diff options
| -rw-r--r-- | src/core/lib/transport/metadata.c | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/src/core/lib/transport/metadata.c b/src/core/lib/transport/metadata.c index 779efbb97d..5847ec9053 100644 --- a/src/core/lib/transport/metadata.c +++ b/src/core/lib/transport/metadata.c @@ -386,10 +386,18 @@ grpc_mdstr *grpc_mdstr_from_buffer(const uint8_t *buf, size_t length) { for (s = shard->strs[idx]; s; s = s->bucket_next) { if (s->hash == hash && GPR_SLICE_LENGTH(s->slice) == length && 0 == memcmp(buf, GPR_SLICE_START_PTR(s->slice), length)) { - GRPC_MDSTR_REF((grpc_mdstr *)s); - gpr_mu_unlock(&shard->mu); - GPR_TIMER_END("grpc_mdstr_from_buffer", 0); - return (grpc_mdstr *)s; + if (gpr_atm_full_fetch_add(&s->refcnt, 1) == 0) { + /* If we get here, we've added a ref to something that was about to + * die - drop it immediately. + * The *only* possible path here (given the shard mutex) should be to + * drop from one ref back to zero - assert that with a CAS */ + GPR_ASSERT(gpr_atm_rel_cas(&s->refcnt, 1, 0)); + /* and treat this as if we were never here... sshhh */ + } else { + gpr_mu_unlock(&shard->mu); + GPR_TIMER_END("grpc_mdstr_from_buffer", 0); + return (grpc_mdstr *)s; + } } } @@ -397,7 +405,7 @@ grpc_mdstr *grpc_mdstr_from_buffer(const uint8_t *buf, size_t length) { if (length + 1 < GPR_SLICE_INLINED_SIZE) { /* string data goes directly into the slice */ s = gpr_malloc(sizeof(internal_string)); - gpr_atm_rel_store(&s->refcnt, 2); + gpr_atm_rel_store(&s->refcnt, 1); s->slice.refcount = NULL; memcpy(s->slice.data.inlined.bytes, buf, length); s->slice.data.inlined.bytes[length] = 0; @@ -406,7 +414,7 @@ grpc_mdstr *grpc_mdstr_from_buffer(const uint8_t *buf, size_t length) { /* string data goes after the internal_string header, and we +1 for null terminator */ s = gpr_malloc(sizeof(internal_string) + length + 1); - gpr_atm_rel_store(&s->refcnt, 2); + gpr_atm_rel_store(&s->refcnt, 1); s->refcount.ref = slice_ref; s->refcount.unref = slice_unref; s->slice.refcount = &s->refcount; @@ -675,20 +683,19 @@ const char *grpc_mdstr_as_c_string(grpc_mdstr *s) { grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *gs DEBUG_ARGS) { internal_string *s = (internal_string *)gs; if (is_mdstr_static(gs)) return gs; - GPR_ASSERT(gpr_atm_full_fetch_add(&s->refcnt, 1) != 0); + GPR_ASSERT(gpr_atm_full_fetch_add(&s->refcnt, 1) > 0); return gs; } void grpc_mdstr_unref(grpc_mdstr *gs DEBUG_ARGS) { internal_string *s = (internal_string *)gs; if (is_mdstr_static(gs)) return; - if (2 == gpr_atm_full_fetch_add(&s->refcnt, -1)) { + if (1 == gpr_atm_full_fetch_add(&s->refcnt, -1)) { strtab_shard *shard = &g_strtab_shard[SHARD_IDX(s->hash, LOG2_STRTAB_SHARD_COUNT)]; gpr_mu_lock(&shard->mu); - if (1 == gpr_atm_no_barrier_load(&s->refcnt)) { - internal_destroy_string(shard, s); - } + GPR_ASSERT(0 == gpr_atm_no_barrier_load(&s->refcnt)); + internal_destroy_string(shard, s); gpr_mu_unlock(&shard->mu); } } |