15 files changed, 312 insertions, 165 deletions

diff --git a/src/core/lib/channel/channel_stack.c b/src/core/lib/channel/channel_stack.c
index e02c164aaf..cedc8ade82 100644
--- a/src/core/lib/channel/channel_stack.c
+++ b/src/core/lib/channel/channel_stack.c
@@ -189,32 +189,30 @@ void grpc_call_stack_init(grpc_exec_ctx *exec_ctx,
   }
 }
 
-void grpc_call_stack_set_pollset_or_pollset_set(
-    grpc_exec_ctx *exec_ctx, grpc_call_stack *call_stack, grpc_pollset *pollset,
-    grpc_pollset_set *pollset_set_alternative) {
+void grpc_call_stack_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
+                                                grpc_call_stack *call_stack,
+                                                grpc_pops *pops) {
   size_t count = call_stack->count;
   grpc_call_element *call_elems;
   char *user_data;
   size_t i;
 
-  GPR_ASSERT((pollset == NULL) + (pollset_set_alternative == NULL) == 1);
-  GPR_ASSERT(pollset != NULL || pollset_set_alternative != NULL);
   call_elems = CALL_ELEMS_FROM_STACK(call_stack);
   user_data = ((char *)call_elems) +
               ROUND_UP_TO_ALIGNMENT_SIZE(count * sizeof(grpc_call_element));
 
   /* init per-filter data */
   for (i = 0; i < count; i++) {
-    call_elems[i].filter->set_pollset_or_pollset_set(
-        exec_ctx, &call_elems[i], pollset, pollset_set_alternative);
+    call_elems[i].filter->set_pollset_or_pollset_set(exec_ctx, &call_elems[i],
+                                                     pops);
     user_data +=
         ROUND_UP_TO_ALIGNMENT_SIZE(call_elems[i].filter->sizeof_call_data);
   }
 }
 
-void grpc_call_stack_ignore_set_pollset_or_pollset_set(
-    grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_pollset *pollset,
-    grpc_pollset_set *pollset_set_alternative) {}
+void grpc_call_stack_ignore_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
+                                                       grpc_call_element *elem,
+                                                       grpc_pops *pops) {}
 
 void grpc_call_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_call_stack *stack) {
   grpc_call_element *elems = CALL_ELEMS_FROM_STACK(stack);
diff --git a/src/core/lib/channel/channel_stack.h b/src/core/lib/channel/channel_stack.h
index 027bb23c1d..c9d13ef193 100644
--- a/src/core/lib/channel/channel_stack.h
+++ b/src/core/lib/channel/channel_stack.h
@@ -46,6 +46,7 @@
 #include <grpc/grpc.h>
 #include <grpc/support/log.h>
 #include "src/core/lib/debug/trace.h"
+#include "src/core/lib/iomgr/pops.h"
 #include "src/core/lib/transport/transport.h"
 
 typedef struct grpc_channel_element grpc_channel_element;
@@ -102,9 +103,7 @@ typedef struct {
   void (*init_call_elem)(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                          grpc_call_element_args *args);
   void (*set_pollset_or_pollset_set)(grpc_exec_ctx *exec_ctx,
-                                     grpc_call_element *elem,
-                                     grpc_pollset *pollset,
-                                     grpc_pollset_set *pollset_set_alternative);
+                                     grpc_call_element *elem, grpc_pops *pops);
   /* Destroy per call data.
      The filter does not need to do any chaining */
   void (*destroy_call_elem)(grpc_exec_ctx *exec_ctx, grpc_call_element *elem);
@@ -201,9 +200,9 @@ void grpc_call_stack_init(grpc_exec_ctx *exec_ctx,
                           grpc_call_stack *call_stack);
 /* Set a pollset or a pollset_set for a call stack: must occur before the first
  * op is started */
-void grpc_call_stack_set_pollset_or_pollset_set(
-    grpc_exec_ctx *exec_ctx, grpc_call_stack *call_stack, grpc_pollset *pollset,
-    grpc_pollset_set *pollset_set_alternative);
+void grpc_call_stack_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
+                                                grpc_call_stack *call_stack,
+                                                grpc_pops *pops);
 
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
 #define GRPC_CALL_STACK_REF(call_stack, reason) \
@@ -228,12 +227,11 @@ void grpc_call_stack_set_pollset_or_pollset_set(
 /* Destroy a call stack */
 void grpc_call_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_call_stack *stack);
 
-/* Ignore set pollset{_set} - used by filters to implement the
- * set_pollset_or_pollset_set method if they don't care about pollsets at all.
- * Does nothing. */
-void grpc_call_stack_ignore_set_pollset_or_pollset_set(
-    grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_pollset *pollset,
-    grpc_pollset_set *pollset_set_alternative);
+/* Ignore set pollset{_set} - used by filters if they don't care about pollsets
+ * at all. Does nothing. */
+void grpc_call_stack_ignore_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
+                                                       grpc_call_element *elem,
+                                                       grpc_pops *pops);
 /* Call the next operation in a call stack */
 void grpc_call_next_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                        grpc_transport_stream_op *op);
diff --git a/src/core/lib/channel/connected_channel.c b/src/core/lib/channel/connected_channel.c
index 405f0a2ecd..314ff6e5ce 100644
--- a/src/core/lib/channel/connected_channel.c
+++ b/src/core/lib/channel/connected_channel.c
@@ -93,22 +93,13 @@ static void init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   GPR_ASSERT(r == 0);
 }
 
-static void set_pollset_or_pollset_set(
-    grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_pollset *pollset,
-    grpc_pollset_set *pollset_set_alternative) {
-  GPR_ASSERT((pollset == NULL) + (pollset_set_alternative == NULL) == 1);
-  GPR_ASSERT(pollset != NULL || pollset_set_alternative != NULL);
-
+static void set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
+                                       grpc_call_element *elem,
+                                       grpc_pops *pops) {
   call_data *calld = elem->call_data;
   channel_data *chand = elem->channel_data;
-  if (pollset != NULL) {
-    grpc_transport_set_pollset(exec_ctx, chand->transport,
-                               TRANSPORT_STREAM_FROM_CALL_DATA(calld), pollset);
-  } else if (pollset_set_alternative != NULL) {
-    grpc_transport_set_pollset_set(exec_ctx, chand->transport,
-                                   TRANSPORT_STREAM_FROM_CALL_DATA(calld),
-                                   pollset_set_alternative);
-  }
+  grpc_transport_set_pops(exec_ctx, chand->transport,
+                          TRANSPORT_STREAM_FROM_CALL_DATA(calld), pops);
 }
 
 /* Destructor for call_data */
diff --git a/src/core/lib/http/httpcli.c b/src/core/lib/http/httpcli.c
index 4cf3358680..d48e954479 100644
--- a/src/core/lib/http/httpcli.c
+++ b/src/core/lib/http/httpcli.c
@@ -62,7 +62,7 @@ typedef struct {
   grpc_httpcli_response_cb on_response;
   void *user_data;
   grpc_httpcli_context *context;
-  grpc_pollset_set *pollset_set;
+  grpc_pops *pops;
   grpc_iomgr_object iomgr_obj;
   gpr_slice_buffer incoming;
   gpr_slice_buffer outgoing;
@@ -97,8 +97,7 @@ static void next_address(grpc_exec_ctx *exec_ctx, internal_request *req);
 
 static void finish(grpc_exec_ctx *exec_ctx, internal_request *req,
                    int success) {
-  grpc_pollset_set_del_pollset_set(exec_ctx, req->context->pollset_set,
-                                   req->pollset_set);
+  grpc_pops_del_to_pollset_set(exec_ctx, req->pops, req->context->pollset_set);
   req->on_response(exec_ctx, req->user_data,
                    success ? &req->parser.http.response : NULL);
   grpc_http_parser_destroy(&req->parser);
@@ -221,10 +220,10 @@ static void on_resolved(grpc_exec_ctx *exec_ctx, void *arg,
 }
 
 static void internal_request_begin(
-    grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
-    grpc_pollset_set *pollset_set, const grpc_httpcli_request *request,
-    gpr_timespec deadline, grpc_httpcli_response_cb on_response,
-    void *user_data, const char *name, gpr_slice request_text) {
+    grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context, grpc_pops *pops,
+    const grpc_httpcli_request *request, gpr_timespec deadline,
+    grpc_httpcli_response_cb on_response, void *user_data, const char *name,
+    gpr_slice request_text) {
   internal_request *req = gpr_malloc(sizeof(internal_request));
   memset(req, 0, sizeof(*req));
   req->request_text = request_text;
@@ -235,7 +234,7 @@ static void internal_request_begin(
   req->handshaker =
       request->handshaker ? request->handshaker : &grpc_httpcli_plaintext;
   req->context = context;
-  req->pollset_set = pollset_set;
+  req->pops = pops;
   grpc_closure_init(&req->on_read, on_read, req);
   grpc_closure_init(&req->done_write, done_write, req);
   gpr_slice_buffer_init(&req->incoming);
@@ -244,15 +243,14 @@ static void internal_request_begin(
   req->host = gpr_strdup(request->host);
   req->ssl_host_override = gpr_strdup(request->ssl_host_override);
 
-  grpc_pollset_set_add_pollset_set(exec_ctx, req->context->pollset_set,
-                                   req->pollset_set);
+  GPR_ASSERT(pops);
+  grpc_pops_add_to_pollset_set(exec_ctx, req->pops, req->context->pollset_set);
   grpc_resolve_address(exec_ctx, request->host, req->handshaker->default_port,
                        on_resolved, req);
 }
 
 void grpc_httpcli_get(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
-                      grpc_pollset_set *pollset_set,
-                      const grpc_httpcli_request *request,
+                      grpc_pops *pops, const grpc_httpcli_request *request,
                       gpr_timespec deadline,
                       grpc_httpcli_response_cb on_response, void *user_data) {
   char *name;
@@ -261,15 +259,14 @@ void grpc_httpcli_get(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
     return;
   }
   gpr_asprintf(&name, "HTTP:GET:%s:%s", request->host, request->http.path);
-  internal_request_begin(exec_ctx, context, pollset_set, request, deadline,
+  internal_request_begin(exec_ctx, context, pops, request, deadline,
                          on_response, user_data, name,
                          grpc_httpcli_format_get_request(request));
   gpr_free(name);
 }
 
 void grpc_httpcli_post(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
-                       grpc_pollset_set *pollset_set,
-                       const grpc_httpcli_request *request,
+                       grpc_pops *pops, const grpc_httpcli_request *request,
                        const char *body_bytes, size_t body_size,
                        gpr_timespec deadline,
                        grpc_httpcli_response_cb on_response, void *user_data) {
@@ -281,8 +278,8 @@ void grpc_httpcli_post(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
   }
   gpr_asprintf(&name, "HTTP:POST:%s:%s", request->host, request->http.path);
   internal_request_begin(
-      exec_ctx, context, pollset_set, request, deadline, on_response, user_data,
-      name, grpc_httpcli_format_post_request(request, body_bytes, body_size));
+      exec_ctx, context, pops, request, deadline, on_response, user_data, name,
+      grpc_httpcli_format_post_request(request, body_bytes, body_size));
   gpr_free(name);
 }
 
diff --git a/src/core/lib/http/httpcli.h b/src/core/lib/http/httpcli.h
index 040b5f4761..1166cfeea7 100644
--- a/src/core/lib/http/httpcli.h
+++ b/src/core/lib/http/httpcli.h
@@ -42,6 +42,7 @@
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/pollset_set.h"
+#include "src/core/lib/iomgr/pops.h"
 
 /* User agent this library reports */
 #define GRPC_HTTPCLI_USER_AGENT "grpc-httpcli/0.0"
@@ -100,8 +101,7 @@ void grpc_httpcli_context_destroy(grpc_httpcli_context *context);
    'on_response' is a callback to report results to (and 'user_data' is a user
      supplied pointer to pass to said call) */
 void grpc_httpcli_get(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
-                      grpc_pollset_set *pollset_set,
-                      const grpc_httpcli_request *request,
+                      grpc_pops *pops, const grpc_httpcli_request *request,
                       gpr_timespec deadline,
                       grpc_httpcli_response_cb on_response, void *user_data);
 
@@ -121,8 +121,7 @@ void grpc_httpcli_get(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
      supplied pointer to pass to said call)
    Does not support ?var1=val1&var2=val2 in the path. */
 void grpc_httpcli_post(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
-                       grpc_pollset_set *pollset_set,
-                       const grpc_httpcli_request *request,
+                       grpc_pops *pops, const grpc_httpcli_request *request,
                        const char *body_bytes, size_t body_size,
                        gpr_timespec deadline,
                        grpc_httpcli_response_cb on_response, void *user_data);
diff --git a/src/core/lib/iomgr/pops.c b/src/core/lib/iomgr/pops.c
new file mode 100644
index 0000000000..c2629f20aa
--- /dev/null
+++ b/src/core/lib/iomgr/pops.c
@@ -0,0 +1,103 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/iomgr/pops.h"
+
+struct grpc_pops {
+  union {
+    grpc_pollset *pollset;
+    grpc_pollset_set *pollset_set;
+  } pops;
+  enum pops_tag { POLLSET, POLLSET_SET } tag;
+};
+
+grpc_pops *grpc_pops_create_from_pollset_set(grpc_pollset_set *pollset_set) {
+  grpc_pops *pops = gpr_malloc(sizeof(grpc_pops));
+  pops->pops.pollset_set = pollset_set;
+  pops->tag = POLLSET_SET;
+  return pops;
+}
+
+grpc_pops *grpc_pops_create_from_pollset(grpc_pollset *pollset) {
+  grpc_pops *pops = gpr_malloc(sizeof(grpc_pops));
+  pops->pops.pollset = pollset;
+  pops->tag = POLLSET;
+  return pops;
+}
+
+void grpc_pops_destroy(grpc_pops *pops) { gpr_free(pops); }
+
+grpc_pollset *grpc_pops_pollset(grpc_pops *pops) {
+  if (pops->tag == POLLSET) {
+    return pops->pops.pollset;
+  }
+  return NULL;
+}
+
+grpc_pollset_set *grpc_pops_pollset_set(grpc_pops *pops) {
+  if (pops->tag == POLLSET_SET) {
+    return pops->pops.pollset_set;
+  }
+  return NULL;
+}
+
+void grpc_pops_add_to_pollset_set(grpc_exec_ctx *exec_ctx, grpc_pops *pops,
+                                  grpc_pollset_set *pss_dst) {
+  if (pops->tag == POLLSET) {
+    GPR_ASSERT(pops->pops.pollset != NULL);
+    grpc_pollset_set_add_pollset(exec_ctx, pss_dst, pops->pops.pollset);
+  } else if (pops->tag == POLLSET_SET) {
+    GPR_ASSERT(pops->pops.pollset_set != NULL);
+    grpc_pollset_set_add_pollset_set(exec_ctx, pss_dst, pops->pops.pollset_set);
+  } else {
+    gpr_log(GPR_ERROR, "Invalid grpc_pops tag '%d'", pops->tag);
+    abort();
+  }
+}
+
+void grpc_pops_del_to_pollset_set(grpc_exec_ctx *exec_ctx, grpc_pops *pops,
+                                  grpc_pollset_set *pss_dst) {
+  if (pops->tag == POLLSET) {
+    GPR_ASSERT(pops->pops.pollset != NULL);
+    grpc_pollset_set_del_pollset(exec_ctx, pss_dst, pops->pops.pollset);
+  } else if (pops->tag == POLLSET_SET) {
+    GPR_ASSERT(pops->pops.pollset_set != NULL);
+    grpc_pollset_set_del_pollset_set(exec_ctx, pss_dst, pops->pops.pollset_set);
+  } else {
+    gpr_log(GPR_ERROR, "Invalid grpc_pops tag '%d'", pops->tag);
+    abort();
+  }
+}
diff --git a/src/core/lib/iomgr/pops.h b/src/core/lib/iomgr/pops.h
new file mode 100644
index 0000000000..24ff85748b
--- /dev/null
+++ b/src/core/lib/iomgr/pops.h
@@ -0,0 +1,69 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_IOMGR_POPS_H
+#define GRPC_CORE_LIB_IOMGR_POPS_H
+
+#include "src/core/lib/iomgr/pollset.h"
+#include "src/core/lib/iomgr/pollset_set.h"
+
+/* A grpc_pops is a pollset-or-pollset_set container. It allows functions that
+ * accept a pollset XOR a pollset_set to do so through an abstract interface.
+ * No ownership is taken. */
+
+typedef struct grpc_pops grpc_pops;
+
+grpc_pops *grpc_pops_create_from_pollset_set(grpc_pollset_set *pollset_set);
+grpc_pops *grpc_pops_create_from_pollset(grpc_pollset *pollset);
+
+/** If \a pops contains a pollset, return it. Otherwise, return NULL */
+grpc_pollset *grpc_pops_pollset(grpc_pops *pops);
+
+/** If \a pops contains a pollset_set, return it. Otherwise, return NULL */
+grpc_pollset_set *grpc_pops_pollset_set(grpc_pops *pops);
+
+void grpc_pops_destroy(grpc_pops *pops);
+
+/** Add the pollset or pollset_set in \a pops to the destination pollset_set \a
+ * pss_dst */
+void grpc_pops_add_to_pollset_set(grpc_exec_ctx *exec_ctx, grpc_pops *pops,
+                                  grpc_pollset_set *pss_dst);
+
+/** Delete the pollset or pollset_set in \a pops from the destination
+ * pollset_set \a
+ * pss_dst */
+void grpc_pops_del_to_pollset_set(grpc_exec_ctx *exec_ctx, grpc_pops *pops,
+                                  grpc_pollset_set *pss_dst);
+/* pollset_set specific */
+
+#endif /* GRPC_CORE_LIB_IOMGR_POPS_H */
diff --git a/src/core/lib/security/client_auth_filter.c b/src/core/lib/security/client_auth_filter.c
index 5db9755c2b..1511659dfe 100644
--- a/src/core/lib/security/client_auth_filter.c
+++ b/src/core/lib/security/client_auth_filter.c
@@ -54,11 +54,11 @@ typedef struct {
   grpc_call_credentials *creds;
   grpc_mdstr *host;
   grpc_mdstr *method;
-  /* pollset_set bound to this call; if we need to make external
+  /* pollset{_set} bound to this call; if we need to make external
      network requests, they should be done under a pollset added to this
      pollset_set so that work can progress when this call wants work to progress
   */
-  grpc_pollset_set *pollset_set;
+  grpc_pops *pops;
   grpc_transport_stream_op op;
   uint8_t security_context_set;
   grpc_linked_mdelem md_links[MAX_CREDENTIALS_METADATA_COUNT];
@@ -184,9 +184,9 @@ static void send_security_metadata(grpc_exec_ctx *exec_ctx,
   build_auth_metadata_context(&chand->security_connector->base,
                               chand->auth_context, calld);
   calld->op = *op; /* Copy op (originates from the caller's stack). */
-  GPR_ASSERT(calld->pollset_set);
+  GPR_ASSERT(calld->pops != NULL);
   grpc_call_credentials_get_request_metadata(
-      exec_ctx, calld->creds, calld->pollset_set, calld->auth_md_context,
+      exec_ctx, calld->creds, calld->pops, calld->auth_md_context,
       on_credentials_metadata, elem);
 }
 
@@ -268,22 +268,13 @@ static void init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                            grpc_call_element_args *args) {
   call_data *calld = elem->call_data;
   memset(calld, 0, sizeof(*calld));
-  calld->pollset_set = grpc_pollset_set_create();
 }
 
-static void set_pollset_or_pollset_set(
-    grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_pollset *pollset,
-    grpc_pollset_set *pollset_set_alternative) {
-  GPR_ASSERT((pollset == NULL) + (pollset_set_alternative == NULL) == 1);
-  GPR_ASSERT(pollset != NULL || pollset_set_alternative != NULL);
-
+static void set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
+                                       grpc_call_element *elem,
+                                       grpc_pops *pops) {
   call_data *calld = elem->call_data;
-  if (pollset != NULL) {
-    grpc_pollset_set_add_pollset(exec_ctx, calld->pollset_set, pollset);
-  } else if (pollset_set_alternative != NULL) {
-    grpc_pollset_set_add_pollset_set(exec_ctx, calld->pollset_set,
-                                     pollset_set_alternative);
-  }
+  calld->pops = pops;
 }
 
 /* Destructor for call_data */
@@ -298,7 +289,6 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx,
     GRPC_MDSTR_UNREF(calld->method);
   }
   reset_auth_metadata_context(&calld->auth_md_context);
-  grpc_pollset_set_destroy(calld->pollset_set);
 }
 
 /* Constructor for channel_data */
diff --git a/src/core/lib/security/credentials.c b/src/core/lib/security/credentials.c
index 8550649cbf..43c061a265 100644
--- a/src/core/lib/security/credentials.c
+++ b/src/core/lib/security/credentials.c
@@ -117,16 +117,16 @@ void grpc_call_credentials_release(grpc_call_credentials *creds) {
 }
 
 void grpc_call_credentials_get_request_metadata(
-    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
-    grpc_pollset_set *pollset_set, grpc_auth_metadata_context context,
-    grpc_credentials_metadata_cb cb, void *user_data) {
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds, grpc_pops *pops,
+    grpc_auth_metadata_context context, grpc_credentials_metadata_cb cb,
+    void *user_data) {
   if (creds == NULL || creds->vtable->get_request_metadata == NULL) {
     if (cb != NULL) {
       cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_OK);
     }
     return;
   }
-  creds->vtable->get_request_metadata(exec_ctx, creds, pollset_set, context, cb,
+  creds->vtable->get_request_metadata(exec_ctx, creds, pops, context, cb,
                                       user_data);
 }
 
@@ -448,7 +448,7 @@ static void jwt_destruct(grpc_call_credentials *creds) {
 
 static void jwt_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                      grpc_call_credentials *creds,
-                                     grpc_pollset_set *pollset_set,
+                                     grpc_pops *pops,
                                      grpc_auth_metadata_context context,
                                      grpc_credentials_metadata_cb cb,
                                      void *user_data) {
@@ -670,9 +670,9 @@ static void on_oauth2_token_fetcher_http_response(
 }
 
 static void oauth2_token_fetcher_get_request_metadata(
-    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
-    grpc_pollset_set *pollset_set, grpc_auth_metadata_context context,
-    grpc_credentials_metadata_cb cb, void *user_data) {
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds, grpc_pops *pops,
+    grpc_auth_metadata_context context, grpc_credentials_metadata_cb cb,
+    void *user_data) {
   grpc_oauth2_token_fetcher_credentials *c =
       (grpc_oauth2_token_fetcher_credentials *)creds;
   gpr_timespec refresh_threshold = gpr_time_from_seconds(
@@ -697,7 +697,7 @@ static void oauth2_token_fetcher_get_request_metadata(
     c->fetch_func(
         exec_ctx,
         grpc_credentials_metadata_request_create(creds, cb, user_data),
-        &c->httpcli_context, pollset_set, on_oauth2_token_fetcher_http_response,
+        &c->httpcli_context, pops, on_oauth2_token_fetcher_http_response,
         gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), refresh_threshold));
   }
 }
@@ -720,7 +720,7 @@ static grpc_call_credentials_vtable compute_engine_vtable = {
 
 static void compute_engine_fetch_oauth2(
     grpc_exec_ctx *exec_ctx, grpc_credentials_metadata_request *metadata_req,
-    grpc_httpcli_context *httpcli_context, grpc_pollset_set *pollset_set,
+    grpc_httpcli_context *httpcli_context, grpc_pops *pops,
     grpc_httpcli_response_cb response_cb, gpr_timespec deadline) {
   grpc_http_header header = {"Metadata-Flavor", "Google"};
   grpc_httpcli_request request;
@@ -729,7 +729,7 @@ static void compute_engine_fetch_oauth2(
   request.http.path = GRPC_COMPUTE_ENGINE_METADATA_TOKEN_PATH;
   request.http.hdr_count = 1;
   request.http.hdrs = &header;
-  grpc_httpcli_get(exec_ctx, httpcli_context, pollset_set, &request, deadline,
+  grpc_httpcli_get(exec_ctx, httpcli_context, pops, &request, deadline,
                    response_cb, metadata_req);
 }
 
@@ -759,7 +759,7 @@ static grpc_call_credentials_vtable refresh_token_vtable = {
 
 static void refresh_token_fetch_oauth2(
     grpc_exec_ctx *exec_ctx, grpc_credentials_metadata_request *metadata_req,
-    grpc_httpcli_context *httpcli_context, grpc_pollset_set *pollset_set,
+    grpc_httpcli_context *httpcli_context, grpc_pops *pops,
     grpc_httpcli_response_cb response_cb, gpr_timespec deadline) {
   grpc_google_refresh_token_credentials *c =
       (grpc_google_refresh_token_credentials *)metadata_req->creds;
@@ -776,7 +776,7 @@ static void refresh_token_fetch_oauth2(
   request.http.hdr_count = 1;
   request.http.hdrs = &header;
   request.handshaker = &grpc_httpcli_ssl;
-  grpc_httpcli_post(exec_ctx, httpcli_context, pollset_set, &request, body,
+  grpc_httpcli_post(exec_ctx, httpcli_context, pops, &request, body,
                     strlen(body), deadline, response_cb, metadata_req);
   gpr_free(body);
 }
@@ -826,9 +826,9 @@ static void on_simulated_token_fetch_done(grpc_exec_ctx *exec_ctx,
 }
 
 static void md_only_test_get_request_metadata(
-    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
-    grpc_pollset_set *pollset_set, grpc_auth_metadata_context context,
-    grpc_credentials_metadata_cb cb, void *user_data) {
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds, grpc_pops *pops,
+    grpc_auth_metadata_context context, grpc_credentials_metadata_cb cb,
+    void *user_data) {
   grpc_md_only_test_credentials *c = (grpc_md_only_test_credentials *)creds;
 
   if (c->is_async) {
@@ -866,9 +866,9 @@ static void access_token_destruct(grpc_call_credentials *creds) {
 }
 
 static void access_token_get_request_metadata(
-    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
-    grpc_pollset_set *pollset_set, grpc_auth_metadata_context context,
-    grpc_credentials_metadata_cb cb, void *user_data) {
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds, grpc_pops *pops,
+    grpc_auth_metadata_context context, grpc_credentials_metadata_cb cb,
+    void *user_data) {
   grpc_access_token_credentials *c = (grpc_access_token_credentials *)creds;
   cb(exec_ctx, user_data, c->access_token_md->entries, 1, GRPC_CREDENTIALS_OK);
 }
@@ -951,7 +951,7 @@ typedef struct {
   grpc_credentials_md_store *md_elems;
   grpc_auth_metadata_context auth_md_context;
   void *user_data;
-  grpc_pollset_set *pollset_set;
+  grpc_pops *pops;
   grpc_credentials_metadata_cb cb;
 } grpc_composite_call_credentials_metadata_context;
 
@@ -994,9 +994,9 @@ static void composite_call_metadata_cb(grpc_exec_ctx *exec_ctx, void *user_data,
   if (ctx->creds_index < ctx->composite_creds->inner.num_creds) {
     grpc_call_credentials *inner_creds =
         ctx->composite_creds->inner.creds_array[ctx->creds_index++];
-    grpc_call_credentials_get_request_metadata(
-        exec_ctx, inner_creds, ctx->pollset_set, ctx->auth_md_context,
-        composite_call_metadata_cb, ctx);
+    grpc_call_credentials_get_request_metadata(exec_ctx, inner_creds, ctx->pops,
+                                               ctx->auth_md_context,
+                                               composite_call_metadata_cb, ctx);
     return;
   }
 
@@ -1007,9 +1007,9 @@ static void composite_call_metadata_cb(grpc_exec_ctx *exec_ctx, void *user_data,
 }
 
 static void composite_call_get_request_metadata(
-    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
-    grpc_pollset_set *pollset_set, grpc_auth_metadata_context auth_md_context,
-    grpc_credentials_metadata_cb cb, void *user_data) {
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds, grpc_pops *pops,
+    grpc_auth_metadata_context auth_md_context, grpc_credentials_metadata_cb cb,
+    void *user_data) {
   grpc_composite_call_credentials *c = (grpc_composite_call_credentials *)creds;
   grpc_composite_call_credentials_metadata_context *ctx;
 
@@ -1019,11 +1019,11 @@ static void composite_call_get_request_metadata(
   ctx->user_data = user_data;
   ctx->cb = cb;
   ctx->composite_creds = c;
-  ctx->pollset_set = pollset_set;
+  ctx->pops = pops;
   ctx->md_elems = grpc_credentials_md_store_create(c->inner.num_creds);
   grpc_call_credentials_get_request_metadata(
-      exec_ctx, c->inner.creds_array[ctx->creds_index++], pollset_set,
-      auth_md_context, composite_call_metadata_cb, ctx);
+      exec_ctx, c->inner.creds_array[ctx->creds_index++], pops, auth_md_context,
+      composite_call_metadata_cb, ctx);
 }
 
 static grpc_call_credentials_vtable composite_call_credentials_vtable = {
@@ -1116,7 +1116,7 @@ static void iam_destruct(grpc_call_credentials *creds) {
 
 static void iam_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                      grpc_call_credentials *creds,
-                                     grpc_pollset_set *pollset_set,
+                                     grpc_pops *pops,
                                      grpc_auth_metadata_context context,
                                      grpc_credentials_metadata_cb cb,
                                      void *user_data) {
@@ -1205,7 +1205,7 @@ static void plugin_md_request_metadata_ready(void *request,
 
 static void plugin_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                         grpc_call_credentials *creds,
-                                        grpc_pollset_set *pollset_set,
+                                        grpc_pops *pops,
                                         grpc_auth_metadata_context context,
                                         grpc_credentials_metadata_cb cb,
                                         void *user_data) {
diff --git a/src/core/lib/security/credentials.h b/src/core/lib/security/credentials.h
index 9512e8e028..3d374949d5 100644
--- a/src/core/lib/security/credentials.h
+++ b/src/core/lib/security/credentials.h
@@ -41,6 +41,7 @@
 
 #include "src/core/lib/http/httpcli.h"
 #include "src/core/lib/http/parser.h"
+#include "src/core/lib/iomgr/pops.h"
 #include "src/core/lib/security/json_token.h"
 #include "src/core/lib/security/security_connector.h"
 
@@ -169,8 +170,7 @@ typedef void (*grpc_credentials_metadata_cb)(grpc_exec_ctx *exec_ctx,
 typedef struct {
   void (*destruct)(grpc_call_credentials *c);
   void (*get_request_metadata)(grpc_exec_ctx *exec_ctx,
-                               grpc_call_credentials *c,
-                               grpc_pollset_set *pollset_set,
+                               grpc_call_credentials *c, grpc_pops *pops,
                                grpc_auth_metadata_context context,
                                grpc_credentials_metadata_cb cb,
                                void *user_data);
@@ -185,9 +185,9 @@ struct grpc_call_credentials {
 grpc_call_credentials *grpc_call_credentials_ref(grpc_call_credentials *creds);
 void grpc_call_credentials_unref(grpc_call_credentials *creds);
 void grpc_call_credentials_get_request_metadata(
-    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
-    grpc_pollset_set *pollset_set, grpc_auth_metadata_context context,
-    grpc_credentials_metadata_cb cb, void *user_data);
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds, grpc_pops *pops,
+    grpc_auth_metadata_context context, grpc_credentials_metadata_cb cb,
+    void *user_data);
 
 typedef struct {
   grpc_call_credentials **creds_array;
@@ -318,7 +318,7 @@ typedef struct grpc_credentials_metadata_request
 typedef void (*grpc_fetch_oauth2_func)(grpc_exec_ctx *exec_ctx,
                                        grpc_credentials_metadata_request *req,
                                        grpc_httpcli_context *http_context,
-                                       grpc_pollset_set *pollset_set,
+                                       grpc_pops *pops,
                                        grpc_httpcli_response_cb response_cb,
                                        gpr_timespec deadline);
 
diff --git a/src/core/lib/security/google_default_credentials.c b/src/core/lib/security/google_default_credentials.c
index d831a986b2..29045f36eb 100644
--- a/src/core/lib/security/google_default_credentials.c
+++ b/src/core/lib/security/google_default_credentials.c
@@ -41,6 +41,7 @@
 
 #include "src/core/lib/http/httpcli.h"
 #include "src/core/lib/http/parser.h"
+#include "src/core/lib/iomgr/pops.h"
 #include "src/core/lib/support/env.h"
 #include "src/core/lib/support/load_file.h"
 #include "src/core/lib/surface/api_trace.h"
@@ -60,8 +61,7 @@ static gpr_once g_once = GPR_ONCE_INIT;
 static void init_default_credentials(void) { gpr_mu_init(&g_state_mu); }
 
 typedef struct {
-  grpc_pollset *pollset;
-  grpc_pollset_set *pollset_set;
+  grpc_pops *pops;
   int is_done;
   int success;
 } compute_engine_detector;
@@ -85,7 +85,7 @@ static void on_compute_engine_detection_http_response(
   }
   gpr_mu_lock(g_polling_mu);
   detector->is_done = 1;
-  grpc_pollset_kick(detector->pollset, NULL);
+  grpc_pollset_kick(grpc_pops_pollset(detector->pops), NULL);
   gpr_mu_unlock(g_polling_mu);
 }
 
@@ -104,11 +104,9 @@ static int is_stack_running_on_compute_engine(void) {
      on compute engine. */
   gpr_timespec max_detection_delay = gpr_time_from_seconds(1, GPR_TIMESPAN);
 
-  detector.pollset = gpr_malloc(grpc_pollset_size());
-  grpc_pollset_init(detector.pollset, &g_polling_mu);
-  detector.pollset_set = grpc_pollset_set_create();
-  grpc_pollset_set_add_pollset(&exec_ctx, detector.pollset_set,
-                               detector.pollset);
+  grpc_pollset *pollset = gpr_malloc(grpc_pollset_size());
+  grpc_pollset_init(pollset, &g_polling_mu);
+  detector.pops = grpc_pops_create_from_pollset(pollset);
   detector.is_done = 0;
   detector.success = 0;
 
@@ -119,7 +117,7 @@ static int is_stack_running_on_compute_engine(void) {
   grpc_httpcli_context_init(&context);
 
   grpc_httpcli_get(
-      &exec_ctx, &context, detector.pollset_set, &request,
+      &exec_ctx, &context, detector.pops, &request,
       gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), max_detection_delay),
       on_compute_engine_detection_http_response, &detector);
 
@@ -130,20 +128,22 @@ static int is_stack_running_on_compute_engine(void) {
   gpr_mu_lock(g_polling_mu);
   while (!detector.is_done) {
     grpc_pollset_worker *worker = NULL;
-    grpc_pollset_work(&exec_ctx, detector.pollset, &worker,
+    grpc_pollset_work(&exec_ctx, grpc_pops_pollset(detector.pops), &worker,
                       gpr_now(GPR_CLOCK_MONOTONIC),
                       gpr_inf_future(GPR_CLOCK_MONOTONIC));
   }
   gpr_mu_unlock(g_polling_mu);
 
   grpc_httpcli_context_destroy(&context);
-  grpc_closure_init(&destroy_closure, destroy_pollset, detector.pollset);
-  grpc_pollset_shutdown(&exec_ctx, detector.pollset, &destroy_closure);
-  grpc_pollset_set_destroy(detector.pollset_set);
+  grpc_closure_init(&destroy_closure, destroy_pollset,
+                    grpc_pops_pollset(detector.pops));
+  grpc_pollset_shutdown(&exec_ctx, grpc_pops_pollset(detector.pops),
+                        &destroy_closure);
   grpc_exec_ctx_finish(&exec_ctx);
   g_polling_mu = NULL;
 
-  gpr_free(detector.pollset);
+  gpr_free(grpc_pops_pollset(detector.pops));
+  grpc_pops_destroy(detector.pops);
 
   return detector.success;
 }
diff --git a/src/core/lib/security/jwt_verifier.c b/src/core/lib/security/jwt_verifier.c
index f764596aa9..a5d200d7a3 100644
--- a/src/core/lib/security/jwt_verifier.c
+++ b/src/core/lib/security/jwt_verifier.c
@@ -37,6 +37,7 @@
 #include <string.h>
 
 #include "src/core/lib/http/httpcli.h"
+#include "src/core/lib/iomgr/pops.h"
 #include "src/core/lib/security/b64.h"
 #include "src/core/lib/tsi/ssl_types.h"
 
@@ -321,7 +322,7 @@ grpc_jwt_verifier_status grpc_jwt_claims_check(const grpc_jwt_claims *claims,
 
 typedef struct {
   grpc_jwt_verifier *verifier;
-  grpc_pollset_set *pollset_set;
+  grpc_pops *pops;
   jose_header *header;
   grpc_jwt_claims *claims;
   char *audience;
@@ -341,8 +342,7 @@ static verifier_cb_ctx *verifier_cb_ctx_create(
   verifier_cb_ctx *ctx = gpr_malloc(sizeof(verifier_cb_ctx));
   memset(ctx, 0, sizeof(verifier_cb_ctx));
   ctx->verifier = verifier;
-  ctx->pollset_set = grpc_pollset_set_create();
-  grpc_pollset_set_add_pollset(&exec_ctx, ctx->pollset_set, pollset);
+  ctx->pops = grpc_pops_create_from_pollset(pollset);
   ctx->header = header;
   ctx->audience = gpr_strdup(audience);
   ctx->claims = claims;
@@ -360,7 +360,7 @@ void verifier_cb_ctx_destroy(verifier_cb_ctx *ctx) {
   gpr_slice_unref(ctx->signature);
   gpr_slice_unref(ctx->signed_data);
   jose_header_destroy(ctx->header);
-  grpc_pollset_set_destroy(ctx->pollset_set);
+  grpc_pops_destroy(ctx->pops);
   /* TODO: see what to do with claims... */
   gpr_free(ctx);
 }
@@ -646,7 +646,7 @@ static void on_openid_config_retrieved(grpc_exec_ctx *exec_ctx, void *user_data,
     *(req.host + (req.http.path - jwks_uri)) = '\0';
   }
   grpc_httpcli_get(
-      exec_ctx, &ctx->verifier->http_ctx, ctx->pollset_set, &req,
+      exec_ctx, &ctx->verifier->http_ctx, ctx->pops, &req,
       gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), grpc_jwt_verifier_max_delay),
       on_keys_retrieved, ctx);
   grpc_json_destroy(json);
@@ -749,7 +749,7 @@ static void retrieve_key_and_verify(grpc_exec_ctx *exec_ctx,
   }
 
   grpc_httpcli_get(
-      exec_ctx, &ctx->verifier->http_ctx, ctx->pollset_set, &req,
+      exec_ctx, &ctx->verifier->http_ctx, ctx->pops, &req,
       gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), grpc_jwt_verifier_max_delay),
       http_cb, ctx);
   gpr_free(req.host);
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index 899784e2c2..4b5a7d7465 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -135,7 +135,7 @@ typedef struct batch_control {
 
 struct grpc_call {
   grpc_completion_queue *cq;
-  grpc_pollset_set *pollset_set;
+  grpc_pops *pops;
   grpc_channel *channel;
   grpc_call *parent;
   grpc_call *first_child;
@@ -259,13 +259,6 @@ grpc_call *grpc_call_create(
   gpr_mu_init(&call->mu);
   call->channel = channel;
   call->cq = cq;
-  if (cq != NULL && pollset_set_alternative != NULL) {
-    gpr_log(
-        GPR_ERROR,
-        "Only one of 'cq' and 'pollset_set_alternative' should be non-NULL.");
-    abort();
-  }
-  call->pollset_set = pollset_set_alternative;
   call->parent = parent_call;
   call->is_client = server_transport_data == NULL;
   if (call->is_client) {
@@ -290,14 +283,18 @@ grpc_call *grpc_call_create(
                        call->context, server_transport_data,
                        CALL_STACK_FROM_CALL(call));
   if (cq != NULL) {
+    GPR_ASSERT(
+        pollset_set_alternative == NULL &&
+        "Only one of 'cq' and 'pollset_set_alternative' should be non-NULL.");
     GRPC_CQ_INTERNAL_REF(cq, "bind");
-    grpc_call_stack_set_pollset_or_pollset_set(
-        &exec_ctx, CALL_STACK_FROM_CALL(call), grpc_cq_pollset(cq), NULL);
+    call->pops = grpc_pops_create_from_pollset(grpc_cq_pollset(cq));
   }
   if (pollset_set_alternative != NULL) {
-    GPR_ASSERT(cq == NULL);
+    call->pops = grpc_pops_create_from_pollset_set(pollset_set_alternative);
+  }
+  if (call->pops != NULL) {
     grpc_call_stack_set_pollset_or_pollset_set(
-        &exec_ctx, CALL_STACK_FROM_CALL(call), NULL, pollset_set_alternative);
+        &exec_ctx, CALL_STACK_FROM_CALL(call), call->pops);
   }
   if (parent_call != NULL) {
     GRPC_CALL_INTERNAL_REF(parent_call, "child");
@@ -352,11 +349,19 @@ grpc_call *grpc_call_create(
 void grpc_call_set_completion_queue(grpc_exec_ctx *exec_ctx, grpc_call *call,
                                     grpc_completion_queue *cq) {
   GPR_ASSERT(cq);
-  GPR_ASSERT(call->pollset_set == NULL);
+
+  if (call->pops != NULL && grpc_pops_pollset_set(call->pops) != NULL) {
+    gpr_log(GPR_ERROR, "A pollset_set is already registered for this call.");
+    abort();
+  }
   call->cq = cq;
   GRPC_CQ_INTERNAL_REF(cq, "bind");
+  if (call->pops != NULL) {
+    grpc_pops_destroy(call->pops);
+  }
+  call->pops = grpc_pops_create_from_pollset(grpc_cq_pollset(cq));
   grpc_call_stack_set_pollset_or_pollset_set(
-      exec_ctx, CALL_STACK_FROM_CALL(call), grpc_cq_pollset(cq), NULL);
+      exec_ctx, CALL_STACK_FROM_CALL(call), call->pops);
 }
 
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
@@ -404,6 +409,7 @@ static void destroy_call(grpc_exec_ctx *exec_ctx, void *call, bool success) {
   if (c->cq) {
     GRPC_CQ_INTERNAL_UNREF(c->cq, "bind");
   }
+  grpc_pops_destroy(c->pops);
   gpr_free(c);
   GPR_TIMER_END("destroy_call", 0);
 }
diff --git a/src/core/lib/transport/transport.c b/src/core/lib/transport/transport.c
index 7f2ae5f52e..ba39693e47 100644
--- a/src/core/lib/transport/transport.c
+++ b/src/core/lib/transport/transport.c
@@ -125,17 +125,18 @@ void grpc_transport_perform_op(grpc_exec_ctx *exec_ctx,
   transport->vtable->perform_op(exec_ctx, transport, op);
 }
 
-void grpc_transport_set_pollset(grpc_exec_ctx *exec_ctx,
-                                grpc_transport *transport, grpc_stream *stream,
-                                grpc_pollset *pollset) {
-  transport->vtable->set_pollset(exec_ctx, transport, stream, pollset);
-}
-
-void grpc_transport_set_pollset_set(grpc_exec_ctx *exec_ctx,
-                                    grpc_transport *transport,
-                                    grpc_stream *stream,
-                                    grpc_pollset_set *pollset_set) {
-  transport->vtable->set_pollset_set(exec_ctx, transport, stream, pollset_set);
+void grpc_transport_set_pops(grpc_exec_ctx *exec_ctx, grpc_transport *transport,
+                             grpc_stream *stream, grpc_pops *pops) {
+  grpc_pollset *pollset;
+  grpc_pollset_set *pollset_set;
+  if ((pollset = grpc_pops_pollset(pops)) != NULL) {
+    transport->vtable->set_pollset(exec_ctx, transport, stream, pollset);
+  } else if ((pollset_set = grpc_pops_pollset_set(pops)) != NULL) {
+    transport->vtable->set_pollset_set(exec_ctx, transport, stream,
+                                       pollset_set);
+  } else {
+    abort();
+  }
 }
 
 void grpc_transport_destroy_stream(grpc_exec_ctx *exec_ctx,
diff --git a/src/core/lib/transport/transport.h b/src/core/lib/transport/transport.h
index 8f0c2d9023..0be080c9ca 100644
--- a/src/core/lib/transport/transport.h
+++ b/src/core/lib/transport/transport.h
@@ -39,6 +39,7 @@
 #include "src/core/lib/channel/context.h"
 #include "src/core/lib/iomgr/pollset.h"
 #include "src/core/lib/iomgr/pollset_set.h"
+#include "src/core/lib/iomgr/pops.h"
 #include "src/core/lib/transport/byte_stream.h"
 #include "src/core/lib/transport/metadata_batch.h"
 
@@ -197,14 +198,8 @@ int grpc_transport_init_stream(grpc_exec_ctx *exec_ctx,
                                grpc_stream_refcount *refcount,
                                const void *server_data);
 
-void grpc_transport_set_pollset(grpc_exec_ctx *exec_ctx,
-                                grpc_transport *transport, grpc_stream *stream,
-                                grpc_pollset *pollset);
-
-void grpc_transport_set_pollset_set(grpc_exec_ctx *exec_ctx,
-                                    grpc_transport *transport,
-                                    grpc_stream *stream,
-                                    grpc_pollset_set *pollset_set);
+void grpc_transport_set_pops(grpc_exec_ctx *exec_ctx, grpc_transport *transport,
+                             grpc_stream *stream, grpc_pops *pops);
 
 /* Destroy transport data for a stream.