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Code Issues Releases Wiki Activity

net/tcp: optimise io_uring zc ubuf refcounting 

io_uring keeps a reference to ubuf_info during submission, so if
tcp_sendmsg_locked() sees msghdr::msg_ubuf in can be sure the buffer
will be kept alive and doesn't need to additionally pin it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Pavel Begunkov 2023-05-15 17:06:37 +01:00 committed by David S. Miller
parent eea96a3e2c
commit a753358472
1 changed files with 6 additions and 3 deletions
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9
net/ipv4/tcp.c
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@ -1231,7 +1231,6 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
if ((flags & MSG_ZEROCOPY) && size) {
if (msg->msg_ubuf) {
uarg = msg->msg_ubuf;
net_zcopy_get(uarg);
zc = sk->sk_route_caps & NETIF_F_SG;
} else if (sock_flag(sk, SOCK_ZEROCOPY)) {
skb = tcp_write_queue_tail(sk);
@ -1458,7 +1457,9 @@ out:
tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
}
out_nopush:
net_zcopy_put(uarg);
/* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
if (uarg && !msg->msg_ubuf)
net_zcopy_put(uarg);
return copied + copied_syn;
do_error:
@ -1467,7 +1468,9 @@ do_error:
if (copied + copied_syn)
goto out;
out_err:
net_zcopy_put_abort(uarg, true);
/* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
if (uarg && !msg->msg_ubuf)
net_zcopy_put_abort(uarg, true);
err = sk_stream_error(sk, flags, err);
/* make sure we wake any epoll edge trigger waiter */
if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) {