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tipc: make resetting of links non-atomic 

In order to facilitate future improvements to the locking structure, we
want to make resetting and establishing of links non-atomic. I.e., the
functions tipc_node_link_up() and tipc_node_link_down() should be called
from outside the node lock context, and grab/release the node lock
themselves. This requires that we can freeze the link state from the
moment it is set to RESETTING or PEER_RESET in one lock context until
it is set to RESET or ESTABLISHING in a later context. The recently
introduced link FSM makes this possible, so we are now ready to introduce
the above change.

This commit implements this.

Tested-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jon Paul Maloy 2015-07-30 18:24:23 -04:00 committed by David S. Miller
parent cf148816ac
commit 598411d70f
3 changed files with 127 additions and 70 deletions
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2
net/tipc/link.c
View File

@ -489,8 +489,8 @@ int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
xmit = true;
mtyp = ACTIVATE_MSG;
break;
case LINK_RESETTING:
case LINK_PEER_RESET:
case LINK_RESETTING:
case LINK_FAILINGOVER:
break;
default:

29
net/tipc/msg.h
View File

@ -916,4 +916,33 @@ static inline bool __tipc_skb_queue_sorted(struct sk_buff_head *list,
return false;
}
/* tipc_skb_queue_splice_tail - append an skb list to lock protected list
* @list: the new list to append. Not lock protected
* @head: target list. Lock protected.
*/
static inline void tipc_skb_queue_splice_tail(struct sk_buff_head *list,
struct sk_buff_head *head)
{
spin_lock_bh(&head->lock);
skb_queue_splice_tail(list, head);
spin_unlock_bh(&head->lock);
}
/* tipc_skb_queue_splice_tail_init - merge two lock protected skb lists
* @list: the new list to add. Lock protected. Will be reinitialized
* @head: target list. Lock protected.
*/
static inline void tipc_skb_queue_splice_tail_init(struct sk_buff_head *list,
struct sk_buff_head *head)
{
struct sk_buff_head tmp;
__skb_queue_head_init(&tmp);
spin_lock_bh(&list->lock);
skb_queue_splice_tail_init(list, &tmp);
spin_unlock_bh(&list->lock);
tipc_skb_queue_splice_tail(&tmp, head);
}
#endif

166
net/tipc/node.c
View File

@ -66,8 +66,12 @@ enum {
NODE_SYNCH_END_EVT = 0xcee
};
static void tipc_node_link_down(struct tipc_node *n, int bearer_id);
static void node_lost_contact(struct tipc_node *n_ptr);
static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
struct sk_buff_head *xmitq,
struct tipc_media_addr **maddr);
static void tipc_node_link_down(struct tipc_node *n, int bearer_id,
bool delete);
static void node_lost_contact(struct tipc_node *n, struct sk_buff_head *inputq);
static void node_established_contact(struct tipc_node *n_ptr);
static void tipc_node_delete(struct tipc_node *node);
static void tipc_node_timeout(unsigned long data);
@ -275,9 +279,8 @@ void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
static void tipc_node_timeout(unsigned long data)
{
struct tipc_node *n = (struct tipc_node *)data;
struct tipc_link_entry *le;
struct sk_buff_head xmitq;
struct tipc_link *l;
struct tipc_media_addr *maddr;
int bearer_id;
int rc = 0;
@ -285,17 +288,16 @@ static void tipc_node_timeout(unsigned long data)
for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
tipc_node_lock(n);
l = n->links[bearer_id].link;
if (l) {
le = &n->links[bearer_id];
if (le->link) {
/* Link tolerance may change asynchronously: */
tipc_node_calculate_timer(n, l);
rc = tipc_link_timeout(l, &xmitq);
if (rc & TIPC_LINK_DOWN_EVT)
tipc_node_link_down(n, bearer_id);
tipc_node_calculate_timer(n, le->link);
rc = tipc_link_timeout(le->link, &xmitq);
}
tipc_node_unlock(n);
maddr = &n->links[bearer_id].maddr;
tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr);
if (rc & TIPC_LINK_DOWN_EVT)
tipc_node_link_down(n, bearer_id, false);
}
if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
tipc_node_get(n);
@ -303,18 +305,21 @@ static void tipc_node_timeout(unsigned long data)
}
/**
* tipc_node_link_up - handle addition of link
*
* __tipc_node_link_up - handle addition of link
* Node lock must be held by caller
* Link becomes active (alone or shared) or standby, depending on its priority.
*/
static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
struct sk_buff_head *xmitq)
static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
struct sk_buff_head *xmitq)
{
int *slot0 = &n->active_links[0];
int *slot1 = &n->active_links[1];
struct tipc_link *ol = node_active_link(n, 0);
struct tipc_link *nl = n->links[bearer_id].link;
if (!nl || !tipc_link_is_up(nl))
return;
if (n->working_links > 1) {
pr_warn("Attempt to establish 3rd link to %x\n", n->addr);
return;
@ -356,28 +361,40 @@ static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
}
/**
* tipc_node_link_down - handle loss of link
* tipc_node_link_up - handle addition of link
*
* Link becomes active (alone or shared) or standby, depending on its priority.
*/
static void tipc_node_link_down(struct tipc_node *n, int bearer_id)
static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
struct sk_buff_head *xmitq)
{
tipc_node_lock(n);
__tipc_node_link_up(n, bearer_id, xmitq);
tipc_node_unlock(n);
}
/**
* __tipc_node_link_down - handle loss of link
*/
static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
struct sk_buff_head *xmitq,
struct tipc_media_addr **maddr)
{
struct tipc_link_entry *le = &n->links[*bearer_id];
int *slot0 = &n->active_links[0];
int *slot1 = &n->active_links[1];
struct tipc_media_addr *maddr = &n->links[bearer_id].maddr;
int i, highest = 0;
struct tipc_link *l, *_l, *tnl;
struct sk_buff_head xmitq;
l = n->links[bearer_id].link;
l = n->links[*bearer_id].link;
if (!l || tipc_link_is_reset(l))
return;
__skb_queue_head_init(&xmitq);
n->working_links--;
n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
n->link_id = l->peer_bearer_id << 16 | bearer_id;
n->link_id = l->peer_bearer_id << 16 | *bearer_id;
tipc_bearer_remove_dest(n->net, l->bearer_id, n->addr);
tipc_bearer_remove_dest(n->net, *bearer_id, n->addr);
pr_debug("Lost link <%s> on network plane %c\n",
l->name, l->net_plane);
@ -404,18 +421,40 @@ static void tipc_node_link_down(struct tipc_node *n, int bearer_id)
if (!tipc_node_is_up(n)) {
tipc_link_reset(l);
node_lost_contact(n);
node_lost_contact(n, &le->inputq);
return;
}
/* There is still a working link => initiate failover */
tnl = node_active_link(n, 0);
tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
n->sync_point = tnl->rcv_nxt + (U16_MAX / 2 - 1);
tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, &xmitq);
tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, xmitq);
tipc_link_reset(l);
tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
tipc_bearer_xmit(n->net, tnl->bearer_id, &xmitq, maddr);
tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
*maddr = &n->links[tnl->bearer_id].maddr;
*bearer_id = tnl->bearer_id;
}
static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
{
struct tipc_link_entry *le = &n->links[bearer_id];
struct tipc_media_addr *maddr;
struct sk_buff_head xmitq;
__skb_queue_head_init(&xmitq);
tipc_node_lock(n);
__tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
if (delete && le->link) {
kfree(le->link);
le->link = NULL;
n->link_cnt--;
}
tipc_node_unlock(n);
tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
tipc_sk_rcv(n->net, &le->inputq);
}
bool tipc_node_is_up(struct tipc_node *n)
@ -437,7 +476,7 @@ void tipc_node_check_dest(struct net *net, u32 onode,
bool sign_match = false;
bool link_up = false;
bool accept_addr = false;
bool reset = true;
*dupl_addr = false;
*respond = false;
@ -460,6 +499,7 @@ void tipc_node_check_dest(struct net *net, u32 onode,
if (sign_match && addr_match && link_up) {
/* All is fine. Do nothing. */
reset = false;
} else if (sign_match && addr_match && !link_up) {
/* Respond. The link will come up in due time */
*respond = true;
@ -531,29 +571,21 @@ void tipc_node_check_dest(struct net *net, u32 onode,
}
memcpy(&l->media_addr, maddr, sizeof(*maddr));
memcpy(curr_maddr, maddr, sizeof(*maddr));
tipc_node_link_down(n, b->identity);
exit:
tipc_node_unlock(n);
if (reset)
tipc_node_link_down(n, b->identity, false);
tipc_node_put(n);
}
void tipc_node_delete_links(struct net *net, int bearer_id)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
struct tipc_link *l;
struct tipc_node *n;
rcu_read_lock();
list_for_each_entry_rcu(n, &tn->node_list, list) {
tipc_node_lock(n);
l = n->links[bearer_id].link;
if (l) {
tipc_node_link_down(n, bearer_id);
n->links[bearer_id].link = NULL;
n->link_cnt--;
}
tipc_node_unlock(n);
kfree(l);
tipc_node_link_down(n, bearer_id, true);
}
rcu_read_unlock();
}
@ -561,19 +593,14 @@ void tipc_node_delete_links(struct net *net, int bearer_id)
static void tipc_node_reset_links(struct tipc_node *n)
{
char addr_string[16];
u32 i;
tipc_node_lock(n);
int i;
pr_warn("Resetting all links to %s\n",
tipc_addr_string_fill(addr_string, n->addr));
for (i = 0; i < MAX_BEARERS; i++) {
if (!n->links[i].link)
continue;
tipc_node_link_down(n, i);
tipc_node_link_down(n, i, false);
}
tipc_node_unlock(n);
}
void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
@ -798,10 +825,12 @@ static void node_established_contact(struct tipc_node *n_ptr)
tipc_bclink_add_node(n_ptr->net, n_ptr->addr);
}
static void node_lost_contact(struct tipc_node *n_ptr)
static void node_lost_contact(struct tipc_node *n_ptr,
struct sk_buff_head *inputq)
{
char addr_string[16];
struct tipc_sock_conn *conn, *safe;
struct tipc_link *l;
struct list_head *conns = &n_ptr->conn_sks;
struct sk_buff *skb;
struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
@ -827,14 +856,11 @@ static void node_lost_contact(struct tipc_node *n_ptr)
/* Abort any ongoing link failover */
for (i = 0; i < MAX_BEARERS; i++) {
struct tipc_link *l_ptr = n_ptr->links[i].link;
if (!l_ptr)
continue;
tipc_link_fsm_evt(l_ptr, LINK_FAILOVER_END_EVT);
kfree_skb(l_ptr->failover_reasm_skb);
l_ptr->failover_reasm_skb = NULL;
tipc_link_reset_fragments(l_ptr);
l = n_ptr->links[i].link;
if (l)
tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);
}
/* Prevent re-contact with node until cleanup is done */
tipc_node_fsm_evt(n_ptr, SELF_LOST_CONTACT_EVT);
@ -848,7 +874,7 @@ static void node_lost_contact(struct tipc_node *n_ptr)
conn->peer_node, conn->port,
conn->peer_port, TIPC_ERR_NO_NODE);
if (likely(skb)) {
skb_queue_tail(n_ptr->inputq, skb);
skb_queue_tail(inputq, skb);
n_ptr->action_flags |= TIPC_MSG_EVT;
}
list_del(&conn->list);
@ -1025,9 +1051,9 @@ int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
l = tipc_node_select_link(n, selector, &bearer_id, &maddr);
if (likely(l))
rc = tipc_link_xmit(l, list, &xmitq);
if (unlikely(rc == -ENOBUFS))
tipc_node_link_down(n, bearer_id);
tipc_node_unlock(n);
if (unlikely(rc == -ENOBUFS))
tipc_node_link_down(n, bearer_id, false);
tipc_node_put(n);
}
if (likely(!rc)) {
@ -1081,8 +1107,8 @@ static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
u16 rcv_nxt, syncpt, dlv_nxt;
int state = n->state;
struct tipc_link *l, *pl = NULL;
struct sk_buff_head;
int i;
struct tipc_media_addr *maddr;
int i, pb_id;
l = n->links[bearer_id].link;
if (!l)
@ -1123,9 +1149,11 @@ static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
/* Initiate or update failover mode if applicable */
if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
syncpt = oseqno + exp_pkts - 1;
if (pl && tipc_link_is_up(pl))
tipc_node_link_down(n, pl->bearer_id);
if (pl && tipc_link_is_up(pl)) {
pb_id = pl->bearer_id;
__tipc_node_link_down(n, &pb_id, xmitq, &maddr);
tipc_skb_queue_splice_tail_init(pl->inputq, l->inputq);
}
/* If pkts arrive out of order, use lowest calculated syncpt */
if (less(syncpt, n->sync_point))
n->sync_point = syncpt;
@ -1146,7 +1174,7 @@ static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
syncpt = iseqno + exp_pkts - 1;
if (!tipc_link_is_up(l)) {
tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
tipc_node_link_up(n, bearer_id, xmitq);
__tipc_node_link_up(n, bearer_id, xmitq);
}
if (n->state == SELF_UP_PEER_UP) {
n->sync_point = syncpt;
@ -1224,7 +1252,7 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
tipc_bclink_sync_state(n, hdr);
/* Release acked broadcast messages */
/* Release acked broadcast packets */
if (unlikely(n->bclink.acked != msg_bcast_ack(hdr)))
tipc_bclink_acknowledge(n, msg_bcast_ack(hdr));
@ -1233,14 +1261,14 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
rc = tipc_link_rcv(le->link, skb, &xmitq);
skb = NULL;
}
unlock:
tipc_node_unlock(n);
if (unlikely(rc & TIPC_LINK_UP_EVT))
tipc_node_link_up(n, bearer_id, &xmitq);
if (unlikely(rc & TIPC_LINK_DOWN_EVT))
tipc_node_link_down(n, bearer_id);
unlock:
tipc_node_unlock(n);
tipc_node_link_down(n, bearer_id, false);
if (!skb_queue_empty(&le->inputq))
tipc_sk_rcv(net, &le->inputq);