1 files changed, 38 insertions, 12 deletions

diff --git a/boost/asio/detail/impl/epoll_reactor.ipp b/boost/asio/detail/impl/epoll_reactor.ipp
index 771edea67c..073bd08825 100644
--- a/boost/asio/detail/impl/epoll_reactor.ipp
+++ b/boost/asio/detail/impl/epoll_reactor.ipp
@@ -127,7 +127,7 @@ void epoll_reactor::fork_service(boost::asio::io_service::fork_event fork_ev)
     for (descriptor_state* state = registered_descriptors_.first();
         state != 0; state = state->next_)
     {
-      ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLOUT | EPOLLPRI | EPOLLET;
+      ev.events = state->registered_events_;
       ev.data.ptr = state;
       int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, state->descriptor_, &ev);
       if (result != 0)
@@ -159,7 +159,8 @@ int epoll_reactor::register_descriptor(socket_type descriptor,
   }
 
   epoll_event ev = { 0, { 0 } };
-  ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLOUT | EPOLLPRI | EPOLLET;
+  ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLPRI | EPOLLET;
+  descriptor_data->registered_events_ = ev.events;
   ev.data.ptr = descriptor_data;
   int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, descriptor, &ev);
   if (result != 0)
@@ -184,7 +185,8 @@ int epoll_reactor::register_internal_descriptor(
   }
 
   epoll_event ev = { 0, { 0 } };
-  ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLOUT | EPOLLPRI | EPOLLET;
+  ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLPRI | EPOLLET;
+  descriptor_data->registered_events_ = ev.events;
   ev.data.ptr = descriptor_data;
   int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, descriptor, &ev);
   if (result != 0)
@@ -222,23 +224,47 @@ void epoll_reactor::start_op(int op_type, socket_type descriptor,
 
   if (descriptor_data->op_queue_[op_type].empty())
   {
-    if (allow_speculative)
+    if (allow_speculative
+        && (op_type != read_op
+          || descriptor_data->op_queue_[except_op].empty()))
     {
-      if (op_type != read_op || descriptor_data->op_queue_[except_op].empty())
+      if (op->perform())
       {
-        if (op->perform())
+        descriptor_lock.unlock();
+        io_service_.post_immediate_completion(op);
+        return;
+      }
+
+      if (op_type == write_op)
+      {
+        if ((descriptor_data->registered_events_ & EPOLLOUT) == 0)
         {
-          descriptor_lock.unlock();
-          io_service_.post_immediate_completion(op);
-          return;
+          epoll_event ev = { 0, { 0 } };
+          ev.events = descriptor_data->registered_events_ | EPOLLOUT;
+          ev.data.ptr = descriptor_data;
+          if (epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, descriptor, &ev) == 0)
+          {
+            descriptor_data->registered_events_ |= ev.events;
+          }
+          else
+          {
+            op->ec_ = boost::system::error_code(errno,
+                boost::asio::error::get_system_category());
+            io_service_.post_immediate_completion(op);
+            return;
+          }
         }
       }
     }
     else
     {
+      if (op_type == write_op)
+      {
+        descriptor_data->registered_events_ |= EPOLLOUT;
+      }
+
       epoll_event ev = { 0, { 0 } };
-      ev.events = EPOLLIN | EPOLLERR | EPOLLHUP
-        | EPOLLOUT | EPOLLPRI | EPOLLET;
+      ev.events = descriptor_data->registered_events_;
       ev.data.ptr = descriptor_data;
       epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, descriptor, &ev);
     }
@@ -440,7 +466,7 @@ int epoll_reactor::do_epoll_create()
   errno = EINVAL;
 #endif // defined(EPOLL_CLOEXEC)
 
-  if (fd == -1 && errno == EINVAL)
+  if (fd == -1 && (errno == EINVAL || errno == ENOSYS))
   {
     fd = epoll_create(epoll_size);
     if (fd != -1)