From: Mukesh Ojha <mojha@codeaurora.org>
To: Colin King <colin.king@canonical.com>,
Eric Dumazet <edumazet@google.com>,
"David S . Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
netdev@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tcp: remove redundant check on tskb
Date: Fri, 5 Apr 2019 12:17:04 +0530 [thread overview]
Message-ID: <b4c8d1bc-0ecf-21cb-fe11-ebe5d7e91712@codeaurora.org> (raw)
In-Reply-To: <20190404144603.27682-1-colin.king@canonical.com>
On 4/4/2019 8:16 PM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> 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@canonical.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Cheers,
-Mukesh
> ---
> 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);
next prev parent reply other threads:[~2019-04-05 6:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-04 14:46 [PATCH] tcp: remove redundant check on tskb Colin King
2019-04-04 15:05 ` Dan Carpenter
2019-04-05 6:47 ` Mukesh Ojha [this message]
2019-04-05 7:46 ` Eric Dumazet
2019-04-07 1:18 ` David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b4c8d1bc-0ecf-21cb-fe11-ebe5d7e91712@codeaurora.org \
--to=mojha@codeaurora.org \
--cc=colin.king@canonical.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=kernel-janitors@vger.kernel.org \
--cc=kuznet@ms2.inr.ac.ru \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=yoshfuji@linux-ipv6.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).