mac80211: Use rhashtable_lookup_get_insert_fast instead of racy code (36922931) · Commits · 戴 / test

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 <herbert@gondor.apana.org.au> Signed-off-by:

Johannes Berg <johannes.berg@intel.com>

net/mac80211/mesh_pathtbl.c

+8 −16

Original line number	Diff line number	Diff line
		@@ -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,
		mpath = rhashtable_lookup_get_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)
		if (!mpath)
		hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
		} while (unlikely(ret == -EEXIST && !mpath));
		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;
		}

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