tree: scan controllers before scanning subsystems in nvme_scan_topology()

The linux sysfs hierarchy only knows about 'controllers' and 'subsystems',
so when scanning the topology we should follow this structure and scan
first for controllers and then for subsystems.
Just scanning for subsystems and all controllers attached to them has
the problem that the hostnqn can only be derived from the controller,
but by the time the controller is scanned the subsystem has already
been created and attached to the default host.
Scanning for controllers first will setup the correct hosts
(and subsystems), so the subsequent scan for subsystems is primarily
there to find all namespaces attached to the subsystems.

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

Author: hreinecke

doc/libnvme.rst

@@ -38,17 +38,6 @@
 ``struct dirent *** subsys``
 
 
-.. c:function:: int nvme_scan_subsystem_ctrls (nvme_subsystem_t s, struct dirent *** ctrls)
-
-
-**Parameters**
-
-``nvme_subsystem_t s``
-  *undescribed*
-
-``struct dirent *** ctrls``
-
-
 .. c:function:: int nvme_scan_subsystem_namespaces (nvme_subsystem_t s, struct dirent *** namespaces)
 
 

doc/man/nvme_scan_subsystem_ctrls.2

@@ -241,7 +241,6 @@ LIBNVME_1_0 {
 		nvme_scan_ctrl_namespaces;
 		nvme_scan_filter;
 		nvme_scan_namespace;
-		nvme_scan_subsystem_ctrls;
 		nvme_scan_subsystem_namespaces;
 		nvme_scan_subsystems;
 		nvme_security_receive;

src/libnvme.map

@@ -93,18 +93,18 @@ int nvme_scan_subsystems(struct dirent ***subsys)
 		       alphasort);
 }
 
-int nvme_scan_subsystem_ctrls(nvme_subsystem_t s, struct dirent ***ctrls)
-{
-	return scandir(nvme_subsystem_get_sysfs_dir(s), ctrls,
-		       nvme_ctrls_filter, alphasort);
-}
-
 int nvme_scan_subsystem_namespaces(nvme_subsystem_t s, struct dirent ***namespaces)
 {
 	return scandir(nvme_subsystem_get_sysfs_dir(s), namespaces,
 		       nvme_namespace_filter, alphasort);
 }
 
+int nvme_scan_ctrls(struct dirent ***ctrls)
+{
+	return scandir(nvme_ctrl_sysfs_dir, ctrls, nvme_ctrls_filter,
+		       alphasort);
+}
+
 int nvme_scan_ctrl_namespace_paths(nvme_ctrl_t c, struct dirent ***namespaces)
 {
 	return scandir(nvme_ctrl_get_sysfs_dir(c), namespaces,

src/nvme/filters.c

@@ -53,22 +53,21 @@ int nvme_subsys_filter(const struct dirent *d);
 int nvme_scan_subsystems(struct dirent ***subsys);
 
 /**
- * nvme_scan_subsystem_ctrls() -
+ * nvme_scan_subsystem_namespaces() -
  * @s:
- * @ctrls:
+ * @namespaces:
  *
  * Return: 
  */
-int nvme_scan_subsystem_ctrls(nvme_subsystem_t s, struct dirent ***ctrls);
+int nvme_scan_subsystem_namespaces(nvme_subsystem_t s, struct dirent ***namespaces);
 
 /**
- * nvme_scan_subsystem_namespaces() -
- * @s:
- * @namespaces:
+ * nvme_scan_ctrls() -
+ * @ctrls:
  *
  * Return: 
  */
-int nvme_scan_subsystem_namespaces(nvme_subsystem_t s, struct dirent ***namespaces);
+int nvme_scan_ctrls(struct dirent ***ctrls);
 
 /**
  * nvme_scan_ctrl_namespace_paths() -

src/nvme/filters.h

@@ -41,7 +41,6 @@ static void __nvme_free_ctrl(nvme_ctrl_t c);
 static int nvme_subsystem_scan_namespace(struct nvme_subsystem *s, char *name);
 static int nvme_scan_subsystem(struct nvme_root *r, const char *name,
 			       nvme_scan_filter_t f);
-static int nvme_subsystem_scan_ctrl(struct nvme_subsystem *s, char *name);
 static int nvme_ctrl_scan_namespace(struct nvme_ctrl *c, char *name);
 static int nvme_ctrl_scan_path(struct nvme_ctrl *c, char *name);
 
@@ -72,8 +71,28 @@ nvme_host_t nvme_default_host(nvme_root_t r)
 
 static int nvme_scan_topology(struct nvme_root *r, nvme_scan_filter_t f)
 {
-	struct dirent **subsys;
-	int i, num_subsys, ret;
+	struct dirent **subsys, **ctrls;
+	int i, num_subsys, num_ctrls, ret;
+
+	num_ctrls = nvme_scan_ctrls(&ctrls);
+	if (num_ctrls < 0) {
+		nvme_msg(LOG_DEBUG, "failed to scan ctrls: %s\n",
+			 strerror(errno));
+		return num_ctrls;
+	}
+
+	for (i = 0; i < num_ctrls; i++) {
+		nvme_ctrl_t c = nvme_scan_ctrl(r, ctrls[i]->d_name);
+		if (!c) {
+			nvme_msg(LOG_DEBUG, "failed to scan ctrl %s: %s\n",
+				 ctrls[i]->d_name, strerror(errno));
+		}
+		if ((f) && !f(c->s)) {
+			nvme_free_ctrl(c);
+		}
+	}
+
+	nvme_free_dirents(ctrls, i);
 
 	num_subsys = nvme_scan_subsystems(&subsys);
 	if (num_subsys < 0) {
@@ -91,6 +110,7 @@ static int nvme_scan_topology(struct nvme_root *r, nvme_scan_filter_t f)
 	}
 
 	nvme_free_dirents(subsys, i);
+
 	return 0;
 }
 
@@ -419,31 +439,6 @@ static int nvme_subsystem_scan_namespaces(struct nvme_subsystem *s)
 	return 0;
 }
 
-static int nvme_subsystem_scan_ctrls(struct nvme_subsystem *s)
-{
-	struct dirent **ctrls;
-	int i, num_ctrls, ret;
-
-	num_ctrls = nvme_scan_subsystem_ctrls(s, &ctrls);
-	if (num_ctrls < 0) {
-		nvme_msg(LOG_DEBUG,
-			 "failed to scan ctrls for subsys %s: %s\n",
-			 s->subsysnqn, strerror(errno));
-		return num_ctrls;
-	}
-
-	for (i = 0; i < num_ctrls; i++) {
-		ret = nvme_subsystem_scan_ctrl(s, ctrls[i]->d_name);
-		if (ret < 0)
-			nvme_msg(LOG_DEBUG,
-				 "failed to scan ctrl %s: %s\n",
-				 ctrls[i]->d_name, strerror(errno));
-	}
-
-	nvme_free_dirents(ctrls, i);
-	return 0;
-}
-
 static int nvme_init_subsystem(nvme_subsystem_t s, const char *name)
 {
 	char *path;
@@ -519,7 +514,6 @@ static int nvme_scan_subsystem(struct nvme_root *r, const char *name,
 	}
 
 	nvme_subsystem_scan_namespaces(s);
-	nvme_subsystem_scan_ctrls(s);
 
 	if (f && !f(s)) {
 		__nvme_free_subsystem(s);
@@ -1330,31 +1324,15 @@ nvme_ctrl_t nvme_scan_ctrl(nvme_root_t r, const char *name)
 		errno = ENOMEM;
 		return NULL;
 	}
-	c = nvme_ctrl_alloc(s, path, name);
-	if (!c)
-		free(path);
-
-	return c;
-}
-
-static int nvme_subsystem_scan_ctrl(struct nvme_subsystem *s, char *name)
-{
-	nvme_ctrl_t c;
-	char *path;
-
-	if (asprintf(&path, "%s/%s", s->sysfs_dir, name) < 0) {
-		errno = ENOMEM;
-		return -1;
-	}
-
 	c = nvme_ctrl_alloc(s, path, name);
 	if (!c) {
 		free(path);
-		return -1;
+		return NULL;
 	}
+
 	nvme_ctrl_scan_namespaces(c);
 	nvme_ctrl_scan_paths(c);
-	return 0;
+	return c;
 }
 
 void nvme_rescan_ctrl(struct nvme_ctrl *c)