libnvme: Re-implement __nvme_lookup_ctrl()

Re-implement __nvme_lookup_ctrl() as equivalent to nvme_lookup_ctrl()
but taking 'struct nvmf_context' as argument. Care needs to be taken
to handle the 'subsysnqn' entry in 'struct nvmf_context'; __nvme_ctrl_find()
needs to be called with a 'NULL' subsysnqn as the controller might be
on any subsystem, and we need to set 'subsysnqn' to the NQN of the
subsystem the controller should be created in rather than the subsysnqn
from 'struct nvmf_context' (which might be empty).

Signed-off-by: Hannes Reinecke <[email protected]>

Author: hreinecke

libnvme/src/nvme/fabrics.c

@@ -2425,9 +2425,7 @@ __public int nvmf_config_modify(struct nvme_global_ctx *ctx,
 		return -ENODEV;
 	}
 
-	c = nvme_lookup_ctrl(s, fctx->transport, fctx->traddr,
-			     fctx->host_traddr, fctx->host_iface,
-			     fctx->trsvcid, NULL);
+	c = __nvme_lookup_ctrl(s, fctx, NULL);
 	if (!c) {
 		nvme_msg(ctx, LOG_ERR, "Failed to lookup controller\n");
 		return -ENODEV;

libnvme/src/nvme/json.c

@@ -83,27 +83,25 @@ static void json_parse_port(nvme_subsystem_t s, struct json_object *port_obj)
 {
 	nvme_ctrl_t c;
 	struct json_object *attr_obj;
-	const char *transport, *traddr = NULL;
-	const char *host_traddr = NULL, *host_iface = NULL, *trsvcid = NULL;
+	struct nvmf_context fctx = {};
 
 	attr_obj = json_object_object_get(port_obj, "transport");
 	if (!attr_obj)
 		return;
-	transport = json_object_get_string(attr_obj);
+	fctx.transport = json_object_get_string(attr_obj);
 	attr_obj = json_object_object_get(port_obj, "traddr");
 	if (attr_obj)
-		traddr = json_object_get_string(attr_obj);
+		fctx.traddr = json_object_get_string(attr_obj);
 	attr_obj = json_object_object_get(port_obj, "host_traddr");
 	if (attr_obj)
-		host_traddr = json_object_get_string(attr_obj);
+		fctx.host_traddr = json_object_get_string(attr_obj);
 	attr_obj = json_object_object_get(port_obj, "host_iface");
 	if (attr_obj)
-		host_iface = json_object_get_string(attr_obj);
+		fctx.host_iface = json_object_get_string(attr_obj);
 	attr_obj = json_object_object_get(port_obj, "trsvcid");
 	if (attr_obj)
-		trsvcid = json_object_get_string(attr_obj);
-	c = nvme_lookup_ctrl(s, transport, traddr, host_traddr,
-			     host_iface, trsvcid, NULL);
+		fctx.trsvcid = json_object_get_string(attr_obj);
+	c = __nvme_lookup_ctrl(s, &fctx, NULL);
 	if (!c)
 		return;
 	json_update_attributes(c, port_obj);

libnvme/src/nvme/private.h

@@ -399,6 +399,9 @@ nvme_ctrl_t nvme_lookup_ctrl(nvme_subsystem_t s, const char *transport,
 			     const char *traddr, const char *host_traddr,
 			     const char *host_iface, const char *trsvcid,
 			     nvme_ctrl_t p);
+nvme_ctrl_t __nvme_lookup_ctrl(nvme_subsystem_t s,
+			       struct nvmf_context *fctx,
+			       nvme_ctrl_t p);
 nvme_ctrl_t nvme_ctrl_find(nvme_subsystem_t s, struct nvmf_context *fctx);
 
 void __nvme_free_host(nvme_host_t h);

libnvme/src/nvme/tree.c

@@ -1451,9 +1451,9 @@ static ctrl_match_t _candidate_init(struct nvme_global_ctx *ctx,
 	return _match_ctrl;
 }
 
-static nvme_ctrl_t __nvme_lookup_ctrl(nvme_subsystem_t s,
-				      struct nvmf_context *fctx,
-				      nvme_ctrl_t p)
+static nvme_ctrl_t __nvme_ctrl_find(nvme_subsystem_t s,
+				    struct nvmf_context *fctx,
+				    nvme_ctrl_t p)
 {
 	struct candidate_args candidate = {};
 	struct nvme_ctrl *c, *matching_c = NULL;
@@ -1503,37 +1503,35 @@ __public bool nvme_ctrl_match_config(struct nvme_ctrl *c, const char *transport,
 
 nvme_ctrl_t nvme_ctrl_find(nvme_subsystem_t s, struct nvmf_context *fctx)
 {
-	return __nvme_lookup_ctrl(s, fctx, NULL/*p*/);
+	return __nvme_ctrl_find(s, fctx, NULL/*p*/);
 }
 
-nvme_ctrl_t nvme_lookup_ctrl(nvme_subsystem_t s, const char *transport,
-			     const char *traddr, const char *host_traddr,
-			     const char *host_iface, const char *trsvcid,
-			     nvme_ctrl_t p)
+nvme_ctrl_t __nvme_lookup_ctrl(nvme_subsystem_t s,
+			       struct nvmf_context *fctx,
+			       nvme_ctrl_t p)
 {
 	struct nvme_global_ctx *ctx;
 	struct nvme_ctrl *c;
+	const char *subsysnqn = fctx->subsysnqn;
 	int ret;
 
-	if (!s || !transport)
+	if (!s || !fctx->transport)
 		return NULL;
 
-	struct nvmf_context fctx = {
-		.transport = transport,
-		.traddr = traddr,
-		.host_traddr = host_traddr,
-		.host_iface = host_iface,
-		.trsvcid = trsvcid,
-		.subsysnqn = NULL,
-	};
-
-	c = __nvme_lookup_ctrl(s, &fctx, p);
-	if (c)
+	/* Clear out subsysnqn; might be different for discovery subsystems */
+	fctx->subsysnqn = NULL;
+	c = __nvme_ctrl_find(s, fctx, p);
+	if (c) {
+		fctx->subsysnqn = subsysnqn;
 		return c;
+	}
 
 	ctx = s->h ? s->h->ctx : NULL;
-	fctx.subsysnqn = s->subsysnqn;
-	ret = _nvme_create_ctrl(ctx, &fctx, &c);
+	/* Set the NQN to the subsystem the controller should be created in */
+	fctx->subsysnqn = s->subsysnqn;
+	ret = _nvme_create_ctrl(ctx, fctx, &c);
+	/* And restore NQN to avoid issues with repetitive calls */
+	fctx->subsysnqn = subsysnqn;
 	if (ret)
 		return NULL;
 
@@ -1543,6 +1541,26 @@ nvme_ctrl_t nvme_lookup_ctrl(nvme_subsystem_t s, const char *transport,
 	return c;
 }
 
+nvme_ctrl_t nvme_lookup_ctrl(nvme_subsystem_t s, const char *transport,
+			     const char *traddr, const char *host_traddr,
+			     const char *host_iface, const char *trsvcid,
+			     nvme_ctrl_t p)
+{
+	if (!s || !transport)
+		return NULL;
+
+	struct nvmf_context fctx = {
+		.transport = transport,
+		.traddr = traddr,
+		.host_traddr = host_traddr,
+		.host_iface = host_iface,
+		.trsvcid = trsvcid,
+		.subsysnqn = NULL,
+	};
+
+	return __nvme_lookup_ctrl(s, &fctx, p);
+}
+
 static int nvme_ctrl_scan_paths(struct nvme_global_ctx *ctx, struct nvme_ctrl *c)
 {
 	_cleanup_dirents_ struct dirents paths = {};
@@ -1893,8 +1911,14 @@ int nvme_ctrl_alloc(struct nvme_global_ctx *ctx, nvme_subsystem_t s,
 skip_address:
 	p = NULL;
 	do {
-		c = nvme_lookup_ctrl(s, transport, traddr,
-				     host_traddr, host_iface, trsvcid, p);
+		struct nvmf_context fctx = {
+			.transport = transport,
+			.traddr = traddr,
+			.host_traddr = host_traddr,
+			.host_iface = host_iface,
+			.trsvcid = trsvcid,
+		};
+		c = __nvme_lookup_ctrl(s, &fctx, p);
 		if (c) {
 			if (!c->name)
 				break;