net: nl80211: __dev_get_by_index instead of dev_get_by_index to find interface

As __cfg80211_rdev_from_attrs(), nl80211_dump_wiphy_parse() and
nl80211_set_wiphy() are all under rtnl_lock protection,
__dev_get_by_index() instead of dev_get_by_index() should be used
to find interface handler in them allowing us to avoid to change
interface reference counter.

Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 65 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b4f40fe84a01..4fa555e4dedc 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -165,7 +165,7 @@ __cfg80211_rdev_from_attrs(struct net *netns, struct nlattr **attrs)
 
         if (attrs[NL80211_ATTR_IFINDEX]) {
                 int ifindex = nla_get_u32(attrs[NL80211_ATTR_IFINDEX]);
-                netdev = dev_get_by_index(netns, ifindex);
+                netdev = __dev_get_by_index(netns, ifindex);
                 if (netdev) {
                         if (netdev->ieee80211_ptr)
                                 tmp = wiphy_to_dev(
@@ -173,8 +173,6 @@ __cfg80211_rdev_from_attrs(struct net *netns, struct nlattr **attrs)
                         else
                                 tmp = NULL;
 
-                        dev_put(netdev);
-
                         /* not wireless device -- return error */
                         if (!tmp)
                                 return ERR_PTR(-EINVAL);
@@ -1656,7 +1654,7 @@ static int nl80211_dump_wiphy_parse(struct sk_buff *skb,
                 struct cfg80211_registered_device *rdev;
                 int ifidx = nla_get_u32(tb[NL80211_ATTR_IFINDEX]);
 
-                netdev = dev_get_by_index(sock_net(skb->sk), ifidx);
+                netdev = __dev_get_by_index(sock_net(skb->sk), ifidx);
                 if (!netdev)
                         return -ENODEV;
                 if (netdev->ieee80211_ptr) {
@@ -1664,7 +1662,6 @@ static int nl80211_dump_wiphy_parse(struct sk_buff *skb,
                                 netdev->ieee80211_ptr->wiphy);
                         state->filter_wiphy = rdev->wiphy_idx;
                 }
-                dev_put(netdev);
         }
 
         return 0;
@@ -1987,7 +1984,7 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
         if (info->attrs[NL80211_ATTR_IFINDEX]) {
                 int ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
 
-                netdev = dev_get_by_index(genl_info_net(info), ifindex);
+                netdev = __dev_get_by_index(genl_info_net(info), ifindex);
                 if (netdev && netdev->ieee80211_ptr)
                         rdev = wiphy_to_dev(netdev->ieee80211_ptr->wiphy);
                 else
@@ -2015,32 +2012,24 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                         rdev, nla_data(info->attrs[NL80211_ATTR_WIPHY_NAME]));
 
         if (result)
-                goto bad_res;
+                return result;
 
         if (info->attrs[NL80211_ATTR_WIPHY_TXQ_PARAMS]) {
                 struct ieee80211_txq_params txq_params;
                 struct nlattr *tb[NL80211_TXQ_ATTR_MAX + 1];
 
-                if (!rdev->ops->set_txq_params) {
-                        result = -EOPNOTSUPP;
-                        goto bad_res;
-                }
+                if (!rdev->ops->set_txq_params)
+                        return -EOPNOTSUPP;
 
-                if (!netdev) {
-                        result = -EINVAL;
-                        goto bad_res;
-                }
+                if (!netdev)
+                        return -EINVAL;
 
                 if (netdev->ieee80211_ptr->iftype != NL80211_IFTYPE_AP &&
-                    netdev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO) {
-                        result = -EINVAL;
-                        goto bad_res;
-                }
+                    netdev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO)
+                        return -EINVAL;
 
-                if (!netif_running(netdev)) {
-                        result = -ENETDOWN;
-                        goto bad_res;
-                }
+                if (!netif_running(netdev))
+                        return -ENETDOWN;
 
                 nla_for_each_nested(nl_txq_params,
                                     info->attrs[NL80211_ATTR_WIPHY_TXQ_PARAMS],
@@ -2051,12 +2040,12 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                                   txq_params_policy);
                         result = parse_txq_params(tb, &txq_params);
                         if (result)
-                                goto bad_res;
+                                return result;
 
                         result = rdev_set_txq_params(rdev, netdev,
                                                      &txq_params);
                         if (result)
-                                goto bad_res;
+                                return result;
                 }
         }
 
@@ -2065,7 +2054,7 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                                 nl80211_can_set_dev_channel(wdev) ? wdev : NULL,
                                 info);
                 if (result)
-                        goto bad_res;
+                        return result;
         }
 
         if (info->attrs[NL80211_ATTR_WIPHY_TX_POWER_SETTING]) {
@@ -2076,19 +2065,15 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                 if (!(rdev->wiphy.features & NL80211_FEATURE_VIF_TXPOWER))
                         txp_wdev = NULL;
 
-                if (!rdev->ops->set_tx_power) {
-                        result = -EOPNOTSUPP;
-                        goto bad_res;
-                }
+                if (!rdev->ops->set_tx_power)
+                        return -EOPNOTSUPP;
 
                 idx = NL80211_ATTR_WIPHY_TX_POWER_SETTING;
                 type = nla_get_u32(info->attrs[idx]);
 
                 if (!info->attrs[NL80211_ATTR_WIPHY_TX_POWER_LEVEL] &&
-                    (type != NL80211_TX_POWER_AUTOMATIC)) {
-                        result = -EINVAL;
-                        goto bad_res;
-                }
+                    (type != NL80211_TX_POWER_AUTOMATIC))
+                        return -EINVAL;
 
                 if (type != NL80211_TX_POWER_AUTOMATIC) {
                         idx = NL80211_ATTR_WIPHY_TX_POWER_LEVEL;
@@ -2097,7 +2082,7 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
 
                 result = rdev_set_tx_power(rdev, txp_wdev, type, mbm);
                 if (result)
-                        goto bad_res;
+                        return result;
         }
 
         if (info->attrs[NL80211_ATTR_WIPHY_ANTENNA_TX] &&
@@ -2105,10 +2090,8 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                 u32 tx_ant, rx_ant;
                 if ((!rdev->wiphy.available_antennas_tx &&
                      !rdev->wiphy.available_antennas_rx) ||
-                    !rdev->ops->set_antenna) {
-                        result = -EOPNOTSUPP;
-                        goto bad_res;
-                }
+                    !rdev->ops->set_antenna)
+                        return -EOPNOTSUPP;