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>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b4f40fe84a0121381d221fd0c18a65043428fc17..4fa555e4dedcb4c354a15d4cab2cbb0c0c9c9f6b 100644 (file)
--- 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;
 
                tx_ant = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_ANTENNA_TX]);
                rx_ant = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_ANTENNA_RX]);
@@ -2116,17 +2099,15 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                /* reject antenna configurations which don't match the
                 * available antenna masks, except for the "all" mask */
                if ((~tx_ant && (tx_ant & ~rdev->wiphy.available_antennas_tx)) ||
-                   (~rx_ant && (rx_ant & ~rdev->wiphy.available_antennas_rx))) {
-                       result = -EINVAL;
-                       goto bad_res;
-               }
+                   (~rx_ant && (rx_ant & ~rdev->wiphy.available_antennas_rx)))
+                       return -EINVAL;
 
                tx_ant = tx_ant & rdev->wiphy.available_antennas_tx;
                rx_ant = rx_ant & rdev->wiphy.available_antennas_rx;
 
                result = rdev_set_antenna(rdev, tx_ant, rx_ant);
                if (result)
-                       goto bad_res;
+                       return result;
        }
 
        changed = 0;
@@ -2134,30 +2115,27 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
        if (info->attrs[NL80211_ATTR_WIPHY_RETRY_SHORT]) {
                retry_short = nla_get_u8(
                        info->attrs[NL80211_ATTR_WIPHY_RETRY_SHORT]);
-               if (retry_short == 0) {
-                       result = -EINVAL;
-                       goto bad_res;
-               }
+               if (retry_short == 0)
+                       return -EINVAL;
+
                changed |= WIPHY_PARAM_RETRY_SHORT;
        }
 
        if (info->attrs[NL80211_ATTR_WIPHY_RETRY_LONG]) {
                retry_long = nla_get_u8(
                        info->attrs[NL80211_ATTR_WIPHY_RETRY_LONG]);
-               if (retry_long == 0) {
-                       result = -EINVAL;
-                       goto bad_res;
-               }
+               if (retry_long == 0)
+                       return -EINVAL;
+
                changed |= WIPHY_PARAM_RETRY_LONG;
        }
 
        if (info->attrs[NL80211_ATTR_WIPHY_FRAG_THRESHOLD]) {
                frag_threshold = nla_get_u32(
                        info->attrs[NL80211_ATTR_WIPHY_FRAG_THRESHOLD]);
-               if (frag_threshold < 256) {
-                       result = -EINVAL;
-                       goto bad_res;
-               }
+               if (frag_threshold < 256)
+                       return -EINVAL;
+
                if (frag_threshold != (u32) -1) {
                        /*
                         * Fragments (apart from the last one) are required to
@@ -2187,10 +2165,8 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                u32 old_frag_threshold, old_rts_threshold;
                u8 old_coverage_class;
 
-               if (!rdev->ops->set_wiphy_params) {
-                       result = -EOPNOTSUPP;
-                       goto bad_res;
-               }
+               if (!rdev->ops->set_wiphy_params)
+                       return -EOPNOTSUPP;
 
                old_retry_short = rdev->wiphy.retry_short;
                old_retry_long = rdev->wiphy.retry_long;
@@ -2218,11 +2194,7 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                        rdev->wiphy.coverage_class = old_coverage_class;
                }
        }
-
- bad_res:
-       if (netdev)
-               dev_put(netdev);
-       return result;
+       return 0;
 }
 
 static inline u64 wdev_id(struct wireless_dev *wdev)