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>
diff --git a/src/vlib/init.h b/src/vlib/init.h
index a936769..6d27114 100644
--- a/src/vlib/init.h
+++ b/src/vlib/init.h
@@ -54,6 +54,10 @@
{
struct _vlib_init_function_list_elt *next_init_function;
vlib_init_function_t *f;
+ char *name;
+ char **runs_before;
+ char **runs_after;
+ char **init_order;
} _vlib_init_function_list_elt_t;
/* Configuration functions: called with configuration input just before
@@ -116,48 +120,54 @@
be called from other modules to resolve init function depend. */
#ifndef CLIB_MARCH_VARIANT
-#define VLIB_DECLARE_INIT_FUNCTION(x, tag) \
-vlib_init_function_t * _VLIB_INIT_FUNCTION_SYMBOL (x, tag) = x; \
-static void __vlib_add_##tag##_function_##x (void) \
- __attribute__((__constructor__)) ; \
-static void __vlib_add_##tag##_function_##x (void) \
-{ \
- vlib_main_t * vm = vlib_get_main(); \
- static _vlib_init_function_list_elt_t _vlib_init_function; \
- _vlib_init_function.next_init_function \
- = vm->tag##_function_registrations; \
- vm->tag##_function_registrations = &_vlib_init_function; \
- _vlib_init_function.f = &x; \
-} \
-static void __vlib_rm_##tag##_function_##x (void) \
- __attribute__((__destructor__)) ; \
-static void __vlib_rm_##tag##_function_##x (void) \
-{ \
- vlib_main_t * vm = vlib_get_main(); \
- _vlib_init_function_list_elt_t *next; \
- if (vm->tag##_function_registrations->f == &x) \
- { \
- vm->tag##_function_registrations = \
- vm->tag##_function_registrations->next_init_function; \
- return; \
- } \
- next = vm->tag##_function_registrations; \
- while (next->next_init_function) \
- { \
- if (next->next_init_function->f == &x) \
- { \
- next->next_init_function = \
- next->next_init_function->next_init_function; \
- return; \
- } \
- next = next->next_init_function; \
- } \
-}
+#define VLIB_DECLARE_INIT_FUNCTION(x, tag) \
+vlib_init_function_t * _VLIB_INIT_FUNCTION_SYMBOL (x, tag) = x; \
+static void __vlib_add_##tag##_function_##x (void) \
+ __attribute__((__constructor__)) ; \
+static _vlib_init_function_list_elt_t _vlib_init_function_##tag_##x; \
+static void __vlib_add_##tag##_function_##x (void) \
+{ \
+ vlib_main_t * vm = vlib_get_main(); \
+ _vlib_init_function_##tag_##x.next_init_function \
+ = vm->tag##_function_registrations; \
+ vm->tag##_function_registrations = &_vlib_init_function_##tag_##x; \
+ _vlib_init_function_##tag_##x.f = &x; \
+ _vlib_init_function_##tag_##x.name = #x; \
+} \
+static void __vlib_rm_##tag##_function_##x (void) \
+ __attribute__((__destructor__)) ; \
+static void __vlib_rm_##tag##_function_##x (void) \
+{ \
+ vlib_main_t * vm = vlib_get_main(); \
+ _vlib_init_function_list_elt_t *this, *prev; \
+ this = vm->tag##_function_registrations; \
+ if (this == 0) \
+ return; \
+ if (this->f == &x) \
+ { \
+ vm->tag##_function_registrations = this->next_init_function; \
+ return; \
+ } \
+ prev = this; \
+ this = this->next_init_function; \
+ while (this) \
+ { \
+ if (this->f == &x) \
+ { \
+ prev->next_init_function = \
+ this->next_init_function; \
+ return; \
+ } \
+ prev = this; \
+ this = this->next_init_function; \
+ } \
+} \
+static _vlib_init_function_list_elt_t _vlib_init_function_##tag_##x
#else
/* create unused pointer to silence compiler warnings and get whole
function optimized out */
#define VLIB_DECLARE_INIT_FUNCTION(x, tag) \
-static __clib_unused void * __clib_unused_##tag##_##x = x;
+static __clib_unused void * __clib_unused_##tag##_##x = x
#endif
#define VLIB_INIT_FUNCTION(x) VLIB_DECLARE_INIT_FUNCTION(x,init)
@@ -316,8 +326,8 @@
*vm);
clib_error_t *vlib_call_all_main_loop_exit_functions (struct vlib_main_t *vm);
clib_error_t *vlib_call_init_exit_functions (struct vlib_main_t *vm,
- _vlib_init_function_list_elt_t *
- head, int call_once);
+ _vlib_init_function_list_elt_t **
+ headp, int call_once);
#define foreach_vlib_module_reference \
_ (node_cli) \
@@ -327,6 +337,7 @@
#define _(x) void vlib_##x##_reference (void);
foreach_vlib_module_reference
#undef _
+#define VLIB_INITS(...) (char*[]) { __VA_ARGS__, 0}
#endif /* included_vlib_init_h */
/*
* fd.io coding-style-patch-verification: ON