[TCP]: Splice receive support.

Support for network splice receive.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jens Axboe 2007-11-06 23:30:13 -08:00 коммит произвёл David S. Miller
Родитель bbdfc2f706
Коммит 9c55e01c0c
7 изменённых файлов: 401 добавлений и 0 удалений

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@ -22,6 +22,7 @@
#include <asm/socket.h>
struct poll_table_struct;
struct pipe_inode_info;
struct inode;
struct net;
@ -172,6 +173,8 @@ struct proto_ops {
struct vm_area_struct * vma);
ssize_t (*sendpage) (struct socket *sock, struct page *page,
int offset, size_t size, int flags);
ssize_t (*splice_read)(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len, unsigned int flags);
};
struct net_proto_family {

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@ -95,6 +95,7 @@
struct net_device;
struct scatterlist;
struct pipe_inode_info;
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
struct nf_conntrack {
@ -1559,6 +1560,11 @@ extern int skb_store_bits(struct sk_buff *skb, int offset,
extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
int offset, u8 *to, int len,
__wsum csum);
extern int skb_splice_bits(struct sk_buff *skb,
unsigned int offset,
struct pipe_inode_info *pipe,
unsigned int len,
unsigned int flags);
extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
extern void skb_split(struct sk_buff *skb,
struct sk_buff *skb1, const u32 len);

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@ -309,6 +309,9 @@ extern int tcp_twsk_unique(struct sock *sk,
extern void tcp_twsk_destructor(struct sock *sk);
extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len, unsigned int flags);
static inline void tcp_dec_quickack_mode(struct sock *sk,
const unsigned int pkts)
{

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@ -52,6 +52,7 @@
#endif
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/splice.h>
#include <linux/cache.h>
#include <linux/rtnetlink.h>
#include <linux/init.h>
@ -71,6 +72,40 @@
static struct kmem_cache *skbuff_head_cache __read_mostly;
static struct kmem_cache *skbuff_fclone_cache __read_mostly;
static void sock_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct sk_buff *skb = (struct sk_buff *) buf->private;
kfree_skb(skb);
}
static void sock_pipe_buf_get(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct sk_buff *skb = (struct sk_buff *) buf->private;
skb_get(skb);
}
static int sock_pipe_buf_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
return 1;
}
/* Pipe buffer operations for a socket. */
static struct pipe_buf_operations sock_pipe_buf_ops = {
.can_merge = 0,
.map = generic_pipe_buf_map,
.unmap = generic_pipe_buf_unmap,
.confirm = generic_pipe_buf_confirm,
.release = sock_pipe_buf_release,
.steal = sock_pipe_buf_steal,
.get = sock_pipe_buf_get,
};
/*
* Keep out-of-line to prevent kernel bloat.
* __builtin_return_address is not used because it is not always
@ -1122,6 +1157,217 @@ fault:
return -EFAULT;
}
/*
* Callback from splice_to_pipe(), if we need to release some pages
* at the end of the spd in case we error'ed out in filling the pipe.
*/
static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
{
struct sk_buff *skb = (struct sk_buff *) spd->partial[i].private;
kfree_skb(skb);
}
/*
* Fill page/offset/length into spd, if it can hold more pages.
*/
static inline int spd_fill_page(struct splice_pipe_desc *spd, struct page *page,
unsigned int len, unsigned int offset,
struct sk_buff *skb)
{
if (unlikely(spd->nr_pages == PIPE_BUFFERS))
return 1;
spd->pages[spd->nr_pages] = page;
spd->partial[spd->nr_pages].len = len;
spd->partial[spd->nr_pages].offset = offset;
spd->partial[spd->nr_pages].private = (unsigned long) skb_get(skb);
spd->nr_pages++;
return 0;
}
/*
* Map linear and fragment data from the skb to spd. Returns number of
* pages mapped.
*/
static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset,
unsigned int *total_len,
struct splice_pipe_desc *spd)
{
unsigned int nr_pages = spd->nr_pages;
unsigned int poff, plen, len, toff, tlen;
int headlen, seg;
toff = *offset;
tlen = *total_len;
if (!tlen)
goto err;
/*
* if the offset is greater than the linear part, go directly to
* the fragments.
*/
headlen = skb_headlen(skb);
if (toff >= headlen) {
toff -= headlen;
goto map_frag;
}
/*
* first map the linear region into the pages/partial map, skipping
* any potential initial offset.
*/
len = 0;
while (len < headlen) {
void *p = skb->data + len;
poff = (unsigned long) p & (PAGE_SIZE - 1);
plen = min_t(unsigned int, headlen - len, PAGE_SIZE - poff);
len += plen;
if (toff) {
if (plen <= toff) {
toff -= plen;
continue;
}
plen -= toff;
poff += toff;
toff = 0;
}
plen = min(plen, tlen);
if (!plen)
break;
/*
* just jump directly to update and return, no point
* in going over fragments when the output is full.
*/
if (spd_fill_page(spd, virt_to_page(p), plen, poff, skb))
goto done;
tlen -= plen;
}
/*
* then map the fragments
*/
map_frag:
for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
plen = f->size;
poff = f->page_offset;
if (toff) {
if (plen <= toff) {
toff -= plen;
continue;
}
plen -= toff;
poff += toff;
toff = 0;
}
plen = min(plen, tlen);
if (!plen)
break;
if (spd_fill_page(spd, f->page, plen, poff, skb))
break;
tlen -= plen;
}
done:
if (spd->nr_pages - nr_pages) {
*offset = 0;
*total_len = tlen;
return 0;
}
err:
return 1;
}
/*
* 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,
struct pipe_inode_info *pipe, unsigned int tlen,
unsigned int flags)
{
struct partial_page partial[PIPE_BUFFERS];
struct page *pages[PIPE_BUFFERS];
struct splice_pipe_desc spd = {
.pages = pages,
.partial = partial,
.flags = flags,
.ops = &sock_pipe_buf_ops,
.spd_release = sock_spd_release,
};
struct sk_buff *skb;
/*
* I'd love to avoid the clone here, but tcp_read_sock()
* ignores reference counts and unconditonally kills the sk_buff
* on return from the actor.
*/
skb = skb_clone(__skb, GFP_KERNEL);
if (unlikely(!skb))
return -ENOMEM;
/*
* __skb_splice_bits() only fails if the output has no room left,
* so no point in going over the frag_list for the error case.
*/
if (__skb_splice_bits(skb, &offset, &tlen, &spd))
goto done;
else if (!tlen)
goto done;
/*
* now see if we have a frag_list to map
*/
if (skb_shinfo(skb)->frag_list) {
struct sk_buff *list = skb_shinfo(skb)->frag_list;
for (; list && tlen; list = list->next) {
if (__skb_splice_bits(list, &offset, &tlen, &spd))
break;
}
}
done:
/*
* drop our reference to the clone, the pipe consumption will
* drop the rest.
*/
kfree_skb(skb);
if (spd.nr_pages) {
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(__skb->sk);
ret = splice_to_pipe(pipe, &spd);
lock_sock(__skb->sk);
return ret;
}
return 0;
}
/**
* skb_store_bits - store bits from kernel buffer to skb
* @skb: destination buffer

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@ -838,6 +838,7 @@ const struct proto_ops inet_stream_ops = {
.recvmsg = sock_common_recvmsg,
.mmap = sock_no_mmap,
.sendpage = tcp_sendpage,
.splice_read = tcp_splice_read,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_sock_common_setsockopt,
.compat_getsockopt = compat_sock_common_getsockopt,

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@ -254,6 +254,10 @@
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/skbuff.h>
#include <linux/splice.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/random.h>
#include <linux/bootmem.h>
#include <linux/cache.h>
@ -265,6 +269,7 @@
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/netdma.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
@ -291,6 +296,15 @@ atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
EXPORT_SYMBOL(tcp_memory_allocated);
EXPORT_SYMBOL(tcp_sockets_allocated);
/*
* TCP splice context
*/
struct tcp_splice_state {
struct pipe_inode_info *pipe;
size_t len;
unsigned int flags;
};
/*
* Pressure flag: try to collapse.
* Technical note: it is used by multiple contexts non atomically.
@ -501,6 +515,120 @@ static inline void tcp_push(struct sock *sk, int flags, int mss_now,
}
}
int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
unsigned int offset, size_t len)
{
struct tcp_splice_state *tss = rd_desc->arg.data;
return skb_splice_bits(skb, offset, tss->pipe, tss->len, tss->flags);
}
static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
{
/* Store TCP splice context information in read_descriptor_t. */
read_descriptor_t rd_desc = {
.arg.data = tss,
};
return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
}
/**
* tcp_splice_read - splice data from TCP socket to a pipe
* @sock: socket to splice from
* @ppos: position (not valid)
* @pipe: pipe to splice to
* @len: number of bytes to splice
* @flags: splice modifier flags
*
* Description:
* Will read pages from given socket and fill them into a pipe.
*
**/
ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct sock *sk = sock->sk;
struct tcp_splice_state tss = {
.pipe = pipe,
.len = len,
.flags = flags,
};
long timeo;
ssize_t spliced;
int ret;
/*
* We can't seek on a socket input
*/
if (unlikely(*ppos))
return -ESPIPE;
ret = spliced = 0;
lock_sock(sk);
timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK);
while (tss.len) {
ret = __tcp_splice_read(sk, &tss);
if (ret < 0)
break;
else if (!ret) {
if (spliced)
break;
if (flags & SPLICE_F_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (sock_flag(sk, SOCK_DONE))
break;
if (sk->sk_err) {
ret = sock_error(sk);
break;
}
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
if (sk->sk_state == TCP_CLOSE) {
/*
* This occurs when user tries to read
* from never connected socket.
*/
if (!sock_flag(sk, SOCK_DONE))
ret = -ENOTCONN;
break;
}
if (!timeo) {
ret = -EAGAIN;
break;
}
sk_wait_data(sk, &timeo);
if (signal_pending(current)) {
ret = sock_intr_errno(timeo);
break;
}
continue;
}
tss.len -= ret;
spliced += ret;
release_sock(sk);
lock_sock(sk);
if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
(sk->sk_shutdown & RCV_SHUTDOWN) || !timeo ||
signal_pending(current))
break;
}
release_sock(sk);
if (spliced)
return spliced;
return ret;
}
static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
size_t psize, int flags)
{
@ -2532,6 +2660,7 @@ EXPORT_SYMBOL(tcp_poll);
EXPORT_SYMBOL(tcp_read_sock);
EXPORT_SYMBOL(tcp_recvmsg);
EXPORT_SYMBOL(tcp_sendmsg);
EXPORT_SYMBOL(tcp_splice_read);
EXPORT_SYMBOL(tcp_sendpage);
EXPORT_SYMBOL(tcp_setsockopt);
EXPORT_SYMBOL(tcp_shutdown);

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@ -112,6 +112,9 @@ static long compat_sock_ioctl(struct file *file,
static int sock_fasync(int fd, struct file *filp, int on);
static ssize_t sock_sendpage(struct file *file, struct page *page,
int offset, size_t size, loff_t *ppos, int more);
static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags);
/*
* Socket files have a set of 'special' operations as well as the generic file ones. These don't appear
@ -134,6 +137,7 @@ static const struct file_operations socket_file_ops = {
.fasync = sock_fasync,
.sendpage = sock_sendpage,
.splice_write = generic_splice_sendpage,
.splice_read = sock_splice_read,
};
/*
@ -691,6 +695,15 @@ static ssize_t sock_sendpage(struct file *file, struct page *page,
return sock->ops->sendpage(sock, page, offset, size, flags);
}
static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct socket *sock = file->private_data;
return sock->ops->splice_read(sock, ppos, pipe, len, flags);
}
static struct sock_iocb *alloc_sock_iocb(struct kiocb *iocb,
struct sock_iocb *siocb)
{