Fix query HSA_AMD_AGENT_MEMORY_POOL_INFO_LINK_INFO

Querying HSA_AMD_AGENT_MEMORY_POOL_INFO_LINK_INFO between a gpu agent
and its own local memory pool returns a wrong information.
Fix: return link with 0 hop count.

[git-p4: depot-paths = "//depot/stg/hsa/drivers/hsa/runtime/": change = 1257544]


[ROCm/ROCR-Runtime commit: 5a584fa1ab]

projects/rocr-runtime/runtime/hsa-runtime/core/inc/runtime.h

@@ -87,6 +87,8 @@ class Runtime {
  public:
   /// @brief Structure to describe connectivity between agents.
   struct LinkInfo {
+    LinkInfo() : num_hop(0), info{0} {}
+
     uint32_t num_hop;
     hsa_amd_memory_pool_link_info_t info;
   };
@@ -133,7 +135,7 @@ class Runtime {
   /// @param [in] node_id_from Node id of the source node.
   /// @param [in] node_id_to Node id of the destination node.
   /// @retval The link information between source and destination nodes.
-  const LinkInfo& GetLinkInfo(uint32_t node_id_from, uint32_t node_id_to);
+  const LinkInfo GetLinkInfo(uint32_t node_id_from, uint32_t node_id_to);
 
   /// @brief Invoke the user provided call back for each agent in the agent
   /// list.

projects/rocr-runtime/runtime/hsa-runtime/core/runtime/runtime.cpp

@@ -263,9 +263,11 @@ void Runtime::RegisterLinkInfo(uint32_t node_id_from, uint32_t node_id_to,
   link_matrix_[idx].info = link_info;
 }
 
-const Runtime::LinkInfo& Runtime::GetLinkInfo(uint32_t node_id_from,
-                                              uint32_t node_id_to) {
-  return link_matrix_[GetIndexLinkInfo(node_id_from, node_id_to)];
+const Runtime::LinkInfo Runtime::GetLinkInfo(uint32_t node_id_from,
+                                             uint32_t node_id_to) {
+  return (node_id_from != node_id_to)
+             ? link_matrix_[GetIndexLinkInfo(node_id_from, node_id_to)]
+             : LinkInfo();  // No link.
 }
 
 uint32_t Runtime::GetIndexLinkInfo(uint32_t node_id_from, uint32_t node_id_to) {