From 57d44a354a43edba4ef9963327d4657d12edbfbc Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 22 May 2023 13:11:25 +0100 Subject: unix: Convert unix_stream_sendpage() to use MSG_SPLICE_PAGES Convert unix_stream_sendpage() to use sendmsg() with MSG_SPLICE_PAGES rather than directly splicing in the pages itself. This allows ->sendpage() to be replaced by something that can handle multiple multipage folios in a single transaction. Signed-off-by: David Howells cc: Kuniyuki Iwashima cc: Jens Axboe cc: Matthew Wilcox Signed-off-by: Jakub Kicinski --- net/unix/af_unix.c | 134 +++-------------------------------------------------- 1 file changed, 7 insertions(+), 127 deletions(-) (limited to 'net/unix') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 976bc1c5e11b..115436ce1f8a 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1839,24 +1839,6 @@ static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, } } -static int maybe_init_creds(struct scm_cookie *scm, - struct socket *socket, - const struct sock *other) -{ - int err; - struct msghdr msg = { .msg_controllen = 0 }; - - err = scm_send(socket, &msg, scm, false); - if (err) - return err; - - if (unix_passcred_enabled(socket, other)) { - scm->pid = get_pid(task_tgid(current)); - current_uid_gid(&scm->creds.uid, &scm->creds.gid); - } - return err; -} - static bool unix_skb_scm_eq(struct sk_buff *skb, struct scm_cookie *scm) { @@ -2292,117 +2274,15 @@ out_err: static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page, int offset, size_t size, int flags) { - int err; - bool send_sigpipe = false; - bool init_scm = true; - struct scm_cookie scm; - struct sock *other, *sk = socket->sk; - struct sk_buff *skb, *newskb = NULL, *tail = NULL; - - if (flags & MSG_OOB) - return -EOPNOTSUPP; + struct bio_vec bvec; + struct msghdr msg = { .msg_flags = flags | MSG_SPLICE_PAGES }; - other = unix_peer(sk); - if (!other || sk->sk_state != TCP_ESTABLISHED) - return -ENOTCONN; - - if (false) { -alloc_skb: - unix_state_unlock(other); - mutex_unlock(&unix_sk(other)->iolock); - newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT, - &err, 0); - if (!newskb) - goto err; - } - - /* we must acquire iolock as we modify already present - * skbs in the sk_receive_queue and mess with skb->len - */ - err = mutex_lock_interruptible(&unix_sk(other)->iolock); - if (err) { - err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS; - goto err; - } - - if (sk->sk_shutdown & SEND_SHUTDOWN) { - err = -EPIPE; - send_sigpipe = true; - goto err_unlock; - } - - unix_state_lock(other); + if (flags & MSG_SENDPAGE_NOTLAST) + msg.msg_flags |= MSG_MORE; - if (sock_flag(other, SOCK_DEAD) || - other->sk_shutdown & RCV_SHUTDOWN) { - err = -EPIPE; - send_sigpipe = true; - goto err_state_unlock; - } - - if (init_scm) { - err = maybe_init_creds(&scm, socket, other); - if (err) - goto err_state_unlock; - init_scm = false; - } - - skb = skb_peek_tail(&other->sk_receive_queue); - if (tail && tail == skb) { - skb = newskb; - } else if (!skb || !unix_skb_scm_eq(skb, &scm)) { - if (newskb) { - skb = newskb; - } else { - tail = skb; - goto alloc_skb; - } - } else if (newskb) { - /* this is fast path, we don't necessarily need to - * call to kfree_skb even though with newskb == NULL - * this - does no harm - */ - consume_skb(newskb); - newskb = NULL; - } - - if (skb_append_pagefrags(skb, page, offset, size, MAX_SKB_FRAGS)) { - tail = skb; - goto alloc_skb; - } - - skb->len += size; - skb->data_len += size; - skb->truesize += size; - refcount_add(size, &sk->sk_wmem_alloc); - - if (newskb) { - err = unix_scm_to_skb(&scm, skb, false); - if (err) - goto err_state_unlock; - spin_lock(&other->sk_receive_queue.lock); - __skb_queue_tail(&other->sk_receive_queue, newskb); - spin_unlock(&other->sk_receive_queue.lock); - } - - unix_state_unlock(other); - mutex_unlock(&unix_sk(other)->iolock); - - other->sk_data_ready(other); - scm_destroy(&scm); - return size; - -err_state_unlock: - unix_state_unlock(other); -err_unlock: - mutex_unlock(&unix_sk(other)->iolock); -err: - kfree_skb(newskb); - if (send_sigpipe && !(flags & MSG_NOSIGNAL)) - send_sig(SIGPIPE, current, 0); - if (!init_scm) - scm_destroy(&scm); - return err; + bvec_set_page(&bvec, page, size, offset); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size); + return unix_stream_sendmsg(socket, &msg, size); } static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg, -- cgit