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authorJohannes Berg <johannes.berg@intel.com>2015-01-16 21:09:00 (GMT)
committerDavid S. Miller <davem@davemloft.net>2015-01-18 06:03:45 (GMT)
commit053c095a82cf773075e83d7233b5cc19a1f73ece (patch)
treec787028efa9a73a182a0f338f87b6294cef4b8b9 /net/xfrm/xfrm_user.c
parentede58ef28e105de94475b2b69fa069c9a2ce6933 (diff)
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/xfrm/xfrm_user.c')
-rw-r--r--net/xfrm/xfrm_user.c27
1 files changed, 18 insertions, 9 deletions
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 8128594..7de2ed9 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1019,7 +1019,8 @@ static int build_spdinfo(struct sk_buff *skb, struct net *net,
return err;
}
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
}
static int xfrm_set_spdinfo(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -1121,7 +1122,8 @@ static int build_sadinfo(struct sk_buff *skb, struct net *net,
return err;
}
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
}
static int xfrm_get_sadinfo(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -1842,7 +1844,8 @@ static int build_aevent(struct sk_buff *skb, struct xfrm_state *x, const struct
if (err)
goto out_cancel;
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
out_cancel:
nlmsg_cancel(skb, nlh);
@@ -2282,7 +2285,8 @@ static int build_migrate(struct sk_buff *skb, const struct xfrm_migrate *m,
goto out_cancel;
}
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
out_cancel:
nlmsg_cancel(skb, nlh);
@@ -2490,7 +2494,8 @@ static int build_expire(struct sk_buff *skb, struct xfrm_state *x, const struct
if (err)
return err;
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
}
static int xfrm_exp_state_notify(struct xfrm_state *x, const struct km_event *c)
@@ -2712,7 +2717,8 @@ static int build_acquire(struct sk_buff *skb, struct xfrm_state *x,
return err;
}
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
}
static int xfrm_send_acquire(struct xfrm_state *x, struct xfrm_tmpl *xt,
@@ -2827,7 +2833,8 @@ static int build_polexpire(struct sk_buff *skb, struct xfrm_policy *xp,
}
upe->hard = !!hard;
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
}
static int xfrm_exp_policy_notify(struct xfrm_policy *xp, int dir, const struct km_event *c)
@@ -2986,7 +2993,8 @@ static int build_report(struct sk_buff *skb, u8 proto,
return err;
}
}
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
}
static int xfrm_send_report(struct net *net, u8 proto,
@@ -3031,7 +3039,8 @@ static int build_mapping(struct sk_buff *skb, struct xfrm_state *x,
um->old_sport = x->encap->encap_sport;
um->reqid = x->props.reqid;
- return nlmsg_end(skb, nlh);
+ nlmsg_end(skb, nlh);
+ return 0;
}
static int xfrm_send_mapping(struct xfrm_state *x, xfrm_address_t *ipaddr,

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