Commit d999297c authored by Jon Paul Maloy's avatar Jon Paul Maloy Committed by David S. Miller
Browse files

tipc: reduce locking scope during packet reception 



We convert packet/message reception according to the same principle
we have been using for message sending and timeout handling:

We move the function tipc_rcv() to node.c, hence handling the initial
packet reception at the link aggregation level. The function grabs
the node lock, selects the receiving link, and accesses it via a new
call tipc_link_rcv(). This function appends buffers to the input
queue for delivery upwards, but it may also append outgoing packets
to the xmit queue, just as we do during regular message sending. The
latter will happen when buffers are forwarded from the link backlog,
or when retransmission is requested.

Upon return of this function, and after having released the node lock,
tipc_rcv() delivers/tranmsits the contents of those queues, but it may
also perform actions such as link activation or reset, as indicated by
the return flags from the link.

This reduces the number of cpu cycles spent inside the node spinlock,
and reduces contention on that lock.

Reviewed-by: default avatarYing Xue <ying.xue@windriver.com>
Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1a20cc25

net/tipc/bcast.c

+23 −0
Original line number Diff line number Diff line
@@ -316,6 +316,29 @@ void tipc_bclink_update_link_state(struct tipc_node *n_ptr, 
	}

}



void tipc_bclink_sync_state(struct tipc_node *n, struct tipc_msg *hdr)

{

	u16 last = msg_last_bcast(hdr);

	int mtyp = msg_type(hdr);



	if (unlikely(msg_user(hdr) != LINK_PROTOCOL))

		return;

	if (mtyp == STATE_MSG) {

		tipc_bclink_update_link_state(n, last);

		return;

	}

	/* Compatibility: older nodes don't know BCAST_PROTOCOL synchronization,

	 * and transfer synch info in LINK_PROTOCOL messages.

	 */

	if (tipc_node_is_up(n))

		return;

	if ((mtyp != RESET_MSG) && (mtyp != ACTIVATE_MSG))

		return;

	n->bclink.last_sent = last;

	n->bclink.last_in = last;

	n->bclink.oos_state = 0;

}



/**

 * bclink_peek_nack - monitor retransmission requests sent by other nodes

 *

net/tipc/bcast.h

+1 −0
Original line number Diff line number Diff line
@@ -133,5 +133,6 @@ void tipc_bclink_wakeup_users(struct net *net); 
int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg);

int tipc_nl_bc_link_set(struct net *net, struct nlattr *attrs[]);

void tipc_bclink_input(struct net *net);

void tipc_bclink_sync_state(struct tipc_node *n, struct tipc_msg *msg);



#endif

net/tipc/core.h

+5 −0
Original line number Diff line number Diff line
@@ -129,6 +129,11 @@ static inline int less(u16 left, u16 right) 
	return less_eq(left, right) && (mod(right) != mod(left));

}



static inline int in_range(u16 val, u16 min, u16 max)

{

	return !less(val, min) && !more(val, max);

}



#ifdef CONFIG_SYSCTL

int tipc_register_sysctl(void);

void tipc_unregister_sysctl(void);

net/tipc/link.c

+301 −372

File changed.

Preview size limit exceeded, changes collapsed.

net/tipc/link.h

+4 −2
Original line number Diff line number Diff line
@@ -58,7 +58,7 @@ enum { 
	TIPC_LINK_TUNNEL

};



/* Events occurring at packet reception or at timeout

/* Events returned from link at packet reception or at timeout

 */

enum {

	TIPC_LINK_UP_EVT       = 1,
@@ -223,6 +223,7 @@ void tipc_link_purge_queues(struct tipc_link *l_ptr); 
void tipc_link_purge_backlog(struct tipc_link *l);

void tipc_link_reset_all(struct tipc_node *node);

void tipc_link_reset(struct tipc_link *l_ptr);

void tipc_link_activate(struct tipc_link *link);

int __tipc_link_xmit(struct net *net, struct tipc_link *link,

		     struct sk_buff_head *list);

int tipc_link_xmit(struct tipc_link *link,	struct sk_buff_head *list,
@@ -244,7 +245,8 @@ int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info); 
int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[]);

void link_prepare_wakeup(struct tipc_link *l);

int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq);



int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,

		  struct sk_buff_head *xmitq);

static inline u32 link_own_addr(struct tipc_link *l)

{

	return msg_prevnode(l->pmsg);

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