lib/bdev: add spdk_bdev_wait_for_examine()

Add spdk_bdev_wait_for_examine() API to be called
in order to report when examine on all registered bdevs finished.
It will be built in to most bdev modules RPC.

New RPC added to allow
- building it into bdev submodule
- user/orchestration to verify examination status manually

Signed-off-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Change-Id: I27db3ae42eea3e692faeea4c2a01d04586bff438
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/5480
Community-CI: Broadcom CI
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: <dongx.yi@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>

CHANGELOG.md

@@ -10,6 +10,9 @@ parameter in spdk_bdev_get_opts function. Two fields `small_buf_pool_size` and
 `large_buf_pool_size` were added into spdk_bdev_opts, which were used to determine
 the small and large buffer pool size of the whole bdev module.
 
+A new API `spdk_bdev_wait_for_examine` was added to allow for checking state of
+examine process. Along with corresponding `bdev_wait_for_examine` RPC.
+
 ### blob
 
 An `opts_size` element was added in the `spdk_bs_opts` structure to solve the

doc/jsonrpc.md

@@ -1320,6 +1320,40 @@ Example response:
 }
 ~~~
 
+## bdev_wait_for_examine {#rpc_bdev_wait_for_examine}
+
+Report when all bdevs have been examined by every bdev module.
+
+### Parameters
+
+None
+
+### Response
+
+The response is sent when all bdev modules had a chance to examine every bdev.
+
+### Example
+
+Example request:
+
+~~~
+{
+  "jsonrpc": "2.0",
+  "method": "bdev_wait_for_examine",
+  "id": 1
+}
+~~~
+
+Example response:
+
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": true
+}
+~~~
+
 ## bdev_get_iostat {#rpc_bdev_get_iostat}
 
 Get I/O statistics of block devices (bdevs).

include/spdk/bdev.h

@@ -209,6 +209,20 @@ void spdk_bdev_get_opts(struct spdk_bdev_opts *opts, size_t opts_size);
 
 int spdk_bdev_set_opts(struct spdk_bdev_opts *opts);
 
+typedef void (*spdk_bdev_wait_for_examine_cb)(void *arg);
+
+/**
+ * Report when all bdevs finished the examine process.
+ * The registered cb_fn will be called just once.
+ * This function needs to be called again to receive
+ * further reports on examine process.
+ *
+ * \param cb_fn Callback function.
+ * \param cb_arg Callback argument.
+ * \return 0 if function was registered, suitable errno value otherwise
+ */
+int spdk_bdev_wait_for_examine(spdk_bdev_wait_for_examine_cb cb_fn, void *cb_arg);
+
 /**
  * Examine a block device explicitly
  *

lib/bdev/bdev.c

@@ -462,6 +462,47 @@ spdk_bdev_set_opts(struct spdk_bdev_opts *opts)
 	return 0;
 }
 
+struct spdk_bdev_wait_for_examine_ctx {
+	struct spdk_poller              *poller;
+	spdk_bdev_wait_for_examine_cb	cb_fn;
+	void				*cb_arg;
+};
+
+static bool
+bdev_module_all_actions_completed(void);
+
+static int
+bdev_wait_for_examine_cb(void *arg)
+{
+	struct spdk_bdev_wait_for_examine_ctx *ctx = arg;
+
+	if (!bdev_module_all_actions_completed()) {
+		return SPDK_POLLER_IDLE;
+	}
+
+	spdk_poller_unregister(&ctx->poller);
+	ctx->cb_fn(ctx->cb_arg);
+	free(ctx);
+
+	return SPDK_POLLER_BUSY;
+}
+
+int
+spdk_bdev_wait_for_examine(spdk_bdev_wait_for_examine_cb cb_fn, void *cb_arg)
+{
+	struct spdk_bdev_wait_for_examine_ctx *ctx;
+
+	ctx = calloc(1, sizeof(*ctx));
+	if (ctx == NULL) {
+		return -ENOMEM;
+	}
+	ctx->cb_fn = cb_fn;
+	ctx->cb_arg = cb_arg;
+	ctx->poller = SPDK_POLLER_REGISTER(bdev_wait_for_examine_cb, ctx, 0);
+
+	return 0;
+}
+
 struct spdk_bdev_examine_item {
 	char *name;
 	TAILQ_ENTRY(spdk_bdev_examine_item) link;

lib/bdev/bdev_rpc.c

@@ -110,6 +110,33 @@ rpc_bdev_set_options(struct spdk_jsonrpc_request *request, const struct spdk_jso
 SPDK_RPC_REGISTER("bdev_set_options", rpc_bdev_set_options, SPDK_RPC_STARTUP)
 SPDK_RPC_REGISTER_ALIAS_DEPRECATED(bdev_set_options, set_bdev_options)
 
+static void
+rpc_bdev_wait_for_examine_cpl(void *arg)
+{
+	struct spdk_jsonrpc_request *request = arg;
+
+	spdk_jsonrpc_send_bool_response(request, true);
+}
+
+static void
+rpc_bdev_wait_for_examine(struct spdk_jsonrpc_request *request,
+			  const struct spdk_json_val *params)
+{
+	int rc;
+
+	if (params != NULL) {
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+						 "bdev_wait_for_examine requires no parameters");
+		return;
+	}
+
+	rc = spdk_bdev_wait_for_examine(rpc_bdev_wait_for_examine_cpl, request);
+	if (rc != 0) {
+		spdk_jsonrpc_send_error_response(request, rc, spdk_strerror(-rc));
+	}
+}
+SPDK_RPC_REGISTER("bdev_wait_for_examine", rpc_bdev_wait_for_examine, SPDK_RPC_RUNTIME)
+
 struct rpc_bdev_examine {
 	char *name;
 };

lib/bdev/spdk_bdev.map

@@ -4,6 +4,7 @@
 	# Public functions in bdev.h
 	spdk_bdev_get_opts;
 	spdk_bdev_set_opts;
+	spdk_bdev_wait_for_examine;
 	spdk_bdev_examine;
 	spdk_bdev_initialize;
 	spdk_bdev_finish;

scripts/rpc.py

@@ -198,6 +198,13 @@ if __name__ == "__main__":
     p.add_argument('-b', '--name', help='Name or alias of the bdev')
     p.set_defaults(func=bdev_examine)
 
+    def bdev_wait_for_examine(args):
+        rpc.bdev.bdev_wait_for_examine(args.client)
+
+    p = subparsers.add_parser('bdev_wait_for_examine',
+                              help="""Report when all bdevs have been examined""")
+    p.set_defaults(func=bdev_wait_for_examine)
+
     def bdev_compress_create(args):
         print_json(rpc.bdev.bdev_compress_create(args.client,
                                                  base_bdev_name=args.base_bdev_name,

scripts/rpc/bdev.py

@@ -41,6 +41,12 @@ def bdev_examine(client, name):
     return client.call('bdev_examine', params)
 
 
+def bdev_wait_for_examine(client):
+    """Report when all bdevs have been examined
+    """
+    return client.call('bdev_wait_for_examine')
+
+
 @deprecated_alias('construct_compress_bdev')
 def bdev_compress_create(client, base_bdev_name, pm_path, lb_size):
     """Construct a compress virtual block device.

test/bdev/blockdev.sh

@@ -346,6 +346,8 @@ case "$test_type" in
 		;;
 esac
 
+"$rpc_py" bdev_wait_for_examine
+
 # Generate json config and use it throughout all the tests
 cat <<- CONF > "$conf_file"
 	        {"subsystems":[