[Xen-changelog] [linux-2.6.18-xen] Add version number to API between netfront and accel plugin.

["Xen patchbot-linux-2.6.18-xen" <patchbot-linux-2.6.18-xen@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir@xxxxxxxxxxxxx>
# Date 1191420090 -3600
# Node ID e7a3f045cb60f2db1e38f65d9cca5934e4234f53
# Parent  df158d6b9e579730ac3868e291ccbb6570980442
Add version number to API between netfront and accel plugin.
Signed-off-by: Kieran Mansley <kmansley@xxxxxxxxxxxxxx>
---
 drivers/xen/netfront/accel.c    |   17 ++++++++++++++++-
 drivers/xen/netfront/netfront.h |   13 +++++++++++--
 2 files changed, 27 insertions(+), 3 deletions(-)

diff -r df158d6b9e57 -r e7a3f045cb60 drivers/xen/netfront/accel.c
--- a/drivers/xen/netfront/accel.c      Wed Oct 03 15:00:42 2007 +0100
+++ b/drivers/xen/netfront/accel.c      Wed Oct 03 15:01:30 2007 +0100
@@ -406,11 +406,26 @@ accelerator_probe_vifs_on_load(struct ne
 /* 
  * Called by the netfront accelerator plugin module when it has loaded 
  */
-int netfront_accelerator_loaded(const char *frontend, 
+int netfront_accelerator_loaded(int version, const char *frontend, 
                                struct netfront_accel_hooks *hooks)
 {
        struct netfront_accelerator *accelerator;
        unsigned flags;
+
+       if (version != NETFRONT_ACCEL_VERSION) {
+               if (version > NETFRONT_ACCEL_VERSION) {
+                       /* Caller has higher version number, leave it
+                          up to them to decide whether to continue.
+                          They can re-call with a lower number if
+                          they're happy to be compatible with us */
+                       return NETFRONT_ACCEL_VERSION;
+               } else {
+                       /* We have a more recent version than caller.
+                          Currently reject, but may in future be able
+                          to be backwardly compatible */
+                       return -EPROTO;
+               }
+       }
 
        spin_lock_irqsave(&accelerators_lock, flags);
 
diff -r df158d6b9e57 -r e7a3f045cb60 drivers/xen/netfront/netfront.h
--- a/drivers/xen/netfront/netfront.h   Wed Oct 03 15:00:42 2007 +0100
+++ b/drivers/xen/netfront/netfront.h   Wed Oct 03 15:01:30 2007 +0100
@@ -98,6 +98,11 @@ struct netfront_accel_hooks {
        int (*check_busy)(struct net_device *dev);
 };
 
+
+/* Version of API/protocol for communication between netfront and
+   acceleration plugin supported */
+#define NETFRONT_ACCEL_VERSION 0x00010000
+
 /* 
  * Per-netfront device state for the accelerator.  This is used to
  * allow efficient per-netfront device access to the accelerator
@@ -221,8 +226,12 @@ struct netfront_info {
  *
  * frontend: the string describing the accelerator, currently the module name 
  * hooks: the hooks for netfront to use to call into the accelerator
- */
-extern int netfront_accelerator_loaded(const char *frontend, 
+ * version: the version of API between frontend and plugin requested
+ * 
+ * return: 0 on success, <0 on error, >0 (with version supported) on
+ * version mismatch
+ */
+extern int netfront_accelerator_loaded(int version, const char *frontend, 
                                       struct netfront_accel_hooks *hooks);
 
 /* 

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog