[PATCH] tcp: remove redundant check on tskb

From: Colin King
Date: Thu Apr 04 2019 - 10:46:13 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The non-null check on tskb is always false because it is in an else
path of a check on tskb and hence tskb is null in this code block.
This is check is therefore redundant and can be removed as well
as the label coalesc.

if (tsbk) {
...
} else {
...
if (unlikely(!skb)) {
if (tskb) /* can never be true, redundant code */
goto coalesc;
return;
}
}

Addresses-Coverity: ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
net/ipv4/tcp_output.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e265d1aeeb66..32061928b054 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3088,7 +3088,6 @@ void tcp_send_fin(struct sock *sk)
tskb = skb_rb_last(&sk->tcp_rtx_queue);

if (tskb) {
-coalesce:
TCP_SKB_CB(tskb)->tcp_flags |= TCPHDR_FIN;
TCP_SKB_CB(tskb)->end_seq++;
tp->write_seq++;
@@ -3104,11 +3103,9 @@ void tcp_send_fin(struct sock *sk)
}
} else {
skb = alloc_skb_fclone(MAX_TCP_HEADER, sk->sk_allocation);
- if (unlikely(!skb)) {
- if (tskb)
- goto coalesce;
+ if (unlikely(!skb))
return;
- }
+
INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
skb_reserve(skb, MAX_TCP_HEADER);
sk_forced_mem_schedule(sk, skb->truesize);
--
2.20.1