linux/net
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
..
6lowpan net/6lowpan: Remove FSF address from GPL statement. 2014-12-05 12:43:04 +01:00
9p 9p/trans_virtio: enable VQs early 2014-10-15 10:25:04 +10:30
802 net: set name_assign_type in alloc_netdev() 2014-07-15 16:12:48 -07:00
8021q net: rename vlan_tx_* helpers since "tx" is misleading there 2015-01-13 17:51:08 -05:00
appletalk new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
atm put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
ax25 new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
batman-adv batman-adv: Kconfig, Add missing DEBUG_FS dependency 2015-01-07 22:17:11 +01:00
bluetooth Bluetooth: Remove unused function 2015-01-16 13:06:38 +02:00
bridge netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
caif put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
can netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
ceph libceph: fix sparse endianness warnings 2015-01-08 20:36:57 +03:00
core netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
dcb dcbnl : Disable software interrupts before taking dcb_lock 2014-11-16 14:50:52 -05:00
dccp net: introduce helper macro for_each_cmsghdr 2014-12-10 22:41:55 -05:00
decnet netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
dns_resolver Merge commit 'v3.16' into next 2014-10-01 00:44:04 +10:00
dsa Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
ethernet net: Add Transparent Ethernet Bridging GRO support. 2015-01-02 15:46:41 -05:00
hsr net/hsr: Remove left-over never-true conditional code. 2014-07-11 15:04:40 -07:00
ieee802154 netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
ipv4 netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
ipv6 netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
ipx switch ipxrtr_route_packet() from iovec to msghdr 2014-11-24 04:28:49 -05:00
irda irda: Convert function pointer arrays and uses to const 2014-12-10 15:33:16 -05:00
iucv net: introduce helper macro for_each_cmsghdr 2014-12-10 22:41:55 -05:00
key new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
l2tp netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
lapb lapb: move EXPORT_SYMBOL after functions. 2014-10-24 15:51:42 -04:00
llc llc: Make llc_sap_action_t function pointer arrays const 2014-12-10 15:21:24 -05:00
mac80211 mac80211: don't defer scans in case of radar detection 2015-01-14 09:37:07 +01:00
mac802154 mac802154: fix kbuild test robot warning 2015-01-03 01:51:51 +01:00
mpls mpls: Fix allowed protocols for mpls gso 2014-12-23 23:57:31 -05:00
netfilter netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
netlabel netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
netlink netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
netrom new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
nfc netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
openvswitch netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
packet netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
phonet netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
rds rds: Fix min() warning in rds_message_inc_copy_to_user() 2014-12-15 11:49:09 -05:00
rfkill Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
rose new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
rxrpc net: introduce helper macro for_each_cmsghdr 2014-12-10 22:41:55 -05:00
sched tc: cls_bpf: rename bpf_len to bpf_num_ops 2015-01-17 23:51:10 -05:00
sctp net: introduce helper macro for_each_cmsghdr 2014-12-10 22:41:55 -05:00
sunrpc rpc: fix xdr_truncate_encode to handle buffer ending on page boundary 2015-01-07 14:03:58 -05:00
switchdev switchdev: introduce switchdev notifier 2015-01-18 00:23:57 -05:00
tipc tipc: fix socket list regression in new nl api 2015-01-18 00:27:05 -05:00
unix netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
vmw_vsock put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
wimax wimax: convert printk to pr_foo() 2014-10-07 20:28:44 -04:00
wireless netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
x25 new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
xfrm netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
compat.c put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
Kconfig net: introduce generic switch devices support 2014-12-02 20:01:20 -08:00
Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-12-16 15:53:03 -08:00
socket.c socket: use ki_nbytes instead of iov_length() 2015-01-17 23:58:37 -05:00
sysctl_net.c