tree: add nvme_subsystem_get

Replace the nvme_lookup_subsystem function with the nvme_subsystem_get
function, which creates the subsystem object if necessary. This allows
retiring the nvme_lookup_subsystem function from the public API.

Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

libnvme/libnvme/nvme.i

@@ -600,15 +600,22 @@ struct nvme_ns {
 	}
 %};
 
-%pythonappend nvme_subsystem::nvme_subsystem(struct nvme_host *host,
+%pythonappend nvme_subsystem::nvme_subsystem(struct nvme_global_ctx *ctx,
+					     struct nvme_host *host,
 					     const char *subsysnqn,
 					     const char *name) {
     self.__parent = host  # Keep a reference to parent to ensure garbage collection happens in the right order}
 %extend nvme_subsystem {
-	nvme_subsystem(struct nvme_host *host,
+	nvme_subsystem(struct nvme_global_ctx *ctx,
+		       struct nvme_host *host,
 		       const char *subsysnqn,
 		       const char *name = NULL) {
-		return nvme_lookup_subsystem(host, name, subsysnqn);
+		struct nvme_subsystem *s;
+
+		if (nvme_subsystem_get(ctx, host, name, subsysnqn, &s))
+			return NULL;
+
+		return s;
 	}
 	~nvme_subsystem() {
 		nvme_free_subsystem($self);

libnvme/src/libnvme.ld

@@ -129,7 +129,6 @@ LIBNVME_2_0 {
 		nvme_lookup_ctrl;
 		nvme_lookup_key;
 		nvme_lookup_keyring;
-		nvme_lookup_subsystem;
 		nvme_mi_admin_admin_passthru;
 		nvme_mi_admin_xfer;
 		nvme_mi_aem_disable;
@@ -248,6 +247,7 @@ LIBNVME_2_0 {
 		nvme_subsys_filter;
 		nvme_subsystem_first_ctrl;
 		nvme_subsystem_first_ns;
+		nvme_subsystem_get;
 		nvme_subsystem_get_application;
 		nvme_subsystem_get_fw_rev;
 		nvme_subsystem_get_host;

libnvme/src/nvme/private.h

@@ -413,6 +413,10 @@ void *__nvme_realloc(void *p, size_t len);
 
 nvme_host_t nvme_lookup_host(struct nvme_global_ctx *ctx, const char *hostnqn,
 			     const char *hostid);
+nvme_subsystem_t nvme_lookup_subsystem(struct nvme_host *h,
+				       const char *name,
+				       const char *subsysnqn);
+
 
 #if (LOG_FUNCNAME == 1)
 #define __nvme_log_func __func__

libnvme/src/nvme/tree.c

@@ -736,6 +736,21 @@ struct nvme_subsystem *nvme_lookup_subsystem(struct nvme_host *h,
 	return nvme_alloc_subsystem(h, name, subsysnqn);
 }
 
+int nvme_subsystem_get(struct nvme_global_ctx *ctx,
+		struct nvme_host *h, const char *name,
+		const char *subsysnqn, struct nvme_subsystem **subsys)
+{
+	struct nvme_subsystem *s;
+
+	s = nvme_lookup_subsystem(h, name, subsysnqn);
+	if (!s)
+		return -ENOMEM;
+
+	*subsys = s;
+
+	return 0;
+}
+
 static void __nvme_free_host(struct nvme_host *h)
 {
 	struct nvme_subsystem *s, *_s;

libnvme/src/nvme/tree.h

@@ -201,19 +201,20 @@ nvme_subsystem_t nvme_first_subsystem(nvme_host_t h);
 nvme_subsystem_t nvme_next_subsystem(nvme_host_t h, nvme_subsystem_t s);
 
 /**
- * nvme_lookup_subsystem() - Lookup nvme_subsystem_t object
+ * nvme_subsystem_get() - Returns nvme_subsystem_t object
+ * @ctx:	struct nvme_global_ctx object
  * @h:		&nvme_host_t object
  * @name:	Name of the subsystem (may be NULL)
  * @subsysnqn:	Subsystem NQN
+ * @s: 		nvme_subsystem_t object
  *
- * Lookup a &nvme_subsystem_t object in @h base on @name (if present)
+ * Returns an &nvme_subsystem_t object in @h base on @name (if present)
  * and @subsysnqn or create one if not found.
  *
- * Return: nvme_subsystem_t object
  */
-nvme_subsystem_t nvme_lookup_subsystem(struct nvme_host *h,
-				       const char *name,
-				       const char *subsysnqn);
+int nvme_subsystem_get(struct nvme_global_ctx *ctx,
+		struct nvme_host *h, const char *name,
+		const char *subsysnqn, struct nvme_subsystem **s);
 
 /**
  * nvme_free_subsystem() - Free a subsystem

libnvme/test/tree.c

@@ -138,7 +138,8 @@ static struct nvme_global_ctx *create_tree()
 	for (int i = 0; i < ARRAY_SIZE(test_data); i++) {
 		struct test_data *d = &test_data[i];
 
-		d->s = nvme_lookup_subsystem(h, d->subsysname, d->subsysnqn);
+		assert(!nvme_subsystem_get(ctx, h, d->subsysname,
+			d->subsysnqn, &d->s));
 		assert(d->s);
 		d->c = nvme_lookup_ctrl(d->s, d->transport, d->traddr,
 					d->host_traddr, d->host_iface,
@@ -235,7 +236,7 @@ static bool ctrl_lookups(struct nvme_global_ctx *ctx)
 	bool pass = true;
 
 	h = nvme_first_host(ctx);
-	s = nvme_lookup_subsystem(h, DEFAULT_SUBSYSNAME, DEFAULT_SUBSYSNQN);
+	nvme_subsystem_get(ctx, h, DEFAULT_SUBSYSNAME, DEFAULT_SUBSYSNQN, &s);
 
 	printf("  lookup controller:\n");
 	for (int i = 0; i < ARRAY_SIZE(test_data); i++) {
@@ -290,7 +291,7 @@ static bool test_src_addr()
 	nvme_host_get(ctx, DEFAULT_HOSTNQN, DEFAULT_HOSTID, &h);
 	assert(h);
 
-	s = nvme_lookup_subsystem(h, DEFAULT_SUBSYSNAME, DEFAULT_SUBSYSNQN);
+	nvme_subsystem_get(ctx, h, DEFAULT_SUBSYSNAME, DEFAULT_SUBSYSNQN, &s);
 	assert(s);
 
 	c = nvme_lookup_ctrl(s, "tcp", "192.168.56.1", NULL, NULL, "8009", NULL);
@@ -466,7 +467,10 @@ static bool ctrl_match(const char *tag,
 	nvme_host_get(ctx, DEFAULT_HOSTNQN, DEFAULT_HOSTID, &h);
 	assert(h);
 
-	s = nvme_lookup_subsystem(h, DEFAULT_SUBSYSNAME, reference->subsysnqn ? reference->subsysnqn : DEFAULT_SUBSYSNQN);
+	assert(!nvme_subsystem_get(ctx, h, DEFAULT_SUBSYSNAME,
+		 reference->subsysnqn ?
+			reference->subsysnqn : DEFAULT_SUBSYSNQN,
+		&s));
 	assert(s);
 
 	reference_ctrl = nvme_lookup_ctrl(s, reference->transport, reference->traddr,
@@ -1079,7 +1083,10 @@ static bool ctrl_config_match(const char *tag,
 	nvme_host_get(ctx, DEFAULT_HOSTNQN, DEFAULT_HOSTID, &h);
 	assert(h);
 
-	s = nvme_lookup_subsystem(h, DEFAULT_SUBSYSNAME, reference->subsysnqn ? reference->subsysnqn : DEFAULT_SUBSYSNQN);
+	assert(!nvme_subsystem_get(ctx, h, DEFAULT_SUBSYSNAME,
+		reference->subsysnqn ?
+			reference->subsysnqn : DEFAULT_SUBSYSNQN,
+		&s));
 	assert(s);
 
 	reference_ctrl = nvme_lookup_ctrl(s, reference->transport, reference->traddr,