forked from Minki/linux
fib_hash: RCU conversion phase 1
First step for RCU conversion of fib_hash : struct fn_zone are created and never deleted. Very classic conversion, using rcu_assign_pointer(), rcu_dereference() and rtnl_dereference() verbs. __rcu markers on fz_next and fn_zone_list They are created under RTNL, we dont need fib_hash_lock anymore in fn_new_zone(). Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
David S. Miller
parent
9bef83edfb
commit
117a8cdea3
@ -57,7 +57,7 @@ struct fib_node {
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#define EMBEDDED_HASH_SIZE (L1_CACHE_BYTES / sizeof(struct hlist_head))
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struct fn_zone {
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struct fn_zone *fz_next; /* Next not empty zone */
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struct fn_zone __rcu *fz_next; /* Next not empty zone */
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struct hlist_head *fz_hash; /* Hash table pointer */
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u32 fz_hashmask; /* (fz_divisor - 1) */
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@ -73,8 +73,8 @@ struct fn_zone {
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};
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struct fn_hash {
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struct fn_zone *fn_zones[33];
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struct fn_zone *fn_zone_list;
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struct fn_zone *fn_zones[33];
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struct fn_zone __rcu *fn_zone_list;
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};
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static inline u32 fn_hash(__be32 key, struct fn_zone *fz)
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@ -219,21 +219,21 @@ fn_new_zone(struct fn_hash *table, int z)
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fz->fz_mask = inet_make_mask(z);
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/* Find the first not empty zone with more specific mask */
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for (i=z+1; i<=32; i++)
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for (i = z + 1; i <= 32; i++)
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if (table->fn_zones[i])
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break;
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write_lock_bh(&fib_hash_lock);
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if (i>32) {
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if (i > 32) {
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/* No more specific masks, we are the first. */
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fz->fz_next = table->fn_zone_list;
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table->fn_zone_list = fz;
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rcu_assign_pointer(fz->fz_next,
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rtnl_dereference(table->fn_zone_list));
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rcu_assign_pointer(table->fn_zone_list, fz);
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} else {
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fz->fz_next = table->fn_zones[i]->fz_next;
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table->fn_zones[i]->fz_next = fz;
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rcu_assign_pointer(fz->fz_next,
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rtnl_dereference(table->fn_zones[i]->fz_next));
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rcu_assign_pointer(table->fn_zones[i]->fz_next, fz);
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}
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table->fn_zones[z] = fz;
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fib_hash_genid++;
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write_unlock_bh(&fib_hash_lock);
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return fz;
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}
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@ -245,8 +245,11 @@ int fib_table_lookup(struct fib_table *tb,
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struct fn_zone *fz;
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struct fn_hash *t = (struct fn_hash *)tb->tb_data;
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rcu_read_lock();
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read_lock(&fib_hash_lock);
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for (fz = t->fn_zone_list; fz; fz = fz->fz_next) {
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for (fz = rcu_dereference(t->fn_zone_list);
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fz != NULL;
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fz = rcu_dereference(fz->fz_next)) {
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struct hlist_head *head;
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struct hlist_node *node;
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struct fib_node *f;
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@ -267,6 +270,7 @@ int fib_table_lookup(struct fib_table *tb,
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err = 1;
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out:
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read_unlock(&fib_hash_lock);
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rcu_read_unlock();
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return err;
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}
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@ -362,6 +366,7 @@ static struct fib_node *fib_find_node(struct fn_zone *fz, __be32 key)
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return NULL;
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}
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/* Caller must hold RTNL. */
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int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
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{
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struct fn_hash *table = (struct fn_hash *) tb->tb_data;
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@ -657,13 +662,16 @@ static int fn_flush_list(struct fn_zone *fz, int idx)
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return found;
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}
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/* caller must hold RTNL. */
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int fib_table_flush(struct fib_table *tb)
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{
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struct fn_hash *table = (struct fn_hash *) tb->tb_data;
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struct fn_zone *fz;
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int found = 0;
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for (fz = table->fn_zone_list; fz; fz = fz->fz_next) {
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for (fz = rtnl_dereference(table->fn_zone_list);
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fz != NULL;
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fz = rtnl_dereference(fz->fz_next)) {
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int i;
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for (i = fz->fz_divisor - 1; i >= 0; i--)
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@ -741,23 +749,29 @@ fn_hash_dump_zone(struct sk_buff *skb, struct netlink_callback *cb,
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int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
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struct netlink_callback *cb)
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{
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int m, s_m;
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int m = 0, s_m;
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struct fn_zone *fz;
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struct fn_hash *table = (struct fn_hash *)tb->tb_data;
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s_m = cb->args[2];
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rcu_read_lock();
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read_lock(&fib_hash_lock);
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for (fz = table->fn_zone_list, m=0; fz; fz = fz->fz_next, m++) {
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if (m < s_m) continue;
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for (fz = rcu_dereference(table->fn_zone_list);
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fz != NULL;
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fz = rcu_dereference(fz->fz_next), m++) {
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if (m < s_m)
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continue;
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if (fn_hash_dump_zone(skb, cb, tb, fz) < 0) {
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cb->args[2] = m;
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read_unlock(&fib_hash_lock);
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rcu_read_unlock();
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return -1;
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}
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memset(&cb->args[3], 0,
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sizeof(cb->args) - 3*sizeof(cb->args[0]));
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}
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read_unlock(&fib_hash_lock);
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rcu_read_unlock();
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cb->args[2] = m;
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return skb->len;
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}
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@ -820,8 +834,9 @@ static struct fib_alias *fib_get_first(struct seq_file *seq)
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iter->genid = fib_hash_genid;
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iter->valid = 1;
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for (iter->zone = table->fn_zone_list; iter->zone;
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iter->zone = iter->zone->fz_next) {
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for (iter->zone = rcu_dereference(table->fn_zone_list);
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iter->zone != NULL;
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iter->zone = rcu_dereference(iter->zone->fz_next)) {
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int maxslot;
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if (!iter->zone->fz_nent)
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@ -906,7 +921,7 @@ static struct fib_alias *fib_get_next(struct seq_file *seq)
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}
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}
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iter->zone = iter->zone->fz_next;
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iter->zone = rcu_dereference(iter->zone->fz_next);
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if (!iter->zone)
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goto out;
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@ -946,9 +961,11 @@ static struct fib_alias *fib_get_idx(struct seq_file *seq, loff_t pos)
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static void *fib_seq_start(struct seq_file *seq, loff_t *pos)
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__acquires(fib_hash_lock)
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__acquires(RCU)
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{
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void *v = NULL;
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rcu_read_lock();
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read_lock(&fib_hash_lock);
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if (fib_get_table(seq_file_net(seq), RT_TABLE_MAIN))
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v = *pos ? fib_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
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@ -963,8 +980,10 @@ static void *fib_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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static void fib_seq_stop(struct seq_file *seq, void *v)
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__releases(fib_hash_lock)
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__releases(RCU)
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{
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read_unlock(&fib_hash_lock);
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rcu_read_unlock();
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}
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static unsigned fib_flag_trans(int type, __be32 mask, struct fib_info *fi)
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