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Fix double handoff for unloaded small messages #84

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Fix double handoff for unloaded small messages #84

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20 changes: 10 additions & 10 deletions homa_incoming.c
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Original file line number Diff line number Diff line change
Expand Up @@ -668,16 +668,6 @@ void homa_data_pkt(struct sk_buff *skb, struct homa_rpc *rpc)
tt_addr(rpc->peer->addr), ntohl(h->seg.offset),
ntohl(h->message_length));

if (h->ack.client_id) {
const struct in6_addr saddr = skb_canonical_ipv6_saddr(skb);

homa_rpc_unlock(rpc);
homa_rpc_acked(rpc->hsk, &saddr, &h->ack);
homa_rpc_lock(rpc);
if (rpc->state == RPC_DEAD)
goto discard;
}

if (rpc->state != RPC_INCOMING && homa_is_client(rpc->id)) {
if (unlikely(rpc->state != RPC_OUTGOING))
goto discard;
Expand Down Expand Up @@ -728,6 +718,16 @@ void homa_data_pkt(struct sk_buff *skb, struct homa_rpc *rpc)
homa_rpc_handoff(rpc);
}

if (h->ack.client_id) {
const struct in6_addr saddr = skb_canonical_ipv6_saddr(skb);

homa_rpc_unlock(rpc);
homa_rpc_acked(rpc->hsk, &saddr, &h->ack);
homa_rpc_lock(rpc);
if (rpc->state == RPC_DEAD)
return;
}

#ifndef __STRIP__ /* See strip.py */
if (ntohs(h->cutoff_version) != homa->cutoff_version) {
/* The sender has out-of-date cutoffs. Note: we may need
Expand Down
12 changes: 9 additions & 3 deletions test/unit_homa_incoming.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1418,10 +1418,16 @@ TEST_F(homa_incoming, homa_data_pkt__handle_ack_rpc_now_dead)
1400, 0), srpc);
homa_rpc_unlock(srpc);
EXPECT_EQ(RPC_DEAD, srpc->state);
/* With the issue #77 fix the piggy-backed ACK is processed *after*
* homa_add_packet has queued the skb, so by the time we observe
* RPC_DEAD the packet has been added (bytes_remaining: 8600 - 1400)
* and the function returns instead of going through `goto discard`
* (kfree_skb on a queued skb would be use-after-free; the msgin
* destructor reaps it on RPC teardown).
*/
EXPECT_SUBSTR("ack 1235; "
"homa_rpc_end invoked; "
"homa_data_pkt discarded packet", unit_log_get());
EXPECT_EQ(8600, srpc->msgin.bytes_remaining);
"homa_rpc_end invoked", unit_log_get());
EXPECT_EQ(7200, srpc->msgin.bytes_remaining);
}
TEST_F(homa_incoming, homa_data_pkt__wrong_client_rpc_state)
{
Expand Down