From 3692293163b8ba1f28bad0e4a7ddf4fa0a7fd34d Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 14 Feb 2019 22:03:26 +0800 Subject: [PATCH] mac80211: Use rhashtable_lookup_get_insert_fast instead of racy code The code in mesh_path_add tries to handle the case where a duplicate entry is added to the rhashtable by doing a lookup after a failed insertion. It also tries to handle races by repeating the insertion should the lookup fail. This is now unnecessary as we have rhashtable API functions that can directly return the mathcing object. Signed-off-by: Herbert Xu Signed-off-by: Johannes Berg --- net/mac80211/mesh_pathtbl.c | 24 ++++++++---------------- 1 file changed, 8 insertions(+), 16 deletions(-) diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c index 88a6d5e18ccc..95eb5064fa91 100644 --- a/net/mac80211/mesh_pathtbl.c +++ b/net/mac80211/mesh_pathtbl.c @@ -404,7 +404,6 @@ struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata, { struct mesh_table *tbl; struct mesh_path *mpath, *new_mpath; - int ret; if (ether_addr_equal(dst, sdata->vif.addr)) /* never add ourselves as neighbours */ @@ -422,25 +421,18 @@ struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata, tbl = sdata->u.mesh.mesh_paths; spin_lock_bh(&tbl->walk_lock); - do { - ret = rhashtable_lookup_insert_fast(&tbl->rhead, - &new_mpath->rhash, - mesh_rht_params); - - if (ret == -EEXIST) - mpath = rhashtable_lookup_fast(&tbl->rhead, - dst, - mesh_rht_params); - else if (!ret) - hlist_add_head(&new_mpath->walk_list, &tbl->walk_head); - } while (unlikely(ret == -EEXIST && !mpath)); + mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead, + &new_mpath->rhash, + mesh_rht_params); + if (!mpath) + hlist_add_head(&new_mpath->walk_list, &tbl->walk_head); spin_unlock_bh(&tbl->walk_lock); - if (ret) { + if (mpath) { kfree(new_mpath); - if (ret != -EEXIST) - return ERR_PTR(ret); + if (IS_ERR(mpath)) + return mpath; new_mpath = mpath; }