To avoid multiple functions changing a backbone gateways crc entry, lock
it using a spinlock.
Signed-off-by: Simon Wunderlich <sw(a)simonwunderlich.de>
Tested-by: Alfons Name <AlfonsName(a)web.de>
---
net/batman-adv/bridge_loop_avoidance.c | 35 +++++++++++++++++++++++++++++-----
net/batman-adv/types.h | 2 ++
2 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index 191a702..c80b015 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -260,7 +260,9 @@ batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw)
}
/* all claims gone, initialize CRC */
+ spin_lock_bh(&backbone_gw->crc_lock);
backbone_gw->crc = BATADV_BLA_CRC_INIT;
+ spin_unlock_bh(&backbone_gw->crc_lock);
}
/**
@@ -408,6 +410,7 @@ batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, u8 *orig,
entry->lasttime = jiffies;
entry->crc = BATADV_BLA_CRC_INIT;
entry->bat_priv = bat_priv;
+ spin_lock_init(&entry->crc_lock);
atomic_set(&entry->request_sent, 0);
atomic_set(&entry->wait_periods, 0);
ether_addr_copy(entry->orig, orig);
@@ -557,7 +560,9 @@ static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
__be16 crc;
memcpy(mac, batadv_announce_mac, 4);
+ spin_lock_bh(&backbone_gw->crc_lock);
crc = htons(backbone_gw->crc);
+ spin_unlock_bh(&backbone_gw->crc_lock);
memcpy(&mac[4], &crc, 2);
batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
@@ -618,14 +623,18 @@ static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
"bla_add_claim(): changing ownership for %pM, vid %d\n",
mac, BATADV_PRINT_VID(vid));
+ spin_lock_bh(&claim->backbone_gw->crc_lock);
claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
+ spin_unlock_bh(&claim->backbone_gw->crc_lock);
batadv_backbone_gw_free_ref(claim->backbone_gw);
}
/* set (new) backbone gw */
atomic_inc(&backbone_gw->refcount);
claim->backbone_gw = backbone_gw;
+ spin_lock_bh(&backbone_gw->crc_lock);
backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
+ spin_unlock_bh(&backbone_gw->crc_lock);
backbone_gw->lasttime = jiffies;
claim_free_ref:
@@ -653,7 +662,9 @@ static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
batadv_choose_claim, claim);
batadv_claim_free_ref(claim); /* reference from the hash is gone */
+ spin_lock_bh(&claim->backbone_gw->crc_lock);
claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
+ spin_unlock_bh(&claim->backbone_gw->crc_lock);
/* don't need the reference from hash_find() anymore */
batadv_claim_free_ref(claim);
@@ -664,7 +675,7 @@ static int batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr,
u8 *backbone_addr, unsigned short vid)
{
struct batadv_bla_backbone_gw *backbone_gw;
- u16 crc;
+ u16 backbone_crc, crc;
if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
return 0;
@@ -683,12 +694,16 @@ static int batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr,
"handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n",
BATADV_PRINT_VID(vid), backbone_gw->orig, crc);
- if (backbone_gw->crc != crc) {
+ spin_lock_bh(&backbone_gw->crc_lock);
+ backbone_crc = backbone_gw->crc;
+ spin_unlock_bh(&backbone_gw->crc_lock);
+
+ if (backbone_crc != crc) {
batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
"handle_announce(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n",
backbone_gw->orig,
BATADV_PRINT_VID(backbone_gw->vid),
- backbone_gw->crc, crc);
+ backbone_crc, crc);
batadv_bla_send_request(backbone_gw);
} else {
@@ -1647,6 +1662,7 @@ int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
struct batadv_bla_claim *claim;
struct batadv_hard_iface *primary_if;
struct hlist_head *head;
+ u16 backbone_crc;
u32 i;
bool is_own;
u8 *primary_addr;
@@ -1669,11 +1685,15 @@ int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
hlist_for_each_entry_rcu(claim, head, hash_entry) {
is_own = batadv_compare_eth(claim->backbone_gw->orig,
primary_addr);
+
+ spin_lock_bh(&claim->backbone_gw->crc_lock);
+ backbone_crc = claim->backbone_gw->crc;
+ spin_lock_bh(&claim->backbone_gw->crc_lock);
seq_printf(seq, " * %pM on %5d by %pM [%c] (%#.4x)\n",
claim->addr, BATADV_PRINT_VID(claim->vid),
claim->backbone_gw->orig,
(is_own ? 'x' : ' '),
- claim->backbone_gw->crc);
+ backbone_crc);
}
rcu_read_unlock();
}
@@ -1692,6 +1712,7 @@ int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
struct batadv_hard_iface *primary_if;
struct hlist_head *head;
int secs, msecs;
+ u16 backbone_crc;
u32 i;
bool is_own;
u8 *primary_addr;
@@ -1722,10 +1743,14 @@ int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
if (is_own)
continue;
+ spin_lock_bh(&backbone_gw->crc_lock);
+ backbone_crc = backbone_gw->crc;
+ spin_unlock_bh(&backbone_gw->crc_lock);
+
seq_printf(seq, " * %pM on %5d %4i.%03is (%#.4x)\n",
backbone_gw->orig,
BATADV_PRINT_VID(backbone_gw->vid), secs,
- msecs, backbone_gw->crc);
+ msecs, backbone_crc);
}
rcu_read_unlock();
}
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 9bdb21c..7c386db 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -906,6 +906,7 @@ struct batadv_socket_packet {
* backbone gateway - no bcast traffic is formwared until the situation was
* resolved
* @crc: crc16 checksum over all claims
+ * @crc_lock: lock protecting crc
* @refcount: number of contexts the object is used
* @rcu: struct used for freeing in an RCU-safe manner
*/
@@ -919,6 +920,7 @@ struct batadv_bla_backbone_gw {
atomic_t wait_periods;
atomic_t request_sent;
u16 crc;
+ spinlock_t crc_lock; /* protects crc */
atomic_t refcount;
struct rcu_head rcu;
};
--
2.5.0