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Merge branch 'af_unix_sendpage'

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Hannes Frederic Sowa says:

====================
net: af_unix: zerocopy stream bits

This series implements zerocopy support for AF_UNIX SOCK_STREAM sockets.

Changelog in the specific patches. Thanks to all the reviewers!
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2015-05-25 00:06:59 -04:00
commit b10e3d6c2e
6 changed files with 284 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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)
{

14
include/linux/skbuff.h
View File

@ -35,6 +35,7 @@
#include <linux/netdev_features.h>
#include <linux/sched.h>
#include <net/flow_dissector.h>
#include <linux/splice.h>
/* A. Checksumming of received packets by device.
*
@ -861,6 +862,9 @@ int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
int len, int odd, struct sk_buff *skb),
void *from, int length);
int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
int offset, size_t size);
struct skb_seq_state {
__u32 lower_offset;
__u32 upper_offset;
@ -2696,9 +2700,15 @@ int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
int len, __wsum csum);
int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
ssize_t skb_socket_splice(struct sock *sk,
struct pipe_inode_info *pipe,
struct splice_pipe_desc *spd);
int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
struct pipe_inode_info *pipe, unsigned int len,
unsigned int flags);
unsigned int flags,
ssize_t (*splice_cb)(struct sock *,
struct pipe_inode_info *,
struct splice_pipe_desc *));
void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,

64
net/core/skbuff.c
View File

@ -1870,15 +1870,39 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
return false;
}
ssize_t skb_socket_splice(struct sock *sk,
struct pipe_inode_info *pipe,
struct splice_pipe_desc *spd)
{
int ret;
/* Drop the socket lock, otherwise we have reverse
* locking dependencies between sk_lock and i_mutex
* here as compared to sendfile(). We enter here
* with the socket lock held, and splice_to_pipe() will
* grab the pipe inode lock. For sendfile() emulation,
* we call into ->sendpage() with the i_mutex lock held
* and networking will grab the socket lock.
*/
release_sock(sk);
ret = splice_to_pipe(pipe, spd);
lock_sock(sk);
return ret;
}
/*
* Map data from the skb to a pipe. Should handle both the linear part,
* the fragments, and the frag list. It does NOT handle frag lists within
* the frag list, if such a thing exists. We'd probably need to recurse to
* handle that cleanly.
*/
int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
struct pipe_inode_info *pipe, unsigned int tlen,
unsigned int flags)
unsigned int flags,
ssize_t (*splice_cb)(struct sock *,
struct pipe_inode_info *,
struct splice_pipe_desc *))
{
struct partial_page partial[MAX_SKB_FRAGS];
struct page *pages[MAX_SKB_FRAGS];
@ -1891,7 +1915,6 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
.spd_release = sock_spd_release,
};
struct sk_buff *frag_iter;
struct sock *sk = skb->sk;
int ret = 0;
/*
@ -1914,23 +1937,12 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
}
done:
if (spd.nr_pages) {
/*
* Drop the socket lock, otherwise we have reverse
* locking dependencies between sk_lock and i_mutex
* here as compared to sendfile(). We enter here
* with the socket lock held, and splice_to_pipe() will
* grab the pipe inode lock. For sendfile() emulation,
* we call into ->sendpage() with the i_mutex lock held
* and networking will grab the socket lock.
*/
release_sock(sk);
ret = splice_to_pipe(pipe, &spd);
lock_sock(sk);
}
if (spd.nr_pages)
ret = splice_cb(sk, pipe, &spd);
return ret;
}
EXPORT_SYMBOL_GPL(skb_splice_bits);
/**
* skb_store_bits - store bits from kernel buffer to skb
@ -2915,6 +2927,24 @@ int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
}
EXPORT_SYMBOL(skb_append_datato_frags);
int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
int offset, size_t size)
{
int i = skb_shinfo(skb)->nr_frags;
if (skb_can_coalesce(skb, i, page, offset)) {
skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
} else if (i < MAX_SKB_FRAGS) {
get_page(page);
skb_fill_page_desc(skb, i, page, offset, size);
} else {
return -EMSGSIZE;
}
return 0;
}
EXPORT_SYMBOL_GPL(skb_append_pagefrags);
/**
* skb_pull_rcsum - pull skb and update receive checksum
* @skb: buffer to update

15
net/ipv4/ip_output.c
View File

@ -1233,11 +1233,9 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
}
while (size > 0) {
int i;
if (skb_is_gso(skb))
if (skb_is_gso(skb)) {
len = size;
else {
} else {
/* Check if the remaining data fits into current packet. */
len = mtu - skb->len;
@ -1289,15 +1287,10 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
continue;
}
i = skb_shinfo(skb)->nr_frags;
if (len > size)
len = size;
if (skb_can_coalesce(skb, i, page, offset)) {
skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len);
} else if (i < MAX_SKB_FRAGS) {
get_page(page);
skb_fill_page_desc(skb, i, page, offset, len);
} else {
if (skb_append_pagefrags(skb, page, offset, len)) {
err = -EMSGSIZE;
goto error;
}

5
net/ipv4/tcp.c
View File

@ -695,8 +695,9 @@ static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
struct tcp_splice_state *tss = rd_desc->arg.data;
int ret;
ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
tss->flags);
ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
min(rd_desc->count, len), tss->flags,
skb_socket_splice);
if (ret > 0)
rd_desc->count -= ret;
return ret;

239
net/unix/af_unix.c
View File

@ -518,6 +518,11 @@ static int unix_ioctl(struct socket *, unsigned int, unsigned long);
static int unix_shutdown(struct socket *, int);
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 *,
@ -558,7 +563,8 @@ static const struct proto_ops unix_stream_ops = {
.sendmsg = unix_stream_sendmsg,
.recvmsg = unix_stream_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
.sendpage = unix_stream_sendpage,
.splice_read = unix_stream_splice_read,
.set_peek_off = unix_set_peek_off,
};
@ -1720,6 +1726,101 @@ out_err:
return sent ? : err;
}
static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
int offset, size_t size, int flags)
{
int err = 0;
bool send_sigpipe = true;
struct sock *other, *sk = socket->sk;
struct sk_buff *skb, *newskb = NULL, *tail = NULL;
if (flags & MSG_OOB)
return -EOPNOTSUPP;
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)->readlock);
newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
&err, 0);
if (!newskb)
return err;
}
/* we must acquire readlock as we modify already present
* skbs in the sk_receive_queue and mess with skb->len
*/
err = mutex_lock_interruptible(&unix_sk(other)->readlock);
if (err) {
err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
send_sigpipe = false;
goto err;
}
if (sk->sk_shutdown & SEND_SHUTDOWN) {
err = -EPIPE;
goto err_unlock;
}
unix_state_lock(other);
if (sock_flag(other, SOCK_DEAD) ||
other->sk_shutdown & RCV_SHUTDOWN) {
err = -EPIPE;
goto err_state_unlock;
}
skb = skb_peek_tail(&other->sk_receive_queue);
if (tail && tail == skb) {
skb = newskb;
} else if (!skb) {
if (newskb)
skb = newskb;
else
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);
}
if (skb_append_pagefrags(skb, page, offset, size)) {
tail = skb;
goto alloc_skb;
}
skb->len += size;
skb->data_len += size;
skb->truesize += size;
atomic_add(size, &sk->sk_wmem_alloc);
if (newskb)
__skb_queue_tail(&other->sk_receive_queue, newskb);
unix_state_unlock(other);
mutex_unlock(&unix_sk(other)->readlock);
other->sk_data_ready(other);
return size;
err_state_unlock:
unix_state_unlock(other);
err_unlock:
mutex_unlock(&unix_sk(other)->readlock);
err:
kfree_skb(newskb);
if (send_sigpipe && !(flags & MSG_NOSIGNAL))
send_sig(SIGPIPE, current, 0);
return err;
}
static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
size_t len)
{
@ -1860,8 +1961,9 @@ out:
* 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);
@ -1869,7 +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) ||
@ -1893,38 +1997,50 @@ 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)
goto out;
err = -EOPNOTSUPP;
if (flags&MSG_OOB)
if (flags & MSG_OOB)
goto out;
target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
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
@ -1940,6 +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;
@ -1962,16 +2079,17 @@ again:
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;
}
continue;
unlock:
unlock:
unix_state_unlock(sk);
break;
}
@ -1980,6 +2098,7 @@ again:
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;
@ -1996,18 +2115,20 @@ again:
} 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;
@ -2045,11 +2166,85 @@ again:
} 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;