net/wireless/nl80211.c: Avoid call to genlmsg_cancel

genlmsg_cancel subtracts some constants from its second argument before
calling nlmsg_cancel.  nlmsg_cancel then calls nlmsg_trim on the same
arguments.  nlmsg_trim tests for NULL before doing any computation, but a
NULL second argument to genlmsg_cancel is no longer NULL due to the initial
subtraction.  Nothing else happens in this execution, so the call to
genlmsg_cancel is simply unnecessary in this case.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression data;
@@

if (data == NULL) { ...
* genlmsg_cancel(..., data);
  ...
  return ...;
}
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Julia Lawall 2011-01-28 15:17:11 +01:00 committed by John W. Linville
parent 76a9f6fd9a
commit efe1cf0c57

View File

@ -2718,7 +2718,7 @@ static int nl80211_get_mesh_config(struct sk_buff *skb,
hdr = nl80211hdr_put(msg, info->snd_pid, info->snd_seq, 0,
NL80211_CMD_GET_MESH_CONFIG);
if (!hdr)
goto nla_put_failure;
goto out;
pinfoattr = nla_nest_start(msg, NL80211_ATTR_MESH_CONFIG);
if (!pinfoattr)
goto nla_put_failure;
@ -2759,6 +2759,7 @@ static int nl80211_get_mesh_config(struct sk_buff *skb,
nla_put_failure:
genlmsg_cancel(msg, hdr);
out:
nlmsg_free(msg);
return -ENOBUFS;
}
@ -2954,7 +2955,7 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
hdr = nl80211hdr_put(msg, info->snd_pid, info->snd_seq, 0,
NL80211_CMD_GET_REG);
if (!hdr)
goto nla_put_failure;
goto put_failure;
NLA_PUT_STRING(msg, NL80211_ATTR_REG_ALPHA2,
cfg80211_regdomain->alpha2);
@ -3001,6 +3002,7 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
nla_put_failure:
genlmsg_cancel(msg, hdr);
put_failure:
nlmsg_free(msg);
err = -EMSGSIZE;
out: