net: af_unix: implement splice for stream af_unix sockets
unix_stream_recvmsg is refactored to unix_stream_read_generic in this patch and enhanced to deal with pipe splicing. The refactoring is inneglible, we mostly have to deal with a non-existing struct msghdr argument. Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Hannes Frederic Sowa
David S. Miller
Родитель
a60e3cc7c9
Коммит
2b514574f7
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@ -261,6 +261,7 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
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return ret;
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}
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EXPORT_SYMBOL_GPL(splice_to_pipe);
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void spd_release_page(struct splice_pipe_desc *spd, unsigned int i)
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{
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@ -1942,6 +1942,7 @@ done:
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return ret;
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}
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EXPORT_SYMBOL_GPL(skb_splice_bits);
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/**
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* skb_store_bits - store bits from kernel buffer to skb
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@ -520,6 +520,9 @@ static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
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static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
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static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
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size_t size, int flags);
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static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
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struct pipe_inode_info *, size_t size,
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unsigned int flags);
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static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
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static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
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static int unix_dgram_connect(struct socket *, struct sockaddr *,
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@ -561,6 +564,7 @@ static const struct proto_ops unix_stream_ops = {
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.recvmsg = unix_stream_recvmsg,
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.mmap = sock_no_mmap,
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.sendpage = unix_stream_sendpage,
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.splice_read = unix_stream_splice_read,
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.set_peek_off = unix_set_peek_off,
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};
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@ -1957,8 +1961,9 @@ out:
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* Sleep until more data has arrived. But check for races..
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*/
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static long unix_stream_data_wait(struct sock *sk, long timeo,
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struct sk_buff *last)
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struct sk_buff *last, unsigned int last_len)
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{
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struct sk_buff *tail;
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DEFINE_WAIT(wait);
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unix_state_lock(sk);
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@ -1966,7 +1971,9 @@ static long unix_stream_data_wait(struct sock *sk, long timeo,
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for (;;) {
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prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
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if (skb_peek_tail(&sk->sk_receive_queue) != last ||
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tail = skb_peek_tail(&sk->sk_receive_queue);
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if (tail != last ||
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(tail && tail->len != last_len) ||
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sk->sk_err ||
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(sk->sk_shutdown & RCV_SHUTDOWN) ||
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signal_pending(current) ||
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@ -1990,38 +1997,50 @@ static unsigned int unix_skb_len(const struct sk_buff *skb)
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return skb->len - UNIXCB(skb).consumed;
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}
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static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
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size_t size, int flags)
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struct unix_stream_read_state {
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int (*recv_actor)(struct sk_buff *, int, int,
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struct unix_stream_read_state *);
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struct socket *socket;
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struct msghdr *msg;
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struct pipe_inode_info *pipe;
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size_t size;
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int flags;
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unsigned int splice_flags;
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};
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static int unix_stream_read_generic(struct unix_stream_read_state *state)
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{
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struct scm_cookie scm;
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struct socket *sock = state->socket;
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struct sock *sk = sock->sk;
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struct unix_sock *u = unix_sk(sk);
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DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
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int copied = 0;
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int flags = state->flags;
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int noblock = flags & MSG_DONTWAIT;
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int check_creds = 0;
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bool check_creds = false;
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int target;
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int err = 0;
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long timeo;
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int skip;
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size_t size = state->size;
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unsigned int last_len;
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err = -EINVAL;
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if (sk->sk_state != TCP_ESTABLISHED)
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goto out;
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err = -EOPNOTSUPP;
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if (flags&MSG_OOB)
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if (flags & MSG_OOB)
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goto out;
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target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
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target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
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timeo = sock_rcvtimeo(sk, noblock);
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memset(&scm, 0, sizeof(scm));
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/* Lock the socket to prevent queue disordering
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* while sleeps in memcpy_tomsg
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*/
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memset(&scm, 0, sizeof(scm));
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err = mutex_lock_interruptible(&u->readlock);
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if (unlikely(err)) {
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/* recvmsg() in non blocking mode is supposed to return -EAGAIN
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@ -2037,6 +2056,7 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
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unix_state_lock(sk);
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last = skb = skb_peek(&sk->sk_receive_queue);
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last_len = last ? last->len : 0;
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again:
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if (skb == NULL) {
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unix_sk(sk)->recursion_level = 0;
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@ -2059,16 +2079,17 @@ again:
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break;
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mutex_unlock(&u->readlock);
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timeo = unix_stream_data_wait(sk, timeo, last);
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timeo = unix_stream_data_wait(sk, timeo, last,
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last_len);
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if (signal_pending(current)
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|| mutex_lock_interruptible(&u->readlock)) {
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if (signal_pending(current) ||
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mutex_lock_interruptible(&u->readlock)) {
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err = sock_intr_errno(timeo);
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goto out;
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}
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continue;
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unlock:
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unlock:
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unix_state_unlock(sk);
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break;
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}
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@ -2077,6 +2098,7 @@ again:
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while (skip >= unix_skb_len(skb)) {
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skip -= unix_skb_len(skb);
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last = skb;
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last_len = skb->len;
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skb = skb_peek_next(skb, &sk->sk_receive_queue);
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if (!skb)
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goto again;
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@ -2093,18 +2115,20 @@ again:
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} else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
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/* Copy credentials */
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scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
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check_creds = 1;
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check_creds = true;
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}
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/* Copy address just once */
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if (sunaddr) {
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unix_copy_addr(msg, skb->sk);
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if (state->msg && state->msg->msg_name) {
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DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
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state->msg->msg_name);
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unix_copy_addr(state->msg, skb->sk);
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sunaddr = NULL;
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}
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chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
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if (skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
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msg, chunk)) {
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chunk = state->recv_actor(skb, skip, chunk, state);
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if (chunk < 0) {
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if (copied == 0)
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copied = -EFAULT;
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break;
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@ -2142,11 +2166,85 @@ again:
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} while (size);
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mutex_unlock(&u->readlock);
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scm_recv(sock, msg, &scm, flags);
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if (state->msg)
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scm_recv(sock, state->msg, &scm, flags);
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else
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scm_destroy(&scm);
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out:
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return copied ? : err;
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}
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static int unix_stream_read_actor(struct sk_buff *skb,
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int skip, int chunk,
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struct unix_stream_read_state *state)
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{
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int ret;
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ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
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state->msg, chunk);
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return ret ?: chunk;
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}
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static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
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size_t size, int flags)
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{
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struct unix_stream_read_state state = {
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.recv_actor = unix_stream_read_actor,
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.socket = sock,
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.msg = msg,
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.size = size,
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.flags = flags
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};
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return unix_stream_read_generic(&state);
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}
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static ssize_t skb_unix_socket_splice(struct sock *sk,
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struct pipe_inode_info *pipe,
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struct splice_pipe_desc *spd)
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{
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int ret;
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struct unix_sock *u = unix_sk(sk);
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mutex_unlock(&u->readlock);
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ret = splice_to_pipe(pipe, spd);
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mutex_lock(&u->readlock);
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return ret;
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}
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static int unix_stream_splice_actor(struct sk_buff *skb,
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int skip, int chunk,
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struct unix_stream_read_state *state)
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{
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return skb_splice_bits(skb, state->socket->sk,
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UNIXCB(skb).consumed + skip,
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state->pipe, chunk, state->splice_flags,
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skb_unix_socket_splice);
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}
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static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
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struct pipe_inode_info *pipe,
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size_t size, unsigned int flags)
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{
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struct unix_stream_read_state state = {
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.recv_actor = unix_stream_splice_actor,
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.socket = sock,
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.pipe = pipe,
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.size = size,
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.splice_flags = flags,
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};
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if (unlikely(*ppos))
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return -ESPIPE;
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if (sock->file->f_flags & O_NONBLOCK ||
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flags & SPLICE_F_NONBLOCK)
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state.flags = MSG_DONTWAIT;
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return unix_stream_read_generic(&state);
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}
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static int unix_shutdown(struct socket *sock, int mode)
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{
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struct sock *sk = sock->sk;
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