linux_dsm_epyc7002/net/openvswitch
Johannes Berg 053c095a82 netlink: make nlmsg_end() and genlmsg_end() void
Contrary to common expectations for an "int" return, these functions
return only a positive value -- if used correctly they cannot even
return 0 because the message header will necessarily be in the skb.

This makes the very common pattern of

  if (genlmsg_end(...) < 0) { ... }

be a whole bunch of dead code. Many places also simply do

  return nlmsg_end(...);

and the caller is expected to deal with it.

This also commonly (at least for me) causes errors, because it is very
common to write

  if (my_function(...))
    /* error condition */

and if my_function() does "return nlmsg_end()" this is of course wrong.

Additionally, there's not a single place in the kernel that actually
needs the message length returned, and if anyone needs it later then
it'll be very easy to just use skb->len there.

Remove this, and make the functions void. This removes a bunch of dead
code as described above. The patch adds lines because I did

-	return nlmsg_end(...);
+	nlmsg_end(...);
+	return 0;

I could have preserved all the function's return values by returning
skb->len, but instead I've audited all the places calling the affected
functions and found that none cared. A few places actually compared
the return value with <= 0 in dump functionality, but that could just
be changed to < 0 with no change in behaviour, so I opted for the more
efficient version.

One instance of the error I've made numerous times now is also present
in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't
check for <0 or <=0 and thus broke out of the loop every single time.
I've preserved this since it will (I think) have caused the messages to
userspace to be formatted differently with just a single message for
every SKB returned to userspace. It's possible that this isn't needed
for the tools that actually use this, but I don't even know what they
are so couldn't test that changing this behaviour would be acceptable.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-18 01:03:45 -05:00
..
actions.c net: rename vlan_tx_* helpers since "tx" is misleading there 2015-01-13 17:51:08 -05:00
datapath.c netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
datapath.h openvswitch: Add support for OVS_FLOW_ATTR_PROBE. 2014-11-09 18:58:44 -08:00
dp_notify.c genetlink: make multicast groups const, prevent abuse 2013-11-19 16:39:06 -05:00
flow_netlink.c openvswitch: Support VXLAN Group Policy extension 2015-01-15 01:11:41 -05:00
flow_netlink.h openvswitch: Add support for OVS_FLOW_ATTR_PROBE. 2014-11-09 18:58:44 -08:00
flow_table.c net: replace remaining users of arch_fast_hash with jhash 2014-12-10 15:17:45 -05:00
flow_table.h openvswitch: Constify various function arguments 2014-11-09 18:58:44 -08:00
flow.c openvswitch: Rename GENEVE_TUN_OPTS() to TUN_METADATA_OPTS() 2015-01-15 01:11:41 -05:00
flow.h openvswitch: Rename GENEVE_TUN_OPTS() to TUN_METADATA_OPTS() 2015-01-15 01:11:41 -05:00
Kconfig openvswitch: Fix build failure. 2014-11-14 01:24:27 -05:00
Makefile ovs: Turn vports with dependencies into separate modules 2014-10-28 14:43:18 -04:00
vport-geneve.c openvswitch: Support VXLAN Group Policy extension 2015-01-15 01:11:41 -05:00
vport-gre.c openvswitch: Introduce ovs_tunnel_route_lookup 2015-01-14 16:32:06 -05:00
vport-internal_dev.c openvswitch: Drop packets when interdev is not up 2014-11-05 23:52:35 -08:00
vport-internal_dev.h openvswitch: introduce rtnl ops stub 2014-07-01 14:40:17 -07:00
vport-netdev.c openvswitch: Constify various function arguments 2014-11-09 18:58:44 -08:00
vport-netdev.h ovs: Turn vports with dependencies into separate modules 2014-10-28 14:43:18 -04:00
vport-vxlan.c openvswitch: Support VXLAN Group Policy extension 2015-01-15 01:11:41 -05:00
vport-vxlan.h openvswitch: Support VXLAN Group Policy extension 2015-01-15 01:11:41 -05:00
vport.c openvswitch: Introduce ovs_tunnel_route_lookup 2015-01-14 16:32:06 -05:00
vport.h openvswitch: Introduce ovs_tunnel_route_lookup 2015-01-14 16:32:06 -05:00