* that transfers data buffers to or from a pipe buffer.
*
* Named by Larry McVoy, original implementation from Linus, extended by
- * Jens to support splicing to files and fixing the initial implementation
- * bugs.
+ * Jens to support splicing to files, network, direct splicing, etc and
+ * fixing lots of bugs.
*
- * Copyright (C) 2005 Jens Axboe <axboe@suse.de>
- * Copyright (C) 2005 Linus Torvalds <torvalds@osdl.org>
+ * Copyright (C) 2005-2006 Jens Axboe <axboe@suse.de>
+ * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org>
+ * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu>
*
*/
#include <linux/fs.h>
/*
* Page got truncated/unhashed. This will cause a 0-byte
- * splice, if this is the first page
+ * splice, if this is the first page.
*/
if (!page->mapping) {
err = -ENODATA;
}
/*
- * uh oh, read-error from disk
+ * Uh oh, read-error from disk.
*/
if (!PageUptodate(page)) {
err = -EIO;
}
/*
- * page is ok afterall, fall through to mapping
+ * Page is ok afterall, fall through to mapping.
*/
unlock_page(page);
}
kunmap(buf->page);
}
+static void page_cache_pipe_buf_get(struct pipe_inode_info *info,
+ struct pipe_buffer *buf)
+{
+ page_cache_get(buf->page);
+}
+
static struct pipe_buf_operations page_cache_pipe_buf_ops = {
.can_merge = 0,
.map = page_cache_pipe_buf_map,
.unmap = page_cache_pipe_buf_unmap,
.release = page_cache_pipe_buf_release,
.steal = page_cache_pipe_buf_steal,
+ .get = page_cache_pipe_buf_get,
};
/*
}
static int
-__generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe,
- size_t len, unsigned int flags)
+__generic_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
{
struct address_space *mapping = in->f_mapping;
unsigned int offset, nr_pages;
pgoff_t index;
int i, error;
- index = in->f_pos >> PAGE_CACHE_SHIFT;
- offset = in->f_pos & ~PAGE_CACHE_MASK;
+ index = *ppos >> PAGE_CACHE_SHIFT;
+ offset = *ppos & ~PAGE_CACHE_MASK;
nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
if (nr_pages > PIPE_BUFFERS)
nr_pages = PIPE_BUFFERS;
/*
- * initiate read-ahead on this page range. however, don't call into
+ * Initiate read-ahead on this page range. however, don't call into
* 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.
*/
do_page_cache_readahead(mapping, in, index, nr_pages);
/*
- * now fill in the holes
+ * Now fill in the holes:
*/
error = 0;
for (i = 0; i < nr_pages; i++, index++) {
*
* Will read pages from given file and fill them into a pipe.
*/
-ssize_t generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe,
- size_t len, unsigned int flags)
+ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
{
ssize_t spliced;
int ret;
spliced = 0;
while (len) {
- ret = __generic_file_splice_read(in, pipe, len, flags);
+ ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
if (ret <= 0)
break;
- in->f_pos += ret;
+ *ppos += ret;
len -= ret;
spliced += ret;
int more;
/*
- * sub-optimal, but we are limited by the pipe ->map. we don't
+ * Sub-optimal, but we are limited by the pipe ->map. We don't
* need a kmap'ed buffer here, we just want to make sure we
* have the page pinned if the pipe page originates from the
- * page cache
+ * page cache.
*/
ptr = buf->ops->map(file, info, buf);
if (IS_ERR(ptr))
offset = sd->pos & ~PAGE_CACHE_MASK;
/*
- * reuse buf page, if SPLICE_F_MOVE is set
+ * Reuse buf page, if SPLICE_F_MOVE is set.
*/
if (sd->flags & SPLICE_F_MOVE) {
/*
if (!PageUptodate(page)) {
/*
- * page got invalidated, repeat
+ * Page got invalidated, repeat.
*/
if (!page->mapping) {
unlock_page(page);
* 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,
- size_t len, unsigned int flags,
+ loff_t *ppos, size_t len, unsigned int flags,
splice_actor *actor)
{
int ret, do_wakeup, err;
sd.total_len = len;
sd.flags = flags;
sd.file = out;
- sd.pos = out->f_pos;
+ sd.pos = *ppos;
if (pipe->inode)
mutex_lock(&pipe->inode->i_mutex);
ret += sd.len;
buf->offset += sd.len;
buf->len -= sd.len;
+
if (!buf->len) {
buf->ops = NULL;
ops->release(pipe, buf);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
- out->f_pos = sd.pos;
return ret;
-
}
/**
*/
ssize_t
generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
- size_t len, unsigned int flags)
+ loff_t *ppos, size_t len, unsigned int flags)
{
struct address_space *mapping = out->f_mapping;
ssize_t ret;
- ret = move_from_pipe(pipe, out, len, flags, pipe_to_file);
+ ret = move_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
/*
- * if file or inode is SYNC and we actually wrote some data, sync it
+ * If file or inode is SYNC and we actually wrote some data, sync it.
*/
if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(mapping->host))
&& ret > 0) {
*
*/
ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out,
- size_t len, unsigned int flags)
+ loff_t *ppos, size_t len, unsigned int flags)
{
- return move_from_pipe(pipe, out, len, flags, pipe_to_sendpage);
+ return move_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage);
}
EXPORT_SYMBOL(generic_splice_sendpage);
* Attempt to initiate a splice from pipe to file.
*/
static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
- size_t len, unsigned int flags)
+ loff_t *ppos, size_t len, unsigned int flags)
{
- loff_t pos;
int ret;
if (unlikely(!out->f_op || !out->f_op->splice_write))
if (unlikely(!(out->f_mode & FMODE_WRITE)))
return -EBADF;
- pos = out->f_pos;
-
- ret = rw_verify_area(WRITE, out, &pos, len);
+ ret = rw_verify_area(WRITE, out, ppos, len);
if (unlikely(ret < 0))
return ret;
- return out->f_op->splice_write(pipe, out, len, flags);
+ return out->f_op->splice_write(pipe, out, ppos, len, flags);
}
/*
* Attempt to initiate a splice from a file to a pipe.
*/
-static long do_splice_to(struct file *in, struct pipe_inode_info *pipe,
- size_t len, unsigned int flags)
+static long do_splice_to(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
{
- loff_t pos, isize, left;
+ loff_t isize, left;
int ret;
if (unlikely(!in->f_op || !in->f_op->splice_read))
if (unlikely(!(in->f_mode & FMODE_READ)))
return -EBADF;
- pos = in->f_pos;
-
- ret = rw_verify_area(READ, in, &pos, len);
+ ret = rw_verify_area(READ, in, ppos, len);
if (unlikely(ret < 0))
return ret;
isize = i_size_read(in->f_mapping->host);
- if (unlikely(in->f_pos >= isize))
+ if (unlikely(*ppos >= isize))
return 0;
- left = isize - in->f_pos;
+ left = isize - *ppos;
if (unlikely(left < len))
len = left;
- return in->f_op->splice_read(in, pipe, len, flags);
+ return in->f_op->splice_read(in, ppos, pipe, len, flags);
}
-long do_splice_direct(struct file *in, struct file *out, size_t len,
- unsigned int flags)
+long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
+ size_t len, unsigned int flags)
{
struct pipe_inode_info *pipe;
long ret, bytes;
+ loff_t out_off;
umode_t i_mode;
int i;
}
/*
- * do the splice
+ * Do the splice.
*/
ret = 0;
bytes = 0;
+ out_off = 0;
while (len) {
size_t read_len, max_read_len;
*/
max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE));
- ret = do_splice_to(in, pipe, max_read_len, flags);
+ ret = do_splice_to(in, ppos, pipe, max_read_len, flags);
if (unlikely(ret < 0))
goto out_release;
* must not do the output in nonblocking mode as then we
* could get stuck data in the internal pipe:
*/
- ret = do_splice_from(pipe, out, read_len,
+ ret = do_splice_from(pipe, out, &out_off, read_len,
flags & ~SPLICE_F_NONBLOCK);
if (unlikely(ret < 0))
goto out_release;
size_t len, unsigned int flags)
{
struct pipe_inode_info *pipe;
+ loff_t offset, *off;
pipe = in->f_dentry->d_inode->i_pipe;
if (pipe) {
if (off_out) {
if (out->f_op->llseek == no_llseek)
return -EINVAL;
- if (copy_from_user(&out->f_pos, off_out,
- sizeof(loff_t)))
+ if (copy_from_user(&offset, off_out, sizeof(loff_t)))
return -EFAULT;
- }
+ off = &offset;
+ } else
+ off = &out->f_pos;
- return do_splice_from(pipe, out, len, flags);
+ return do_splice_from(pipe, out, off, len, flags);
}
pipe = out->f_dentry->d_inode->i_pipe;
if (off_in) {
if (in->f_op->llseek == no_llseek)
return -EINVAL;
- if (copy_from_user(&in->f_pos, off_in, sizeof(loff_t)))
+ if (copy_from_user(&offset, off_in, sizeof(loff_t)))
return -EFAULT;
- }
+ off = &offset;
+ } else
+ off = &in->f_pos;
- return do_splice_to(in, pipe, len, flags);
+ return do_splice_to(in, off, pipe, len, flags);
}
return -EINVAL;
return error;
}
+
+/*
+ * Link contents of ipipe to opipe.
+ */
+static int link_pipe(struct pipe_inode_info *ipipe,
+ struct pipe_inode_info *opipe,
+ size_t len, unsigned int flags)
+{
+ struct pipe_buffer *ibuf, *obuf;
+ int ret = 0, do_wakeup = 0, i;
+
+ /*
+ * Potential ABBA deadlock, work around it by ordering lock
+ * grabbing by inode address. Otherwise two different processes
+ * could deadlock (one doing tee from A -> B, the other from B -> A).
+ */
+ if (ipipe->inode < opipe->inode) {
+ mutex_lock(&ipipe->inode->i_mutex);
+ mutex_lock(&opipe->inode->i_mutex);
+ } else {
+ mutex_lock(&opipe->inode->i_mutex);
+ mutex_lock(&ipipe->inode->i_mutex);
+ }
+
+ for (i = 0;; i++) {
+ if (!opipe->readers) {
+ send_sig(SIGPIPE, current, 0);
+ if (!ret)
+ ret = -EPIPE;
+ break;
+ }
+ if (ipipe->nrbufs - i) {
+ ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (PIPE_BUFFERS - 1));
+
+ /*
+ * If we have room, fill this buffer
+ */
+ if (opipe->nrbufs < PIPE_BUFFERS) {
+ int nbuf = (opipe->curbuf + opipe->nrbufs) & (PIPE_BUFFERS - 1);
+
+ /*
+ * Get a reference to this pipe buffer,
+ * so we can copy the contents over.
+ */
+ ibuf->ops->get(ipipe, ibuf);
+
+ obuf = opipe->bufs + nbuf;
+ *obuf = *ibuf;
+
+ if (obuf->len > len)
+ obuf->len = len;
+
+ opipe->nrbufs++;
+ do_wakeup = 1;
+ ret += obuf->len;
+ len -= obuf->len;
+
+ if (!len)
+ break;
+ if (opipe->nrbufs < PIPE_BUFFERS)
+ continue;
+ }
+
+ /*
+ * We have input available, but no output room.
+ * If we already copied data, return that.
+ */
+ if (flags & SPLICE_F_NONBLOCK) {
+ if (!ret)
+ ret = -EAGAIN;
+ break;
+ }
+ if (signal_pending(current)) {
+ if (!ret)
+ ret = -ERESTARTSYS;
+ break;
+ }
+ if (do_wakeup) {
+ smp_mb();
+ if (waitqueue_active(&opipe->wait))
+ wake_up_interruptible(&opipe->wait);
+ kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN);
+ do_wakeup = 0;
+ }
+
+ opipe->waiting_writers++;
+ pipe_wait(opipe);
+ opipe->waiting_writers--;
+ continue;
+ }
+
+ /*
+ * No input buffers, do the usual checks for available
+ * writers and blocking and wait if necessary
+ */
+ if (!ipipe->writers)
+ break;
+ if (!ipipe->waiting_writers) {
+ if (ret)
+ break;
+ }
+ if (flags & SPLICE_F_NONBLOCK) {
+ if (!ret)
+ ret = -EAGAIN;
+ break;
+ }
+ if (signal_pending(current)) {
+ if (!ret)
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ if (waitqueue_active(&ipipe->wait))
+ wake_up_interruptible_sync(&ipipe->wait);
+ kill_fasync(&ipipe->fasync_writers, SIGIO, POLL_OUT);
+
+ pipe_wait(ipipe);
+ }
+
+ mutex_unlock(&ipipe->inode->i_mutex);
+ mutex_unlock(&opipe->inode->i_mutex);
+
+ if (do_wakeup) {
+ smp_mb();
+ if (waitqueue_active(&opipe->wait))
+ wake_up_interruptible(&opipe->wait);
+ kill_fasync(&opipe->fasync_readers, SIGIO, POLL_IN);
+ }
+
+ return ret;
+}
+
+/*
+ * This is a tee(1) implementation that works on pipes. It doesn't copy
+ * any data, it simply references the 'in' pages on the 'out' pipe.
+ * The 'flags' used are the SPLICE_F_* variants, currently the only
+ * applicable one is SPLICE_F_NONBLOCK.
+ */
+static long do_tee(struct file *in, struct file *out, size_t len,
+ unsigned int flags)
+{
+ struct pipe_inode_info *ipipe = in->f_dentry->d_inode->i_pipe;
+ struct pipe_inode_info *opipe = out->f_dentry->d_inode->i_pipe;
+
+ /*
+ * Link ipipe to the two output pipes, consuming as we go along.
+ */
+ if (ipipe && opipe)
+ return link_pipe(ipipe, opipe, len, flags);
+
+ return -EINVAL;
+}
+
+asmlinkage long sys_tee(int fdin, int fdout, size_t len, unsigned int flags)
+{
+ struct file *in;
+ int error, fput_in;
+
+ if (unlikely(!len))
+ return 0;
+
+ error = -EBADF;
+ in = fget_light(fdin, &fput_in);
+ if (in) {
+ if (in->f_mode & FMODE_READ) {
+ int fput_out;
+ struct file *out = fget_light(fdout, &fput_out);
+
+ if (out) {
+ if (out->f_mode & FMODE_WRITE)
+ error = do_tee(in, out, len, flags);
+ fput_light(out, fput_out);
+ }
+ }
+ fput_light(in, fput_in);
+ }
+
+ return error;
+}
projects / linux-2.6 / blobdiff