GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-25 16:11:45 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Merge branch 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block

Browse source 
* 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [PATCH] splice: add ->splice_write support for /dev/null
  [PATCH] splice: rearrange moving to/from pipe helpers
  [PATCH] Add support for the sys_vmsplice syscall
  [PATCH] splice: fix offset problems
  [PATCH] splice: fix min() warning
This commit is contained in:
Linus Torvalds 2006-04-26 07:47:55 -07:00
commit 7b97ebfb93
11 changed files with 328 additions and 77 deletions
Download patch file Download diff file Expand all files Collapse all files

1
arch/ia64/kernel/entry.S
View file

@ -1610,5 +1610,6 @@ sys_call_table:
data8 sys_get_robust_list data8 sys_get_robust_list
data8 sys_sync_file_range // 1300 data8 sys_sync_file_range // 1300
data8 sys_tee data8 sys_tee
data8 sys_vmsplice
.org sys_call_table + 8*NR_syscalls // guard against failures to increase NR_syscalls .org sys_call_table + 8*NR_syscalls // guard against failures to increase NR_syscalls

1
arch/powerpc/kernel/systbl.S
View file

@ -324,6 +324,7 @@ COMPAT_SYS(ppoll)
SYSCALL(unshare) SYSCALL(unshare)
SYSCALL(splice) SYSCALL(splice)
SYSCALL(tee) SYSCALL(tee)
SYSCALL(vmsplice)
/* /*
* please add new calls to arch/powerpc/platforms/cell/spu_callbacks.c * please add new calls to arch/powerpc/platforms/cell/spu_callbacks.c

1
arch/powerpc/platforms/cell/spu_callbacks.c
View file

@ -318,6 +318,7 @@ void *spu_syscall_table[] = {
[__NR_unshare] sys_unshare, [__NR_unshare] sys_unshare,
[__NR_splice] sys_splice, [__NR_splice] sys_splice,
[__NR_tee] sys_tee, [__NR_tee] sys_tee,
[__NR_vmsplice] sys_vmsplice,
}; };
long spu_sys_callback(struct spu_syscall_block *s) long spu_sys_callback(struct spu_syscall_block *s)

14
drivers/char/mem.c
View file

@ -27,6 +27,7 @@
#include <linux/crash_dump.h> #include <linux/crash_dump.h>
#include <linux/backing-dev.h> #include <linux/backing-dev.h>
#include <linux/bootmem.h> #include <linux/bootmem.h>
#include <linux/pipe_fs_i.h>
#include <asm/uaccess.h> #include <asm/uaccess.h>
#include <asm/io.h> #include <asm/io.h>
@ -578,6 +579,18 @@ static ssize_t write_null(struct file * file, const char __user * buf,
return count; return count;
} }
static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
struct splice_desc *sd)
{
return sd->len;
}
static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out,
loff_t *ppos, size_t len, unsigned int flags)
{
return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
}
#ifdef CONFIG_MMU #ifdef CONFIG_MMU
/* /*
* For fun, we are using the MMU for this. * For fun, we are using the MMU for this.
@ -785,6 +798,7 @@ static struct file_operations null_fops = {
.llseek = null_lseek, .llseek = null_lseek,
.read = read_null, .read = read_null,
.write = write_null, .write = write_null,
.splice_write = splice_write_null,
}; };
#if defined(CONFIG_ISA) || !defined(__mc68000__) #if defined(CONFIG_ISA) || !defined(__mc68000__)

355
fs/splice.c
View file

@ -27,15 +27,22 @@
#include <linux/buffer_head.h> #include <linux/buffer_head.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/syscalls.h> #include <linux/syscalls.h>
#include <linux/uio.h>
struct partial_page {
unsigned int offset;
unsigned int len;
};
/* /*
* Passed to the actors * Passed to splice_to_pipe
*/ */
struct splice_desc { struct splice_pipe_desc {
unsigned int len, total_len; /* current and remaining length */ struct page **pages; /* page map */
struct partial_page *partial; /* pages[] may not be contig */
int nr_pages; /* number of pages in map */
unsigned int flags; /* splice flags */ unsigned int flags; /* splice flags */
struct file *file; /* file to read/write */ struct pipe_buf_operations *ops;/* ops associated with output pipe */
loff_t pos; /* file position */
}; };
/* /*
@ -128,6 +135,19 @@ static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
kunmap(buf->page); kunmap(buf->page);
} }
static void *user_page_pipe_buf_map(struct file *file,
struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
return kmap(buf->page);
}
static void user_page_pipe_buf_unmap(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
kunmap(buf->page);
}
static void page_cache_pipe_buf_get(struct pipe_inode_info *info, static void page_cache_pipe_buf_get(struct pipe_inode_info *info,
struct pipe_buffer *buf) struct pipe_buffer *buf)
{ {
@ -143,19 +163,33 @@ static struct pipe_buf_operations page_cache_pipe_buf_ops = {
.get = page_cache_pipe_buf_get, .get = page_cache_pipe_buf_get,
}; };
static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
return 1;
}
static struct pipe_buf_operations user_page_pipe_buf_ops = {
.can_merge = 0,
.map = user_page_pipe_buf_map,
.unmap = user_page_pipe_buf_unmap,
.release = page_cache_pipe_buf_release,
.steal = user_page_pipe_buf_steal,
.get = page_cache_pipe_buf_get,
};
/* /*
* Pipe output worker. This sets up our pipe format with the page cache * Pipe output worker. This sets up our pipe format with the page cache
* pipe buffer operations. Otherwise very similar to the regular pipe_writev(). * pipe buffer operations. Otherwise very similar to the regular pipe_writev().
*/ */
static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages, static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
int nr_pages, unsigned long len, struct splice_pipe_desc *spd)
unsigned int offset, unsigned int flags)
{ {
int ret, do_wakeup, i; int ret, do_wakeup, page_nr;
ret = 0; ret = 0;
do_wakeup = 0; do_wakeup = 0;
i = 0; page_nr = 0;
if (pipe->inode) if (pipe->inode)
mutex_lock(&pipe->inode->i_mutex); mutex_lock(&pipe->inode->i_mutex);
@ -171,27 +205,19 @@ static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
if (pipe->nrbufs < PIPE_BUFFERS) { if (pipe->nrbufs < PIPE_BUFFERS) {
int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1); int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1);
struct pipe_buffer *buf = pipe->bufs + newbuf; struct pipe_buffer *buf = pipe->bufs + newbuf;
struct page *page = pages[i++];
unsigned long this_len;
this_len = PAGE_CACHE_SIZE - offset; buf->page = spd->pages[page_nr];
if (this_len > len) buf->offset = spd->partial[page_nr].offset;
this_len = len; buf->len = spd->partial[page_nr].len;
buf->ops = spd->ops;
buf->page = page;
buf->offset = offset;
buf->len = this_len;
buf->ops = &page_cache_pipe_buf_ops;
pipe->nrbufs++; pipe->nrbufs++;
page_nr++;
ret += buf->len;
if (pipe->inode) if (pipe->inode)
do_wakeup = 1; do_wakeup = 1;
ret += this_len; if (!--spd->nr_pages)
len -= this_len;
offset = 0;
if (!--nr_pages)
break;
if (!len)
break; break;
if (pipe->nrbufs < PIPE_BUFFERS) if (pipe->nrbufs < PIPE_BUFFERS)
continue; continue;
@ -199,7 +225,7 @@ static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
break; break;
} }
if (flags & SPLICE_F_NONBLOCK) { if (spd->flags & SPLICE_F_NONBLOCK) {
if (!ret) if (!ret)
ret = -EAGAIN; ret = -EAGAIN;
break; break;
@ -234,8 +260,8 @@ static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
} }
while (i < nr_pages) while (page_nr < spd->nr_pages)
page_cache_release(pages[i++]); page_cache_release(spd->pages[page_nr++]);
return ret; return ret;
} }
@ -246,17 +272,24 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
unsigned int flags) unsigned int flags)
{ {
struct address_space *mapping = in->f_mapping; struct address_space *mapping = in->f_mapping;
unsigned int loff, offset, nr_pages; unsigned int loff, nr_pages;
struct page *pages[PIPE_BUFFERS]; struct page *pages[PIPE_BUFFERS];
struct partial_page partial[PIPE_BUFFERS];
struct page *page; struct page *page;
pgoff_t index, end_index; pgoff_t index, end_index;
loff_t isize; loff_t isize;
size_t bytes; size_t total_len;
int i, error; int error;
struct splice_pipe_desc spd = {
.pages = pages,
.partial = partial,
.flags = flags,
.ops = &page_cache_pipe_buf_ops,
};
index = *ppos >> PAGE_CACHE_SHIFT; index = *ppos >> PAGE_CACHE_SHIFT;
loff = offset = *ppos & ~PAGE_CACHE_MASK; loff = *ppos & ~PAGE_CACHE_MASK;
nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
if (nr_pages > PIPE_BUFFERS) if (nr_pages > PIPE_BUFFERS)
nr_pages = PIPE_BUFFERS; nr_pages = PIPE_BUFFERS;
@ -266,15 +299,15 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
* read-ahead if this is a non-zero offset (we are likely doing small * read-ahead if this is a non-zero offset (we are likely doing small
* chunk splice and the page is already there) for a single page. * chunk splice and the page is already there) for a single page.
*/ */
if (!offset || nr_pages > 1) if (!loff || spd.nr_pages > 1)
do_page_cache_readahead(mapping, in, index, nr_pages); do_page_cache_readahead(mapping, in, index, spd.nr_pages);
/* /*
* Now fill in the holes: * Now fill in the holes:
*/ */
error = 0; error = 0;
bytes = 0; total_len = 0;
for (i = 0; i < nr_pages; i++, index++) { for (spd.nr_pages = 0; spd.nr_pages < nr_pages; spd.nr_pages++, index++) {
unsigned int this_len; unsigned int this_len;
if (!len) if (!len)
@ -283,7 +316,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
/* /*
* this_len is the max we'll use from this page * this_len is the max we'll use from this page
*/ */
this_len = min(len, PAGE_CACHE_SIZE - loff); this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
find_page: find_page:
/* /*
* lookup the page for this index * lookup the page for this index
@ -367,26 +400,29 @@ readpage:
*/ */
if (end_index == index) { if (end_index == index) {
loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK); loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK);
if (bytes + loff > isize) { if (total_len + loff > isize) {
page_cache_release(page); page_cache_release(page);
break; break;
} }
/* /*
* force quit after adding this page * force quit after adding this page
*/ */
nr_pages = i; nr_pages = spd.nr_pages;
this_len = min(this_len, loff); this_len = min(this_len, loff);
loff = 0;
} }
} }
fill_it: fill_it:
pages[i] = page; pages[spd.nr_pages] = page;
bytes += this_len; partial[spd.nr_pages].offset = loff;
partial[spd.nr_pages].len = this_len;
len -= this_len; len -= this_len;
total_len += this_len;
loff = 0; loff = 0;
} }
if (i) if (spd.nr_pages)
return move_to_pipe(pipe, pages, i, bytes, offset, flags); return splice_to_pipe(pipe, &spd);
return error; return error;
} }
@ -439,14 +475,13 @@ EXPORT_SYMBOL(generic_file_splice_read);
/* /*
* Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos' * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
* using sendpage(). * using sendpage(). Return the number of bytes sent.
*/ */
static int pipe_to_sendpage(struct pipe_inode_info *info, static int pipe_to_sendpage(struct pipe_inode_info *info,
struct pipe_buffer *buf, struct splice_desc *sd) struct pipe_buffer *buf, struct splice_desc *sd)
{ {
struct file *file = sd->file; struct file *file = sd->file;
loff_t pos = sd->pos; loff_t pos = sd->pos;
unsigned int offset;
ssize_t ret; ssize_t ret;
void *ptr; void *ptr;
int more; int more;
@ -461,16 +496,13 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
if (IS_ERR(ptr)) if (IS_ERR(ptr))
return PTR_ERR(ptr); return PTR_ERR(ptr);
offset = pos & ~PAGE_CACHE_MASK;
more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,more); ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len,
&pos, more);
buf->ops->unmap(info, buf); buf->ops->unmap(info, buf);
if (ret == sd->len) return ret;
return 0;
return -EIO;
} }
/* /*
@ -499,7 +531,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
struct file *file = sd->file; struct file *file = sd->file;
struct address_space *mapping = file->f_mapping; struct address_space *mapping = file->f_mapping;
gfp_t gfp_mask = mapping_gfp_mask(mapping); gfp_t gfp_mask = mapping_gfp_mask(mapping);
unsigned int offset; unsigned int offset, this_len;
struct page *page; struct page *page;
pgoff_t index; pgoff_t index;
char *src; char *src;
@ -515,6 +547,10 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
index = sd->pos >> PAGE_CACHE_SHIFT; index = sd->pos >> PAGE_CACHE_SHIFT;
offset = sd->pos & ~PAGE_CACHE_MASK; offset = sd->pos & ~PAGE_CACHE_MASK;
this_len = sd->len;
if (this_len + offset > PAGE_CACHE_SIZE)
this_len = PAGE_CACHE_SIZE - offset;
/* /*
* Reuse buf page, if SPLICE_F_MOVE is set. * Reuse buf page, if SPLICE_F_MOVE is set.
*/ */
@ -558,7 +594,7 @@ find_page:
* the full page. * the full page.
*/ */
if (!PageUptodate(page)) { if (!PageUptodate(page)) {
if (sd->len < PAGE_CACHE_SIZE) { if (this_len < PAGE_CACHE_SIZE) {
ret = mapping->a_ops->readpage(file, page); ret = mapping->a_ops->readpage(file, page);
if (unlikely(ret)) if (unlikely(ret))
goto out; goto out;
@ -582,7 +618,7 @@ find_page:
} }
} }
ret = mapping->a_ops->prepare_write(file, page, 0, sd->len); ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
if (ret == AOP_TRUNCATED_PAGE) { if (ret == AOP_TRUNCATED_PAGE) {
page_cache_release(page); page_cache_release(page);
goto find_page; goto find_page;
@ -592,18 +628,22 @@ find_page:
if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {
char *dst = kmap_atomic(page, KM_USER0); char *dst = kmap_atomic(page, KM_USER0);
memcpy(dst + offset, src + buf->offset, sd->len); memcpy(dst + offset, src + buf->offset, this_len);
flush_dcache_page(page); flush_dcache_page(page);
kunmap_atomic(dst, KM_USER0); kunmap_atomic(dst, KM_USER0);
} }
ret = mapping->a_ops->commit_write(file, page, 0, sd->len); ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
if (ret == AOP_TRUNCATED_PAGE) { if (ret == AOP_TRUNCATED_PAGE) {
page_cache_release(page); page_cache_release(page);
goto find_page; goto find_page;
} else if (ret) } else if (ret)
goto out; goto out;
/*
* Return the number of bytes written.
*/
ret = this_len;
mark_page_accessed(page); mark_page_accessed(page);
balance_dirty_pages_ratelimited(mapping); balance_dirty_pages_ratelimited(mapping);
out: out:
@ -616,17 +656,14 @@ out_nomem:
return ret; return ret;
} }
typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
struct splice_desc *);
/* /*
* Pipe input worker. Most of this logic works like a regular pipe, the * Pipe input worker. Most of this logic works like a regular pipe, the
* key here is the 'actor' worker passed in that actually moves the data * key here is the 'actor' worker passed in that actually moves the data
* to the wanted destination. See pipe_to_file/pipe_to_sendpage above. * to the wanted destination. See pipe_to_file/pipe_to_sendpage above.
*/ */
static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out, ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags, loff_t *ppos, size_t len, unsigned int flags,
splice_actor *actor) splice_actor *actor)
{ {
int ret, do_wakeup, err; int ret, do_wakeup, err;
struct splice_desc sd; struct splice_desc sd;
@ -652,16 +689,22 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
sd.len = sd.total_len; sd.len = sd.total_len;
err = actor(pipe, buf, &sd); err = actor(pipe, buf, &sd);
if (err) { if (err <= 0) {
if (!ret && err != -ENODATA) if (!ret && err != -ENODATA)
ret = err; ret = err;
break; break;
} }
ret += sd.len; ret += err;
buf->offset += sd.len; buf->offset += err;
buf->len -= sd.len; buf->len -= err;
sd.len -= err;
sd.pos += err;
sd.total_len -= err;
if (sd.len)
continue;
if (!buf->len) { if (!buf->len) {
buf->ops = NULL; buf->ops = NULL;
@ -672,8 +715,6 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
do_wakeup = 1; do_wakeup = 1;
} }
sd.pos += sd.len;
sd.total_len -= sd.len;
if (!sd.total_len) if (!sd.total_len)
break; break;
} }
@ -741,7 +782,7 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
struct address_space *mapping = out->f_mapping; struct address_space *mapping = out->f_mapping;
ssize_t ret; ssize_t ret;
ret = move_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); ret = splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
if (ret > 0) { if (ret > 0) {
struct inode *inode = mapping->host; struct inode *inode = mapping->host;
@ -783,7 +824,7 @@ EXPORT_SYMBOL(generic_file_splice_write);
ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out, ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags) loff_t *ppos, size_t len, unsigned int flags)
{ {
return move_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage); return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage);
} }
EXPORT_SYMBOL(generic_splice_sendpage); EXPORT_SYMBOL(generic_splice_sendpage);
@ -870,7 +911,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
/* /*
* We don't have an immediate reader, but we'll read the stuff * We don't have an immediate reader, but we'll read the stuff
* out of the pipe right after the move_to_pipe(). So set * out of the pipe right after the splice_to_pipe(). So set
* PIPE_READERS appropriately. * PIPE_READERS appropriately.
*/ */
pipe->readers = 1; pipe->readers = 1;
@ -1010,6 +1051,174 @@ static long do_splice(struct file *in, loff_t __user *off_in,
return -EINVAL; return -EINVAL;
} }
/*
* Map an iov into an array of pages and offset/length tupples. With the
* partial_page structure, we can map several non-contiguous ranges into
* our ones pages[] map instead of splitting that operation into pieces.
* Could easily be exported as a generic helper for other users, in which
* case one would probably want to add a 'max_nr_pages' parameter as well.
*/
static int get_iovec_page_array(const struct iovec __user *iov,
unsigned int nr_vecs, struct page **pages,
struct partial_page *partial)
{
int buffers = 0, error = 0;
/*
* It's ok to take the mmap_sem for reading, even
* across a "get_user()".
*/
down_read(&current->mm->mmap_sem);
while (nr_vecs) {
unsigned long off, npages;
void __user *base;
size_t len;
int i;
/*
* Get user address base and length for this iovec.
*/
error = get_user(base, &iov->iov_base);
if (unlikely(error))
break;
error = get_user(len, &iov->iov_len);
if (unlikely(error))
break;
/*
* Sanity check this iovec. 0 read succeeds.
*/
if (unlikely(!len))
break;
error = -EFAULT;
if (unlikely(!base))
break;
/*
* Get this base offset and number of pages, then map
* in the user pages.
*/
off = (unsigned long) base & ~PAGE_MASK;
npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
if (npages > PIPE_BUFFERS - buffers)
npages = PIPE_BUFFERS - buffers;
error = get_user_pages(current, current->mm,
(unsigned long) base, npages, 0, 0,
&pages[buffers], NULL);
if (unlikely(error <= 0))
break;
/*
* Fill this contiguous range into the partial page map.
*/
for (i = 0; i < error; i++) {
const int plen = min_t(size_t, len, PAGE_SIZE) - off;
partial[buffers].offset = off;
partial[buffers].len = plen;
off = 0;
len -= plen;
buffers++;
}
/*
* We didn't complete this iov, stop here since it probably
* means we have to move some of this into a pipe to
* be able to continue.
*/
if (len)
break;
/*
* Don't continue if we mapped fewer pages than we asked for,
* or if we mapped the max number of pages that we have
* room for.
*/
if (error < npages || buffers == PIPE_BUFFERS)
break;
nr_vecs--;
iov++;
}
up_read(&current->mm->mmap_sem);
if (buffers)
return buffers;
return error;
}
/*
* vmsplice splices a user address range into a pipe. It can be thought of
* as splice-from-memory, where the regular splice is splice-from-file (or
* to file). In both cases the output is a pipe, naturally.
*
* Note that vmsplice only supports splicing _from_ user memory to a pipe,
* not the other way around. Splicing from user memory is a simple operation
* that can be supported without any funky alignment restrictions or nasty
* vm tricks. We simply map in the user memory and fill them into a pipe.
* The reverse isn't quite as easy, though. There are two possible solutions
* for that:
*
* - memcpy() the data internally, at which point we might as well just
* do a regular read() on the buffer anyway.
* - Lots of nasty vm tricks, that are neither fast nor flexible (it
* has restriction limitations on both ends of the pipe).
*
* Alas, it isn't here.
*
*/
static long do_vmsplice(struct file *file, const struct iovec __user *iov,
unsigned long nr_segs, unsigned int flags)
{
struct pipe_inode_info *pipe = file->f_dentry->d_inode->i_pipe;
struct page *pages[PIPE_BUFFERS];
struct partial_page partial[PIPE_BUFFERS];
struct splice_pipe_desc spd = {
.pages = pages,
.partial = partial,
.flags = flags,
.ops = &user_page_pipe_buf_ops,
};
if (unlikely(!pipe))
return -EBADF;
if (unlikely(nr_segs > UIO_MAXIOV))
return -EINVAL;
else if (unlikely(!nr_segs))
return 0;
spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial);
if (spd.nr_pages <= 0)
return spd.nr_pages;
return splice_to_pipe(pipe, &spd);
}
asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov,
unsigned long nr_segs, unsigned int flags)
{
struct file *file;
long error;
int fput;
error = -EBADF;
file = fget_light(fd, &fput);
if (file) {
if (file->f_mode & FMODE_WRITE)
error = do_vmsplice(file, iov, nr_segs, flags);
fput_light(file, fput);
}
return error;
}
asmlinkage long sys_splice(int fd_in, loff_t __user *off_in, asmlinkage long sys_splice(int fd_in, loff_t __user *off_in,
int fd_out, loff_t __user *off_out, int fd_out, loff_t __user *off_out,
size_t len, unsigned int flags) size_t len, unsigned int flags)

3
include/asm-i386/unistd.h
View file

@ -321,8 +321,9 @@
#define __NR_splice 313 #define __NR_splice 313
#define __NR_sync_file_range 314 #define __NR_sync_file_range 314
#define __NR_tee 315 #define __NR_tee 315
#define __NR_vmsplice 316
#define NR_syscalls 316 #define NR_syscalls 317
/* /*
* user-visible error numbers are in the range -1 - -128: see * user-visible error numbers are in the range -1 - -128: see

3
include/asm-ia64/unistd.h
View file

@ -290,12 +290,13 @@
#define __NR_get_robust_list 1299 #define __NR_get_robust_list 1299
#define __NR_sync_file_range 1300 #define __NR_sync_file_range 1300
#define __NR_tee 1301 #define __NR_tee 1301
#define __NR_vmsplice 1302
#ifdef __KERNEL__ #ifdef __KERNEL__
#include <linux/config.h> #include <linux/config.h>
#define NR_syscalls 278 /* length of syscall table */ #define NR_syscalls 279 /* length of syscall table */
#define __ARCH_WANT_SYS_RT_SIGACTION #define __ARCH_WANT_SYS_RT_SIGACTION

3
include/asm-powerpc/unistd.h
View file

@ -303,8 +303,9 @@
#define __NR_unshare 282 #define __NR_unshare 282
#define __NR_splice 283 #define __NR_splice 283
#define __NR_tee 284 #define __NR_tee 284
#define __NR_vmsplice 285
#define __NR_syscalls 285 #define __NR_syscalls 286
#ifdef __KERNEL__ #ifdef __KERNEL__
#define __NR__exit __NR_exit #define __NR__exit __NR_exit

4
include/asm-x86_64/unistd.h
View file

@ -615,8 +615,10 @@ __SYSCALL(__NR_splice, sys_splice)
__SYSCALL(__NR_tee, sys_tee) __SYSCALL(__NR_tee, sys_tee)
#define __NR_sync_file_range 277 #define __NR_sync_file_range 277
__SYSCALL(__NR_sync_file_range, sys_sync_file_range) __SYSCALL(__NR_sync_file_range, sys_sync_file_range)
#define __NR_vmsplice 278
__SYSCALL(__NR_vmsplice, sys_vmsplice)
#define __NR_syscall_max __NR_sync_file_range #define __NR_syscall_max __NR_vmsplice
#ifndef __NO_STUBS #ifndef __NO_STUBS

17
include/linux/pipe_fs_i.h
View file

@ -61,4 +61,21 @@ void __free_pipe_info(struct pipe_inode_info *);
/* from/to, of course */ /* from/to, of course */
#define SPLICE_F_MORE (0x04) /* expect more data */ #define SPLICE_F_MORE (0x04) /* expect more data */
/*
* Passed to the actors
*/
struct splice_desc {
unsigned int len, total_len; /* current and remaining length */
unsigned int flags; /* splice flags */
struct file *file; /* file to read/write */
loff_t pos; /* file position */
};
typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *,
struct splice_desc *);
extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *,
loff_t *, size_t, unsigned int,
splice_actor *);
#endif #endif

3
include/linux/syscalls.h
View file

@ -574,6 +574,9 @@ asmlinkage long sys_splice(int fd_in, loff_t __user *off_in,
int fd_out, loff_t __user *off_out, int fd_out, loff_t __user *off_out,
size_t len, unsigned int flags); size_t len, unsigned int flags);
asmlinkage long sys_vmsplice(int fd, const struct iovec __user *iov,
unsigned long nr_segs, unsigned int flags);
asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags); asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags);
asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes, asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,