src/basic/barrier.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4
   5 #include <stdbool.h>
   6 #include <stdint.h>
   7 #include <sys/types.h>
   8
   9 #include "macro.h"
  10
  11 /* See source file for an API description. */
  12
  13 typedef struct Barrier Barrier;
  14
  15 enum {
  16         BARRIER_SINGLE                  = 1LL,
  17         BARRIER_ABORTION                = INT64_MAX,
  18
  19         /* bias values to store state; keep @WE < @THEY < @I */
  20         BARRIER_BIAS                    = INT64_MIN,
  21         BARRIER_WE_ABORTED              = BARRIER_BIAS + 1LL,
  22         BARRIER_THEY_ABORTED            = BARRIER_BIAS + 2LL,
  23         BARRIER_I_ABORTED               = BARRIER_BIAS + 3LL,
  24 };
  25
  26 enum {
  27         BARRIER_PARENT,
  28         BARRIER_CHILD,
  29 };
  30
  31 struct Barrier {
  32         int me;
  33         int them;
  34         int pipe[2];
  35         int64_t barriers;
  36 };
  37
  38 #define BARRIER_NULL {-1, -1, {-1, -1}, 0}
  39
  40 int barrier_create(Barrier *obj);
  41 void barrier_destroy(Barrier *b);
  42
  43 DEFINE_TRIVIAL_CLEANUP_FUNC(Barrier*, barrier_destroy);
  44
  45 void barrier_set_role(Barrier *b, unsigned int role);
  46
  47 bool barrier_place(Barrier *b);
  48 bool barrier_abort(Barrier *b);
  49
  50 bool barrier_wait_next(Barrier *b);
  51 bool barrier_wait_abortion(Barrier *b);
  52 bool barrier_sync_next(Barrier *b);
  53 bool barrier_sync(Barrier *b);
  54
  55 static inline bool barrier_i_aborted(Barrier *b) {
  56         return IN_SET(b->barriers, BARRIER_I_ABORTED, BARRIER_WE_ABORTED);
  57 }
  58
  59 static inline bool barrier_they_aborted(Barrier *b) {
  60         return IN_SET(b->barriers, BARRIER_THEY_ABORTED, BARRIER_WE_ABORTED);
  61 }
  62
  63 static inline bool barrier_we_aborted(Barrier *b) {
  64         return b->barriers == BARRIER_WE_ABORTED;
  65 }
  66
  67 static inline bool barrier_is_aborted(Barrier *b) {
  68         return IN_SET(b->barriers,
  69                       BARRIER_I_ABORTED, BARRIER_THEY_ABORTED, BARRIER_WE_ABORTED);
  70 }
  71
  72 static inline bool barrier_place_and_sync(Barrier *b) {
  73         (void) barrier_place(b);
  74         return barrier_sync(b);
  75 }