Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261847AbVBJCw2 (ORCPT ); Wed, 9 Feb 2005 21:52:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261873AbVBJCw2 (ORCPT ); Wed, 9 Feb 2005 21:52:28 -0500 Received: from e33.co.us.ibm.com ([32.97.110.131]:2479 "EHLO e33.co.us.ibm.com") by vger.kernel.org with ESMTP id S261847AbVBJCty (ORCPT ); Wed, 9 Feb 2005 21:49:54 -0500 From: Tom Zanussi MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16906.52160.870346.806462@tut.ibm.com> Date: Wed, 9 Feb 2005 20:49:36 -0600 To: linux-kernel Cc: Greg KH , Andrew Morton , Andi Kleen , Roman Zippel , Robert Wisniewski , Tim Bird , Christoph Hellwig , karim@opersys.com Subject: [PATCH] relayfs redux, part 4 X-Mailer: VM 7.17 under 21.4 (patch 15) "Security Through Obscurity" XEmacs Lucid Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 43967 Lines: 1632 Hi, Here's the latest relayfs patch, incorporating the previous round of suggestions. Thanks to everyone who sent comments. Here's a list of the major changes: - replaced remap_page_range() and reserved bits with a nopage() handler. - buffers are now allocated/freed as part of inode alloc/destroy. - got rid of the automatic creation/teardown of directory hierarchies, and exported create/remove dir functions instead. - replaced the fileop callback with explicit map/unmap callbacks - these were the only fileops currently being used by anything, so I got rid of the other cases. - relay_write() and __relay_write() no longer return a value - it doesn't really make sense for clients to check a return value in the fast path anyway. - added a buf_full() callback to notify users that a buffer has become full and therefore events might be lost. - got rid of the 'helper' macros, which weren't helping much. - various other bits of code and comment cleanup. Also, there was some question as to whether or not the memcpy in relay_write() was being inlined properly - I looked at the generated assembly code, and it seems to be, but I'll be taking a closer look later. This is what the API now looks like: API functions: rchan *relay_open(base_filename, parent, subbuf_size, n_subbufs, flags, callbacks); void relay_close(chan); dentry *relayfs_create_dir(name, parent); int relayfs_remove_dir(dentry); void relay_reset(chan); void relay_write(chan, data, length); void __relay_write(chan, data, length); void *relay_reserve(chan, length); void relay_subbufs_consumed(chan, subbufs_consumed, cpu); void relay_commit(buf, subbuf_idx, count); callbacks: int subbuf_start(buf, subbuf, prev_subbuf_idx); int deliver(buffer, subbuf, subbuf_idx); void buf_mapped(buf, filp); void buf_unmapped(buf, filp); void buf_full(buf); As before, I've tested this code on a single proc machine using a hacked version of the kprobes network packet tracing module, which can be found here: http://prdownloads.sourceforge.net/dprobes/plog.tar.gz?download If people are more or less happy with the current version, I'll do some SMP testing and write some Documentation. Thanks, Tom Signed-off-by: Tom Zanussi fs/Kconfig | 12 fs/Makefile | 1 fs/relayfs/Makefile | 4 fs/relayfs/buffers.c | 119 ++++++++ fs/relayfs/buffers.h | 14 + fs/relayfs/inode.c | 447 ++++++++++++++++++++++++++++++++ fs/relayfs/relay.c | 616 +++++++++++++++++++++++++++++++++++++++++++++ fs/relayfs/relay.h | 31 ++ include/linux/relayfs_fs.h | 253 ++++++++++++++++++ 9 files changed, 1497 insertions(+) diff -urpN -X dontdiff linux-2.6.10/fs/Kconfig linux-2.6.10-cur/fs/Kconfig --- linux-2.6.10/fs/Kconfig 2004-12-24 15:34:58.000000000 -0600 +++ linux-2.6.10-cur/fs/Kconfig 2005-01-31 21:49:27.000000000 -0600 @@ -972,6 +972,18 @@ config RAMFS To compile this as a module, choose M here: the module will be called ramfs. +config RELAYFS_FS + tristate "Relayfs file system support" + ---help--- + Relayfs is a high-speed data relay filesystem designed to provide + an efficient mechanism for tools and facilities to relay large + amounts of data from kernel space to user space. + + To compile this code as a module, choose M here: the module will be + called relayfs. + + If unsure, say N. + endmenu menu "Miscellaneous filesystems" diff -urpN -X dontdiff linux-2.6.10/fs/Makefile linux-2.6.10-cur/fs/Makefile --- linux-2.6.10/fs/Makefile 2004-12-24 15:34:58.000000000 -0600 +++ linux-2.6.10-cur/fs/Makefile 2005-01-31 21:49:27.000000000 -0600 @@ -94,3 +94,4 @@ obj-$(CONFIG_AFS_FS) += afs/ obj-$(CONFIG_BEFS_FS) += befs/ obj-$(CONFIG_HOSTFS) += hostfs/ obj-$(CONFIG_HPPFS) += hppfs/ +obj-$(CONFIG_RELAYFS_FS) += relayfs/ diff -urpN -X dontdiff linux-2.6.10/fs/relayfs/Makefile linux-2.6.10-cur/fs/relayfs/Makefile --- linux-2.6.10/fs/relayfs/Makefile 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.10-cur/fs/relayfs/Makefile 2005-02-03 06:34:11.000000000 -0600 @@ -0,0 +1,4 @@ +obj-$(CONFIG_RELAYFS_FS) += relayfs.o + +relayfs-y := relay.o buffers.o inode.o + diff -urpN -X dontdiff linux-2.6.10/fs/relayfs/buffers.c linux-2.6.10-cur/fs/relayfs/buffers.c --- linux-2.6.10/fs/relayfs/buffers.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.10-cur/fs/relayfs/buffers.c 2005-02-03 08:16:39.000000000 -0600 @@ -0,0 +1,119 @@ +/* + * RelayFS buffer management code. + * + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) + * + * This file is released under the GPL. + */ + +#include +#include +#include +#include "buffers.h" + +/** + * alloc_page_array - alloc array to hold pages, but not pages + * @size: the total size of the memory represented by the page array + * @page_count: the number of pages the array can hold + * + * Returns a pointer to the page array if successful, NULL otherwise. + */ +static inline struct page **alloc_page_array(int size, int *page_count) +{ + int n_pages; + struct page **page_array; + + size = PAGE_ALIGN(size); + n_pages = size >> PAGE_SHIFT; + + page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL); + if (!page_array) + return NULL; + *page_count = n_pages; + + return page_array; +} + +/** + * depopulate_page_array - free and unreserve all pages in the array + * @page_array: pointer to the page array + * @page_count: number of pages to free + */ +static void depopulate_page_array(struct page **page_array, int page_count) +{ + int i; + + for (i = 0; i < page_count; i++) + __free_page(page_array[i]); +} + +/** + * populate_page_array - allocate and reserve pages + * @page_array: pointer to the page array + * @page_count: number of pages to allocate + * + * Returns 0 if successful, negative otherwise. + */ +static int populate_page_array(struct page **page_array, int page_count) +{ + int i; + + for (i = 0; i < page_count; i++) { + page_array[i] = alloc_page(GFP_KERNEL); + if (unlikely(!page_array[i])) { + depopulate_page_array(page_array, i); + return -ENOMEM; + } + } + return 0; +} + +/** + * relay_alloc_rchan_buf - allocate a channel buffer + * @size: total size of the buffer + * @page_array: receives a pointer to the buffer's page array + * @page_count: receives the number of pages allocated + * + * Returns a pointer to the resulting buffer, NULL if unsuccessful + */ +void *relay_alloc_rchan_buf(unsigned long size, struct page ***page_array, + int *page_count) +{ + void *mem; + + *page_array = alloc_page_array(size, page_count); + if (!*page_array) + return NULL; + + if (populate_page_array(*page_array, *page_count)) { + kfree(*page_array); + *page_array = NULL; + return NULL; + } + + mem = vmap(*page_array, *page_count, GFP_KERNEL, PAGE_KERNEL); + if (!mem) { + depopulate_page_array(*page_array, *page_count); + kfree(*page_array); + *page_array = NULL; + return NULL; + } + memset(mem, 0, size); + + return mem; +} + +/** + * relay_free_rchan_buf - free a channel buffer + * @buf: pointer to the buffer to free + * @page_array: pointer to the buffer's page array + * @page_count: number of pages in page array + */ +void relay_free_rchan_buf(void *buf, struct page **page_array, + int page_count) +{ + vunmap(buf); + depopulate_page_array(page_array, page_count); + kfree(page_array); +} diff -urpN -X dontdiff linux-2.6.10/fs/relayfs/buffers.h linux-2.6.10-cur/fs/relayfs/buffers.h --- linux-2.6.10/fs/relayfs/buffers.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.10-cur/fs/relayfs/buffers.h 2005-01-31 21:49:27.000000000 -0600 @@ -0,0 +1,14 @@ +#ifndef _BUFFERS_H +#define _BUFFERS_H + +/* This inspired by rtai/shmem */ +#define FIX_SIZE(x) (((x) - 1) & PAGE_MASK) + PAGE_SIZE + +extern void *relay_alloc_rchan_buf(unsigned long size, + struct page ***page_array, + int *page_count); +extern void relay_free_rchan_buf(void *buf, + struct page **page_array, + int page_count); + +#endif/* _BUFFERS_H */ diff -urpN -X dontdiff linux-2.6.10/fs/relayfs/inode.c linux-2.6.10-cur/fs/relayfs/inode.c --- linux-2.6.10/fs/relayfs/inode.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.10-cur/fs/relayfs/inode.c 2005-02-06 00:22:18.000000000 -0600 @@ -0,0 +1,447 @@ +/* + * VFS-related code for RelayFS, a high-speed data relay filesystem. + * + * Copyright (C) 2003 - Tom Zanussi , IBM Corp + * Copyright (C) 2003 - Karim Yaghmour + * + * Based on ramfs, Copyright (C) 2002 - Linus Torvalds + * + * This file is released under the GPL. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "relay.h" + +#define RELAYFS_MAGIC 0x26F82121 + +static struct vfsmount * relayfs_mount; +static int relayfs_mount_count; +static kmem_cache_t * relayfs_inode_cachep; + +static struct backing_dev_info relayfs_backing_dev_info = { + .ra_pages = 0, /* No readahead */ + .memory_backed = 1, /* Does not contribute to dirty memory */ +}; + +static struct inode *relayfs_get_inode(struct super_block *sb, int mode, + struct rchan *chan) +{ + struct rchan_buf *buf = NULL; + struct inode *inode; + + if (S_ISREG(mode)) { + BUG_ON(!chan); + buf = rchan_create_buf(chan); + if (!buf) + return NULL; + } + + inode = new_inode(sb); + if (!inode) { + rchan_destroy_buf(buf); + return NULL; + } + + inode->i_mode = mode; + inode->i_uid = 0; + inode->i_gid = 0; + inode->i_blksize = PAGE_CACHE_SIZE; + inode->i_blocks = 0; + inode->i_mapping->backing_dev_info = &relayfs_backing_dev_info; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + switch (mode & S_IFMT) { + case S_IFREG: + inode->i_fop = &relayfs_file_operations; + RELAYFS_I(inode)->buf = buf; + break; + case S_IFDIR: + inode->i_op = &simple_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inode->i_nlink++; + break; + default: + break; + } + + return inode; +} + +/** + * relayfs_create_entry - create a relayfs directory or file + * @name: the name of the file to create + * @parent: parent directory + * @mode: mode + * @chan: relay channel associated with the file + * @dentry: result dentry + * + * Creates a file or directory with the specifed permissions. + */ +static int relayfs_create_entry(const char *name, struct dentry *parent, + int mode, struct rchan *chan, + struct dentry **dentry) +{ + struct qstr qname; + struct dentry *d; + struct inode *inode; + int error = 0; + + BUG_ON(!(S_ISREG(mode) || S_ISDIR(mode))); + + error = simple_pin_fs("relayfs", &relayfs_mount, &relayfs_mount_count); + if (error) { + printk(KERN_ERR "Couldn't mount relayfs: errcode %d\n", error); + return error; + } + + qname.name = name; + qname.len = strlen(name); + qname.hash = full_name_hash(name, qname.len); + + if (!parent) + if (relayfs_mount && relayfs_mount->mnt_sb) + parent = relayfs_mount->mnt_sb->s_root; + + if (!parent) { + simple_release_fs(&relayfs_mount, &relayfs_mount_count); + return -EINVAL; + } + + parent = dget(parent); + down(&parent->d_inode->i_sem); + d = lookup_hash(&qname, parent); + if (IS_ERR(d)) { + error = PTR_ERR(d); + goto release_mount; + } + + if (d->d_inode) { + error = -EEXIST; + goto release_mount; + } + + inode = relayfs_get_inode(parent->d_inode->i_sb, mode, chan); + if (!inode) { + error = -ENOSPC; + goto release_mount; + } + + d_instantiate(d, inode); + dget(d); /* Extra count - pin the dentry in core */ + + if (S_ISDIR(mode)) + parent->d_inode->i_nlink++; + + goto exit; + +release_mount: + simple_release_fs(&relayfs_mount, &relayfs_mount_count); + +exit: + *dentry = d; + up(&parent->d_inode->i_sem); + dput(parent); + + return error; +} + +/** + * relayfs_create_file - create a file in the relay filesystem + * @name: the name of the file to create + * @parent: parent directory + * @mode: mode, if not specied the default perms are used + * @chan: channel associated with the file + * + * Returns file dentry if successful, NULL otherwise. + * + * The file will be created user r on behalf of current user. + */ +struct dentry *relayfs_create_file(const char *name, struct dentry *parent, + int mode, struct rchan *chan) +{ + struct dentry *dentry; + int error; + + if (!mode) + mode = S_IRUSR; + mode = (mode & S_IALLUGO) | S_IFREG; + + error = relayfs_create_entry(name, parent, mode, chan, &dentry); + if (error) + return NULL; + + return dentry; +} + +/** + * relayfs_create_dir - create a directory in the relay filesystem + * @name: the name of the directory to create + * @parent: parent directory, NULL if parent should be fs root + * + * Returns directory dentry if successful, NULL otherwise. + * + * The directory will be created world rwx on behalf of current user. + */ +struct dentry *relayfs_create_dir(const char *name, struct dentry *parent) +{ + int error; + struct dentry *dentry = NULL; + int mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + + if (!name) + return NULL; + + error = relayfs_create_entry(name, parent, mode, NULL, &dentry); + if (error) + return NULL; + + return dentry; +} + +/** + * relayfs_remove - remove a file or directory in the relay filesystem + * @dentry: file or directory dentry + */ +int relayfs_remove(struct dentry *dentry) +{ + struct dentry *parent = dentry->d_parent; + + if (!parent) + return -EINVAL; + + parent = dget(parent); + down(&parent->d_inode->i_sem); + if (dentry->d_inode) { + simple_unlink(parent->d_inode, dentry); + d_delete(dentry); + } + dput(dentry); + up(&parent->d_inode->i_sem); + dput(parent); + + simple_release_fs(&relayfs_mount, &relayfs_mount_count); + + return 0; +} + +/** + * relayfs_remove_dir - remove a directory in the relay filesystem + * @dentry: directory dentry + * + * Returns 0 if successful, negative otherwise. + */ +int relayfs_remove_dir(struct dentry *dentry) +{ + if (!dentry) + return -EINVAL; + + return relayfs_remove(dentry); +} + +/** + * relayfs_open - open file op for relayfs files + * @inode: the inode + * @filp: the file + * + * Associates the channel buffer with the file, and increments the + * channel buffer refcount. + */ +int relayfs_open(struct inode *inode, struct file *filp) +{ + struct rchan_buf *buf = RELAYFS_I(inode)->buf; + kref_get(&buf->kref); + + return 0; +} + +/** + * relayfs_mmap - mmap file op for relayfs files + * @filp: the file + * @vma: the vma describing what to map + * + * Calls upon relay_mmap_buffer to map the file into user space. + */ +int relayfs_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct inode *inode = filp->f_dentry->d_inode; + struct rchan_buf *buf = RELAYFS_I(inode)->buf; + + return relay_mmap_buffer(buf, vma); +} + +/** + * relayfs_poll - poll file op for relayfs files + * @filp: the file + * @wait: poll table + * + * Poll implemention. + */ +unsigned int relayfs_poll(struct file *filp, poll_table *wait) +{ + unsigned int mask = 0; + struct inode *inode = filp->f_dentry->d_inode; + struct rchan_buf *buf = RELAYFS_I(inode)->buf; + + 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; +} + +/** + * relayfs_release - release file op for relayfs files + * @inode: the inode + * @filp: the file + * + * Decrements the channel refcount, as the filesystem is + * no longer using it. + */ +int relayfs_release(struct inode *inode, struct file *filp) +{ + struct rchan_buf *buf = RELAYFS_I(inode)->buf; + + kref_put(&buf->kref, relay_destroy_buf); + + return 0; +} + +/** + * relayfs alloc_inode() implementation + */ +static struct inode *relayfs_alloc_inode(struct super_block *sb) +{ + struct relayfs_inode_info *p; + p = (struct relayfs_inode_info *)kmem_cache_alloc(relayfs_inode_cachep, + SLAB_KERNEL); + if (!p) + return NULL; + p->buf = NULL; + + return &p->vfs_inode; +} + +/** + * relayfs destroy_inode() implementation + */ +static void relayfs_destroy_inode(struct inode *inode) +{ + if (RELAYFS_I(inode)->buf) + rchan_destroy_buf(RELAYFS_I(inode)->buf); + + kmem_cache_free(relayfs_inode_cachep, RELAYFS_I(inode)); +} + +static void init_once(void *p, kmem_cache_t *cachep, unsigned long flags) +{ + struct relayfs_inode_info *i = p; + if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR) + inode_init_once(&i->vfs_inode); +} + +struct file_operations relayfs_file_operations = { + .open = relayfs_open, + .poll = relayfs_poll, + .mmap = relayfs_mmap, + .release = relayfs_release, +}; + +static struct super_operations relayfs_ops = { + .statfs = simple_statfs, + .drop_inode = generic_delete_inode, + .alloc_inode = relayfs_alloc_inode, + .destroy_inode = relayfs_destroy_inode, +}; + +static int relayfs_fill_super(struct super_block * sb, void * data, int silent) +{ + struct inode *inode; + struct dentry *root; + int mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = RELAYFS_MAGIC; + sb->s_op = &relayfs_ops; + inode = relayfs_get_inode(sb, mode, NULL); + + if (!inode) + return -ENOMEM; + + root = d_alloc_root(inode); + if (!root) { + iput(inode); + return -ENOMEM; + } + sb->s_root = root; + + return 0; +} + +static struct super_block * relayfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *data) +{ + return get_sb_single(fs_type, flags, data, relayfs_fill_super); +} + +static struct file_system_type relayfs_fs_type = { + .owner = THIS_MODULE, + .name = "relayfs", + .get_sb = relayfs_get_sb, + .kill_sb = kill_litter_super, +}; + +static int __init init_relayfs_fs(void) +{ + int err; + + relayfs_inode_cachep = kmem_cache_create("relayfs_inode_cache", + sizeof(struct relayfs_inode_info), 0, + 0, init_once, NULL); + if (!relayfs_inode_cachep) + return -ENOMEM; + + err = register_filesystem(&relayfs_fs_type); + if (err) + kmem_cache_destroy(relayfs_inode_cachep); + + return err; +} + +static void __exit exit_relayfs_fs(void) +{ + unregister_filesystem(&relayfs_fs_type); + kmem_cache_destroy(relayfs_inode_cachep); +} + +module_init(init_relayfs_fs) +module_exit(exit_relayfs_fs) + +EXPORT_SYMBOL_GPL(relayfs_open); +EXPORT_SYMBOL_GPL(relayfs_poll); +EXPORT_SYMBOL_GPL(relayfs_mmap); +EXPORT_SYMBOL_GPL(relayfs_release); +EXPORT_SYMBOL_GPL(relayfs_file_operations); +EXPORT_SYMBOL_GPL(relayfs_create_dir); +EXPORT_SYMBOL_GPL(relayfs_remove_dir); + +MODULE_AUTHOR("Tom Zanussi and Karim Yaghmour "); +MODULE_DESCRIPTION("Relay Filesystem"); +MODULE_LICENSE("GPL"); + diff -urpN -X dontdiff linux-2.6.10/fs/relayfs/relay.c linux-2.6.10-cur/fs/relayfs/relay.c --- linux-2.6.10/fs/relayfs/relay.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.10-cur/fs/relayfs/relay.c 2005-02-06 00:22:32.000000000 -0600 @@ -0,0 +1,616 @@ +/* + * Public API and common code for RelayFS. + * + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) + * + * This file is released under the GPL. + */ + +#include +#include +#include +#include +#include +#include +#include +#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) +{ + int produced = atomic_read(&buf->subbufs_produced); + int consumed = atomic_read(&buf->subbufs_consumed); + + return (produced - consumed) ? 0 : 1; +} + +/** + * relay_buf_full - boolean, is the channel buffer full? + * @buf: channel buffer + * + * Returns 1 if the buffer is full, 0 otherwise. + */ +static inline int relay_buf_full(struct rchan_buf *buf) +{ + int produced, consumed; + + if (relay_mode_continuous(buf->chan)) + return 0; + + produced = atomic_read(&buf->subbufs_produced); + consumed = atomic_read(&buf->subbufs_consumed); + + return (produced - consumed > buf->chan->n_subbufs - 1) ? 1 : 0; +} + +/* + * 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_buffer: - mmap 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_buffer(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; +} + +/* + * 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, + unsigned prev_subbuf_idx) +{ + return 0; +} + +/* + * deliver() default callback. Does nothing. + */ +static void deliver_default_callback (struct rchan_buf *buf, + void *subbuf, + unsigned subbuf_idx) +{ +} + +/* + * 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) +{ +} + +/* + * buf_full() default callback. Does nothing. + */ +static void buf_full_default_callback(struct rchan_buf *buf) +{ +} + +/* relay channel default callbacks */ +static struct rchan_callbacks default_channel_callbacks = { + .subbuf_start = subbuf_start_default_callback, + .deliver = deliver_default_callback, + .buf_mapped = buf_mapped_default_callback, + .buf_unmapped = buf_unmapped_default_callback, + .buf_full = buf_full_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); +} + +/** + * get_next_subbuf - return next sub-buffer within channel buffer + * @buf: channel buffer + */ +static inline void *get_next_subbuf(struct rchan_buf *buf) +{ + void *next = buf->data + buf->chan->subbuf_size; + + if (next >= buf->start + buf->chan->subbuf_size * buf->chan->n_subbufs) + next = buf->start; + + return next; +} + +/** + * rchan_destroy_buf - destroy an rchan_buf struct and associated buffer + * @buf: the buffer struct + */ +void rchan_destroy_buf(struct rchan_buf *buf) +{ + if (likely(buf->start)) + relay_free_rchan_buf(buf->start, buf->page_array, buf->page_count); + kfree(buf->padding); + kfree(buf->commit); + kfree(buf); +} + +/** + * relay_destroy_buf - destroy 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_destroy_buf(struct kref *kref) +{ + struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref); + relayfs_remove(buf->dentry); +} + +/** + * __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, int init) +{ + int i; + + if (init) { + init_waitqueue_head(&buf->read_wait); + kref_init(&buf->kref); + } + + atomic_set(&buf->subbufs_produced, 0); + atomic_set(&buf->subbufs_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->commit[i] = 0; + } + + INIT_WORK(&buf->wake_readers, NULL, NULL); +} + +/** + * relay_reset - reset the channel + * @chan: the channel + * + * Returns 0 if successful, negative if not. + * + * 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) +{ + int i; + + for (i = 0; i < NR_CPUS; i++) + if (chan->buf[i] != NULL) + __relay_reset(chan->buf[i], 0); +} + +/** + * check_attribute_flags - check sanity of channel attributes + * @attibute_flags: channel attributes + * + * Returns 0 if successful, negative otherwise. + */ +static inline int check_attribute_flags(u32 attribute_flags) +{ + if ((attribute_flags & RELAY_MODE_CONTINUOUS) && + (attribute_flags & RELAY_MODE_NO_OVERWRITE)) + return -EINVAL; /* Can't have it both ways */ + + if (!(attribute_flags & RELAY_MODE_CONTINUOUS) && + !(attribute_flags & RELAY_MODE_NO_OVERWRITE)) + return -EINVAL; /* Gotta have it one way */ + + return 0; +} + +/** + * rchan_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 *rchan_create_buf(struct rchan *chan) +{ + struct page **page_array; + int page_count; + struct rchan_buf *buf; + + buf = kcalloc(1, sizeof(struct rchan_buf), GFP_KERNEL); + if (!buf) + return NULL; + + buf->padding = kmalloc(chan->n_subbufs * sizeof(unsigned *), GFP_KERNEL); + if (!buf->padding) + goto free_buf; + + buf->commit = kmalloc(chan->n_subbufs * sizeof(unsigned *), GFP_KERNEL); + if (!buf->commit) + goto free_padding; + + buf->start = relay_alloc_rchan_buf(chan->alloc_size, &page_array, &page_count); + if (!buf->start) + goto free_commit; + + buf->page_array = page_array; + buf->page_count = page_count; + buf->chan = chan; + return buf; + +free_commit: + kfree(buf->commit); + +free_padding: + kfree(buf->padding); + +free_buf: + kfree(buf); + return NULL; +} + +/** + * 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) +{ + struct rchan_buf *buf; + struct dentry *dentry; + + /* Create file in fs */ + dentry = relayfs_create_file(filename, parent, S_IRUSR, chan); + if (!dentry) + return NULL; + + buf = RELAYFS_I(dentry->d_inode)->buf; + buf->dentry = dentry; + __relay_reset(buf, 1); + + return buf; +} + +static void relay_close_buf(struct rchan_buf *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->deliver) + cb->deliver = deliver_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->buf_full) + cb->buf_full = buf_full_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 + * @attribute_flags: channel attributes + * @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, + unsigned subbuf_size, + unsigned n_subbufs, + u32 attribute_flags, + struct rchan_callbacks *cb) +{ + int i; + struct rchan *chan; + char *tmpname; + + if (!base_filename) + return NULL; + + if (check_attribute_flags(attribute_flags)) + return NULL; + + chan = kcalloc(1, sizeof(struct rchan), GFP_KERNEL); + if (!chan) + return NULL; + + chan->version = RELAYFS_CHANNEL_VERSION; + chan->flags = attribute_flags; + chan->n_subbufs = n_subbufs; + chan->subbuf_size = subbuf_size; + chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs); + setup_callbacks(chan, cb); + + 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); + if (!chan->buf[i]) + goto free_bufs; + } + + kfree(tmpname); + return chan; + +free_bufs: + for (i = 0; i < NR_CPUS; i++) + if (chan->buf[i]) + relay_close_buf(chan->buf[i]); + kfree(tmpname); + +free_chan: + kfree(chan); + return NULL; +} + +/** + * deliver_check - deliver a guaranteed full sub-buffer if applicable + */ +static inline void deliver_check(struct rchan_buf *buf, + unsigned subbuf_idx) +{ + unsigned full; + void *subbuf; + + full = buf->chan->subbuf_size - buf->padding[subbuf_idx]; + + if (buf->commit[subbuf_idx] == full) { + subbuf = buf->start + subbuf_idx * buf->chan->subbuf_size; + buf->chan->cb->deliver(buf, subbuf, subbuf_idx); + } +} + +/** + * 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. + */ +unsigned relay_switch_subbuf(struct rchan_buf *buf, unsigned length) +{ + int cur_subbuf, prev_subbuf, subbufs_produced; + unsigned start = 0, padding = buf->chan->subbuf_size - buf->offset; + + if (unlikely(relay_buf_full(buf))) + return 0; + + subbufs_produced = atomic_read(&buf->subbufs_produced); + cur_subbuf = prev_subbuf = subbufs_produced % buf->chan->n_subbufs; + buf->padding[cur_subbuf] = padding; + + atomic_inc(&buf->subbufs_produced); + + if (waitqueue_active(&buf->read_wait)) { + PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf); + schedule_delayed_work(&buf->wake_readers, 1); + } + + if (unlikely(relay_buf_full(buf))) { + return 0; + buf->chan->cb->buf_full(buf); + } + + buf->data = get_next_subbuf(buf); + cur_subbuf = (subbufs_produced + 1) % buf->chan->n_subbufs; + buf->padding[cur_subbuf] = buf->commit[cur_subbuf] = 0; + start = buf->chan->cb->subbuf_start(buf, buf->data, prev_subbuf); + deliver_check(buf, prev_subbuf); + + buf->offset = start; + + return length; +} + +/** + * relay_commit - add count bytes to a sub-buffer's commit count + * @buf: channel buffer + * @subbuf_idx: sub-buffer index to add to + * @count: number of bytes committed + * + * Invokes deliver() callback if sub-buffer is completely written + */ +void relay_commit(struct rchan_buf *buf, + unsigned subbuf_idx, + unsigned count) +{ + if (subbuf_idx >= buf->chan->n_subbufs) + return; + + buf->commit[subbuf_idx] += count; + + deliver_check(buf, subbuf_idx); +} + +/** + * relay_subbufs_consumed - update the buffer's sub-buffers-consumed count + * @chan: the channel + * @subbufs_consumed: number of sub-buffers to add to current buf's count + * @cpu: the cpu associated with the channel buffer to update + * + * 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 + * is MODE_CONTINUOUS. + */ +void relay_subbufs_consumed(struct rchan *chan, int subbufs_consumed, int cpu) +{ + int produced, consumed; + struct rchan_buf *buf = chan->buf[cpu]; + + atomic_add(subbufs_consumed, &buf->subbufs_consumed); + produced = atomic_read(&buf->subbufs_produced); + consumed = atomic_read(&buf->subbufs_consumed); + if (consumed > produced) + atomic_set(&buf->subbufs_consumed, produced); +} + +/** + * relay_close_buf - close a channel buffer + * @buf: channel buffer + * + * Finalizes the last sub-buffer and marks the buffer as finalized. + * The channel buffer and channel buffer data structure are then freed + * automatically when the last reference is given up. + */ +static void relay_close_buf(struct rchan_buf *buf) +{ + relay_switch_subbuf(buf, 0); + + buf->finalized = 1; + buf->chan->cb = &default_channel_callbacks; + + kref_put(&buf->kref, relay_destroy_buf); +} + +/** + * relay_close - close the channel + * @chan: the channel + * + * Closes all channel buffers and frees the channel. + */ +void relay_close(struct rchan *chan) +{ + int i; + + for (i = 0; i < NR_CPUS; i++) + if (chan->buf[i]) + relay_close_buf(chan->buf[i]); + kfree(chan); +} + +EXPORT_SYMBOL_GPL(relay_open); +EXPORT_SYMBOL_GPL(relay_close); +EXPORT_SYMBOL_GPL(relay_reset); +EXPORT_SYMBOL_GPL(relay_subbufs_consumed); +EXPORT_SYMBOL_GPL(relay_switch_subbuf); +EXPORT_SYMBOL_GPL(relay_commit); diff -urpN -X dontdiff linux-2.6.10/fs/relayfs/relay.h linux-2.6.10-cur/fs/relayfs/relay.h --- linux-2.6.10/fs/relayfs/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.10-cur/fs/relayfs/relay.h 2005-02-05 23:00:10.000000000 -0600 @@ -0,0 +1,31 @@ +/* + * fs/relayfs/relay.h + * + * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com), Opersys inc. + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * + * RelayFS internal definitions and declarations + */ + +#ifndef _RELAY_H +#define _RELAY_H + +/* + * Internal relayfs kernel API, fs/relayfs/relay.c + */ + +#define relay_mode_continuous(chan) (((chan)->flags & RELAY_MODE_CONTINUOUS) ? 1 : 0) + +struct dentry *relayfs_create_file(const char *name, + struct dentry *parent, + int mode, + struct rchan *chan); +extern int relayfs_remove(struct dentry *dentry); +extern int relay_mmap_buffer(struct rchan_buf *buf, + struct vm_area_struct *vma); +extern struct rchan_buf *rchan_create_buf(struct rchan *chan); +extern void rchan_destroy_buf(struct rchan_buf *buf); +extern void relay_destroy_buf(struct kref *kref); +extern int relay_buf_empty(struct rchan_buf *buf); + +#endif /* _RELAY_H */ diff -urpN -X dontdiff linux-2.6.10/include/linux/relayfs_fs.h linux-2.6.10-cur/include/linux/relayfs_fs.h --- linux-2.6.10/include/linux/relayfs_fs.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.10-cur/include/linux/relayfs_fs.h 2005-02-06 00:21:44.000000000 -0600 @@ -0,0 +1,253 @@ +/* + * linux/include/linux/relayfs_fs.h + * + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) + * + * RelayFS definitions and declarations + */ + +#ifndef _LINUX_RELAYFS_FS_H +#define _LINUX_RELAYFS_FS_H + +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Tracks changes to rchan_buf struct + */ +#define RELAYFS_CHANNEL_VERSION 3 + +/* + * Relay attribute flags + */ +#define RELAY_MODE_CONTINUOUS 0x1 +#define RELAY_MODE_NO_OVERWRITE 0x2 + +/* + * Per-cpu relay channel buffer + */ +struct rchan_buf +{ + void *start; /* start of channel buffer */ + void *data; /* start of current sub-buffer */ + unsigned offset; /* current offset into sub-buffer */ + atomic_t subbufs_produced; /* count of sub-buffers produced */ + atomic_t subbufs_consumed; /* count of sub-buffers consumed */ + struct rchan *chan; /* associated channel */ + wait_queue_head_t read_wait; /* reader wait queue */ + struct work_struct wake_readers; /* reader wake-up work struct */ + struct dentry *dentry; /* channel file dentry */ + struct kref kref; /* channel refcount */ + struct page **page_array; /* array of current buffer pages */ + int page_count; /* number of current buffer pages */ + unsigned *padding; /* padding counts per sub-buffer */ + unsigned *commit; /* commit counts per sub-buffer */ + int finalized; /* buffer has been finalized */ +} ____cacheline_aligned; + +/* + * Relay channel data structure + */ +struct rchan +{ + u32 version; /* the version of this struct */ + unsigned subbuf_size; /* sub-buffer size */ + unsigned n_subbufs; /* number of sub-buffers per buffer */ + unsigned alloc_size; /* total buffer size allocated */ + u32 flags; /* relay channel attributes */ + struct rchan_callbacks *cb; /* client callbacks */ + struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */ +}; + +/* + * Relayfs inode + */ +struct relayfs_inode_info +{ + struct inode vfs_inode; + struct rchan_buf *buf; +}; + +static inline struct relayfs_inode_info *RELAYFS_I(struct inode *inode) +{ + return container_of(inode, struct relayfs_inode_info, vfs_inode); +} + +/* + * Relay channel client callbacks + */ +struct rchan_callbacks +{ + /* + * subbuf_start - called on buffer-switch to a new sub-buffer + * @buf: the channel buffer containing the new sub-buffer + * @subbuf: the start of the new sub-buffer + * @prev_subbuf_idx: the previous sub-buffer's index + * + */ + int (*subbuf_start) (struct rchan_buf *buf, + void *subbuf, + unsigned prev_subbuf_idx); + + /* + * deliver - deliver a guaranteed full sub-buffer to client + * @buf: the channel buffer containing the sub-buffer + * @subbuf: the start of the new sub-buffer + * @subbuf_idx: the sub-buffer's index + * + * Only works if relay_commit is also used + */ + void (*deliver) (struct rchan_buf *buf, + void *subbuf, + unsigned subbuf_idx); + + /* + * buf_mapped - relayfs buffer mmap notification + * @buf: the channel buffer + * @filp: relayfs file pointer + * + * Called when a relayfs file is successfully mmapped + */ + void (*buf_mapped)(struct rchan_buf *buf, + struct file *filp); + + /* + * buf_unmapped - relayfs buffer unmap notification + * @buf: the channel buffer + * @filp: relayfs file pointer + * + * Called when a relayfs file is successfully unmapped + */ + void (*buf_unmapped)(struct rchan_buf *buf, + struct file *filp); + + /* + * buf_full - relayfs buffer full notification + * @buf: the channel channel buffer + * + * Called when a relayfs buffer becomes full + */ + void (*buf_full)(struct rchan_buf *buf); +}; + +/* + * relayfs kernel API, fs/relayfs/relay.c + */ + +struct rchan *relay_open(const char *base_filename, + struct dentry *parent, + unsigned subbuf_size, + unsigned n_subbufs, + u32 flags, + struct rchan_callbacks *cb); +extern void relay_close(struct rchan *chan); +extern void relay_subbufs_consumed(struct rchan *chan, + int subbufs_consumed, + int cpu); +extern void relay_reset(struct rchan *chan); +extern unsigned relay_switch_subbuf(struct rchan_buf *buf, + unsigned length); +extern void relay_commit(struct rchan_buf *buf, + unsigned subbuf_idx, + unsigned count); +extern struct dentry *relayfs_create_dir(const char *name, + struct dentry *parent); +extern int relayfs_remove_dir(struct dentry *dentry); + +/** + * relay_write - write data into the channel + * @chan: relay channel + * @data: data to be written + * @length: number of bytes to write + * + * Writes data into the current cpu's channel buffer. + * + * Can be called in any context. Try __relay_write() if you know + * you won't be logging in interrupt context. + */ +static inline void relay_write(struct rchan *chan, + const void *data, + unsigned length) +{ + unsigned long flags; + struct rchan_buf *buf; + + local_irq_save(flags); + buf = chan->buf[smp_processor_id()]; + if (unlikely(buf->offset + length > chan->subbuf_size)) + length = relay_switch_subbuf(buf, length); + memcpy(buf->data + buf->offset, data, length); + buf->offset += length; + local_irq_restore(flags); +} + +/** + * __relay_write - write data into the channel + * @chan: relay channel + * @data: data to be written + * @length: number of bytes to write + * + * Writes data into the current cpu's channel buffer. + * + * Preempt-safe but not irq-safe. Use relay_write() if you might + * be logging in interrupt context. + */ +static inline void __relay_write(struct rchan *chan, + const void *data, + unsigned length) +{ + struct rchan_buf *buf; + + buf = chan->buf[get_cpu()]; + if (unlikely(buf->offset + length > buf->chan->subbuf_size)) + length = relay_switch_subbuf(buf, length); + memcpy(buf->data + buf->offset, data, length); + buf->offset += length; + put_cpu(); +} + +/** + * relay_reserve - reserve slot in channel buffer + * @chan: relay channel + * @length: number of bytes to reserve + * + * Returns pointer to reserved slot, NULL if full. + * + * Reserves slot in the current cpu's channel buffer. + * Not irq- or preempt-safe - caller must provide synchronization. + */ +static inline void *relay_reserve(struct rchan *chan, unsigned length) +{ + void *reserved; + struct rchan_buf *buf = chan->buf[smp_processor_id()]; + + if (unlikely(buf->offset + length > buf->chan->subbuf_size)) { + length = relay_switch_subbuf(buf, length); + if (!length) + return NULL; + } + reserved = buf->data + buf->offset; + buf->offset += length; + + return reserved; +} + +/* + * exported relayfs file operations, fs/relayfs/inode.c + */ + +extern struct file_operations relayfs_file_operations; +extern int relayfs_open(struct inode *inode, struct file *filp); +extern unsigned int relayfs_poll(struct file *filp, poll_table *wait); +extern int relayfs_mmap(struct file *filp, struct vm_area_struct *vma); +extern int relayfs_release(struct inode *inode, struct file *filp); + +#endif /* _LINUX_RELAYFS_FS_H */ + - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/