ompi_request_complete with signal

Rewrite the ompi_request_complete function to take in account the
with_signal argument. Change the comment to explain the expected
behavior.
Alter all the ompi_request_complete uses to make sure the status of the
request is set before calling ompi_request_complete.

bot:label:enhancement

Author: bosilca

ompi/mca/io/ompio/io_ompio_file_read.c

@@ -2,7 +2,7 @@
  *  Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
  *                          University Research and Technology
  *                          Corporation.  All rights reserved.
- *  Copyright (c) 2004-2005 The University of Tennessee and The University
+ *  Copyright (c) 2004-2016 The University of Tennessee and The University
  *                          of Tennessee Research Foundation.  All rights
  *                          reserved.
  *  Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
@@ -233,9 +233,9 @@ int ompio_io_ompio_file_iread (mca_io_ompio_file_t *fh,
     ompio_req->req_ompi.req_state = OMPI_REQUEST_ACTIVE;
 
     if ( 0 == count ) {
-	ompi_request_complete (&ompio_req->req_ompi, 0);
 	ompio_req->req_ompi.req_status.MPI_ERROR = OMPI_SUCCESS;
 	ompio_req->req_ompi.req_status._ucount = 0;
+	ompi_request_complete (&ompio_req->req_ompi, false);
 	return OMPI_SUCCESS;
     }
 
@@ -299,9 +299,9 @@ int ompio_io_ompio_file_iread (mca_io_ompio_file_t *fh,
 	ompi_status_public_t status;
 	ret = ompio_io_ompio_file_read (fh, buf, count, datatype, &status);
 
-	ompi_request_complete (&ompio_req->req_ompi, 0);
 	ompio_req->req_ompi.req_status.MPI_ERROR = ret;
 	ompio_req->req_ompi.req_status._ucount = status._ucount;
+	ompi_request_complete (&ompio_req->req_ompi, false);
     }
 
     *request = (ompi_request_t *) ompio_req;

ompi/mca/io/ompio/io_ompio_file_write.c

@@ -2,7 +2,7 @@
  * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2004-2005 The University of Tennessee and The University
+ * Copyright (c) 2004-2016 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
@@ -225,9 +225,9 @@ int ompio_io_ompio_file_iwrite (mca_io_ompio_file_t *fh,
     ompio_req->req_ompi.req_state = OMPI_REQUEST_ACTIVE;
 
   if ( 0 == count ) {
-	ompi_request_complete (&ompio_req->req_ompi, 0);
 	ompio_req->req_ompi.req_status.MPI_ERROR = OMPI_SUCCESS;
 	ompio_req->req_ompi.req_status._ucount = 0;
+	ompi_request_complete (&ompio_req->req_ompi, false);
 	return OMPI_SUCCESS;
     }
 
@@ -288,9 +288,9 @@ int ompio_io_ompio_file_iwrite (mca_io_ompio_file_t *fh,
 	ompi_status_public_t status;
 	ret = ompio_io_ompio_file_write(fh,buf,count,datatype, &status);
 
-	ompi_request_complete (&ompio_req->req_ompi, 0);
 	ompio_req->req_ompi.req_status.MPI_ERROR = ret;
 	ompio_req->req_ompi.req_status._ucount = status._ucount;
+	ompi_request_complete (&ompio_req->req_ompi, false);
     }
 
     *request = (ompi_request_t *) ompio_req;

ompi/mca/io/ompio/io_ompio_request.c

@@ -85,7 +85,7 @@ int mca_io_ompio_component_progress ( void )
         if ( NULL != req->req_progress_fn ) {
             if ( req->req_progress_fn(req) ) {
                 completed++;
-                ompi_request_complete (&req->req_ompi, 1);
+                ompi_request_complete (&req->req_ompi, true);
                 /* The fbtl progress function is expected to set the
                  * status elements
                  */

ompi/request/request.h

@@ -398,12 +398,16 @@ static inline void ompi_request_wait_completion(ompi_request_t *req)
 #endif
 /**
  *  Signal or mark a request as complete. If with_signal is true this will
- *  wake any thread pending on the request and ompi_request_lock should be
- *  held while calling this function. If with_signal is false, there will
- *  signal generated, and no lock required. This is a special case when
- *  the function is called from the critical path for small messages, where
- *  we know the current execution flow created the request, and is still
- *  in the _START macro.
+ *  wake any thread pending on the request. If with_signal is false, the
+ *  opposite will be true, the request will simply be marked as completed
+ *  and no effort will be made to correctly (atomically) handle the associated
+ *  synchronization primitive. This is a special case when the function
+ *  is called from the critical path for small messages, where we know
+ *  the current execution flow created the request, and no synchronized wait
+ *  has been set.
+ *  BEWARE: The error code should be set on the request prior to calling
+ *  this function, or the synchronization primitive might not be correctly
+ *  triggered.
  */
 static inline int ompi_request_complete(ompi_request_t* request, bool with_signal)
 {
@@ -412,13 +416,16 @@ static inline int ompi_request_complete(ompi_request_t* request, bool with_signa
         request->req_complete_cb = NULL;
     }
 
-    if(!OPAL_ATOMIC_CMPSET_PTR(&request->req_complete, REQUEST_PENDING, REQUEST_COMPLETED)) {
-        ompi_wait_sync_t *tmp_sync = (ompi_wait_sync_t *) OPAL_ATOMIC_SWP_PTR(&request->req_complete,
-                                                                              REQUEST_COMPLETED);
-        /* In the case where another thread concurrently changed the request to REQUEST_PENDING */
-        if( REQUEST_PENDING != tmp_sync )
-            wait_sync_update(tmp_sync, 1, request->req_status.MPI_ERROR);
-    }
+    if( OPAL_LIKELY(with_signal) ) {
+        if(!OPAL_ATOMIC_CMPSET_PTR(&request->req_complete, REQUEST_PENDING, REQUEST_COMPLETED)) {
+            ompi_wait_sync_t *tmp_sync = (ompi_wait_sync_t *) OPAL_ATOMIC_SWP_PTR(&request->req_complete,
+                                                                                  REQUEST_COMPLETED);
+            /* In the case where another thread concurrently changed the request to REQUEST_PENDING */
+            if( REQUEST_PENDING != tmp_sync )
+                wait_sync_update(tmp_sync, 1, request->req_status.MPI_ERROR);
+        }
+    } else
+        request->req_complete = REQUEST_COMPLETED;
 
     if( OPAL_UNLIKELY(MPI_SUCCESS != request->req_status.MPI_ERROR) ) {
         ompi_request_failed++;