diff options
Diffstat (limited to 'src/core/lib/support/mpscq.c')
-rw-r--r-- | src/core/lib/support/mpscq.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/src/core/lib/support/mpscq.c b/src/core/lib/support/mpscq.c index 25b055b172..cdd6335f82 100644 --- a/src/core/lib/support/mpscq.c +++ b/src/core/lib/support/mpscq.c @@ -38,7 +38,7 @@ void gpr_mpscq_init(gpr_mpscq *q) { gpr_atm_no_barrier_store(&q->head, (gpr_atm)&q->stub); q->tail = &q->stub; - gpr_atm_no_barrier_store(&q->stub.next, 0); + gpr_atm_no_barrier_store(&q->stub.next, (gpr_atm)NULL); } void gpr_mpscq_destroy(gpr_mpscq *q) { @@ -47,16 +47,17 @@ void gpr_mpscq_destroy(gpr_mpscq *q) { } void gpr_mpscq_push(gpr_mpscq *q, gpr_mpscq_node *n) { - gpr_atm_no_barrier_store(&n->next, 0); + gpr_atm_no_barrier_store(&n->next, (gpr_atm)NULL); gpr_mpscq_node *prev = (gpr_mpscq_node *)gpr_atm_full_xchg(&q->head, (gpr_atm)n); - gpr_atm_rel_store(&prev->next, (gpr_atm)n); + gpr_atm_no_barrier_store(&prev->next, (gpr_atm)n); } gpr_mpscq_node *gpr_mpscq_pop(gpr_mpscq *q) { gpr_mpscq_node *tail = q->tail; gpr_mpscq_node *next = (gpr_mpscq_node *)gpr_atm_acq_load(&tail->next); if (tail == &q->stub) { + // indicates the list is actually (ephemerally) empty if (next == NULL) return NULL; q->tail = next; tail = next; @@ -68,7 +69,8 @@ gpr_mpscq_node *gpr_mpscq_pop(gpr_mpscq *q) { } gpr_mpscq_node *head = (gpr_mpscq_node *)gpr_atm_acq_load(&q->head); if (tail != head) { - return 0; + // indicates a retry is in order: we're still adding + return NULL; } gpr_mpscq_push(q, &q->stub); next = (gpr_mpscq_node *)gpr_atm_acq_load(&tail->next); @@ -76,5 +78,6 @@ gpr_mpscq_node *gpr_mpscq_pop(gpr_mpscq *q) { q->tail = next; return tail; } + // indicates a retry is in order: we're still adding return NULL; } |