tipc: Allow retransmission of cloned buffers

Forward port commit
fc477e160af086f6e30c3d4fdf5f5c000d29beb5
from git://tipc.cslab.ericsson.net/pub/git/people/allan/tipc.git

Origional commit message:

Allow retransmission of cloned buffers

This patch fixes an issue with TIPC's message retransmission logic
that prevented retransmission of clone sk_buffs.  Originally intended
as a means of avoiding wasted work in retransmitting messages that
were still on the driver's outbound queue, it also prevented TIPC
from retransmitting messages through other means -- such as the
secondary bearer of the broadcast link, or another interface in a
set of bonded interfaces.  This fix removes existing checks for
cloned sk_buffs that prevented such retransmission.

Origionally-Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 5 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 1a7e4665af80..49f2be8622a9 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1553,7 +1553,7 @@ u32 tipc_link_push_packet(struct link *l_ptr)
 
         /* Continue retransmission now, if there is anything: */
 
-        if (r_q_size && buf && !skb_cloned(buf)) {
+        if (r_q_size && buf) {
                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
@@ -1722,15 +1722,16 @@ void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
         dbg("Retransmitting %u in link %x\n", retransmits, l_ptr);
 
         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
-                if (!skb_cloned(buf)) {
+                if (l_ptr->retransm_queue_size == 0) {
                         msg_dbg(msg, ">NO_RETR->BCONG>");
                         dbg_print_link(l_ptr, "   ");
                         l_ptr->retransm_queue_head = msg_seqno(msg);
                         l_ptr->retransm_queue_size = retransmits;
-                        return;
                 } else {
-                        /* Don't retransmit if driver already has the buffer */
+                        err("Unexpected retransmit on link %s (qsize=%d)\n",
+                            l_ptr->name, l_ptr->retransm_queue_size);
                 }
+                return;
         } else {
                 /* Detect repeated retransmit failures on uncongested bearer */
 
@@ -1745,7 +1746,7 @@ void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
                 }
         }
 
-        while (retransmits && (buf != l_ptr->next_out) && buf && !skb_cloned(buf)) {
+        while (retransmits && (buf != l_ptr->next_out) && buf) {
                 msg = buf_msg(buf);
                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);