode_object failed\n");
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
+						 "spdk_json_decode_object failed");
+		goto out;
+	}
+
+	rc = ublk_start_disk(req.bdev_name, req.ublk_id, req.num_queues, req.queue_depth);
+	if (rc != 0) {
+		spdk_jsonrpc_send_error_response(request, rc, spdk_strerror(-rc));
+		goto out;
+	}
+
+	w = spdk_jsonrpc_begin_result(request);
+	spdk_json_write_uint32(w, req.ublk_id);
+	spdk_jsonrpc_end_result(request, w);
+	goto out;
+
+out:
+	free(req.bdev_name);
+}
+
+SPDK_RPC_REGISTER("ublk_start_disk", rpc_ublk_start_disk, SPDK_RPC_RUNTIME)
+
+struct rpc_ublk_stop_disk {
+	uint32_t ublk_id;
+	struct spdk_jsonrpc_request *request;
+};
+
+static void
+free_rpc_ublk_stop_disk(struct rpc_ublk_stop_disk *req)
+{
+	free(req);
+}
+
+static const struct spdk_json_object_decoder rpc_ublk_stop_disk_decoders[] = {
+	{"ublk_id", offsetof(struct rpc_ublk_stop_disk, ublk_id), spdk_json_decode_uint32},
+};
+
+static void
+rpc_ublk_stop_disk_done(void *cb_arg)
+{
+	struct rpc_ublk_stop_disk *req = cb_arg;
+
+	spdk_jsonrpc_send_bool_response(req->request, true);
+	free_rpc_ublk_stop_disk(req);
+}
+
+static void
+rpc_ublk_stop_disk(struct spdk_jsonrpc_request *request,
+		   const struct spdk_json_val *params)
+{
+	struct rpc_ublk_stop_disk *req;
+	int rc;
+
+	req = calloc(1, sizeof(*req));
+	if (req == NULL) {
+		SPDK_ERRLOG("could not allocate request.\n");
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR, "Out of memory");
+		return;
+	}
+	req->request = request;
+
+	if (spdk_json_decode_object(params, rpc_ublk_stop_disk_decoders,
+				    SPDK_COUNTOF(rpc_ublk_stop_disk_decoders),
+				    req)) {
+		SPDK_ERRLOG("spdk_json_decode_object failed\n");
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
+						 "spdk_json_decode_object failed");
+		goto invalid;
+	}
+
+	rc = ublk_stop_disk(req->ublk_id, rpc_ublk_stop_disk_done, req);
+	if (rc) {
+		spdk_jsonrpc_send_error_response(request, rc, spdk_strerror(-rc));
+		goto invalid;
+	}
+	return;
+
+invalid:
+	free_rpc_ublk_stop_disk(req);
+}
+
+SPDK_RPC_REGISTER("ublk_stop_disk", rpc_ublk_stop_disk, SPDK_RPC_RUNTIME)

python/spdk/rpc/ublk.py

@@ -11,3 +11,20 @@ def ublk_create_target(client, cpumask=None):
 
 def ublk_destroy_target(client):
     return client.call('ublk_destroy_target')
+
+
+def ublk_start_disk(client, bdev_name, ublk_id=1, num_queues=1, queue_depth=128):
+    params = {
+        'bdev_name': bdev_name,
+        'ublk_id': ublk_id
+    }
+    if num_queues:
+        params['num_queues'] = num_queues
+    if queue_depth:
+        params['queue_depth'] = queue_depth
+    return client.call('ublk_start_disk', params)
+
+
+def ublk_stop_disk(client, ublk_id=1):
+    params = {'ublk_id': ublk_id}
+    return client.call('ublk_stop_disk', params)

scripts/rpc.py

@@ -2236,6 +2236,30 @@ Format: 'user:u1 secret:s1 muser:mu1 msecret:ms1,user:u2 secret:s2 muser:mu2 mse
                               help='Destroy spdk ublk target for ublk dev')
     p.set_defaults(func=ublk_destroy_target)
 
+    def ublk_start_disk(args):
+        print(rpc.ublk.ublk_start_disk(args.client,
+                                       bdev_name=args.bdev_name,
+                                       ublk_id=args.ublk_id,
+                                       num_queues=args.num_queues,
+                                       queue_depth=args.queue_depth))
+
+    p = subparsers.add_parser('ublk_start_disk',
+                              help='Export a bdev as a ublk device')
+    p.add_argument('bdev_name', help='Blockdev name to be exported. Example: Malloc0.')
+    p.add_argument('ublk_id', help='ublk device id to be assigned. Example: 1.', type=int)
+    p.add_argument('-q', '--num-queues', help="the total number of queues. Example: 1", type=int, required=False)
+    p.add_argument('-d', '--queue-depth', help="queue depth. Example: 128", type=int, required=False)
+    p.set_defaults(func=ublk_start_disk)
+
+    def ublk_stop_disk(args):
+        rpc.ublk.ublk_stop_disk(args.client,
+                                ublk_id=args.ublk_id)
+
+    p = subparsers.add_parser('ublk_stop_disk',
+                              help='Stop a ublk device')
+    p.add_argument('ublk_id', help='ublk device id to be deleted. Example: 1.', type=int)
+    p.set_defaults(func=ublk_stop_disk)
+
     # nbd
     def nbd_start_disk(args):
         print(rpc.nbd.nbd_start_disk(args.client,