diff mbox series

[net,v2,3/4] tcp: refactor tcp_read_skb() a bit

Message ID 20220808033106.130263-4-xiyou.wangcong@gmail.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series tcp: some bug fixes for tcp_read_skb() | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 2 this patch: 2
netdev/cc_maintainers warning 5 maintainers not CCed: yoshfuji@linux-ipv6.org davem@davemloft.net dsahern@kernel.org kuba@kernel.org pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 2 this patch: 2
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 35 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Cong Wang Aug. 8, 2022, 3:31 a.m. UTC 
From: Cong Wang <cong.wang@bytedance.com>

As tcp_read_skb() only reads one skb at a time, the while loop is
unnecessary, we can turn it into an if. This also simplifies the
code logic.

Cc: Eric Dumazet <edumazet@google.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 net/ipv4/tcp.c | 25 ++++++++-----------------
 1 file changed, 8 insertions(+), 17 deletions(-)

Comments

Jakub Kicinski Aug. 12, 2022, 11:55 p.m. UTC | #1 
On Sun,  7 Aug 2022 20:31:05 -0700 Cong Wang wrote:
> From: Cong Wang <cong.wang@bytedance.com>
> 
> As tcp_read_skb() only reads one skb at a time, the while loop is
> unnecessary, we can turn it into an if. This also simplifies the
> code logic.

I think Eric is AFK so we should just apply these, they LGTM.
One minor nit below.

> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -1761,27 +1761,18 @@ int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
>  	if (sk->sk_state == TCP_LISTEN)
>  		return -ENOTCONN;
>  
> -	while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
> -		int used;
> -
> +	skb = tcp_recv_skb(sk, seq, &offset);
> +	if (skb) {

if (!skb)
	return 0;

?
diff mbox series

Patch

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 181a0d350123..5212a7512269 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1761,27 +1761,18 @@  int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
 	if (sk->sk_state == TCP_LISTEN)
 		return -ENOTCONN;
 
-	while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
-		int used;
-
+	skb = tcp_recv_skb(sk, seq, &offset);
+	if (skb) {
 		__skb_unlink(skb, &sk->sk_receive_queue);
 		WARN_ON(!skb_set_owner_sk_safe(skb, sk));
-		used = recv_actor(sk, skb);
-		if (used <= 0) {
-			if (!copied)
-				copied = used;
-			break;
-		}
-		seq += used;
-		copied += used;
-
-		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
-			++seq;
-			break;
+		copied = recv_actor(sk, skb);
+		if (copied > 0) {
+			seq += copied;
+			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
+				++seq;
 		}
-		break;
+		consume_skb(skb);
 	}
-	consume_skb(skb);
 	WRITE_ONCE(tp->copied_seq, seq);
 
 	tcp_rcv_space_adjust(sk);