[B.A.T.M.A.N.] [PATCH 04/28] batman-adv: protect neighbor list with rcu locks

Sven Eckelmann
2011-03-05T12:28:18Z

net/batman-adv/originator.c | 35 ++++++++++++++++++++++++++++-------
net/batman-adv/routing.c | 41 +++++++++++++++++++++++++++--------------
net/batman-adv/types.h | 2 ++
3 files changed, 57 insertions(+), 21 deletions(-)

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 68b04e7..6cb9af3 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -67,6 +67,14 @@ void neigh_node_free_ref(struct kref *refcount)
kfree(neigh_node);
}

+static void neigh_node_free_rcu(struct rcu_head *rcu)
+{
+ struct neigh_node *neigh_node;
+
+ neigh_node = container_of(rcu, struct neigh_node, rcu);
+ kref_put(&neigh_node->refcount, neigh_node_free_ref);
+}
+
struct neigh_node *create_neighbor(struct orig_node *orig_node,
struct orig_node *orig_neigh_node,
uint8_t *neigh,
@@ -89,7 +97,9 @@ struct neigh_node *create_neighbor(struct orig_node *orig_node,
neigh_node->if_incoming = if_incoming;
kref_init(&neigh_node->refcount);

- hlist_add_head(&neigh_node->list, &orig_node->neigh_list);
+ spin_lock_bh(&orig_node->neigh_list_lock);
+ hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
+ spin_unlock_bh(&orig_node->neigh_list_lock);
return neigh_node;
}

@@ -100,13 +110,17 @@ static void free_orig_node(void *data, void *arg)
struct orig_node *orig_node = (struct orig_node *)data;
struct bat_priv *bat_priv = (struct bat_priv *)arg;

+ spin_lock_bh(&orig_node->neigh_list_lock);
+
/* for all neighbors towards this originator ... */
hlist_for_each_entry_safe(neigh_node, node, node_tmp,
&orig_node->neigh_list, list) {
- hlist_del(&neigh_node->list);
- kref_put(&neigh_node->refcount, neigh_node_free_ref);
+ hlist_del_rcu(&neigh_node->list);
+ call_rcu(&neigh_node->rcu, neigh_node_free_rcu);
}

+ spin_unlock_bh(&orig_node->neigh_list_lock);
+
frag_list_free(&orig_node->frag_list);
hna_global_del_orig(bat_priv, orig_node, "originator timed out");

@@ -151,6 +165,7 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
return NULL;

INIT_HLIST_HEAD(&orig_node->neigh_list);
+ spin_lock_init(&orig_node->neigh_list_lock);

memcpy(orig_node->orig, addr, ETH_ALEN);
orig_node->router = NULL;
@@ -200,6 +215,8 @@ static bool purge_orig_neighbors(struct bat_priv *bat_priv,

*best_neigh_node = NULL;

+ spin_lock_bh(&orig_node->neigh_list_lock);
+
/* for all neighbors towards this originator ... */
hlist_for_each_entry_safe(neigh_node, node, node_tmp,
&orig_node->neigh_list, list) {
@@ -225,14 +242,16 @@ static bool purge_orig_neighbors(struct bat_priv *bat_priv,

neigh_purged = true;

- hlist_del(&neigh_node->list);
- kref_put(&neigh_node->refcount, neigh_node_free_ref);
+ hlist_del_rcu(&neigh_node->list);
+ call_rcu(&neigh_node->rcu, neigh_node_free_rcu);
} else {
if ((!*best_neigh_node) ||
(neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
*best_neigh_node = neigh_node;
}
}
+
+ spin_unlock_bh(&orig_node->neigh_list_lock);
return neigh_purged;
}

@@ -384,11 +403,13 @@ int orig_seq_print_text(struct seq_file *seq, void *offset)
neigh_node->addr,
neigh_node->if_incoming->net_dev->name);

- hlist_for_each_entry(neigh_node, node,
- &orig_node->neigh_list, list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(neigh_node, node,
+ &orig_node->neigh_list, list) {
seq_printf(seq, " %pM (%3i)", neigh_node->addr,
neigh_node->tq_avg);
}
+ rcu_read_unlock();

seq_printf(seq, "\n");
batman_count++;
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index e8379ba..97f3216 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -153,14 +153,16 @@ static int is_bidirectional_neigh(struct orig_node *orig_node,
unsigned char total_count;

if (orig_node == orig_neigh_node) {
- hlist_for_each_entry(tmp_neigh_node, node,
- &orig_node->neigh_list, list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(tmp_neigh_node, node,
+ &orig_node->neigh_list, list) {

if (compare_orig(tmp_neigh_node->addr,
orig_neigh_node->orig) &&
(tmp_neigh_node->if_incoming == if_incoming))
neigh_node = tmp_neigh_node;
}
+ rcu_read_unlock();

if (!neigh_node)
neigh_node = create_neighbor(orig_node,
@@ -174,14 +176,16 @@ static int is_bidirectional_neigh(struct orig_node *orig_node,
neigh_node->last_valid = jiffies;
} else {
/* find packet count of corresponding one hop neighbor */
- hlist_for_each_entry(tmp_neigh_node, node,
- &orig_neigh_node->neigh_list, list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(tmp_neigh_node, node,
+ &orig_neigh_node->neigh_list, list) {

if (compare_orig(tmp_neigh_node->addr,
orig_neigh_node->orig) &&
(tmp_neigh_node->if_incoming == if_incoming))
neigh_node = tmp_neigh_node;
}
+ rcu_read_unlock();

if (!neigh_node)
neigh_node = create_neighbor(orig_neigh_node,
@@ -266,8 +270,9 @@ static void update_orig(struct bat_priv *bat_priv,
bat_dbg(DBG_BATMAN, bat_priv, "update_originator(): "
"Searching and updating originator entry of received packet\n");

- hlist_for_each_entry(tmp_neigh_node, node,
- &orig_node->neigh_list, list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(tmp_neigh_node, node,
+ &orig_node->neigh_list, list) {
if (compare_orig(tmp_neigh_node->addr, ethhdr->h_source) &&
(tmp_neigh_node->if_incoming == if_incoming)) {
neigh_node = tmp_neigh_node;
@@ -282,6 +287,7 @@ static void update_orig(struct bat_priv *bat_priv,
tmp_neigh_node->tq_avg =
ring_buffer_avg(tmp_neigh_node->tq_recv);
}
+ rcu_read_unlock();

if (!neigh_node) {
struct orig_node *orig_tmp;
@@ -410,8 +416,9 @@ static char count_real_packets(struct ethhdr *ethhdr,
&orig_node->batman_seqno_reset))
return -1;

- hlist_for_each_entry(tmp_neigh_node, node,
- &orig_node->neigh_list, list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(tmp_neigh_node, node,
+ &orig_node->neigh_list, list) {

is_duplicate |= get_bit_status(tmp_neigh_node->real_bits,
orig_node->last_real_seqno,
@@ -431,6 +438,7 @@ static char count_real_packets(struct ethhdr *ethhdr,
tmp_neigh_node->real_packet_count =
bit_packet_count(tmp_neigh_node->real_bits);
}
+ rcu_read_unlock();

if (need_update) {
bat_dbg(DBG_BATMAN, bat_priv,
@@ -481,15 +489,19 @@ void update_bonding_candidates(struct orig_node *orig_node)
* as "bonding partner" */

/* first, zero the list */
- hlist_for_each_entry(tmp_neigh_node, node,
- &orig_node->neigh_list, list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(tmp_neigh_node, node,
+ &orig_node->neigh_list, list) {
tmp_neigh_node->next_bond_candidate = NULL;
}
+ rcu_read_unlock();

first_candidate = NULL;
last_candidate = NULL;
- hlist_for_each_entry(tmp_neigh_node, node,
- &orig_node->neigh_list, list) {
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(tmp_neigh_node, node,
+ &orig_node->neigh_list, list) {

/* only consider if it has the same primary address ... */
if (memcmp(orig_node->orig,
@@ -506,8 +518,8 @@ void update_bonding_candidates(struct orig_node *orig_node)
* select this candidate because of possible interference. */

interference_candidate = 0;
- hlist_for_each_entry(tmp_neigh_node2, node2,
- &orig_node->neigh_list, list) {
+ hlist_for_each_entry_rcu(tmp_neigh_node2, node2,
+ &orig_node->neigh_list, list) {

if (tmp_neigh_node2 == tmp_neigh_node)
continue;
@@ -541,6 +553,7 @@ void update_bonding_candidates(struct orig_node *orig_node)

candidates++;
}
+ rcu_read_unlock();

if (candidates > 0) {
first_candidate->next_bond_candidate = last_candidate;
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 779c5c3..d4fa727 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -85,6 +85,7 @@ struct orig_node {
uint32_t last_bcast_seqno;
struct hlist_head neigh_list;
struct list_head frag_list;
+ spinlock_t neigh_list_lock; /* protects neighbor list */
unsigned long last_frag_packet;
struct {
uint8_t candidates;
@@ -116,6 +117,7 @@ struct neigh_node {
unsigned long last_valid;
unsigned long real_bits[NUM_WORDS];
struct kref refcount;
+ struct rcu_head rcu;
struct orig_node *orig_node;
struct batman_if *if_incoming;
};
--
1.7.2.3