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authorJohannes Berg <johannes.berg@intel.com>2015-01-16 22:09:00 +0100
committerDavid S. Miller <davem@davemloft.net>2015-01-18 01:03:45 -0500
commit053c095a82cf773075e83d7233b5cc19a1f73ece (patch)
treec787028efa9a73a182a0f338f87b6294cef4b8b9 /net/netlabel
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/netlabel')
-rw-r--r--net/netlabel/netlabel_cipso_v4.c3
-rw-r--r--net/netlabel/netlabel_mgmt.c6
-rw-r--r--net/netlabel/netlabel_unlabeled.c3
3 files changed, 8 insertions, 4 deletions
diff --git a/net/netlabel/netlabel_cipso_v4.c b/net/netlabel/netlabel_cipso_v4.c
index c2f2a53a4879..179625353cac 100644
--- a/net/netlabel/netlabel_cipso_v4.c
+++ b/net/netlabel/netlabel_cipso_v4.c
@@ -641,7 +641,8 @@ static int netlbl_cipsov4_listall_cb(struct cipso_v4_doi *doi_def, void *arg)
if (ret_val != 0)
goto listall_cb_failure;
- return genlmsg_end(cb_arg->skb, data);
+ genlmsg_end(cb_arg->skb, data);
+ return 0;
listall_cb_failure:
genlmsg_cancel(cb_arg->skb, data);
diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
index e66e977ef2fa..8b3b789c43c2 100644
--- a/net/netlabel/netlabel_mgmt.c
+++ b/net/netlabel/netlabel_mgmt.c
@@ -456,7 +456,8 @@ static int netlbl_mgmt_listall_cb(struct netlbl_dom_map *entry, void *arg)
goto listall_cb_failure;
cb_arg->seq++;
- return genlmsg_end(cb_arg->skb, data);
+ genlmsg_end(cb_arg->skb, data);
+ return 0;
listall_cb_failure:
genlmsg_cancel(cb_arg->skb, data);
@@ -620,7 +621,8 @@ static int netlbl_mgmt_protocols_cb(struct sk_buff *skb,
if (ret_val != 0)
goto protocols_cb_failure;
- return genlmsg_end(skb, data);
+ genlmsg_end(skb, data);
+ return 0;
protocols_cb_failure:
genlmsg_cancel(skb, data);
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 78a63c18779e..aec7994f78cf 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -1163,7 +1163,8 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
goto list_cb_failure;
cb_arg->seq++;
- return genlmsg_end(cb_arg->skb, data);
+ genlmsg_end(cb_arg->skb, data);
+ return 0;
list_cb_failure:
genlmsg_cancel(cb_arg->skb, data);

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