6 files changed, 19 insertions, 23 deletions
diff --git a/src/core/iomgr/pollset.h b/src/core/iomgr/pollset.h
index c474e4dbf1..337596cb74 100644
--- a/src/core/iomgr/pollset.h
+++ b/src/core/iomgr/pollset.h
@@ -74,10 +74,9 @@ void grpc_pollset_destroy(grpc_pollset *pollset);
    grpc_pollset_work, and it is guaranteed that GRPC_POLLSET_MU(pollset) will
    not be released by grpc_pollset_work AFTER worker has been destroyed.
 
-   Returns true if some work has been done, and false if the deadline
-   expired. */
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline);
+   Tries not to block past deadline. */
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+                       gpr_timespec now, gpr_timespec deadline);
 
 /* Break one polling thread out of polling work for this pollset.
    If specific_worker is GRPC_POLLSET_KICK_BROADCAST, kick ALL the workers.
diff --git a/src/core/iomgr/pollset_multipoller_with_epoll.c b/src/core/iomgr/pollset_multipoller_with_epoll.c
index 5ea9dd2101..fe66ebed77 100644
--- a/src/core/iomgr/pollset_multipoller_with_epoll.c
+++ b/src/core/iomgr/pollset_multipoller_with_epoll.c
@@ -181,7 +181,7 @@ static void multipoll_with_epoll_pollset_maybe_work(
   pfds[1].events = POLLIN;
   pfds[1].revents = 0;
 
-  poll_rv = poll(pfds, 2, timeout_ms);
+  poll_rv = grpc_poll_function(pfds, 2, timeout_ms);
 
   if (poll_rv < 0) {
     if (errno != EINTR) {
diff --git a/src/core/iomgr/pollset_multipoller_with_poll_posix.c b/src/core/iomgr/pollset_multipoller_with_poll_posix.c
index 001fcecf76..30ee6e24db 100644
--- a/src/core/iomgr/pollset_multipoller_with_poll_posix.c
+++ b/src/core/iomgr/pollset_multipoller_with_poll_posix.c
@@ -144,7 +144,7 @@ static void multipoll_with_poll_pollset_maybe_work(
                                         POLLOUT, &watchers[i]);
   }
 
-  r = poll(pfds, pfd_count, timeout);
+  r = grpc_poll_function(pfds, pfd_count, timeout);
 
   for (i = 1; i < pfd_count; i++) {
     grpc_fd_end_poll(&watchers[i], pfds[i].revents & POLLIN,
diff --git a/src/core/iomgr/pollset_posix.c b/src/core/iomgr/pollset_posix.c
index a01f9ff727..6bd1b61f24 100644
--- a/src/core/iomgr/pollset_posix.c
+++ b/src/core/iomgr/pollset_posix.c
@@ -38,7 +38,6 @@
 #include "src/core/iomgr/pollset_posix.h"
 
 #include <errno.h>
-#include <poll.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -57,6 +56,8 @@
 GPR_TLS_DECL(g_current_thread_poller);
 GPR_TLS_DECL(g_current_thread_worker);
 
+grpc_poll_function_type grpc_poll_function = poll;
+
 static void remove_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
   worker->prev->next = worker->next;
   worker->next->prev = worker->prev;
@@ -89,6 +90,7 @@ static void push_front_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
 }
 
 void grpc_pollset_kick(grpc_pollset *p, grpc_pollset_worker *specific_worker) {
+  /* pollset->mu already held */
   if (specific_worker != NULL) {
     if (specific_worker == GRPC_POLLSET_KICK_BROADCAST) {
       for (specific_worker = p->root_worker.next;
@@ -168,14 +170,10 @@ static void finish_shutdown(grpc_pollset *pollset) {
   pollset->shutdown_done_cb(pollset->shutdown_done_arg);
 }
 
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline) {
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+                       gpr_timespec now, gpr_timespec deadline) {
   /* pollset->mu already held */
-  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
   int added_worker = 0;
-  if (gpr_time_cmp(now, deadline) > 0) {
-    return 0;
-  }
   /* this must happen before we (potentially) drop pollset->mu */
   worker->next = worker->prev = NULL;
   /* TODO(ctiller): pool these */
@@ -217,7 +215,6 @@ done:
       gpr_mu_lock(&pollset->mu);
     }
   }
-  return 1;
 }
 
 void grpc_pollset_shutdown(grpc_pollset *pollset,
@@ -456,7 +453,7 @@ static void basic_pollset_maybe_work(grpc_pollset *pollset,
 
   /* poll fd count (argument 2) is shortened by one if we have no events
      to poll on - such that it only includes the kicker */
-  r = poll(pfd, nfds, timeout);
+  r = grpc_poll_function(pfd, nfds, timeout);
   GRPC_TIMER_MARK(GRPC_PTAG_POLL_FINISHED, r);
 
   if (fd) {
diff --git a/src/core/iomgr/pollset_posix.h b/src/core/iomgr/pollset_posix.h
index a3ea353de6..69bd9cca8c 100644
--- a/src/core/iomgr/pollset_posix.h
+++ b/src/core/iomgr/pollset_posix.h
@@ -34,6 +34,8 @@
 #ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 #define GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 
+#include <poll.h>
+
 #include <grpc/support/sync.h>
 #include "src/core/iomgr/wakeup_fd_posix.h"
 
@@ -118,4 +120,8 @@ void grpc_poll_become_multipoller(grpc_pollset *pollset, struct grpc_fd **fds,
  * be locked) */
 int grpc_pollset_has_workers(grpc_pollset *pollset);
 
+/* override to allow tests to hook poll() usage */
+typedef int (*grpc_poll_function_type)(struct pollfd *, nfds_t, int);
+extern grpc_poll_function_type grpc_poll_function;
+
 #endif /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H */
diff --git a/src/core/iomgr/pollset_windows.c b/src/core/iomgr/pollset_windows.c
index 8710395ab3..07522c8a0c 100644
--- a/src/core/iomgr/pollset_windows.c
+++ b/src/core/iomgr/pollset_windows.c
@@ -99,14 +99,9 @@ void grpc_pollset_destroy(grpc_pollset *pollset) {
   gpr_mu_destroy(&pollset->mu);
 }
 
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline) {
-  gpr_timespec now;
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker, 
+                       gpr_timespec now, gpr_timespec deadline) {
   int added_worker = 0;
-  now = gpr_now(GPR_CLOCK_MONOTONIC);
-  if (gpr_time_cmp(now, deadline) > 0) {
-    return 0 /* GPR_FALSE */;
-  }
   worker->next = worker->prev = NULL;
   gpr_cv_init(&worker->cv);
   if (grpc_maybe_call_delayed_callbacks(&pollset->mu, 1 /* GPR_TRUE */)) {
@@ -127,7 +122,6 @@ done:
   if (added_worker) {
     remove_worker(pollset, worker);
   }
-  return 1 /* GPR_TRUE */;
 }
 
 void grpc_pollset_kick(grpc_pollset *p, grpc_pollset_worker *specific_worker) {