diff options
author | Johannes Berg <johannes.berg@intel.com> | 2015-01-16 22:09:00 +0100 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2015-01-18 01:03:45 -0500 |
commit | 053c095a82cf773075e83d7233b5cc19a1f73ece (patch) | |
tree | c787028efa9a73a182a0f338f87b6294cef4b8b9 /net/ipv6 | |
parent | ede58ef28e105de94475b2b69fa069c9a2ce6933 (diff) | |
download | linux-053c095a82cf773075e83d7233b5cc19a1f73ece.tar.bz2 |
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>
Diffstat (limited to 'net/ipv6')
-rw-r--r-- | net/ipv6/addrconf.c | 32 | ||||
-rw-r--r-- | net/ipv6/addrlabel.c | 5 | ||||
-rw-r--r-- | net/ipv6/ip6_fib.c | 1 | ||||
-rw-r--r-- | net/ipv6/ip6mr.c | 3 | ||||
-rw-r--r-- | net/ipv6/route.c | 3 |
5 files changed, 26 insertions, 18 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index f7c8bbeb27b7..8975d9501d50 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -489,7 +489,8 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex, nla_put_s32(skb, NETCONFA_PROXY_NEIGH, devconf->proxy_ndp) < 0) goto nla_put_failure; - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; nla_put_failure: nlmsg_cancel(skb, nlh); @@ -619,7 +620,7 @@ static int inet6_netconf_dump_devconf(struct sk_buff *skb, cb->nlh->nlmsg_seq, RTM_NEWNETCONF, NLM_F_MULTI, - -1) <= 0) { + -1) < 0) { rcu_read_unlock(); goto done; } @@ -635,7 +636,7 @@ cont: NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, RTM_NEWNETCONF, NLM_F_MULTI, - -1) <= 0) + -1) < 0) goto done; else h++; @@ -646,7 +647,7 @@ cont: NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, RTM_NEWNETCONF, NLM_F_MULTI, - -1) <= 0) + -1) < 0) goto done; else h++; @@ -4047,7 +4048,8 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa, if (nla_put_u32(skb, IFA_FLAGS, ifa->flags) < 0) goto error; - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; error: nlmsg_cancel(skb, nlh); @@ -4076,7 +4078,8 @@ static int inet6_fill_ifmcaddr(struct sk_buff *skb, struct ifmcaddr6 *ifmca, return -EMSGSIZE; } - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; } static int inet6_fill_ifacaddr(struct sk_buff *skb, struct ifacaddr6 *ifaca, @@ -4101,7 +4104,8 @@ static int inet6_fill_ifacaddr(struct sk_buff *skb, struct ifacaddr6 *ifaca, return -EMSGSIZE; } - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; } enum addr_type_t { @@ -4134,7 +4138,7 @@ static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb, cb->nlh->nlmsg_seq, RTM_NEWADDR, NLM_F_MULTI); - if (err <= 0) + if (err < 0) break; nl_dump_check_consistent(cb, nlmsg_hdr(skb)); } @@ -4151,7 +4155,7 @@ static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb, cb->nlh->nlmsg_seq, RTM_GETMULTICAST, NLM_F_MULTI); - if (err <= 0) + if (err < 0) break; } break; @@ -4166,7 +4170,7 @@ static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb, cb->nlh->nlmsg_seq, RTM_GETANYCAST, NLM_F_MULTI); - if (err <= 0) + if (err < 0) break; } break; @@ -4638,7 +4642,8 @@ static int inet6_fill_ifinfo(struct sk_buff *skb, struct inet6_dev *idev, goto nla_put_failure; nla_nest_end(skb, protoinfo); - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; nla_put_failure: nlmsg_cancel(skb, nlh); @@ -4670,7 +4675,7 @@ static int inet6_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) if (inet6_fill_ifinfo(skb, idev, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, - RTM_NEWLINK, NLM_F_MULTI) <= 0) + RTM_NEWLINK, NLM_F_MULTI) < 0) goto out; cont: idx++; @@ -4747,7 +4752,8 @@ static int inet6_fill_prefix(struct sk_buff *skb, struct inet6_dev *idev, ci.valid_time = ntohl(pinfo->valid); if (nla_put(skb, PREFIX_CACHEINFO, sizeof(ci), &ci)) goto nla_put_failure; - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; nla_put_failure: nlmsg_cancel(skb, nlh); diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c index fd0dc47f471d..e43e79d0a612 100644 --- a/net/ipv6/addrlabel.c +++ b/net/ipv6/addrlabel.c @@ -490,7 +490,8 @@ static int ip6addrlbl_fill(struct sk_buff *skb, return -EMSGSIZE; } - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; } static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb) @@ -510,7 +511,7 @@ static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb) cb->nlh->nlmsg_seq, RTM_NEWADDRLABEL, NLM_F_MULTI); - if (err <= 0) + if (err < 0) break; } idx++; diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 03c520a4ebeb..53775ee7d376 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -277,7 +277,6 @@ static int fib6_dump_node(struct fib6_walker *w) w->leaf = rt; return 1; } - WARN_ON(res == 0); } w->leaf = NULL; return 0; diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 722669754bbf..34b682617f50 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -2388,7 +2388,8 @@ static int ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb, if (err < 0 && err != -ENOENT) goto nla_put_failure; - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; nla_put_failure: nlmsg_cancel(skb, nlh); diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 34dcbb59df75..c60f15775c53 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2725,7 +2725,8 @@ static int rt6_fill_node(struct net *net, if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, rt->dst.error) < 0) goto nla_put_failure; - return nlmsg_end(skb, nlh); + nlmsg_end(skb, nlh); + return 0; nla_put_failure: nlmsg_cancel(skb, nlh); |