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rds: use RCU to protect the connection hash

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The connection hash was almost entirely RCU ready, this
just makes the final couple of changes to use RCU instead
of spinlocks for everything.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2010-05-11 15:15:15 -07:00 committed by Andy Grover
parent abf454398c
commit bcf50ef2ce
1 changed files with 22 additions and 22 deletions
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44
net/rds/connection.c
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@ -62,6 +62,7 @@ static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
var |= RDS_INFO_CONNECTION_FLAG_##suffix; \
} while (0)
/* rcu read lock must be held or the connection spinlock */
static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
__be32 laddr, __be32 faddr,
struct rds_transport *trans)
@ -69,7 +70,7 @@ static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
struct rds_connection *conn, *ret = NULL;
struct hlist_node *pos;
hlist_for_each_entry(conn, pos, head, c_hash_node) {
hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
conn->c_trans == trans) {
ret = conn;
@ -119,7 +120,8 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
unsigned long flags;
int ret;
spin_lock_irqsave(&rds_conn_lock, flags);
rcu_read_lock();
conn = rds_conn_lookup(head, laddr, faddr, trans);
if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
!is_outgoing) {
@ -130,7 +132,7 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
parent = conn;
conn = parent->c_passive;
}
spin_unlock_irqrestore(&rds_conn_lock, flags);
rcu_read_unlock();
if (conn)
goto out;
@ -227,7 +229,7 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
kmem_cache_free(rds_conn_slab, conn);
conn = found;
} else {
hlist_add_head(&conn->c_hash_node, head);
hlist_add_head_rcu(&conn->c_hash_node, head);
rds_cong_add_conn(conn);
rds_conn_count++;
}
@ -306,8 +308,13 @@ void rds_conn_shutdown(struct rds_connection *conn)
* to the conn hash, so we never trigger a reconnect on this
* conn - the reconnect is always triggered by the active peer. */
cancel_delayed_work_sync(&conn->c_conn_w);
if (!hlist_unhashed(&conn->c_hash_node))
rcu_read_lock();
if (!hlist_unhashed(&conn->c_hash_node)) {
rcu_read_unlock();
rds_queue_reconnect(conn);
} else {
rcu_read_unlock();
}
}
/*
@ -323,14 +330,12 @@ void rds_conn_destroy(struct rds_connection *conn)
/* Ensure conn will not be scheduled for reconnect */
spin_lock_irq(&rds_conn_lock);
hlist_del_init(&conn->c_hash_node);
hlist_del_init_rcu(&conn->c_hash_node);
spin_unlock_irq(&rds_conn_lock);
/* wait for the rds thread to shut it down */
atomic_set(&conn->c_state, RDS_CONN_ERROR);
cancel_delayed_work(&conn->c_conn_w);
queue_work(rds_wq, &conn->c_down_w);
flush_workqueue(rds_wq);
synchronize_rcu();
rds_conn_shutdown(conn);
/* tear down queued messages */
list_for_each_entry_safe(rm, rtmp,
@ -369,17 +374,16 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
struct list_head *list;
struct rds_connection *conn;
struct rds_message *rm;
unsigned long flags;
unsigned int total = 0;
size_t i;
len /= sizeof(struct rds_info_message);
spin_lock_irqsave(&rds_conn_lock, flags);
rcu_read_lock();
for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
i++, head++) {
hlist_for_each_entry(conn, pos, head, c_hash_node) {
hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
if (want_send)
list = &conn->c_send_queue;
else
@ -399,8 +403,7 @@ static void rds_conn_message_info(struct socket *sock, unsigned int len,
spin_unlock(&conn->c_lock);
}
}
spin_unlock_irqrestore(&rds_conn_lock, flags);
rcu_read_unlock();
lens->nr = total;
lens->each = sizeof(struct rds_info_message);
@ -430,19 +433,17 @@ void rds_for_each_conn_info(struct socket *sock, unsigned int len,
uint64_t buffer[(item_len + 7) / 8];
struct hlist_head *head;
struct hlist_node *pos;
struct hlist_node *tmp;
struct rds_connection *conn;
unsigned long flags;
size_t i;
spin_lock_irqsave(&rds_conn_lock, flags);
rcu_read_lock();
lens->nr = 0;
lens->each = item_len;
for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
i++, head++) {
hlist_for_each_entry_safe(conn, pos, tmp, head, c_hash_node) {
hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
/* XXX no c_lock usage.. */
if (!visitor(conn, buffer))
@ -458,8 +459,7 @@ void rds_for_each_conn_info(struct socket *sock, unsigned int len,
lens->nr++;
}
}
spin_unlock_irqrestore(&rds_conn_lock, flags);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(rds_for_each_conn_info);