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net: af_unix: implement splice for stream af_unix sockets

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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 2015-05-21 17:00:01 +02:00 committed by David S. Miller
parent a60e3cc7c9
commit 2b514574f7
3 changed files with 121 additions and 21 deletions
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1
fs/splice.c
View File

@ -261,6 +261,7 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
return ret;
}
EXPORT_SYMBOL_GPL(splice_to_pipe);
void spd_release_page(struct splice_pipe_desc *spd, unsigned int i)
{

1
net/core/skbuff.c
View File

@ -1942,6 +1942,7 @@ int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
return ret;
}
EXPORT_SYMBOL_GPL(skb_splice_bits);
/**
* skb_store_bits - store bits from kernel buffer to skb

134
net/unix/af_unix.c
View File

@ -520,6 +520,9 @@ static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
size_t size, int flags);
static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
struct pipe_inode_info *, size_t size,
unsigned int flags);
static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
static int unix_dgram_connect(struct socket *, struct sockaddr *,
@ -561,6 +564,7 @@ static const struct proto_ops unix_stream_ops = {
.recvmsg = unix_stream_recvmsg,
.mmap = sock_no_mmap,
.sendpage = unix_stream_sendpage,
.splice_read = unix_stream_splice_read,
.set_peek_off = unix_set_peek_off,
};
@ -1957,8 +1961,9 @@ static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
* Sleep until more data has arrived. But check for races..
*/
static long unix_stream_data_wait(struct sock *sk, long timeo,
struct sk_buff *last)
struct sk_buff *last, unsigned int last_len)
{
struct sk_buff *tail;
DEFINE_WAIT(wait);
unix_state_lock(sk);
@ -1966,7 +1971,9 @@ static long unix_stream_data_wait(struct sock *sk, long timeo,
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
if (skb_peek_tail(&sk->sk_receive_queue) != last ||
tail = skb_peek_tail(&sk->sk_receive_queue);
if (tail != last ||
(tail && tail->len != last_len) ||
sk->sk_err ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
signal_pending(current) ||
@ -1990,20 +1997,33 @@ static unsigned int unix_skb_len(const struct sk_buff *skb)
return skb->len - UNIXCB(skb).consumed;
}
static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
size_t size, int flags)
struct unix_stream_read_state {
int (*recv_actor)(struct sk_buff *, int, int,
struct unix_stream_read_state *);
struct socket *socket;
struct msghdr *msg;
struct pipe_inode_info *pipe;
size_t size;
int flags;
unsigned int splice_flags;
};
static int unix_stream_read_generic(struct unix_stream_read_state *state)
{
struct scm_cookie scm;
struct socket *sock = state->socket;
struct sock *sk = sock->sk;
struct unix_sock *u = unix_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
int copied = 0;
int flags = state->flags;
int noblock = flags & MSG_DONTWAIT;
int check_creds = 0;
bool check_creds = false;
int target;
int err = 0;
long timeo;
int skip;
size_t size = state->size;
unsigned int last_len;
err = -EINVAL;
if (sk->sk_state != TCP_ESTABLISHED)
@ -2016,12 +2036,11 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
timeo = sock_rcvtimeo(sk, noblock);
memset(&scm, 0, sizeof(scm));
/* Lock the socket to prevent queue disordering
* while sleeps in memcpy_tomsg
*/
memset(&scm, 0, sizeof(scm));
err = mutex_lock_interruptible(&u->readlock);
if (unlikely(err)) {
/* recvmsg() in non blocking mode is supposed to return -EAGAIN
@ -2037,6 +2056,7 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
unix_state_lock(sk);
last = skb = skb_peek(&sk->sk_receive_queue);
last_len = last ? last->len : 0;
again:
if (skb == NULL) {
unix_sk(sk)->recursion_level = 0;
@ -2059,10 +2079,11 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
break;
mutex_unlock(&u->readlock);
timeo = unix_stream_data_wait(sk, timeo, last);
timeo = unix_stream_data_wait(sk, timeo, last,
last_len);
if (signal_pending(current)
|| mutex_lock_interruptible(&u->readlock)) {
if (signal_pending(current) ||
mutex_lock_interruptible(&u->readlock)) {
err = sock_intr_errno(timeo);
goto out;
}
@ -2077,6 +2098,7 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
while (skip >= unix_skb_len(skb)) {
skip -= unix_skb_len(skb);
last = skb;
last_len = skb->len;
skb = skb_peek_next(skb, &sk->sk_receive_queue);
if (!skb)
goto again;
@ -2093,18 +2115,20 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
} else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
/* Copy credentials */
scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
check_creds = 1;
check_creds = true;
}
/* Copy address just once */
if (sunaddr) {
unix_copy_addr(msg, skb->sk);
if (state->msg && state->msg->msg_name) {
DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
state->msg->msg_name);
unix_copy_addr(state->msg, skb->sk);
sunaddr = NULL;
}
chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
if (skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
msg, chunk)) {
chunk = state->recv_actor(skb, skip, chunk, state);
if (chunk < 0) {
if (copied == 0)
copied = -EFAULT;
break;
@ -2142,11 +2166,85 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
} while (size);
mutex_unlock(&u->readlock);
scm_recv(sock, msg, &scm, flags);
if (state->msg)
scm_recv(sock, state->msg, &scm, flags);
else
scm_destroy(&scm);
out:
return copied ? : err;
}
static int unix_stream_read_actor(struct sk_buff *skb,
int skip, int chunk,
struct unix_stream_read_state *state)
{
int ret;
ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
state->msg, chunk);
return ret ?: chunk;
}
static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
size_t size, int flags)
{
struct unix_stream_read_state state = {
.recv_actor = unix_stream_read_actor,
.socket = sock,
.msg = msg,
.size = size,
.flags = flags
};
return unix_stream_read_generic(&state);
}
static ssize_t skb_unix_socket_splice(struct sock *sk,
struct pipe_inode_info *pipe,
struct splice_pipe_desc *spd)
{
int ret;
struct unix_sock *u = unix_sk(sk);
mutex_unlock(&u->readlock);
ret = splice_to_pipe(pipe, spd);
mutex_lock(&u->readlock);
return ret;
}
static int unix_stream_splice_actor(struct sk_buff *skb,
int skip, int chunk,
struct unix_stream_read_state *state)
{
return skb_splice_bits(skb, state->socket->sk,
UNIXCB(skb).consumed + skip,
state->pipe, chunk, state->splice_flags,
skb_unix_socket_splice);
}
static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe,
size_t size, unsigned int flags)
{
struct unix_stream_read_state state = {
.recv_actor = unix_stream_splice_actor,
.socket = sock,
.pipe = pipe,
.size = size,
.splice_flags = flags,
};
if (unlikely(*ppos))
return -ESPIPE;
if (sock->file->f_flags & O_NONBLOCK ||
flags & SPLICE_F_NONBLOCK)
state.flags = MSG_DONTWAIT;
return unix_stream_read_generic(&state);
}
static int unix_shutdown(struct socket *sock, int mode)
{
struct sock *sk = sock->sk;