[B.A.T.M.A.N.] [PATCH 6/9] batman-adv: protect each hash row with rcu locks

From: Marek Lindner lindner_marek@yahoo.de

Signed-off-by: Marek Lindner lindner_marek@yahoo.de --- Could we move those '!= NULL' and ' == ' as an extra patch?

batman-adv/hash.c | 36 +++++++++++++----- batman-adv/hash.h | 77 ++++++++++++++++++++++++++------------- batman-adv/icmp_socket.c | 2 + batman-adv/originator.c | 27 ++++++++++---- batman-adv/routing.c | 16 ++++++++- batman-adv/translation-table.c | 14 +++++++ batman-adv/unicast.c | 7 +++- batman-adv/vis.c | 18 +++++++-- 8 files changed, 148 insertions(+), 49 deletions(-)

diff --git a/batman-adv/hash.c b/batman-adv/hash.c index fec9bbd..aaf3e0c 100644 --- a/batman-adv/hash.c +++ b/batman-adv/hash.c @@ -27,13 +27,16 @@ static void hash_init(struct hashtable_t *hash) { int i;

- for (i = 0 ; i < hash->size; i++) + for (i = 0 ; i < hash->size; i++) { INIT_HLIST_HEAD(&hash->table[i]); + spin_lock_init(&hash->list_locks[i]); + } }

/* free only the hashtable and the hash itself. */ void hash_destroy(struct hashtable_t *hash) { + kfree(hash->list_locks); kfree(hash->table); kfree(hash); } @@ -43,20 +46,33 @@ struct hashtable_t *hash_new(int size) { struct hashtable_t *hash;

- hash = kmalloc(sizeof(struct hashtable_t) , GFP_ATOMIC); - - if (hash == NULL) + hash = kmalloc(sizeof(struct hashtable_t), GFP_ATOMIC); + if (!hash) return NULL;

- hash->size = size; hash->table = kmalloc(sizeof(struct element_t *) * size, GFP_ATOMIC); + if (!hash->table) + goto free_hash;

- if (hash->table == NULL) { - kfree(hash); - return NULL; - } + hash->list_locks = kmalloc(sizeof(spinlock_t) * size, GFP_ATOMIC); + if (!hash->list_locks) + goto free_table;

+ hash->size = size; hash_init(hash); - return hash; + +free_table: + kfree(hash->table); +free_hash: + kfree(hash); + return NULL; +} + +void bucket_free_rcu(struct rcu_head *rcu) +{ + struct element_t *bucket; + + bucket = container_of(rcu, struct element_t, rcu); + kfree(bucket); } diff --git a/batman-adv/hash.h b/batman-adv/hash.h index 0801f9c..d47735c 100644 --- a/batman-adv/hash.h +++ b/batman-adv/hash.h @@ -39,10 +39,12 @@ typedef void (*hashdata_free_cb)(void *, void *); struct element_t { void *data; /* pointer to the data */ struct hlist_node hlist; /* bucket list pointer */ + struct rcu_head rcu; };

struct hashtable_t { - struct hlist_head *table; /* the hashtable itself, with the buckets */ + struct hlist_head *table; /* the hashtable itself with the buckets */ + spinlock_t *list_locks; /* spinlock for each hash list entry */ int size; /* size of hashtable */ };

@@ -57,6 +59,8 @@ void *hash_remove_element(struct hashtable_t *hash, struct element_t *elem); /* free only the hashtable and the hash itself. */ void hash_destroy(struct hashtable_t *hash);

+void bucket_free_rcu(struct rcu_head *rcu); + /* remove the hash structure. if hashdata_free_cb != NULL, this function will be * called to remove the elements inside of the hash. if you don't remove the * elements, memory might be leaked. */ @@ -66,19 +70,22 @@ static inline void hash_delete(struct hashtable_t *hash, struct hlist_head *head; struct hlist_node *walk, *safe; struct element_t *bucket; + spinlock_t *list_lock; int i;

for (i = 0; i < hash->size; i++) { head = &hash->table[i]; + list_lock = &hash->list_locks[i];

- hlist_for_each_safe(walk, safe, head) { - bucket = hlist_entry(walk, struct element_t, hlist); - if (free_cb != NULL) + spin_lock_bh(list_lock); + hlist_for_each_entry_safe(bucket, walk, safe, head, hlist) { + if (free_cb) free_cb(bucket->data, arg);

- hlist_del(walk); - kfree(bucket); + hlist_del_rcu(walk); + call_rcu(&bucket->rcu, bucket_free_rcu); } + spin_unlock_bh(list_lock); }

hash_destroy(hash); @@ -93,29 +100,39 @@ static inline int hash_add(struct hashtable_t *hash, struct hlist_head *head; struct hlist_node *walk, *safe; struct element_t *bucket; + spinlock_t *list_lock;

if (!hash) - return -1; + goto err;

index = choose(data, hash->size); head = &hash->table[index]; + list_lock = &hash->list_locks[index];

- hlist_for_each_safe(walk, safe, head) { - bucket = hlist_entry(walk, struct element_t, hlist); + rcu_read_lock(); + hlist_for_each_entry_safe(bucket, walk, safe, head, hlist) { if (compare(bucket->data, data)) - return -1; + goto err_unlock; } + rcu_read_unlock();

/* no duplicate found in list, add new element */ bucket = kmalloc(sizeof(struct element_t), GFP_ATOMIC); - - if (bucket == NULL) - return -1; + if (!bucket) + goto err;

bucket->data = data; - hlist_add_head(&bucket->hlist, head); + + spin_lock_bh(list_lock); + hlist_add_head_rcu(&bucket->hlist, head); + spin_unlock_bh(list_lock);

return 0; + +err_unlock: + rcu_read_unlock(); +err: + return -1; }

/* removes data from hash, if found. returns pointer do data on success, so you @@ -130,25 +147,31 @@ static inline void *hash_remove(struct hashtable_t *hash, struct hlist_node *walk; struct element_t *bucket; struct hlist_head *head; - void *data_save; + void *data_save = NULL;

index = choose(data, hash->size); head = &hash->table[index];

+ spin_lock_bh(&hash->list_locks[index]); hlist_for_each_entry(bucket, walk, head, hlist) { if (compare(bucket->data, data)) { data_save = bucket->data; - hlist_del(walk); - kfree(bucket); - return data_save; + hlist_del_rcu(walk); + call_rcu(&bucket->rcu, bucket_free_rcu); + break; } } + spin_unlock_bh(&hash->list_locks[index]);

- return NULL; + return data_save; }

-/* finds data, based on the key in keydata. returns the found data on success, - * or NULL on error */ +/** + * finds data, based on the key in keydata. returns the found data on success, + * or NULL on error + * + * caller must lock with rcu_read_lock() / rcu_read_unlock() + **/ static inline void *hash_find(struct hashtable_t *hash, hashdata_compare_cb compare, hashdata_choose_cb choose, void *keydata) @@ -157,6 +180,7 @@ static inline void *hash_find(struct hashtable_t *hash, struct hlist_head *head; struct hlist_node *walk; struct element_t *bucket; + void *bucket_data = NULL;

if (!hash) return NULL; @@ -164,13 +188,14 @@ static inline void *hash_find(struct hashtable_t *hash, index = choose(keydata , hash->size); head = &hash->table[index];

- hlist_for_each(walk, head) { - bucket = hlist_entry(walk, struct element_t, hlist); - if (compare(bucket->data, keydata)) - return bucket->data; + hlist_for_each_entry(bucket, walk, head, hlist) { + if (compare(bucket->data, keydata)) { + bucket_data = bucket->data; + break; + } }

- return NULL; + return bucket_data; }

#endif /* _NET_BATMAN_ADV_HASH_H_ */ diff --git a/batman-adv/icmp_socket.c b/batman-adv/icmp_socket.c index ecf6d7f..a9a10ed 100644 --- a/batman-adv/icmp_socket.c +++ b/batman-adv/icmp_socket.c @@ -221,9 +221,11 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff, goto dst_unreach;

spin_lock_bh(&bat_priv->orig_hash_lock); + rcu_read_lock(); orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash, compare_orig, choose_orig, icmp_packet->dst)); + rcu_read_unlock();

if (!orig_node) goto unlock; diff --git a/batman-adv/originator.c b/batman-adv/originator.c index 4d6d125..a43cda4 100644 --- a/batman-adv/originator.c +++ b/batman-adv/originator.c @@ -150,9 +150,11 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr) int size; int hash_added;

+ rcu_read_lock(); orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash, compare_orig, choose_orig, addr)); + rcu_read_unlock();

if (orig_node) return orig_node; @@ -289,6 +291,7 @@ static void _purge_orig(struct bat_priv *bat_priv) struct hlist_node *walk, *safe; struct hlist_head *head; struct element_t *bucket; + spinlock_t *list_lock; struct orig_node *orig_node; int i;

@@ -300,22 +303,26 @@ static void _purge_orig(struct bat_priv *bat_priv) /* for all origins... */ for (i = 0; i < hash->size; i++) { head = &hash->table[i]; + list_lock = &hash->list_locks[i];

+ spin_lock_bh(list_lock); hlist_for_each_entry_safe(bucket, walk, safe, head, hlist) { orig_node = bucket->data;

if (purge_orig_node(bat_priv, orig_node)) { if (orig_node->gw_flags) gw_node_delete(bat_priv, orig_node); - hlist_del(walk); - kfree(bucket); + hlist_del_rcu(walk); + call_rcu(&bucket->rcu, bucket_free_rcu); free_orig_node(orig_node, bat_priv); + continue; }

if (time_after(jiffies, orig_node->last_frag_packet + msecs_to_jiffies(FRAG_TIMEOUT))) frag_list_free(&orig_node->frag_list); } + spin_unlock_bh(list_lock); }

spin_unlock_bh(&bat_priv->orig_hash_lock); @@ -382,7 +389,8 @@ int orig_seq_print_text(struct seq_file *seq, void *offset) for (i = 0; i < hash->size; i++) { head = &hash->table[i];

- hlist_for_each_entry(bucket, walk, head, hlist) { + rcu_read_lock(); + hlist_for_each_entry_rcu(bucket, walk, head, hlist) { orig_node = bucket->data;

if (!orig_node->router) @@ -403,17 +411,16 @@ int orig_seq_print_text(struct seq_file *seq, void *offset) neigh_node->addr, neigh_node->if_incoming->net_dev->name);

- 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++; } + rcu_read_unlock(); }

spin_unlock_bh(&bat_priv->orig_hash_lock); @@ -471,18 +478,21 @@ int orig_hash_add_if(struct batman_if *batman_if, int max_if_num) for (i = 0; i < hash->size; i++) { head = &hash->table[i];

- hlist_for_each_entry(bucket, walk, head, hlist) { + rcu_read_lock(); + hlist_for_each_entry_rcu(bucket, walk, head, hlist) { orig_node = bucket->data;

if (orig_node_add_if(orig_node, max_if_num) == -1) goto err; } + rcu_read_unlock(); }

spin_unlock_bh(&bat_priv->orig_hash_lock); return 0;

err: + rcu_read_unlock(); spin_unlock_bh(&bat_priv->orig_hash_lock); return -ENOMEM; } @@ -557,7 +567,8 @@ int orig_hash_del_if(struct batman_if *batman_if, int max_if_num) for (i = 0; i < hash->size; i++) { head = &hash->table[i];

- hlist_for_each_entry(bucket, walk, head, hlist) { + rcu_read_lock(); + hlist_for_each_entry_rcu(bucket, walk, head, hlist) { orig_node = bucket->data;

ret = orig_node_del_if(orig_node, max_if_num, @@ -566,6 +577,7 @@ int orig_hash_del_if(struct batman_if *batman_if, int max_if_num) if (ret == -1) goto err; } + rcu_read_unlock(); }

/* renumber remaining batman interfaces _inside_ of orig_hash_lock */ @@ -590,6 +602,7 @@ int orig_hash_del_if(struct batman_if *batman_if, int max_if_num) return 0;

err: + rcu_read_unlock(); spin_unlock_bh(&bat_priv->orig_hash_lock); return -ENOMEM; } diff --git a/batman-adv/routing.c b/batman-adv/routing.c index ae383d6..035f159 100644 --- a/batman-adv/routing.c +++ b/batman-adv/routing.c @@ -53,7 +53,8 @@ void slide_own_bcast_window(struct batman_if *batman_if) for (i = 0; i < hash->size; i++) { head = &hash->table[i];

- hlist_for_each_entry(bucket, walk, head, hlist) { + rcu_read_lock(); + hlist_for_each_entry_rcu(bucket, walk, head, hlist) { orig_node = bucket->data; word_index = batman_if->if_num * NUM_WORDS; word = &(orig_node->bcast_own[word_index]); @@ -62,6 +63,7 @@ void slide_own_bcast_window(struct batman_if *batman_if) orig_node->bcast_own_sum[batman_if->if_num] = bit_packet_count(word); } + rcu_read_unlock(); }

spin_unlock_bh(&bat_priv->orig_hash_lock); @@ -858,9 +860,11 @@ static int recv_my_icmp_packet(struct bat_priv *bat_priv, /* answer echo request (ping) */ /* get routing information */ spin_lock_bh(&bat_priv->orig_hash_lock); + rcu_read_lock(); orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash, compare_orig, choose_orig, icmp_packet->orig)); + rcu_read_unlock(); ret = NET_RX_DROP;

if ((orig_node != NULL) && @@ -920,9 +924,11 @@ static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv,

/* get routing information */ spin_lock_bh(&bat_priv->orig_hash_lock); + rcu_read_lock(); orig_node = ((struct orig_node *) hash_find(bat_priv->orig_hash, compare_orig, choose_orig, icmp_packet->orig)); + rcu_read_unlock(); ret = NET_RX_DROP;

if ((orig_node != NULL) && @@ -1014,9 +1020,11 @@ int recv_icmp_packet(struct sk_buff *skb, struct batman_if *recv_if)

/* get routing information */ spin_lock_bh(&bat_priv->orig_hash_lock); + rcu_read_lock(); orig_node = ((struct orig_node *) hash_find(bat_priv->orig_hash, compare_orig, choose_orig, icmp_packet->dst)); + rcu_read_unlock();

if ((orig_node != NULL) && (orig_node->router != NULL)) { @@ -1087,9 +1095,11 @@ struct neigh_node *find_router(struct bat_priv *bat_priv, router_orig->orig, ETH_ALEN) == 0) { primary_orig_node = router_orig; } else { + rcu_read_lock(); primary_orig_node = hash_find(bat_priv->orig_hash, compare_orig, choose_orig, router_orig->primary_addr); + rcu_read_unlock();

if (!primary_orig_node) return orig_node->router; @@ -1192,9 +1202,11 @@ int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if,

/* get routing information */ spin_lock_bh(&bat_priv->orig_hash_lock); + rcu_read_lock(); orig_node = ((struct orig_node *) hash_find(bat_priv->orig_hash, compare_orig, choose_orig, unicast_packet->dest)); + rcu_read_unlock();

router = find_router(bat_priv, orig_node, recv_if);

@@ -1338,9 +1350,11 @@ int recv_bcast_packet(struct sk_buff *skb, struct batman_if *recv_if) return NET_RX_DROP;

spin_lock_bh(&bat_priv->orig_hash_lock); + rcu_read_lock(); orig_node = ((struct orig_node *) hash_find(bat_priv->orig_hash, compare_orig, choose_orig, bcast_packet->orig)); + rcu_read_unlock();

if (orig_node == NULL) { spin_unlock_bh(&bat_priv->orig_hash_lock); diff --git a/batman-adv/translation-table.c b/batman-adv/translation-table.c index a19e16c..6f6ee58 100644 --- a/batman-adv/translation-table.c +++ b/batman-adv/translation-table.c @@ -61,10 +61,12 @@ void hna_local_add(struct net_device *soft_iface, uint8_t *addr) int required_bytes;

spin_lock_bh(&bat_priv->hna_lhash_lock); + rcu_read_lock(); hna_local_entry = ((struct hna_local_entry *)hash_find(bat_priv->hna_local_hash, compare_orig, choose_orig, addr)); + rcu_read_unlock(); spin_unlock_bh(&bat_priv->hna_lhash_lock);

if (hna_local_entry) { @@ -117,9 +119,11 @@ void hna_local_add(struct net_device *soft_iface, uint8_t *addr) /* remove address from global hash if present */ spin_lock_bh(&bat_priv->hna_ghash_lock);

+ rcu_read_lock(); hna_global_entry = ((struct hna_global_entry *) hash_find(bat_priv->hna_global_hash, compare_orig, choose_orig, addr)); + rcu_read_unlock();

if (hna_global_entry) _hna_global_del_orig(bat_priv, hna_global_entry, @@ -253,9 +257,11 @@ void hna_local_remove(struct bat_priv *bat_priv,

spin_lock_bh(&bat_priv->hna_lhash_lock);

+ rcu_read_lock(); hna_local_entry = (struct hna_local_entry *) hash_find(bat_priv->hna_local_hash, compare_orig, choose_orig, addr); + rcu_read_unlock();

if (hna_local_entry) hna_local_del(bat_priv, hna_local_entry, message); @@ -335,9 +341,11 @@ void hna_global_add_orig(struct bat_priv *bat_priv, spin_lock_bh(&bat_priv->hna_ghash_lock);

hna_ptr = hna_buff + (hna_buff_count * ETH_ALEN); + rcu_read_lock(); hna_global_entry = (struct hna_global_entry *) hash_find(bat_priv->hna_global_hash, compare_orig, choose_orig, hna_ptr); + rcu_read_unlock();

if (!hna_global_entry) { spin_unlock_bh(&bat_priv->hna_ghash_lock); @@ -369,9 +377,11 @@ void hna_global_add_orig(struct bat_priv *bat_priv, spin_lock_bh(&bat_priv->hna_lhash_lock);

hna_ptr = hna_buff + (hna_buff_count * ETH_ALEN); + rcu_read_lock(); hna_local_entry = (struct hna_local_entry *) hash_find(bat_priv->hna_local_hash, compare_orig, choose_orig, hna_ptr); + rcu_read_unlock();

if (hna_local_entry) hna_local_del(bat_priv, hna_local_entry, @@ -484,9 +494,11 @@ void hna_global_del_orig(struct bat_priv *bat_priv,

while ((hna_buff_count + 1) * ETH_ALEN <= orig_node->hna_buff_len) { hna_ptr = orig_node->hna_buff + (hna_buff_count * ETH_ALEN); + rcu_read_lock(); hna_global_entry = (struct hna_global_entry *) hash_find(bat_priv->hna_global_hash, compare_orig, choose_orig, hna_ptr); + rcu_read_unlock();

if ((hna_global_entry) && (hna_global_entry->orig_node == orig_node)) @@ -522,9 +534,11 @@ struct orig_node *transtable_search(struct bat_priv *bat_priv, uint8_t *addr) struct hna_global_entry *hna_global_entry;

spin_lock_bh(&bat_priv->hna_ghash_lock); + rcu_read_lock(); hna_global_entry = (struct hna_global_entry *) hash_find(bat_priv->hna_global_hash, compare_orig, choose_orig, addr); + rcu_read_unlock(); spin_unlock_bh(&bat_priv->hna_ghash_lock);

if (!hna_global_entry) diff --git a/batman-adv/unicast.c b/batman-adv/unicast.c index dc2e28b..0b2ea82 100644 --- a/batman-adv/unicast.c +++ b/batman-adv/unicast.c @@ -179,9 +179,11 @@ int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,

*new_skb = NULL; spin_lock_bh(&bat_priv->orig_hash_lock); + rcu_read_lock(); orig_node = ((struct orig_node *) hash_find(bat_priv->orig_hash, compare_orig, choose_orig, unicast_packet->orig)); + rcu_read_unlock();

if (!orig_node) { pr_debug("couldn't find originator in orig_hash\n"); @@ -285,11 +287,14 @@ int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) /* get routing information */ if (is_multicast_ether_addr(ethhdr->h_dest)) orig_node = (struct orig_node *)gw_get_selected(bat_priv); - else + else { + rcu_read_lock(); orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash, compare_orig, choose_orig, ethhdr->h_dest)); + rcu_read_unlock(); + }

/* check for hna host */ if (!orig_node) diff --git a/batman-adv/vis.c b/batman-adv/vis.c index d7f5b6b..653673e 100644 --- a/batman-adv/vis.c +++ b/batman-adv/vis.c @@ -380,8 +380,10 @@ static struct vis_info *add_packet(struct bat_priv *bat_priv, sizeof(struct vis_packet));

memcpy(search_packet->vis_orig, vis_packet->vis_orig, ETH_ALEN); + rcu_read_lock(); old_info = hash_find(bat_priv->vis_hash, vis_info_cmp, vis_info_choose, &search_elem); + rcu_read_unlock(); kfree_skb(search_elem.skb_packet);

if (old_info != NULL) { @@ -540,7 +542,8 @@ static int find_best_vis_server(struct bat_priv *bat_priv, for (i = 0; i < hash->size; i++) { head = &hash->table[i];

- hlist_for_each_entry(bucket, walk, head, hlist) { + rcu_read_lock(); + hlist_for_each_entry_rcu(bucket, walk, head, hlist) { orig_node = bucket->data; if ((orig_node) && (orig_node->router) && (orig_node->flags & VIS_SERVER) && @@ -550,6 +553,7 @@ static int find_best_vis_server(struct bat_priv *bat_priv, ETH_ALEN); } } + rcu_read_unlock(); }

return best_tq; @@ -605,7 +609,8 @@ static int generate_vis_packet(struct bat_priv *bat_priv) for (i = 0; i < hash->size; i++) { head = &hash->table[i];

- hlist_for_each_entry(bucket, walk, head, hlist) { + rcu_read_lock(); + hlist_for_each_entry_rcu(bucket, walk, head, hlist) { orig_node = bucket->data; neigh_node = orig_node->router;

@@ -632,10 +637,12 @@ static int generate_vis_packet(struct bat_priv *bat_priv) packet->entries++;

if (vis_packet_full(info)) { + rcu_read_unlock(); spin_unlock_bh(&bat_priv->orig_hash_lock); return 0; } } + rcu_read_unlock(); }

spin_unlock_bh(&bat_priv->orig_hash_lock); @@ -721,7 +728,8 @@ static void broadcast_vis_packet(struct bat_priv *bat_priv, for (i = 0; i < hash->size; i++) { head = &hash->table[i];

- hlist_for_each_entry(bucket, walk, head, hlist) { + rcu_read_lock(); + hlist_for_each_entry_rcu(bucket, walk, head, hlist) { orig_node = bucket->data;

/* if it's a vis server and reachable, send it. */ @@ -746,7 +754,7 @@ static void broadcast_vis_packet(struct bat_priv *bat_priv,

spin_lock_bh(&bat_priv->orig_hash_lock); } - + rcu_read_unlock(); }

spin_unlock_bh(&bat_priv->orig_hash_lock); @@ -763,9 +771,11 @@ static void unicast_vis_packet(struct bat_priv *bat_priv,

spin_lock_bh(&bat_priv->orig_hash_lock); packet = (struct vis_packet *)info->skb_packet->data; + rcu_read_lock(); orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash, compare_orig, choose_orig, packet->target_orig)); + rcu_read_unlock();

if ((!orig_node) || (!orig_node->router)) goto out;