Makefile.rules and atomic CMPXCHG handling update to support 2.6.33 kernel.

[lincan.git] / lincan / include / can_queue.h

diff --git a/lincan/include/can_queue.h b/lincan/include/can_queue.h
index 42eeef4bae5c7f5d7862fed3d938a6d17caefaa4..bf9486d01ca79769f8776db835f37d40591a1fd2 100644 (file)
--- a/lincan/include/can_queue.h
+++ b/lincan/include/can_queue.h
@@ -1,10 +1,35 @@
-/* can_queue.h - CAN queues and message passing infrastructure 
- * Linux CAN-bus device driver.
- * Written by Pavel Pisa - OCERA team member
- * email:pisa@cmp.felk.cvut.cz
- * This software is released under the GPL-License.
- * Version lincan-0.3  17 Jun 2004
- */
+/**************************************************************************/
+/* File: can_queue.h - CAN queues and message passing infrastructure      */
+/*                                                                        */
+/* LinCAN - (Not only) Linux CAN bus driver                               */
+/* Copyright (C) 2002-2009 DCE FEE CTU Prague <http://dce.felk.cvut.cz>   */
+/* Copyright (C) 2002-2009 Pavel Pisa <pisa@cmp.felk.cvut.cz>             */
+/* Funded by OCERA and FRESCOR IST projects                               */
+/*                                                                        */
+/* LinCAN is free software; you can redistribute it and/or modify it      */
+/* under terms of the GNU General Public License as published by the      */
+/* Free Software Foundation; either version 2, or (at your option) any    */
+/* later version.  LinCAN is distributed in the hope that it will be      */
+/* useful, but WITHOUT ANY WARRANTY; without even the implied warranty    */
+/* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU    */
+/* General Public License for more details. You should have received a    */
+/* copy of the GNU General Public License along with LinCAN; see file     */
+/* COPYING. If not, write to the Free Software Foundation, 675 Mass Ave,  */
+/* Cambridge, MA 02139, USA.                                              */
+/*                                                                        */
+/* To allow use of LinCAN in the compact embedded systems firmware        */
+/* and RT-executives (RTEMS for example), main authors agree with next    */
+/* special exception:                                                     */
+/*                                                                        */
+/* Including LinCAN header files in a file, instantiating LinCAN generics */
+/* or templates, or linking other files with LinCAN objects to produce    */
+/* an application image/executable, does not by itself cause the          */
+/* resulting application image/executable to be covered by                */
+/* the GNU General Public License.                                        */
+/* This exception does not however invalidate any other reasons           */
+/* why the executable file might be covered by the GNU Public License.    */
+/* Publication of enhanced or derived LinCAN files is required although.  */
+/**************************************************************************/
 
 #ifndef _CAN_QUEUE_H
 #define _CAN_QUEUE_H
@@ -621,11 +646,13 @@ void canque_edge_decref(struct canque_edge_t *edge)
                if(x<=1)
                        return __canque_edge_decref(edge);
                y=x;
+           #ifdef CAN_HAVE_ATOMIC_CMPXCHG
+               atomic_cmpxchg(&edge->edge_used, x, x-1);
+           #else /* workaround for case that atomic_cmpxchg is not defined */
                /* This code strongly depends on the definition of atomic_t !!!! */
-               /* x=cmpxchg(&edge->edge_used, x, x-1); */
-               /* Next alternative could be more portable */
                x=__cmpxchg(&edge->edge_used, x, x-1, sizeof(atomic_t));
                /* If even this does not help, comment out CAN_HAVE_ARCH_CMPXCHG in can_sysdep.h */
+           #endif
        } while(x!=y);
 }
 #endif