From 6d8ca69ed3d9bbafc0e3d3f1752b0119b2676e30 Mon Sep 17 00:00:00 2001
From: David Garcia Quintas <dgq@google.com>
Date: Thu, 11 May 2017 14:29:34 -0700
Subject: [PATCH] Fixes to subchannel and its index
---
src/core/ext/filters/client_channel/subchannel.c | 2 +-
.../ext/filters/client_channel/subchannel_index.c | 12 +++++++++++-
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/src/core/ext/filters/client_channel/subchannel.c b/src/core/ext/filters/client_channel/subchannel.c
index 1af3393a62..dd14bf1d02 100644
--- a/src/core/ext/filters/client_channel/subchannel.c
+++ b/src/core/ext/filters/client_channel/subchannel.c
@@ -283,6 +283,7 @@ static void disconnect(grpc_exec_ctx *exec_ctx, grpc_subchannel *c) {
void grpc_subchannel_unref(grpc_exec_ctx *exec_ctx,
grpc_subchannel *c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
+ // add a weak ref and subtract a strong ref (atomically)
old_refs = ref_mutate(c, (gpr_atm)1 - (gpr_atm)(1 << INTERNAL_REF_BITS),
1 REF_MUTATE_PURPOSE("STRONG_UNREF"));
if ((old_refs & STRONG_REF_MASK) == (1 << INTERNAL_REF_BITS)) {
@@ -656,7 +657,6 @@ static bool publish_transport_locked(grpc_exec_ctx *exec_ctx,
gpr_free(sw_subchannel);
grpc_channel_stack_destroy(exec_ctx, stk);
gpr_free(con);
- GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
return false;
}
diff --git a/src/core/ext/filters/client_channel/subchannel_index.c b/src/core/ext/filters/client_channel/subchannel_index.c
index f6ef4a845e..b25dbfcf51 100644
--- a/src/core/ext/filters/client_channel/subchannel_index.c
+++ b/src/core/ext/filters/client_channel/subchannel_index.c
@@ -183,8 +183,11 @@ grpc_subchannel *grpc_subchannel_index_register(grpc_exec_ctx *exec_ctx,
enter_ctx(exec_ctx);
grpc_subchannel *c = NULL;
+ bool need_to_unref_constructed;
while (c == NULL) {
+ need_to_unref_constructed = false;
+
// Compare and swap loop:
// - take a reference to the current index
gpr_mu_lock(&g_mu);
@@ -193,9 +196,12 @@ grpc_subchannel *grpc_subchannel_index_register(grpc_exec_ctx *exec_ctx,
// - Check to see if a subchannel already exists
c = gpr_avl_get(index, key);
+ if (c != NULL) {
+ c = GRPC_SUBCHANNEL_REF_FROM_WEAK_REF(c, "index_register");
+ }
if (c != NULL) {
// yes -> we're done
- GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, constructed, "index_register");
+ need_to_unref_constructed = true;
} else {
// no -> update the avl and compare/swap
gpr_avl updated =
@@ -219,6 +225,10 @@ grpc_subchannel *grpc_subchannel_index_register(grpc_exec_ctx *exec_ctx,
leave_ctx(exec_ctx);
+ if (need_to_unref_constructed) {
+ GRPC_SUBCHANNEL_UNREF(exec_ctx, constructed, "index_register");
+ }
+
return c;
}
--
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