init / exit function ordering

The vlib init function subsystem now supports a mix of procedural and
formally-specified ordering constraints. We should eliminate procedural
knowledge wherever possible.

The following schemes are *roughly* equivalent:

static clib_error_t *init_runs_first (vlib_main_t *vm)
{
   clib_error_t *error;

   ... do some stuff...

   if ((error = vlib_call_init_function (init_runs_next)))
     return error;
   ...
}
VLIB_INIT_FUNCTION (init_runs_first);

and

static clib_error_t *init_runs_first (vlib_main_t *vm)
{
   ... do some stuff...
}
VLIB_INIT_FUNCTION (init_runs_first) =
{
    .runs_before = VLIB_INITS("init_runs_next"),
};

The first form will [most likely] call "init_runs_next" on the
spot. The second form means that "init_runs_first" runs before
"init_runs_next," possibly much earlier in the sequence.

Please DO NOT construct sets of init functions where A before B
actually means A *right before* B. It's not necessary - simply combine
A and B - and it leads to hugely annoying debugging exercises when
trying to switch from ad-hoc procedural ordering constraints to formal
ordering constraints.

Change-Id: I5e4353503bf43b4acb11a45fb33c79a5ade8426c
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 2 insertions, 8 deletions

diff --git a/src/vnet/ethernet/node.c b/src/vnet/ethernet/node.c
index 87c447f44d3..286ec3c0e78 100755
--- a/src/vnet/ethernet/node.c
+++ b/src/vnet/ethernet/node.c
@@ -2025,11 +2025,9 @@ next_by_ethertype_register (next_by_ethertype_t * l3_next,
   return 0;
 }
 
-
-static clib_error_t *
-ethernet_input_init (vlib_main_t * vm)
+void
+ethernet_input_init (vlib_main_t * vm, ethernet_main_t * em)
 {
-  ethernet_main_t *em = &ethernet_main;
   __attribute__ ((unused)) vlan_table_t *invalid_vlan_table;
   __attribute__ ((unused)) qinq_table_t *invalid_qinq_table;
 
@@ -2048,12 +2046,8 @@ ethernet_input_init (vlib_main_t * vm)
   pool_get (em->vlan_pool, invalid_vlan_table);	// first id = 0
   // The first qinq pool will always be reserved for an invalid table
   pool_get (em->qinq_pool, invalid_qinq_table);	// first id = 0
-
-  return 0;
 }
 
-VLIB_INIT_FUNCTION (ethernet_input_init);
-
 void
 ethernet_register_input_type (vlib_main_t * vm,
 			      ethernet_type_t type, u32 node_index)