diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c index b132ab9ad607..715e491dfbc3 100644 --- a/drivers/firewire/net.c +++ b/drivers/firewire/net.c @@ -250,7 +250,11 @@ static int fwnet_header_cache(const struct neighbour *neigh, h = (struct fwnet_header *)((u8 *)hh->hh_data + HH_DATA_OFF(sizeof(*h))); h->h_proto = type; memcpy(h->h_dest, neigh->ha, net->addr_len); - hh->hh_len = FWNET_HLEN; + + /* Pairs with the READ_ONCE() in neigh_resolve_output(), + * neigh_hh_output() and neigh_update_hhs(). + */ + smp_store_release(&hh->hh_len, FWNET_HLEN); return 0; } diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 50a67bd6a434..6a86e49181db 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -468,7 +468,7 @@ static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb do { seq = read_seqbegin(&hh->hh_lock); - hh_len = hh->hh_len; + hh_len = READ_ONCE(hh->hh_len); if (likely(hh_len <= HH_DATA_MOD)) { hh_alen = HH_DATA_MOD; diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 8c82e95f7539..652da6369037 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1197,7 +1197,7 @@ static void neigh_update_hhs(struct neighbour *neigh) if (update) { hh = &neigh->hh; - if (hh->hh_len) { + if (READ_ONCE(hh->hh_len)) { write_seqlock_bh(&hh->hh_lock); update(hh, neigh->dev, neigh->ha); write_sequnlock_bh(&hh->hh_lock); @@ -1476,7 +1476,7 @@ int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb) struct net_device *dev = neigh->dev; unsigned int seq; - if (dev->header_ops->cache && !neigh->hh.hh_len) + if (dev->header_ops->cache && !READ_ONCE(neigh->hh.hh_len)) neigh_hh_init(neigh); do { diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index 17374afee28f..9040fe55e0f5 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -244,7 +244,12 @@ int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 eth->h_proto = type; memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); memcpy(eth->h_dest, neigh->ha, ETH_ALEN); - hh->hh_len = ETH_HLEN; + + /* Pairs with READ_ONCE() in neigh_resolve_output(), + * neigh_hh_output() and neigh_update_hhs(). + */ + smp_store_release(&hh->hh_len, ETH_HLEN); + return 0; } EXPORT_SYMBOL(eth_header_cache);