Refs trac:3130: fix the openib BTL to properly set the memalign malloc

hook early in the setup, but ''not'' during the component register
function.  And then properly unset it if was set.

This commit was SVN r26697.

The following Trac tickets were found above:
  Ticket 3130 --> https://svn.open-mpi.org/trac/ompi/ticket/3130

ompi/mca/btl/openib/btl_openib_component.c

@@ -116,6 +116,7 @@ static int btl_openib_component_progress(void);
  * Local variables
  */
 static mca_btl_openib_device_t *receive_queues_device = NULL;
+static bool malloc_hook_set = false;
 mca_btl_openib_component_t mca_btl_openib_component = {
     {
         /* First, the mca_base_component_t struct containing meta information
@@ -189,13 +190,6 @@ static int btl_openib_component_register(void)
         return OMPI_ERR_NOT_AVAILABLE;
     }
 
-#if BTL_OPENIB_MALLOC_HOOKS_ENABLED
-    mca_btl_openib_component.previous_malloc_hook = __malloc_hook;
-    if (mca_btl_openib_component.use_memalign > 0) {
-        __malloc_hook = btl_openib_malloc_hook; 
-    }
-#endif
-
     return OMPI_SUCCESS;
 }
 
@@ -275,7 +269,12 @@ static int btl_openib_component_close(void)
     }
     
 #if BTL_OPENIB_MALLOC_HOOKS_ENABLED
-    __malloc_hook = mca_btl_openib_component.previous_malloc_hook;
+    /* Must check to see whether the malloc hook was set before
+       assigning it back because ompi_info will call _register() and
+       then _close() (which won't set the hook) */
+    if (malloc_hook_set) {
+        __malloc_hook = mca_btl_openib_component.previous_malloc_hook;
+    }
 #endif
 
     return rc;
@@ -2598,6 +2597,17 @@ btl_openib_component_init(int *num_btl_modules,
     *num_btl_modules = 0;
     num_devs = 0;
 
+#if BTL_OPENIB_MALLOC_HOOKS_ENABLED
+    /* If we got this far, then setup the memory alloc hook (because
+       we're most likely going to be using this component). The hook is to be set up
+       as early as possible in this function since we want most of the allocated resources
+       be aligned.*/
+    if (mca_btl_openib_component.use_memalign > 0) {
+        mca_btl_openib_component.previous_malloc_hook = __malloc_hook;
+        __malloc_hook = btl_openib_malloc_hook; 
+        malloc_hook_set = true;
+    }
+#endif
     /* Currently refuse to run if MPI_THREAD_MULTIPLE is enabled */
     if (ompi_mpi_thread_multiple && !mca_btl_base_thread_multiple_override) {
         BTL_VERBOSE(("openib BTL disqualifying itself because MPI_THREAD_MULTIPLE is being used"));
@@ -3052,7 +3062,6 @@ btl_openib_component_init(int *num_btl_modules,
      * to memory corruption issues when fork is called
      */
     ompi_warn_fork();
-
     return btls;
 
  no_btls:
@@ -3066,6 +3075,12 @@ btl_openib_component_init(int *num_btl_modules,
 
     mca_btl_openib_component.ib_num_btls = 0;
     btl_openib_modex_send();
+#if BTL_OPENIB_MALLOC_HOOKS_ENABLED
+    /*Unset malloc hook since the component won't start*/
+    if (malloc_hook_set) {
+        __malloc_hook = mca_btl_openib_component.previous_malloc_hook;
+    }
+#endif
     return NULL;
 }