openvswitch: Allow OVS_USERSPACE_ATTR_USERDATA to be variable length.

Until now, the optional OVS_USERSPACE_ATTR_USERDATA attribute had to be
exactly 64 bits long, if it was present.  However, 64 bits is not enough
space to associate as much information with a flow as would be convenient
for some userspace features now under development.  This commit generalizes
the attribute, allowing it to be any length.

This generalization is backward-compatible: if userspace only uses 64-bit
attributes, then it will not see any change in behavior.

CC: Romain Lenglet <rlenglet@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/include/linux/openvswitch.h b/include/linux/openvswitch.h
index 99e6414a40d9..67d6c7b03581 100644
--- a/include/linux/openvswitch.h
+++ b/include/linux/openvswitch.h
@@ -127,7 +127,8 @@ enum ovs_packet_cmd {
  * for %OVS_PACKET_CMD_EXECUTE.  It has nested %OVS_ACTION_ATTR_* attributes.
  * @OVS_PACKET_ATTR_USERDATA: Present for an %OVS_PACKET_CMD_ACTION
  * notification if the %OVS_ACTION_ATTR_USERSPACE action specified an
- * %OVS_USERSPACE_ATTR_USERDATA attribute.
+ * %OVS_USERSPACE_ATTR_USERDATA attribute, with the same length and content
+ * specified there.
  *
  * These attributes follow the &struct ovs_header within the Generic Netlink
  * payload for %OVS_PACKET_* commands.
@@ -137,7 +138,7 @@ enum ovs_packet_attr {
         OVS_PACKET_ATTR_PACKET,      /* Packet data. */
         OVS_PACKET_ATTR_KEY,         /* Nested OVS_KEY_ATTR_* attributes. */
         OVS_PACKET_ATTR_ACTIONS,     /* Nested OVS_ACTION_ATTR_* attributes. */
-        OVS_PACKET_ATTR_USERDATA,    /* u64 OVS_ACTION_ATTR_USERSPACE arg. */
+        OVS_PACKET_ATTR_USERDATA,    /* OVS_ACTION_ATTR_USERSPACE arg. */
         __OVS_PACKET_ATTR_MAX
 };
 
@@ -389,13 +390,13 @@ enum ovs_sample_attr {
  * enum ovs_userspace_attr - Attributes for %OVS_ACTION_ATTR_USERSPACE action.
  * @OVS_USERSPACE_ATTR_PID: u32 Netlink PID to which the %OVS_PACKET_CMD_ACTION
  * message should be sent.  Required.
- * @OVS_USERSPACE_ATTR_USERDATA: If present, its u64 argument is copied to the
- * %OVS_PACKET_CMD_ACTION message as %OVS_PACKET_ATTR_USERDATA,
+ * @OVS_USERSPACE_ATTR_USERDATA: If present, its variable-length argument is
+ * copied to the %OVS_PACKET_CMD_ACTION message as %OVS_PACKET_ATTR_USERDATA.
  */
 enum ovs_userspace_attr {
         OVS_USERSPACE_ATTR_UNSPEC,
         OVS_USERSPACE_ATTR_PID,       /* u32 Netlink PID to receive upcalls. */
-        OVS_USERSPACE_ATTR_USERDATA,  /* u64 optional user-specified cookie. */
+        OVS_USERSPACE_ATTR_USERDATA,  /* Optional user-specified cookie. */
         __OVS_USERSPACE_ATTR_MAX
 };