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   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sat, 16 Mar 2019 17:43:58 +0100
   3 Subject: [PATCH] mac80211: mesh: drop redundant rcu_read_lock/unlock calls
   4
   5 The callers of these functions are all within RCU locked sections
   6
   7 Signed-off-by: Felix Fietkau <nbd@nbd.name>
   8 ---
   9
  10 --- a/net/mac80211/mesh_hwmp.c
  11 +++ b/net/mac80211/mesh_hwmp.c
  12 @@ -1122,16 +1122,13 @@ int mesh_nexthop_resolve(struct ieee8021
  13         struct mesh_path *mpath;
  14         struct sk_buff *skb_to_free = NULL;
  15         u8 *target_addr = hdr->addr3;
  16 -       int err = 0;
  17
  18         /* Nulls are only sent to peers for PS and should be pre-addressed */
  19         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
  20                 return 0;
  21
  22 -       rcu_read_lock();
  23 -       err = mesh_nexthop_lookup(sdata, skb);
  24 -       if (!err)
  25 -               goto endlookup;
  26 +       if (!mesh_nexthop_lookup(sdata, skb))
  27 +               return 0;
  28
  29         /* no nexthop found, start resolving */
  30         mpath = mesh_path_lookup(sdata, target_addr);
  31 @@ -1139,8 +1136,7 @@ int mesh_nexthop_resolve(struct ieee8021
  32                 mpath = mesh_path_add(sdata, target_addr);
  33                 if (IS_ERR(mpath)) {
  34                         mesh_path_discard_frame(sdata, skb);
  35 -                       err = PTR_ERR(mpath);
  36 -                       goto endlookup;
  37 +                       return PTR_ERR(mpath);
  38                 }
  39         }
  40
  41 @@ -1154,13 +1150,10 @@ int mesh_nexthop_resolve(struct ieee8021
  42         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
  43         ieee80211_set_qos_hdr(sdata, skb);
  44         skb_queue_tail(&mpath->frame_queue, skb);
  45 -       err = -ENOENT;
  46         if (skb_to_free)
  47                 mesh_path_discard_frame(sdata, skb_to_free);
  48
  49 -endlookup:
  50 -       rcu_read_unlock();
  51 -       return err;
  52 +       return -ENOENT;
  53  }
  54
  55  /**
  56 @@ -1180,13 +1173,10 @@ int mesh_nexthop_lookup(struct ieee80211
  57         struct sta_info *next_hop;
  58         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
  59         u8 *target_addr = hdr->addr3;
  60 -       int err = -ENOENT;
  61
  62 -       rcu_read_lock();
  63         mpath = mesh_path_lookup(sdata, target_addr);
  64 -
  65         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
  66 -               goto endlookup;
  67 +               return -ENOENT;
  68
  69         if (time_after(jiffies,
  70                        mpath->exp_time -
  71 @@ -1201,12 +1191,10 @@ int mesh_nexthop_lookup(struct ieee80211
  72                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
  73                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
  74                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
  75 -               err = 0;
  76 +               return 0;
  77         }
  78
  79 -endlookup:
  80 -       rcu_read_unlock();
  81 -       return err;
  82 +       return -ENOENT;
  83  }
  84
  85  void mesh_path_timer(struct timer_list *t)
  86 --- a/net/mac80211/mesh_pathtbl.c
  87 +++ b/net/mac80211/mesh_pathtbl.c
  88 @@ -219,7 +219,7 @@ static struct mesh_path *mpath_lookup(st
  89  {
  90         struct mesh_path *mpath;
  91
  92 -       mpath = rhashtable_lookup_fast(&tbl->rhead, dst, mesh_rht_params);
  93 +       mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
  94
  95         if (mpath && mpath_expired(mpath)) {
  96                 spin_lock_bh(&mpath->state_lock);