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tcp_output: move useg assignment to right before segment while loop

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There were a couple cases in-between that could cause an exit from
tcp_output which don't use useg. With large send buffers, pcb->unacked
may be large and calculating useg is wasted in these exit cases

Some compilers may be re-ordering this already, but it doesn't hurt to
correctly arrange the code
This commit is contained in:
Joel Cunningham 2017-08-29 16:54:53 -05:00
parent 1d4ca0bff6
commit 28e519b72d
1 changed files with 6 additions and 6 deletions
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12
src/core/tcp_out.c
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@ -1151,12 +1151,6 @@ tcp_output(struct tcp_pcb *pcb)
lwip_ntohl(seg->tcphdr->seqno), pcb->lastack));
}
/* useg should point to last segment on unacked queue */
useg = pcb->unacked;
if (useg != NULL) {
for (; useg->next != NULL; useg = useg->next);
}
netif = tcp_route(pcb, &pcb->local_ip, &pcb->remote_ip);
if (netif == NULL) {
return ERR_RTE;
@ -1192,6 +1186,12 @@ tcp_output(struct tcp_pcb *pcb)
}
/* Stop persist timer, above conditions are not active */
pcb->persist_backoff = 0;
/* useg should point to last segment on unacked queue */
useg = pcb->unacked;
if (useg != NULL) {
for (; useg->next != NULL; useg = useg->next);
}
/* data available and window allows it to be sent? */
while (seg != NULL &&
lwip_ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {