graph: implement internal operation helpers

Adding internal graph API helpers support to check whether a graph has
isolated nodes and any node have a loop to itself and BFS
algorithm implementation etc.

Signed-off-by: Jerin Jacob <jerinj@marvell.com>
Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>

lib/librte_graph/Makefile

@@ -16,6 +16,7 @@ EXPORT_MAP := rte_graph_version.map
 # all source are stored in SRCS-y
 SRCS-$(CONFIG_RTE_LIBRTE_GRAPH) += node.c
 SRCS-$(CONFIG_RTE_LIBRTE_GRAPH) += graph.c
+SRCS-$(CONFIG_RTE_LIBRTE_GRAPH) += graph_ops.c
 SRCS-$(CONFIG_RTE_LIBRTE_GRAPH) += graph_debug.c
 
 # install header files

lib/librte_graph/graph.c

@@ -7,6 +7,7 @@
 #include "graph_private.h"
 
 static rte_spinlock_t graph_lock = RTE_SPINLOCK_INITIALIZER;
+int rte_graph_logtype;
 
 void
 graph_spinlock_lock(void)

lib/librte_graph/graph_ops.c

@@ -0,0 +1,169 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2020 Marvell International Ltd.
+ */
+
+#include <stdbool.h>
+#include <string.h>
+
+#include <rte_common.h>
+#include <rte_errno.h>
+
+#include "graph_private.h"
+
+/* Check whether a node has next_node to itself */
+static inline int
+node_has_loop_edge(struct node *node)
+{
+	rte_edge_t i;
+	char *name;
+	int rc = 0;
+
+	for (i = 0; i < node->nb_edges; i++) {
+		if (strncmp(node->name, node->next_nodes[i],
+			    RTE_NODE_NAMESIZE) == 0) {
+			name = node->name;
+			rc = 1;
+			SET_ERR_JMP(EINVAL, fail, "Node %s has loop to self",
+				    name);
+		}
+	}
+fail:
+	return rc;
+}
+
+int
+graph_node_has_loop_edge(struct graph *graph)
+{
+	struct graph_node *graph_node;
+
+	STAILQ_FOREACH(graph_node, &graph->node_list, next)
+		if (node_has_loop_edge(graph_node->node))
+			return 1;
+
+	return 0;
+}
+
+rte_node_t
+graph_src_nodes_count(struct graph *graph)
+{
+	struct graph_node *graph_node;
+	rte_node_t rc = 0;
+
+	STAILQ_FOREACH(graph_node, &graph->node_list, next)
+		if (graph_node->node->flags & RTE_NODE_SOURCE_F)
+			rc++;
+
+	if (rc == 0)
+		SET_ERR_JMP(EINVAL, fail, "Graph needs at least a source node");
+fail:
+	return rc;
+}
+
+/* Check whether a node has next_node to a source node */
+int
+graph_node_has_edge_to_src_node(struct graph *graph)
+{
+	struct graph_node *graph_node;
+	struct node *node;
+	rte_edge_t i;
+
+	STAILQ_FOREACH(graph_node, &graph->node_list, next) {
+		for (i = 0; i < graph_node->node->nb_edges; i++) {
+			node = graph_node->adjacency_list[i]->node;
+			if (node->flags & RTE_NODE_SOURCE_F)
+				SET_ERR_JMP(
+					EEXIST, fail,
+					"Node %s points to the source node %s",
+					graph_node->node->name, node->name);
+		}
+	}
+
+	return 0;
+fail:
+	return 1;
+}
+
+rte_node_t
+graph_nodes_count(struct graph *graph)
+{
+	struct graph_node *graph_node;
+	rte_node_t count = 0;
+
+	STAILQ_FOREACH(graph_node, &graph->node_list, next)
+		count++;
+
+	return count;
+}
+
+void
+graph_mark_nodes_as_not_visited(struct graph *graph)
+{
+	struct graph_node *graph_node;
+
+	STAILQ_FOREACH(graph_node, &graph->node_list, next)
+		graph_node->visited = false;
+}
+
+int
+graph_bfs(struct graph *graph, struct graph_node *start)
+{
+	struct graph_node **queue, *v, *tmp;
+	uint16_t head = 0, tail = 0;
+	rte_edge_t i;
+	size_t sz;
+
+	sz = sizeof(struct graph_node *) * graph_nodes_count(graph);
+	queue = malloc(sz);
+	if (queue == NULL)
+		SET_ERR_JMP(ENOMEM, fail, "Failed to alloc BFS queue of %zu",
+			    sz);
+
+	/* BFS algorithm */
+	queue[tail++] = start;
+	start->visited = true;
+	while (head != tail) {
+		v = queue[head++];
+		for (i = 0; i < v->node->nb_edges; i++) {
+			tmp = v->adjacency_list[i];
+			if (tmp->visited == false) {
+				queue[tail++] = tmp;
+				tmp->visited = true;
+			}
+		}
+	}
+
+	free(queue);
+	return 0;
+
+fail:
+	return -rte_errno;
+}
+
+/* Check whether a node has connected path or parent node */
+int
+graph_has_isolated_node(struct graph *graph)
+{
+	struct graph_node *graph_node;
+
+	graph_mark_nodes_as_not_visited(graph);
+
+	STAILQ_FOREACH(graph_node, &graph->node_list, next) {
+		if (graph_node->node->flags & RTE_NODE_SOURCE_F) {
+			if (graph_node->node->nb_edges == 0)
+				SET_ERR_JMP(EINVAL, fail,
+					    "%s node needs minimum one edge",
+					    graph_node->node->name);
+			if (graph_bfs(graph, graph_node))
+				goto fail;
+		}
+	}
+
+	STAILQ_FOREACH(graph_node, &graph->node_list, next)
+		if (graph_node->visited == false)
+			SET_ERR_JMP(EINVAL, fail, "Found isolated node %s",
+				    graph_node->node->name);
+
+	return 0;
+fail:
+	return 1;
+}

lib/librte_graph/graph_private.h

@@ -13,6 +13,16 @@
 
 #include "rte_graph.h"
 
+extern int rte_graph_logtype;
+
+#define GRAPH_LOG(level, ...)                                                  \
+	rte_log(RTE_LOG_##level, rte_graph_logtype,                            \
+		RTE_FMT("GRAPH: %s():%u " RTE_FMT_HEAD(__VA_ARGS__, ) "\n",    \
+			__func__, __LINE__, RTE_FMT_TAIL(__VA_ARGS__, )))
+
+#define graph_err(...) GRAPH_LOG(ERR, __VA_ARGS__)
+#define graph_info(...) GRAPH_LOG(INFO, __VA_ARGS__)
+#define graph_dbg(...) GRAPH_LOG(DEBUG, __VA_ARGS__)
 
 #define ID_CHECK(id, id_max)                                                   \
 	do {                                                                   \
@@ -22,6 +32,12 @@
 		}                                                              \
 	} while (0)
 
+#define SET_ERR_JMP(err, where, fmt, ...)                                      \
+	do {                                                                   \
+		graph_err(fmt, ##__VA_ARGS__);                                 \
+		rte_errno = err;                                               \
+		goto where;                                                    \
+	} while (0)
 
 /**
  * @internal
@@ -41,6 +57,52 @@ struct node {
 	char next_nodes[][RTE_NODE_NAMESIZE]; /**< Names of next nodes. */
 };
 
+/**
+ * @internal
+ *
+ * Structure that holds the graph node data.
+ */
+struct graph_node {
+	STAILQ_ENTRY(graph_node) next; /**< Next graph node in the list. */
+	struct node *node; /**< Pointer to internal node. */
+	bool visited;      /**< Flag used in BFS to mark node visited. */
+	struct graph_node *adjacency_list[]; /**< Adjacency list of the node. */
+};
+
+/**
+ * @internal
+ *
+ * Structure that holds graph internal data.
+ */
+struct graph {
+	STAILQ_ENTRY(graph) next;
+	/**< List of graphs. */
+	char name[RTE_GRAPH_NAMESIZE];
+	/**< Name of the graph. */
+	const struct rte_memzone *mz;
+	/**< Memzone to store graph data. */
+	rte_graph_off_t nodes_start;
+	/**< Node memory start offset in graph reel. */
+	rte_node_t src_node_count;
+	/**< Number of source nodes in a graph. */
+	struct rte_graph *graph;
+	/**< Pointer to graph data. */
+	rte_node_t node_count;
+	/**< Total number of nodes. */
+	uint32_t cir_start;
+	/**< Circular buffer start offset in graph reel. */
+	uint32_t cir_mask;
+	/**< Circular buffer mask for wrap around. */
+	rte_graph_t id;
+	/**< Graph identifier. */
+	size_t mem_sz;
+	/**< Memory size of the graph. */
+	int socket;
+	/**< Socket identifier where memory is allocated. */
+	STAILQ_HEAD(gnode_list, graph_node) node_list;
+	/**< Nodes in a graph. */
+};
+
 /* Node functions */
 STAILQ_HEAD(node_head, node);
 
@@ -67,6 +129,19 @@ struct node_head *node_list_head_get(void);
  */
 struct node *node_from_name(const char *name);
 
+/* Graph list functions */
+STAILQ_HEAD(graph_head, graph);
+
+/**
+ * @internal
+ *
+ * Get the head of the graph list.
+ *
+ * @return
+ *   Pointer to the graph head.
+ */
+struct graph_head *graph_list_head_get(void);
+
 /* Lock functions */
 /**
  * @internal
@@ -82,6 +157,104 @@ void graph_spinlock_lock(void);
  */
 void graph_spinlock_unlock(void);
 
+/* Graph operations */
+/**
+ * @internal
+ *
+ * Run a BFS(Breadth First Search) on the graph marking all
+ * the graph nodes as visited.
+ *
+ * @param graph
+ *   Pointer to the internal graph object.
+ * @param start
+ *   Pointer to the starting graph node.
+ *
+ * @return
+ *   - 0: Success.
+ *   - -ENOMEM: Not enough memory for BFS.
+ */
+int graph_bfs(struct graph *graph, struct graph_node *start);
+
+/**
+ * @internal
+ *
+ * Check if there is an isolated node in the given graph.
+ *
+ * @param graph
+ *   Pointer to the internal graph object.
+ *
+ * @return
+ *   - 0: No isolated node found.
+ *   - 1: Isolated node found.
+ */
+int graph_has_isolated_node(struct graph *graph);
+
+/**
+ * @internal
+ *
+ * Check whether a node in the graph has next_node to a source node.
+ *
+ * @param graph
+ *   Pointer to the internal graph object.
+ *
+ * @return
+ *   - 0: Node has an edge to source node.
+ *   - 1: Node doesn't have an edge to source node.
+ */
+int graph_node_has_edge_to_src_node(struct graph *graph);
+
+/**
+ * @internal
+ *
+ * Checks whether node in the graph has a edge to itself i.e. forms a
+ * loop.
+ *
+ * @param graph
+ *   Pointer to the internal graph object.
+ *
+ * @return
+ *   - 0: Node has an edge to itself.
+ *   - 1: Node doesn't have an edge to itself.
+ */
+int graph_node_has_loop_edge(struct graph *graph);
+
+/**
+ * @internal
+ *
+ * Get the count of source nodes in the graph.
+ *
+ * @param graph
+ *   Pointer to the internal graph object.
+ *
+ * @return
+ *   Number of source nodes.
+ */
+rte_node_t graph_src_nodes_count(struct graph *graph);
+
+/**
+ * @internal
+ *
+ * Get the count of total number of nodes in the graph.
+ *
+ * @param graph
+ *   Pointer to the internal graph object.
+ *
+ * @return
+ *   Number of nodes.
+ */
+rte_node_t graph_nodes_count(struct graph *graph);
+
+/**
+ * @internal
+ *
+ * Clear the visited flag of all the nodes in the graph.
+ *
+ * @param graph
+ *   Pointer to the internal graph object.
+ */
+void graph_mark_nodes_as_not_visited(struct graph *graph);
+
+
 /**
  * @internal
  *

lib/librte_graph/meson.build

@@ -3,7 +3,7 @@
 
 name = 'graph'
 
-sources = files('node.c', 'graph.c', 'graph_debug.c')
+sources = files('node.c', 'graph.c', 'graph_ops.c', 'graph_debug.c')
 headers = files('rte_graph.h')
 
 deps += ['eal']