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

{

	struct page *page = buf->page;

	buf->flags &= ~PIPE_BUF_FLAG_STOLEN;

	/*

	 * If nobody else uses this page, and we don't already have a

	 * temporary page, let's keep track of it as a one-deep

static int anon_pipe_buf_steal(struct pipe_inode_info *info,

			       struct pipe_buffer *buf)

{

	buf->stolen = 1;

	buf->flags |= PIPE_BUF_FLAG_STOLEN;

	return 0;

}

#include <linux/pipe_fs_i.h>

#include <linux/mm_inline.h>

#include <linux/swap.h>

#include <linux/writeback.h>

#include <linux/buffer_head.h>

#include <linux/module.h>

#include <linux/syscalls.h>

/*

 * Passed to the actors

	loff_t pos;			/* file position */

};

/*

 * Attempt to steal a page from a pipe buffer. This should perhaps go into

 * a vm helper function, it's already simplified quite a bit by the

 * addition of remove_mapping(). If success is returned, the caller may

 * attempt to reuse this page for another destination.

 */

static int page_cache_pipe_buf_steal(struct pipe_inode_info *info,

				     struct pipe_buffer *buf)

{

	struct page *page = buf->page;

	struct address_space *mapping = page_mapping(page);

	WARN_ON(!PageLocked(page));

	WARN_ON(!PageUptodate(page));

	if (!remove_mapping(page_mapping(page), page))

		return 1;

	/*

	 * At least for ext2 with nobh option, we need to wait on writeback

	 * completing on this page, since we'll remove it from the pagecache.

	 * Otherwise truncate wont wait on the page, allowing the disk

	 * blocks to be reused by someone else before we actually wrote our

	 * data to them. fs corruption ensues.

	 */

	wait_on_page_writeback(page);

	if (PageLRU(page)) {

		struct zone *zone = page_zone(page);

	if (PagePrivate(page))

		try_to_release_page(page, mapping_gfp_mask(mapping));

		spin_lock_irq(&zone->lru_lock);

		BUG_ON(!PageLRU(page));

		__ClearPageLRU(page);

		del_page_from_lru(zone, page);

		spin_unlock_irq(&zone->lru_lock);

	}

	if (!remove_mapping(mapping, page))

		return 1;

	buf->stolen = 1;

	buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU;

	return 0;

}

{

	page_cache_release(buf->page);

	buf->page = NULL;

	buf->stolen = 0;

	buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU);

}

static void *page_cache_pipe_buf_map(struct file *file,

static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,

				      struct pipe_buffer *buf)

{

	if (!buf->stolen)

	unlock_page(buf->page);

	kunmap(buf->page);

}

	.steal = page_cache_pipe_buf_steal,

};

/*

 * Pipe output worker. This sets up our pipe format with the page cache

 * pipe buffer operations. Otherwise very similar to the regular pipe_writev().

 */

static ssize_t move_to_pipe(struct inode *inode, struct page **pages,

			    int nr_pages, unsigned long offset,

			    unsigned long len, unsigned int flags)

	 * fill shadow[] with pages at the right locations, so we only

	 * have to fill holes

	 */

	memset(shadow, 0, i * sizeof(struct page *));

	for (j = 0, pidx = index; j < i; pidx++, j++)

		shadow[pages[j]->index - pidx] = pages[j];

	memset(shadow, 0, nr_pages * sizeof(struct page *));

	for (j = 0; j < i; j++)

		shadow[pages[j]->index - index] = pages[j];

	/*

	 * now fill in the holes

	return move_to_pipe(pipe, pages, i, offset, len, flags);

}

/**

 * generic_file_splice_read - splice data from file to a pipe

 * @in:		file to splice from

 * @pipe:	pipe to splice to

 * @len:	number of bytes to splice

 * @flags:	splice modifier flags

 *

 * Will read pages from given file and fill them into a pipe.

 *

 */

ssize_t generic_file_splice_read(struct file *in, struct inode *pipe,

				 size_t len, unsigned int flags)

{

	return ret;

}

EXPORT_SYMBOL(generic_file_splice_read);

/*

 * Send 'len' bytes to socket from 'file' at position 'pos' using sendpage().

 * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'

 * using sendpage().

 */

static int pipe_to_sendpage(struct pipe_inode_info *info,

			    struct pipe_buffer *buf, struct splice_desc *sd)

	unsigned int offset;

	ssize_t ret;

	void *ptr;

	int more;

	/*

	 * sub-optimal, but we are limited by the pipe ->map. we don't

		return PTR_ERR(ptr);

	offset = pos & ~PAGE_CACHE_MASK;

	more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;

	ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,

					sd->len < sd->total_len);

	ret = file->f_op->sendpage(file, buf->page, offset, sd->len, &pos,more);

	buf->ops->unmap(info, buf);

	if (ret == sd->len)

 *	- Destination page does not exist, we can add the pipe page to

 *	  the page cache and avoid the copy.

 *

 * For now we just do the slower thing and always copy pages over, it's

 * easier than migrating pages from the pipe to the target file. For the

 * case of doing file | file splicing, the migrate approach had some LRU

 * nastiness...

 * If asked to move pages to the output file (SPLICE_F_MOVE is set in

 * sd->flags), we attempt to migrate pages from the pipe to the output

 * file address space page cache. This is possible if no one else has

 * the pipe page referenced outside of the pipe and page cache. If

 * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create

 * a new page in the output file page cache and fill/dirty that.

 */

static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,

			struct splice_desc *sd)

{

	struct file *file = sd->file;

	struct address_space *mapping = file->f_mapping;

	gfp_t gfp_mask = mapping_gfp_mask(mapping);

	unsigned int offset;

	struct page *page;

	pgoff_t index;

	 * reuse buf page, if SPLICE_F_MOVE is set

	 */

	if (sd->flags & SPLICE_F_MOVE) {

		/*

		 * If steal succeeds, buf->page is now pruned from the vm

		 * side (LRU and page cache) and we can reuse it.

		 */

		if (buf->ops->steal(info, buf))

			goto find_page;

		page = buf->page;

		if (add_to_page_cache_lru(page, mapping, index,

						mapping_gfp_mask(mapping)))

		if (add_to_page_cache(page, mapping, index, gfp_mask))

			goto find_page;

		if (!(buf->flags & PIPE_BUF_FLAG_LRU))

			lru_cache_add(page);

	} else {

find_page:

		ret = -ENOMEM;

		page = find_or_create_page(mapping, index,

						mapping_gfp_mask(mapping));

		page = find_or_create_page(mapping, index, gfp_mask);

		if (!page)

			goto out;

	}

	ret = mapping->a_ops->prepare_write(file, page, 0, sd->len);

	if (ret)

	if (ret == AOP_TRUNCATED_PAGE) {

		page_cache_release(page);

		goto find_page;

	} else if (ret)

		goto out;

	if (!buf->stolen) {

	if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {

		char *dst = kmap_atomic(page, KM_USER0);

		memcpy(dst + offset, src + buf->offset, sd->len);

	}

	ret = mapping->a_ops->commit_write(file, page, 0, sd->len);

	if (ret < 0)

	if (ret == AOP_TRUNCATED_PAGE) {

		page_cache_release(page);

		goto find_page;

	} else if (ret)

		goto out;

	set_page_dirty(page);

	ret = write_one_page(page, 0);

	balance_dirty_pages_ratelimited(mapping);

out:

	if (ret < 0)

		unlock_page(page);

	if (!buf->stolen)

	if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {

		page_cache_release(page);

		unlock_page(page);

	}

	buf->ops->unmap(info, buf);

	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

 * 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.

 */

static ssize_t move_from_pipe(struct inode *inode, struct file *out,

			      size_t len, unsigned int flags,

			      splice_actor *actor)

}

/**

 * generic_file_splice_write - splice data from a pipe to a file

 * @inode:	pipe inode

 * @out:	file to write to

 * @len:	number of bytes to splice

 * @flags:	splice modifier flags

 *

 * Will either move or copy pages (determined by @flags options) from

 * the given pipe inode to the given file.

 *

 */

ssize_t generic_file_splice_write(struct inode *inode, struct file *out,

				  size_t len, unsigned int flags)

{

	return move_from_pipe(inode, out, len, flags, pipe_to_file);

	struct address_space *mapping = out->f_mapping;

	ssize_t ret = move_from_pipe(inode, out, len, flags, pipe_to_file);

	/*

	 * 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) {

		struct inode *inode = mapping->host;

		int err;

		mutex_lock(&inode->i_mutex);

		err = generic_osync_inode(mapping->host, mapping,

						OSYNC_METADATA|OSYNC_DATA);

		mutex_unlock(&inode->i_mutex);

		if (err)

			ret = err;

	}

	return ret;

}

EXPORT_SYMBOL(generic_file_splice_write);

/**

 * generic_splice_sendpage - splice data from a pipe to a socket

 * @inode:	pipe inode

 * @out:	socket to write to

 * @len:	number of bytes to splice

 * @flags:	splice modifier flags

 *

 * Will send @len bytes from the pipe to a network socket. No data copying

 * is involved.

 *

 */

ssize_t generic_splice_sendpage(struct inode *inode, struct file *out,

				size_t len, unsigned int flags)

{

	return move_from_pipe(inode, out, len, flags, pipe_to_sendpage);

}

EXPORT_SYMBOL(generic_file_splice_write);

EXPORT_SYMBOL(generic_file_splice_read);

EXPORT_SYMBOL(generic_splice_sendpage);

/*

 * Attempt to initiate a splice from pipe to file.

 */

static long do_splice_from(struct inode *pipe, struct file *out, size_t len,

			   unsigned int flags)

{

	return out->f_op->splice_write(pipe, out, len, flags);

}

/*

 * Attempt to initiate a splice from a file to a pipe.

 */

static long do_splice_to(struct file *in, struct inode *pipe, size_t len,

			 unsigned int flags)

{

	return in->f_op->splice_read(in, pipe, len, flags);

}

/*

 * Determine where to splice to/from.

 */

static long do_splice(struct file *in, struct file *out, size_t len,

		      unsigned int flags)

{

#define PIPE_BUFFERS (16)

#define PIPE_BUF_FLAG_STOLEN	0x01

#define PIPE_BUF_FLAG_LRU	0x02

struct pipe_buffer {

	struct page *page;

	unsigned int offset, len;

	struct pipe_buf_operations *ops;

	unsigned int stolen;

	unsigned int flags;

};

struct pipe_buf_operations {

#define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */

				 /* we may still block on the fd we splice */

				 /* from/to, of course */

#define SPLICE_F_MORE	(0x04)	/* expect more data */

#endif