}
/**
- * link_schedule_user - schedule user for wakeup after congestion
+ * link_schedule_user - schedule a message sender for wakeup after congestion
* @link: congested link
- * @oport: sending port
- * @chain_sz: size of buffer chain that was attempted sent
- * @imp: importance of message attempted sent
+ * @list: message that was attempted sent
* Create pseudo msg to send back to user when congestion abates
+ * Only consumes message if there is an error
*/
-static bool link_schedule_user(struct tipc_link *link, u32 oport,
- uint chain_sz, uint imp)
+static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
{
- struct sk_buff *buf;
+ struct tipc_msg *msg = buf_msg(skb_peek(list));
+ int imp = msg_importance(msg);
+ u32 oport = msg_origport(msg);
+ u32 addr = link_own_addr(link);
+ struct sk_buff *skb;
- buf = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
- link_own_addr(link), link_own_addr(link),
- oport, 0, 0);
- if (!buf)
- return false;
- TIPC_SKB_CB(buf)->chain_sz = chain_sz;
- TIPC_SKB_CB(buf)->chain_imp = imp;
- skb_queue_tail(&link->wakeupq, buf);
+ /* This really cannot happen... */
+ if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
+ pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
+ tipc_link_reset(link);
+ goto err;
+ }
+ /* Non-blocking sender: */
+ if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
+ return -ELINKCONG;
+
+ /* Create and schedule wakeup pseudo message */
+ skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
+ addr, addr, oport, 0, 0);
+ if (!skb)
+ goto err;
+ TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
+ TIPC_SKB_CB(skb)->chain_imp = imp;
+ skb_queue_tail(&link->wakeupq, skb);
link->stats.link_congs++;
- return true;
+ return -ELINKCONG;
+err:
+ __skb_queue_purge(list);
+ return -ENOBUFS;
}
/**
}
}
-/* tipc_link_cong: determine return value and how to treat the
- * sent buffer during link congestion.
- * - For plain, errorless user data messages we keep the buffer and
- * return -ELINKONG.
- * - For all other messages we discard the buffer and return -EHOSTUNREACH
- * - For TIPC internal messages we also reset the link
- */
-static int tipc_link_cong(struct tipc_link *link, struct sk_buff_head *list)
-{
- struct sk_buff *skb = skb_peek(list);
- struct tipc_msg *msg = buf_msg(skb);
- int imp = msg_importance(msg);
- u32 oport = msg_tot_origport(msg);
-
- if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
- pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
- tipc_link_reset(link);
- goto drop;
- }
- if (unlikely(msg_errcode(msg)))
- goto drop;
- if (unlikely(msg_reroute_cnt(msg)))
- goto drop;
- if (TIPC_SKB_CB(skb)->wakeup_pending)
- return -ELINKCONG;
- if (link_schedule_user(link, oport, skb_queue_len(list), imp))
- return -ELINKCONG;
-drop:
- __skb_queue_purge(list);
- return -EHOSTUNREACH;
-}
-
/**
* __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
* @link: link to use
* @list: chain of buffers containing message
*
- * Consumes the buffer chain, except when returning -ELINKCONG
- * Returns 0 if success, otherwise errno: -ELINKCONG, -EMSGSIZE (plain socket
- * user data messages) or -EHOSTUNREACH (all other messages/senders)
- * Only the socket functions tipc_send_stream() and tipc_send_packet() need
- * to act on the return value, since they may need to do more send attempts.
+ * Consumes the buffer chain, except when returning -ELINKCONG,
+ * since the caller then may want to make more send attempts.
+ * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
+ * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
*/
int __tipc_link_xmit(struct net *net, struct tipc_link *link,
struct sk_buff_head *list)
/* Match backlog limit against msg importance: */
if (unlikely(link->backlog[imp].len >= link->backlog[imp].limit))
- return tipc_link_cong(link, list);
+ return link_schedule_user(link, list);
if (unlikely(msg_size(msg) > mtu)) {
__skb_queue_purge(list);
return __tipc_link_xmit(link->owner->net, link, &head);
}
+/* tipc_link_xmit_skb(): send single buffer to destination
+ * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
+ * messages, which will not be rejected
+ * The only exception is datagram messages rerouted after secondary
+ * lookup, which are rare and safe to dispose of anyway.
+ * TODO: Return real return value, and let callers use
+ * tipc_wait_for_sendpkt() where applicable
+ */
int tipc_link_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
u32 selector)
{
struct sk_buff_head head;
+ int rc;
skb2list(skb, &head);
- return tipc_link_xmit(net, &head, dnode, selector);
+ rc = tipc_link_xmit(net, &head, dnode, selector);
+ if (rc == -ELINKCONG)
+ kfree_skb(skb);
+ return 0;
}
/**
m->hdr[0] = htonl((msg_word(m, 0) & ~0x1ffff) | sz);
}
+static inline unchar *msg_data(struct tipc_msg *m)
+{
+ return ((unchar *)m) + msg_hdr_sz(m);
+}
+
+static inline struct tipc_msg *msg_get_wrapped(struct tipc_msg *m)
+{
+ return (struct tipc_msg *)msg_data(m);
+}
/*
* Word 1
static inline u32 msg_origport(struct tipc_msg *m)
{
+ if (msg_user(m) == MSG_FRAGMENTER)
+ m = msg_get_wrapped(m);
return msg_word(m, 4);
}
msg_set_word(m, 10, n);
}
-static inline unchar *msg_data(struct tipc_msg *m)
-{
- return ((unchar *)m) + msg_hdr_sz(m);
-}
-
-static inline struct tipc_msg *msg_get_wrapped(struct tipc_msg *m)
-{
- return (struct tipc_msg *)msg_data(m);
-}
-
/*
* Constants and routines used to read and write TIPC internal message headers
*/
msg_set_bits(m, 9, 0, 0xffff, n);
}
-static inline u32 msg_tot_origport(struct tipc_msg *m)
-{
- if ((msg_user(m) == MSG_FRAGMENTER) && (msg_type(m) == FIRST_FRAGMENT))
- return msg_origport(msg_get_wrapped(m));
- return msg_origport(m);
-}
-
struct sk_buff *tipc_buf_acquire(u32 size);
bool tipc_msg_validate(struct sk_buff *skb);
bool tipc_msg_reverse(u32 own_addr, struct sk_buff *buf, u32 *dnode,
projects / linux-platform-drivers-x86.git / commitdiff