[PATCH] relayfs: Convert to generic relay API.

[Paul Mundt <lethal@linux-sh.org>]

On Sun, Feb 19, 2006 at 11:27:48PM +0200, Paul Mundt wrote:
> On Sun, Feb 19, 2006 at 04:21:22PM -0500, Dave Jones wrote:
> > On Sun, Feb 19, 2006 at 11:07:33PM +0200, Paul Mundt wrote:
> >  > This is a small patch set for getting rid of relayfs, and moving the core of
> >  > its functionality to kernel/relay.c. The API is kept consistent for everything
> >  > but the relayfs-specific bits, meaning people will have to use other file
> >  > systems to implement relay channel buffers.
> > 
> > What about the userspace visible API for things already using relayfs,
> > like systemtap ?  Whilst technically these patches may make sense,
> > yanking the rug underneath applications as soon as they've started
> > using it without warning or a migration period doesn't sound too good an idea.
> > 
> Yes, that's why this is only done in the last two patches. The rest are
> completely independent and don't interfere with the API (well, ok,
> FIX_SIZE() needs to be dropped in fs/relayfs if it's fetching it from the
> header, but that's it).
> 
> > It's taken us *years* to try and get rid of devfs, why should relayfs
> > get ripped out any quicker, when it has valid users?
> > 
> I'm not advocating its removal, I'm more interested in using it from
> sysfs and debugfs where it makes more sense. Splitting up CONFIG_RELAY
> and CONFIG_RELAYFS_FS will allow for both, and it'll also be possible to
> migrate the existing CONFIG_RELAYFS_FS code to use CONFIG_RELAY without
> breaking the userspace APIs if we want to get rid of the duplication. The
> only issue will be wrapping up the default callbacks, but that's a
> trivial ifdef.

And here's a patch doing that.. any other objections?

This strips down relayfs to a minimum, removing everything already
provided by CONFIG_RELAY. This leaves a userspace API compatible
implementation on top of the new framework.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

---

 fs/Kconfig                 |    1 
 fs/relayfs/Makefile        |    3 
 fs/relayfs/buffers.c       |  190 -----------------
 fs/relayfs/buffers.h       |   12 -
 fs/relayfs/inode.c         |  269 -------------------------
 fs/relayfs/relay.c         |  482 --------------------------------------------
 fs/relayfs/relay.h         |    8 -
 include/linux/relayfs_fs.h |    1 
 kernel/relay.c             |    9 +
 9 files changed, 12 insertions(+), 963 deletions(-)
 delete mode 100644 fs/relayfs/buffers.c
 delete mode 100644 fs/relayfs/buffers.h
 delete mode 100644 fs/relayfs/relay.c
 delete mode 100644 fs/relayfs/relay.h

51d322e2944117ed6c01b79b73e18f15c2b8d09e
diff --git a/fs/Kconfig b/fs/Kconfig
index e9749b0..6245587 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -861,6 +861,7 @@ config RAMFS
 
 config RELAYFS_FS
 	tristate "Relayfs file system support"
+	select RELAY
 	---help---
 	  Relayfs is a high-speed data relay filesystem designed to provide
 	  an efficient mechanism for tools and facilities to relay large
diff --git a/fs/relayfs/Makefile b/fs/relayfs/Makefile
index e76e182..b45ffc0 100644
--- a/fs/relayfs/Makefile
+++ b/fs/relayfs/Makefile
@@ -1,4 +1,3 @@
 obj-$(CONFIG_RELAYFS_FS) += relayfs.o
 
-relayfs-y := relay.o inode.o buffers.o
-
+relayfs-y := inode.o
diff --git a/fs/relayfs/buffers.c b/fs/relayfs/buffers.c
deleted file mode 100644
index 1018781..0000000
--- a/fs/relayfs/buffers.c
+++ /dev/null
@@ -1,190 +0,0 @@
-/*
- * RelayFS buffer management code.
- *
- * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
- * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
- *
- * This file is released under the GPL.
- */
-
-#include <linux/module.h>
-#include <linux/vmalloc.h>
-#include <linux/mm.h>
-#include <linux/relayfs_fs.h>
-#include "relay.h"
-#include "buffers.h"
-
-/*
- * close() vm_op implementation for relayfs file mapping.
- */
-static void relay_file_mmap_close(struct vm_area_struct *vma)
-{
-	struct rchan_buf *buf = vma->vm_private_data;
-	buf->chan->cb->buf_unmapped(buf, vma->vm_file);
-}
-
-/*
- * nopage() vm_op implementation for relayfs file mapping.
- */
-static struct page *relay_buf_nopage(struct vm_area_struct *vma,
-				     unsigned long address,
-				     int *type)
-{
-	struct page *page;
-	struct rchan_buf *buf = vma->vm_private_data;
-	unsigned long offset = address - vma->vm_start;
-
-	if (address > vma->vm_end)
-		return NOPAGE_SIGBUS; /* Disallow mremap */
-	if (!buf)
-		return NOPAGE_OOM;
-
-	page = vmalloc_to_page(buf->start + offset);
-	if (!page)
-		return NOPAGE_OOM;
-	get_page(page);
-
-	if (type)
-		*type = VM_FAULT_MINOR;
-
-	return page;
-}
-
-/*
- * vm_ops for relay file mappings.
- */
-static struct vm_operations_struct relay_file_mmap_ops = {
-	.nopage = relay_buf_nopage,
-	.close = relay_file_mmap_close,
-};
-
-/**
- *	relay_mmap_buf: - mmap channel buffer to process address space
- *	@buf: relay channel buffer
- *	@vma: vm_area_struct describing memory to be mapped
- *
- *	Returns 0 if ok, negative on error
- *
- *	Caller should already have grabbed mmap_sem.
- */
-int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
-{
-	unsigned long length = vma->vm_end - vma->vm_start;
-	struct file *filp = vma->vm_file;
-
-	if (!buf)
-		return -EBADF;
-
-	if (length != (unsigned long)buf->chan->alloc_size)
-		return -EINVAL;
-
-	vma->vm_ops = &relay_file_mmap_ops;
-	vma->vm_private_data = buf;
-	buf->chan->cb->buf_mapped(buf, filp);
-
-	return 0;
-}
-
-/**
- *	relay_alloc_buf - allocate a channel buffer
- *	@buf: the buffer struct
- *	@size: total size of the buffer
- *
- *	Returns a pointer to the resulting buffer, NULL if unsuccessful
- */
-static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
-{
-	void *mem;
-	unsigned int i, j, n_pages;
-
-	size = PAGE_ALIGN(size);
-	n_pages = size >> PAGE_SHIFT;
-
-	buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
-	if (!buf->page_array)
-		return NULL;
-
-	for (i = 0; i < n_pages; i++) {
-		buf->page_array[i] = alloc_page(GFP_KERNEL);
-		if (unlikely(!buf->page_array[i]))
-			goto depopulate;
-	}
-	mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL);
-	if (!mem)
-		goto depopulate;
-
-	memset(mem, 0, size);
-	buf->page_count = n_pages;
-	return mem;
-
-depopulate:
-	for (j = 0; j < i; j++)
-		__free_page(buf->page_array[j]);
-	kfree(buf->page_array);
-	return NULL;
-}
-
-/**
- *	relay_create_buf - allocate and initialize a channel buffer
- *	@alloc_size: size of the buffer to allocate
- *	@n_subbufs: number of sub-buffers in the channel
- *
- *	Returns channel buffer if successful, NULL otherwise
- */
-struct rchan_buf *relay_create_buf(struct rchan *chan)
-{
-	struct rchan_buf *buf = kcalloc(1, sizeof(struct rchan_buf), GFP_KERNEL);
-	if (!buf)
-		return NULL;
-
-	buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL);
-	if (!buf->padding)
-		goto free_buf;
-
-	buf->start = relay_alloc_buf(buf, chan->alloc_size);
-	if (!buf->start)
-		goto free_buf;
-
-	buf->chan = chan;
-	kref_get(&buf->chan->kref);
-	return buf;
-
-free_buf:
-	kfree(buf->padding);
-	kfree(buf);
-	return NULL;
-}
-
-/**
- *	relay_destroy_buf - destroy an rchan_buf struct and associated buffer
- *	@buf: the buffer struct
- */
-void relay_destroy_buf(struct rchan_buf *buf)
-{
-	struct rchan *chan = buf->chan;
-	unsigned int i;
-
-	if (likely(buf->start)) {
-		vunmap(buf->start);
-		for (i = 0; i < buf->page_count; i++)
-			__free_page(buf->page_array[i]);
-		kfree(buf->page_array);
-	}
-	kfree(buf->padding);
-	kfree(buf);
-	kref_put(&chan->kref, relay_destroy_channel);
-}
-
-/**
- *	relay_remove_buf - remove a channel buffer
- *
- *	Removes the file from the relayfs fileystem, which also frees the
- *	rchan_buf_struct and the channel buffer.  Should only be called from
- *	kref_put().
- */
-void relay_remove_buf(struct kref *kref)
-{
-	struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref);
-	buf->chan->cb->remove_buf_file(buf->dentry);
-	relay_destroy_buf(buf);
-}
diff --git a/fs/relayfs/buffers.h b/fs/relayfs/buffers.h
deleted file mode 100644
index 37a1249..0000000
--- a/fs/relayfs/buffers.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BUFFERS_H
-#define _BUFFERS_H
-
-/* This inspired by rtai/shmem */
-#define FIX_SIZE(x) (((x) - 1) & PAGE_MASK) + PAGE_SIZE
-
-extern int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma);
-extern struct rchan_buf *relay_create_buf(struct rchan *chan);
-extern void relay_destroy_buf(struct rchan_buf *buf);
-extern void relay_remove_buf(struct kref *kref);
-
-#endif/* _BUFFERS_H */
diff --git a/fs/relayfs/inode.c b/fs/relayfs/inode.c
index 3835230..6f58381 100644
--- a/fs/relayfs/inode.c
+++ b/fs/relayfs/inode.c
@@ -19,8 +19,6 @@
 #include <linux/namei.h>
 #include <linux/poll.h>
 #include <linux/relayfs_fs.h>
-#include "relay.h"
-#include "buffers.h"
 
 #define RELAYFS_MAGIC			0xF0B4A981
 
@@ -246,267 +244,6 @@ int relayfs_remove_dir(struct dentry *de
 	return relayfs_remove(dentry);
 }
 
-/**
- *	relay_file_open - open file op for relay files
- *	@inode: the inode
- *	@filp: the file
- *
- *	Increments the channel buffer refcount.
- */
-static int relay_file_open(struct inode *inode, struct file *filp)
-{
-	struct rchan_buf *buf = inode->u.generic_ip;
-	kref_get(&buf->kref);
-	filp->private_data = buf;
-
-	return 0;
-}
-
-/**
- *	relay_file_mmap - mmap file op for relay files
- *	@filp: the file
- *	@vma: the vma describing what to map
- *
- *	Calls upon relay_mmap_buf to map the file into user space.
- */
-static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	struct rchan_buf *buf = filp->private_data;
-	return relay_mmap_buf(buf, vma);
-}
-
-/**
- *	relay_file_poll - poll file op for relay files
- *	@filp: the file
- *	@wait: poll table
- *
- *	Poll implemention.
- */
-static unsigned int relay_file_poll(struct file *filp, poll_table *wait)
-{
-	unsigned int mask = 0;
-	struct rchan_buf *buf = filp->private_data;
-
-	if (buf->finalized)
-		return POLLERR;
-
-	if (filp->f_mode & FMODE_READ) {
-		poll_wait(filp, &buf->read_wait, wait);
-		if (!relay_buf_empty(buf))
-			mask |= POLLIN | POLLRDNORM;
-	}
-
-	return mask;
-}
-
-/**
- *	relay_file_release - release file op for relay files
- *	@inode: the inode
- *	@filp: the file
- *
- *	Decrements the channel refcount, as the filesystem is
- *	no longer using it.
- */
-static int relay_file_release(struct inode *inode, struct file *filp)
-{
-	struct rchan_buf *buf = filp->private_data;
-	kref_put(&buf->kref, relay_remove_buf);
-
-	return 0;
-}
-
-/**
- *	relay_file_read_consume - update the consumed count for the buffer
- */
-static void relay_file_read_consume(struct rchan_buf *buf,
-				    size_t read_pos,
-				    size_t bytes_consumed)
-{
-	size_t subbuf_size = buf->chan->subbuf_size;
-	size_t n_subbufs = buf->chan->n_subbufs;
-	size_t read_subbuf;
-
-	if (buf->bytes_consumed + bytes_consumed > subbuf_size) {
-		relay_subbufs_consumed(buf->chan, buf->cpu, 1);
-		buf->bytes_consumed = 0;
-	}
-
-	buf->bytes_consumed += bytes_consumed;
-	read_subbuf = read_pos / buf->chan->subbuf_size;
-	if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
-		if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
-		    (buf->offset == subbuf_size))
-			return;
-		relay_subbufs_consumed(buf->chan, buf->cpu, 1);
-		buf->bytes_consumed = 0;
-	}
-}
-
-/**
- *	relay_file_read_avail - boolean, are there unconsumed bytes available?
- */
-static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos)
-{
-	size_t bytes_produced, bytes_consumed, write_offset;
-	size_t subbuf_size = buf->chan->subbuf_size;
-	size_t n_subbufs = buf->chan->n_subbufs;
-	size_t produced = buf->subbufs_produced % n_subbufs;
-	size_t consumed = buf->subbufs_consumed % n_subbufs;
-
-	write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
-
-	if (consumed > produced) {
-		if ((produced > n_subbufs) &&
-		    (produced + n_subbufs - consumed <= n_subbufs))
-			produced += n_subbufs;
-	} else if (consumed == produced) {
-		if (buf->offset > subbuf_size) {
-			produced += n_subbufs;
-			if (buf->subbufs_produced == buf->subbufs_consumed)
-				consumed += n_subbufs;
-		}
-	}
-
-	if (buf->offset > subbuf_size)
-		bytes_produced = (produced - 1) * subbuf_size + write_offset;
-	else
-		bytes_produced = produced * subbuf_size + write_offset;
-	bytes_consumed = consumed * subbuf_size + buf->bytes_consumed;
-
-	if (bytes_produced == bytes_consumed)
-		return 0;
-
-	relay_file_read_consume(buf, read_pos, 0);
-
-	return 1;
-}
-
-/**
- *	relay_file_read_subbuf_avail - return bytes available in sub-buffer
- */
-static size_t relay_file_read_subbuf_avail(size_t read_pos,
-					   struct rchan_buf *buf)
-{
-	size_t padding, avail = 0;
-	size_t read_subbuf, read_offset, write_subbuf, write_offset;
-	size_t subbuf_size = buf->chan->subbuf_size;
-
-	write_subbuf = (buf->data - buf->start) / subbuf_size;
-	write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
-	read_subbuf = read_pos / subbuf_size;
-	read_offset = read_pos % subbuf_size;
-	padding = buf->padding[read_subbuf];
-
-	if (read_subbuf == write_subbuf) {
-		if (read_offset + padding < write_offset)
-			avail = write_offset - (read_offset + padding);
-	} else
-		avail = (subbuf_size - padding) - read_offset;
-
-	return avail;
-}
-
-/**
- *	relay_file_read_start_pos - find the first available byte to read
- *
- *	If the read_pos is in the middle of padding, return the
- *	position of the first actually available byte, otherwise
- *	return the original value.
- */
-static size_t relay_file_read_start_pos(size_t read_pos,
-					struct rchan_buf *buf)
-{
-	size_t read_subbuf, padding, padding_start, padding_end;
-	size_t subbuf_size = buf->chan->subbuf_size;
-	size_t n_subbufs = buf->chan->n_subbufs;
-
-	read_subbuf = read_pos / subbuf_size;
-	padding = buf->padding[read_subbuf];
-	padding_start = (read_subbuf + 1) * subbuf_size - padding;
-	padding_end = (read_subbuf + 1) * subbuf_size;
-	if (read_pos >= padding_start && read_pos < padding_end) {
-		read_subbuf = (read_subbuf + 1) % n_subbufs;
-		read_pos = read_subbuf * subbuf_size;
-	}
-
-	return read_pos;
-}
-
-/**
- *	relay_file_read_end_pos - return the new read position
- */
-static size_t relay_file_read_end_pos(struct rchan_buf *buf,
-				      size_t read_pos,
-				      size_t count)
-{
-	size_t read_subbuf, padding, end_pos;
-	size_t subbuf_size = buf->chan->subbuf_size;
-	size_t n_subbufs = buf->chan->n_subbufs;
-
-	read_subbuf = read_pos / subbuf_size;
-	padding = buf->padding[read_subbuf];
-	if (read_pos % subbuf_size + count + padding == subbuf_size)
-		end_pos = (read_subbuf + 1) * subbuf_size;
-	else
-		end_pos = read_pos + count;
-	if (end_pos >= subbuf_size * n_subbufs)
-		end_pos = 0;
-
-	return end_pos;
-}
-
-/**
- *	relay_file_read - read file op for relay files
- *	@filp: the file
- *	@buffer: the userspace buffer
- *	@count: number of bytes to read
- *	@ppos: position to read from
- *
- *	Reads count bytes or the number of bytes available in the
- *	current sub-buffer being read, whichever is smaller.
- */
-static ssize_t relay_file_read(struct file *filp,
-			       char __user *buffer,
-			       size_t count,
-			       loff_t *ppos)
-{
-	struct rchan_buf *buf = filp->private_data;
-	struct inode *inode = filp->f_dentry->d_inode;
-	size_t read_start, avail;
-	ssize_t ret = 0;
-	void *from;
-
-	mutex_lock(&inode->i_mutex);
-	if(!relay_file_read_avail(buf, *ppos))
-		goto out;
-
-	read_start = relay_file_read_start_pos(*ppos, buf);
-	avail = relay_file_read_subbuf_avail(read_start, buf);
-	if (!avail)
-		goto out;
-
-	from = buf->start + read_start;
-	ret = count = min(count, avail);
-	if (copy_to_user(buffer, from, count)) {
-		ret = -EFAULT;
-		goto out;
-	}
-	relay_file_read_consume(buf, read_start, count);
-	*ppos = relay_file_read_end_pos(buf, read_start, count);
-out:
-	mutex_unlock(&inode->i_mutex);
-	return ret;
-}
-
-struct file_operations relay_file_operations = {
-	.open		= relay_file_open,
-	.poll		= relay_file_poll,
-	.mmap		= relay_file_mmap,
-	.read		= relay_file_read,
-	.llseek		= no_llseek,
-	.release	= relay_file_release,
-};
-
 static struct super_operations relayfs_ops = {
 	.statfs		= simple_statfs,
 	.drop_inode	= generic_delete_inode,
@@ -558,18 +295,12 @@ static int __init init_relayfs_fs(void)
 
 static void __exit exit_relayfs_fs(void)
 {
-
-
-
-
-
 	unregister_filesystem(&relayfs_fs_type);
 }
 
 module_init(init_relayfs_fs)
 module_exit(exit_relayfs_fs)
 
-EXPORT_SYMBOL_GPL(relay_file_operations);
 EXPORT_SYMBOL_GPL(relayfs_create_dir);
 EXPORT_SYMBOL_GPL(relayfs_remove_dir);
 EXPORT_SYMBOL_GPL(relayfs_create_file);
diff --git a/fs/relayfs/relay.c b/fs/relayfs/relay.c
deleted file mode 100644
index abf3cea..0000000
--- a/fs/relayfs/relay.c
+++ /dev/null
@@ -1,482 +0,0 @@
-/*
- * Public API and common code for RelayFS.
- *
- * See Documentation/filesystems/relayfs.txt for an overview of relayfs.
- *
- * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
- * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
- *
- * This file is released under the GPL.
- */
-
-#include <linux/errno.h>
-#include <linux/stddef.h>
-#include <linux/slab.h>
-#include <linux/module.h>
-#include <linux/string.h>
-#include <linux/relayfs_fs.h>
-#include "relay.h"
-#include "buffers.h"
-
-/**
- *	relay_buf_empty - boolean, is the channel buffer empty?
- *	@buf: channel buffer
- *
- *	Returns 1 if the buffer is empty, 0 otherwise.
- */
-int relay_buf_empty(struct rchan_buf *buf)
-{
-	return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1;
-}
-
-/**
- *	relay_buf_full - boolean, is the channel buffer full?
- *	@buf: channel buffer
- *
- *	Returns 1 if the buffer is full, 0 otherwise.
- */
-int relay_buf_full(struct rchan_buf *buf)
-{
-	size_t ready = buf->subbufs_produced - buf->subbufs_consumed;
-	return (ready >= buf->chan->n_subbufs) ? 1 : 0;
-}
-
-/*
- * High-level relayfs kernel API and associated functions.
- */
-
-/*
- * rchan_callback implementations defining default channel behavior.  Used
- * in place of corresponding NULL values in client callback struct.
- */
-
-/*
- * subbuf_start() default callback.  Does nothing.
- */
-static int subbuf_start_default_callback (struct rchan_buf *buf,
-					  void *subbuf,
-					  void *prev_subbuf,
-					  size_t prev_padding)
-{
-	if (relay_buf_full(buf))
-		return 0;
-
-	return 1;
-}
-
-/*
- * buf_mapped() default callback.  Does nothing.
- */
-static void buf_mapped_default_callback(struct rchan_buf *buf,
-					struct file *filp)
-{
-}
-
-/*
- * buf_unmapped() default callback.  Does nothing.
- */
-static void buf_unmapped_default_callback(struct rchan_buf *buf,
-					  struct file *filp)
-{
-}
-
-/*
- * create_buf_file_create() default callback.  Creates file to represent buf.
- */
-static struct dentry *create_buf_file_default_callback(const char *filename,
-						       struct dentry *parent,
-						       int mode,
-						       struct rchan_buf *buf,
-						       int *is_global)
-{
-	return relayfs_create_file(filename, parent, mode,
-				   &relay_file_operations, buf);
-}
-
-/*
- * remove_buf_file() default callback.  Removes file representing relay buffer.
- */
-static int remove_buf_file_default_callback(struct dentry *dentry)
-{
-	return relayfs_remove(dentry);
-}
-
-/* relay channel default callbacks */
-static struct rchan_callbacks default_channel_callbacks = {
-	.subbuf_start = subbuf_start_default_callback,
-	.buf_mapped = buf_mapped_default_callback,
-	.buf_unmapped = buf_unmapped_default_callback,
-	.create_buf_file = create_buf_file_default_callback,
-	.remove_buf_file = remove_buf_file_default_callback,
-};
-
-/**
- *	wakeup_readers - wake up readers waiting on a channel
- *	@private: the channel buffer
- *
- *	This is the work function used to defer reader waking.  The
- *	reason waking is deferred is that calling directly from write
- *	causes problems if you're writing from say the scheduler.
- */
-static void wakeup_readers(void *private)
-{
-	struct rchan_buf *buf = private;
-	wake_up_interruptible(&buf->read_wait);
-}
-
-/**
- *	__relay_reset - reset a channel buffer
- *	@buf: the channel buffer
- *	@init: 1 if this is a first-time initialization
- *
- *	See relay_reset for description of effect.
- */
-static inline void __relay_reset(struct rchan_buf *buf, unsigned int init)
-{
-	size_t i;
-
-	if (init) {
-		init_waitqueue_head(&buf->read_wait);
-		kref_init(&buf->kref);
-		INIT_WORK(&buf->wake_readers, NULL, NULL);
-	} else {
-		cancel_delayed_work(&buf->wake_readers);
-		flush_scheduled_work();
-	}
-
-	buf->subbufs_produced = 0;
-	buf->subbufs_consumed = 0;
-	buf->bytes_consumed = 0;
-	buf->finalized = 0;
-	buf->data = buf->start;
-	buf->offset = 0;
-
-	for (i = 0; i < buf->chan->n_subbufs; i++)
-		buf->padding[i] = 0;
-
-	buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0);
-}
-
-/**
- *	relay_reset - reset the channel
- *	@chan: the channel
- *
- *	This has the effect of erasing all data from all channel buffers
- *	and restarting the channel in its initial state.  The buffers
- *	are not freed, so any mappings are still in effect.
- *
- *	NOTE: Care should be taken that the channel isn't actually
- *	being used by anything when this call is made.
- */
-void relay_reset(struct rchan *chan)
-{
-	unsigned int i;
-	struct rchan_buf *prev = NULL;
-
-	if (!chan)
-		return;
-
-	for (i = 0; i < NR_CPUS; i++) {
-		if (!chan->buf[i] || chan->buf[i] == prev)
-			break;
-		__relay_reset(chan->buf[i], 0);
-		prev = chan->buf[i];
-	}
-}
-
-/**
- *	relay_open_buf - create a new channel buffer in relayfs
- *
- *	Internal - used by relay_open().
- */
-static struct rchan_buf *relay_open_buf(struct rchan *chan,
-					const char *filename,
-					struct dentry *parent,
-					int *is_global)
-{
-	struct rchan_buf *buf;
-	struct dentry *dentry;
-
-	if (*is_global)
-		return chan->buf[0];
-
- 	buf = relay_create_buf(chan);
- 	if (!buf)
- 		return NULL;
-
-	/* Create file in fs */
- 	dentry = chan->cb->create_buf_file(filename, parent, S_IRUSR,
- 					   buf, is_global);
- 	if (!dentry) {
- 		relay_destroy_buf(buf);
-		return NULL;
- 	}
-
-	buf->dentry = dentry;
-	__relay_reset(buf, 1);
-
-	return buf;
-}
-
-/**
- *	relay_close_buf - close a channel buffer
- *	@buf: channel buffer
- *
- *	Marks the buffer finalized and restores the default callbacks.
- *	The channel buffer and channel buffer data structure are then freed
- *	automatically when the last reference is given up.
- */
-static inline void relay_close_buf(struct rchan_buf *buf)
-{
-	buf->finalized = 1;
-	buf->chan->cb = &default_channel_callbacks;
-	cancel_delayed_work(&buf->wake_readers);
-	flush_scheduled_work();
-	kref_put(&buf->kref, relay_remove_buf);
-}
-
-static inline void setup_callbacks(struct rchan *chan,
-				   struct rchan_callbacks *cb)
-{
-	if (!cb) {
-		chan->cb = &default_channel_callbacks;
-		return;
-	}
-
-	if (!cb->subbuf_start)
-		cb->subbuf_start = subbuf_start_default_callback;
-	if (!cb->buf_mapped)
-		cb->buf_mapped = buf_mapped_default_callback;
-	if (!cb->buf_unmapped)
-		cb->buf_unmapped = buf_unmapped_default_callback;
-	if (!cb->create_buf_file)
-		cb->create_buf_file = create_buf_file_default_callback;
-	if (!cb->remove_buf_file)
-		cb->remove_buf_file = remove_buf_file_default_callback;
-	chan->cb = cb;
-}
-
-/**
- *	relay_open - create a new relayfs channel
- *	@base_filename: base name of files to create
- *	@parent: dentry of parent directory, NULL for root directory
- *	@subbuf_size: size of sub-buffers
- *	@n_subbufs: number of sub-buffers
- *	@cb: client callback functions
- *
- *	Returns channel pointer if successful, NULL otherwise.
- *
- *	Creates a channel buffer for each cpu using the sizes and
- *	attributes specified.  The created channel buffer files
- *	will be named base_filename0...base_filenameN-1.  File
- *	permissions will be S_IRUSR.
- */
-struct rchan *relay_open(const char *base_filename,
-			 struct dentry *parent,
-			 size_t subbuf_size,
-			 size_t n_subbufs,
-			 struct rchan_callbacks *cb)
-{
-	unsigned int i;
-	struct rchan *chan;
-	char *tmpname;
-	int is_global = 0;
-
-	if (!base_filename)
-		return NULL;
-
-	if (!(subbuf_size && n_subbufs))
-		return NULL;
-
-	chan = kcalloc(1, sizeof(struct rchan), GFP_KERNEL);
-	if (!chan)
-		return NULL;
-
-	chan->version = RELAYFS_CHANNEL_VERSION;
-	chan->n_subbufs = n_subbufs;
-	chan->subbuf_size = subbuf_size;
-	chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
-	setup_callbacks(chan, cb);
-	kref_init(&chan->kref);
-
-	tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL);
-	if (!tmpname)
-		goto free_chan;
-
-	for_each_online_cpu(i) {
-		sprintf(tmpname, "%s%d", base_filename, i);
-		chan->buf[i] = relay_open_buf(chan, tmpname, parent,
-					      &is_global);
-		chan->buf[i]->cpu = i;
-		if (!chan->buf[i])
-			goto free_bufs;
-	}
-
-	kfree(tmpname);
-	return chan;
-
-free_bufs:
-	for (i = 0; i < NR_CPUS; i++) {
-		if (!chan->buf[i])
-			break;
-		relay_close_buf(chan->buf[i]);
-		if (is_global)
-			break;
-	}
-	kfree(tmpname);
-
-free_chan:
-	kref_put(&chan->kref, relay_destroy_channel);
-	return NULL;
-}
-
-/**
- *	relay_switch_subbuf - switch to a new sub-buffer
- *	@buf: channel buffer
- *	@length: size of current event
- *
- *	Returns either the length passed in or 0 if full.
-
- *	Performs sub-buffer-switch tasks such as invoking callbacks,
- *	updating padding counts, waking up readers, etc.
- */
-size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
-{
-	void *old, *new;
-	size_t old_subbuf, new_subbuf;
-
-	if (unlikely(length > buf->chan->subbuf_size))
-		goto toobig;
-
-	if (buf->offset != buf->chan->subbuf_size + 1) {
-		buf->prev_padding = buf->chan->subbuf_size - buf->offset;
-		old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
-		buf->padding[old_subbuf] = buf->prev_padding;
-		buf->subbufs_produced++;
-		if (waitqueue_active(&buf->read_wait)) {
-			PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf);
-			schedule_delayed_work(&buf->wake_readers, 1);
-		}
-	}
-
-	old = buf->data;
-	new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
-	new = buf->start + new_subbuf * buf->chan->subbuf_size;
-	buf->offset = 0;
-	if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) {
-		buf->offset = buf->chan->subbuf_size + 1;
-		return 0;
-	}
-	buf->data = new;
-	buf->padding[new_subbuf] = 0;
-
-	if (unlikely(length + buf->offset > buf->chan->subbuf_size))
-		goto toobig;
-
-	return length;
-
-toobig:
-	buf->chan->last_toobig = length;
-	return 0;
-}
-
-/**
- *	relay_subbufs_consumed - update the buffer's sub-buffers-consumed count
- *	@chan: the channel
- *	@cpu: the cpu associated with the channel buffer to update
- *	@subbufs_consumed: number of sub-buffers to add to current buf's count
- *
- *	Adds to the channel buffer's consumed sub-buffer count.
- *	subbufs_consumed should be the number of sub-buffers newly consumed,
- *	not the total consumed.
- *
- *	NOTE: kernel clients don't need to call this function if the channel
- *	mode is 'overwrite'.
- */
-void relay_subbufs_consumed(struct rchan *chan,
-			    unsigned int cpu,
-			    size_t subbufs_consumed)
-{
-	struct rchan_buf *buf;
-
-	if (!chan)
-		return;
-
-	if (cpu >= NR_CPUS || !chan->buf[cpu])
-		return;
-
-	buf = chan->buf[cpu];
-	buf->subbufs_consumed += subbufs_consumed;
-	if (buf->subbufs_consumed > buf->subbufs_produced)
-		buf->subbufs_consumed = buf->subbufs_produced;
-}
-
-/**
- *	relay_destroy_channel - free the channel struct
- *
- *	Should only be called from kref_put().
- */
-void relay_destroy_channel(struct kref *kref)
-{
-	struct rchan *chan = container_of(kref, struct rchan, kref);
-	kfree(chan);
-}
-
-/**
- *	relay_close - close the channel
- *	@chan: the channel
- *
- *	Closes all channel buffers and frees the channel.
- */
-void relay_close(struct rchan *chan)
-{
-	unsigned int i;
-	struct rchan_buf *prev = NULL;
-
-	if (!chan)
-		return;
-
-	for (i = 0; i < NR_CPUS; i++) {
-		if (!chan->buf[i] || chan->buf[i] == prev)
-			break;
-		relay_close_buf(chan->buf[i]);
-		prev = chan->buf[i];
-	}
-
-	if (chan->last_toobig)
-		printk(KERN_WARNING "relayfs: one or more items not logged "
-		       "[item size (%Zd) > sub-buffer size (%Zd)]\n",
-		       chan->last_toobig, chan->subbuf_size);
-
-	kref_put(&chan->kref, relay_destroy_channel);
-}
-
-/**
- *	relay_flush - close the channel
- *	@chan: the channel
- *
- *	Flushes all channel buffers i.e. forces buffer switch.
- */
-void relay_flush(struct rchan *chan)
-{
-	unsigned int i;
-	struct rchan_buf *prev = NULL;
-
-	if (!chan)
-		return;
-
-	for (i = 0; i < NR_CPUS; i++) {
-		if (!chan->buf[i] || chan->buf[i] == prev)
-			break;
-		relay_switch_subbuf(chan->buf[i], 0);
-		prev = chan->buf[i];
-	}
-}
-
-EXPORT_SYMBOL_GPL(relay_open);
-EXPORT_SYMBOL_GPL(relay_close);
-EXPORT_SYMBOL_GPL(relay_flush);
-EXPORT_SYMBOL_GPL(relay_reset);
-EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
-EXPORT_SYMBOL_GPL(relay_switch_subbuf);
-EXPORT_SYMBOL_GPL(relay_buf_full);
diff --git a/fs/relayfs/relay.h b/fs/relayfs/relay.h
deleted file mode 100644
index 0993d3e..0000000
--- a/fs/relayfs/relay.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#ifndef _RELAY_H
-#define _RELAY_H
-
-extern int relayfs_remove(struct dentry *dentry);
-extern int relay_buf_empty(struct rchan_buf *buf);
-extern void relay_destroy_channel(struct kref *kref);
-
-#endif /* _RELAY_H */
diff --git a/include/linux/relayfs_fs.h b/include/linux/relayfs_fs.h
index 435ebb1..1ef4108 100644
--- a/include/linux/relayfs_fs.h
+++ b/include/linux/relayfs_fs.h
@@ -183,6 +183,7 @@ extern struct dentry *relayfs_create_fil
 					  struct file_operations *fops,
 					  void *data);
 extern int relayfs_remove_file(struct dentry *dentry);
+extern int relayfs_remove(struct dentry *dentry);
 
 /**
  *	relay_write - write data into the channel
diff --git a/kernel/relay.c b/kernel/relay.c
index 7dd674b..9cff3b3 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -278,7 +278,12 @@ static struct dentry *create_buf_file_de
 						       struct rchan_buf *buf,
 						       int *is_global)
 {
+#ifdef CONFIG_RELAYFS_FS
+	return relayfs_create_file(filename, parent, mode,
+				   &relay_file_operations, buf);
+#else
 	return NULL;
+#endif
 }
 
 /*
@@ -286,7 +291,11 @@ static struct dentry *create_buf_file_de
  */
 static int remove_buf_file_default_callback(struct dentry *dentry)
 {
+#ifdef CONFIG_RELAYFS_FS
+	return relayfs_remove(dentry);
+#else
 	return -EINVAL;
+#endif
 }
 
 /* relay channel default callbacks */
-- 
1.0.GIT