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Commit 7b97ebfb authored by Linus Torvalds's avatar Linus Torvalds
Browse files
* '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
parents 07db8696 1ebd32fc
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+1 −0
Original line number Diff line number Diff line
@@ -1610,5 +1610,6 @@ sys_call_table:
	data8 sys_get_robust_list
	data8 sys_sync_file_range		// 1300
	data8 sys_tee
	data8 sys_vmsplice

	.org sys_call_table + 8*NR_syscalls	// guard against failures to increase NR_syscalls
+1 −0
Original line number Diff line number Diff line
@@ -324,6 +324,7 @@ COMPAT_SYS(ppoll)
SYSCALL(unshare)
SYSCALL(splice)
SYSCALL(tee)
SYSCALL(vmsplice)

/*
 * please add new calls to arch/powerpc/platforms/cell/spu_callbacks.c
+1 −0
Original line number Diff line number Diff line
@@ -318,6 +318,7 @@ void *spu_syscall_table[] = {
	[__NR_unshare]			sys_unshare,
	[__NR_splice]			sys_splice,
	[__NR_tee]			sys_tee,
	[__NR_vmsplice]			sys_vmsplice,
};

long spu_sys_callback(struct spu_syscall_block *s)
+14 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@
#include <linux/crash_dump.h>
#include <linux/backing-dev.h>
#include <linux/bootmem.h>
#include <linux/pipe_fs_i.h>

#include <asm/uaccess.h>
#include <asm/io.h>
@@ -578,6 +579,18 @@ static ssize_t write_null(struct file * file, const char __user * buf,
	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
/*
 * For fun, we are using the MMU for this.
@@ -785,6 +798,7 @@ static struct file_operations null_fops = {
	.llseek		= null_lseek,
	.read		= read_null,
	.write		= write_null,
	.splice_write	= splice_write_null,
};

#if defined(CONFIG_ISA) || !defined(__mc68000__)
+282 −73
Original line number Diff line number Diff line
@@ -27,15 +27,22 @@
#include <linux/buffer_head.h>
#include <linux/module.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 {
	unsigned int len, total_len;	/* current and remaining length */
struct splice_pipe_desc {
	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 */
	struct file *file;		/* file to read/write */
	loff_t pos;			/* file position */
	struct pipe_buf_operations *ops;/* ops associated with output pipe */
};

/*
@@ -128,6 +135,19 @@ static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
	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,
				    struct pipe_buffer *buf)
{
@@ -143,19 +163,33 @@ static struct pipe_buf_operations page_cache_pipe_buf_ops = {
	.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 buffer operations. Otherwise very similar to the regular pipe_writev().
 */
static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
			    int nr_pages, unsigned long len,
			    unsigned int offset, unsigned int flags)
static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
			      struct splice_pipe_desc *spd)
{
	int ret, do_wakeup, i;
	int ret, do_wakeup, page_nr;

	ret = 0;
	do_wakeup = 0;
	i = 0;
	page_nr = 0;

	if (pipe->inode)
		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) {
			int newbuf = (pipe->curbuf + pipe->nrbufs) & (PIPE_BUFFERS - 1);
			struct pipe_buffer *buf = pipe->bufs + newbuf;
			struct page *page = pages[i++];
			unsigned long this_len;

			this_len = PAGE_CACHE_SIZE - offset;
			if (this_len > len)
				this_len = len;

			buf->page = page;
			buf->offset = offset;
			buf->len = this_len;
			buf->ops = &page_cache_pipe_buf_ops;
			buf->page = spd->pages[page_nr];
			buf->offset = spd->partial[page_nr].offset;
			buf->len = spd->partial[page_nr].len;
			buf->ops = spd->ops;
			pipe->nrbufs++;
			page_nr++;
			ret += buf->len;

			if (pipe->inode)
				do_wakeup = 1;

			ret += this_len;
			len -= this_len;
			offset = 0;
			if (!--nr_pages)
				break;
			if (!len)
			if (!--spd->nr_pages)
				break;
			if (pipe->nrbufs < PIPE_BUFFERS)
				continue;
@@ -199,7 +225,7 @@ static ssize_t move_to_pipe(struct pipe_inode_info *pipe, struct page **pages,
			break;
		}

		if (flags & SPLICE_F_NONBLOCK) {
		if (spd->flags & SPLICE_F_NONBLOCK) {
			if (!ret)
				ret = -EAGAIN;
			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);
	}

	while (i < nr_pages)
		page_cache_release(pages[i++]);
	while (page_nr < spd->nr_pages)
		page_cache_release(spd->pages[page_nr++]);

	return ret;
}
@@ -246,17 +272,24 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
			   unsigned int flags)
{
	struct address_space *mapping = in->f_mapping;
	unsigned int loff, offset, nr_pages;
	unsigned int loff, nr_pages;
	struct page *pages[PIPE_BUFFERS];
	struct partial_page partial[PIPE_BUFFERS];
	struct page *page;
	pgoff_t index, end_index;
	loff_t isize;
	size_t bytes;
	int i, error;
	size_t total_len;
	int error;
	struct splice_pipe_desc spd = {
		.pages = pages,
		.partial = partial,
		.flags = flags,
		.ops = &page_cache_pipe_buf_ops,
	};

	index = *ppos >> PAGE_CACHE_SHIFT;
	loff = offset = *ppos & ~PAGE_CACHE_MASK;
	nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
	loff = *ppos & ~PAGE_CACHE_MASK;
	nr_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;

	if (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
	 * chunk splice and the page is already there) for a single page.
	 */
	if (!offset || nr_pages > 1)
		do_page_cache_readahead(mapping, in, index, nr_pages);
	if (!loff || spd.nr_pages > 1)
		do_page_cache_readahead(mapping, in, index, spd.nr_pages);

	/*
	 * Now fill in the holes:
	 */
	error = 0;
	bytes = 0;
	for (i = 0; i < nr_pages; i++, index++) {
	total_len = 0;
	for (spd.nr_pages = 0; spd.nr_pages < nr_pages; spd.nr_pages++, index++) {
		unsigned int this_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 = min(len, PAGE_CACHE_SIZE - loff);
		this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
find_page:
		/*
		 * lookup the page for this index
@@ -367,26 +400,29 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
			 */
			if (end_index == index) {
				loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK);
				if (bytes + loff > isize) {
				if (total_len + loff > isize) {
					page_cache_release(page);
					break;
				}
				/*
				 * force quit after adding this page
				 */
				nr_pages = i;
				nr_pages = spd.nr_pages;
				this_len = min(this_len, loff);
				loff = 0;
			}
		}
fill_it:
		pages[i] = page;
		bytes += this_len;
		pages[spd.nr_pages] = page;
		partial[spd.nr_pages].offset = loff;
		partial[spd.nr_pages].len = this_len;
		len -= this_len;
		total_len += this_len;
		loff = 0;
	}

	if (i)
		return move_to_pipe(pipe, pages, i, bytes, offset, flags);
	if (spd.nr_pages)
		return splice_to_pipe(pipe, &spd);

	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'
 * using sendpage().
 * using sendpage(). Return the number of bytes sent.
 */
static int pipe_to_sendpage(struct pipe_inode_info *info,
			    struct pipe_buffer *buf, struct splice_desc *sd)
{
	struct file *file = sd->file;
	loff_t pos = sd->pos;
	unsigned int offset;
	ssize_t ret;
	void *ptr;
	int more;
@@ -461,16 +496,13 @@ static int pipe_to_sendpage(struct pipe_inode_info *info,
	if (IS_ERR(ptr))
		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,more);
	ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len,
				   &pos, more);

	buf->ops->unmap(info, buf);
	if (ret == sd->len)
		return 0;

	return -EIO;
	return ret;
}

/*
@@ -499,7 +531,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
	struct file *file = sd->file;
	struct address_space *mapping = file->f_mapping;
	gfp_t gfp_mask = mapping_gfp_mask(mapping);
	unsigned int offset;
	unsigned int offset, this_len;
	struct page *page;
	pgoff_t index;
	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;
	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.
	 */
@@ -558,7 +594,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
		 * the full page.
		 */
		if (!PageUptodate(page)) {
			if (sd->len < PAGE_CACHE_SIZE) {
			if (this_len < PAGE_CACHE_SIZE) {
				ret = mapping->a_ops->readpage(file, page);
				if (unlikely(ret))
					goto out;
@@ -582,7 +618,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
		}
	}

	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) {
		page_cache_release(page);
		goto find_page;
@@ -592,18 +628,22 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
	if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {
		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);
		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) {
		page_cache_release(page);
		goto find_page;
	} else if (ret)
		goto out;

	/*
	 * Return the number of bytes written.
	 */
	ret = this_len;
	mark_page_accessed(page);
	balance_dirty_pages_ratelimited(mapping);
out:
@@ -616,15 +656,12 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *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 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,
			 splice_actor *actor)
{
@@ -652,16 +689,22 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
				sd.len = sd.total_len;

			err = actor(pipe, buf, &sd);
			if (err) {
			if (err <= 0) {
				if (!ret && err != -ENODATA)
					ret = err;

				break;
			}

			ret += sd.len;
			buf->offset += sd.len;
			buf->len -= sd.len;
			ret += err;
			buf->offset += err;
			buf->len -= err;

			sd.len -= err;
			sd.pos += err;
			sd.total_len -= err;
			if (sd.len)
				continue;

			if (!buf->len) {
				buf->ops = NULL;
@@ -672,8 +715,6 @@ static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
					do_wakeup = 1;
			}

			sd.pos += sd.len;
			sd.total_len -= sd.len;
			if (!sd.total_len)
				break;
		}
@@ -741,7 +782,7 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
	struct address_space *mapping = out->f_mapping;
	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) {
		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,
				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);
@@ -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
		 * 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 = 1;
@@ -1010,6 +1051,174 @@ static long do_splice(struct file *in, loff_t __user *off_in,
	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,
			   int fd_out, loff_t __user *off_out,
			   size_t len, unsigned int flags)
Loading