From f8d50682cd1245f6f5ce4c846ca6f1bdc11255a6 Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Tue, 14 May 2019 18:01:44 -0400 Subject: 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 --- src/vlib/init.h | 91 ++++++++++++++++++++++++++++++++------------------------- 1 file changed, 51 insertions(+), 40 deletions(-) (limited to 'src/vlib/init.h') diff --git a/src/vlib/init.h b/src/vlib/init.h index a9367697a85..6d2711489d8 100644 --- a/src/vlib/init.h +++ b/src/vlib/init.h @@ -54,6 +54,10 @@ typedef struct _vlib_init_function_list_elt { 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 @@ typedef struct vlib_config_function_runtime_t 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 @@ clib_error_t *vlib_call_all_main_loop_enter_functions (struct vlib_main_t *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 @@ clib_error_t *vlib_call_init_exit_functions (struct vlib_main_t *vm, #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 -- cgit 1.2.3-korg