Make metadata unref atomic

We used to need to lock the metadata context to unref an mdelem. This
change makes it possible to lock only when the mdelem refcount would
reach zero.

1 files changed, 2 insertions, 5 deletions

diff --git a/src/core/transport/chttp2/stream_encoder.c b/src/core/transport/chttp2/stream_encoder.c
index 83227e677d..2cbf90fb84 100644
--- a/src/core/transport/chttp2/stream_encoder.c
+++ b/src/core/transport/chttp2/stream_encoder.c
@@ -584,7 +584,6 @@ void grpc_chttp2_encode(grpc_stream_op *ops, size_t ops_count, int eof,
   size_t max_take_size;
   gpr_uint32 curop = 0;
   gpr_uint32 unref_op;
-  grpc_mdctx *mdctx = compressor->mdctx;
   grpc_linked_mdelem *l;
   int need_unref = 0;
   gpr_timespec deadline;
@@ -650,17 +649,15 @@ void grpc_chttp2_encode(grpc_stream_op *ops, size_t ops_count, int eof,
   finish_frame(&st, 1, eof);
 
   if (need_unref) {
-    grpc_mdctx_lock(mdctx);
     for (unref_op = 0; unref_op < curop; unref_op++) {
       op = &ops[unref_op];
       if (op->type != GRPC_OP_METADATA) continue;
       for (l = op->data.metadata.list.head; l; l = l->next) {
-        if (l->md) GRPC_MDCTX_LOCKED_MDELEM_UNREF(mdctx, l->md);
+        if (l->md) GRPC_MDELEM_UNREF(l->md);
       }
       for (l = op->data.metadata.garbage.head; l; l = l->next) {
-        GRPC_MDCTX_LOCKED_MDELEM_UNREF(mdctx, l->md);
+        GRPC_MDELEM_UNREF(l->md);
       }
     }
-    grpc_mdctx_unlock(mdctx);
   }
 }