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-rw-r--r--fs/relayfs/Makefile4
-rw-r--r--fs/relayfs/buffers.c189
-rw-r--r--fs/relayfs/buffers.h12
-rw-r--r--fs/relayfs/inode.c609
-rw-r--r--fs/relayfs/relay.c431
-rw-r--r--fs/relayfs/relay.h12
6 files changed, 1257 insertions, 0 deletions
diff --git a/fs/relayfs/Makefile b/fs/relayfs/Makefile
new file mode 100644
index 000000000000..e76e182cdb38
--- /dev/null
+++ b/fs/relayfs/Makefile
@@ -0,0 +1,4 @@
1obj-$(CONFIG_RELAYFS_FS) += relayfs.o
2
3relayfs-y := relay.o inode.o buffers.o
4
diff --git a/fs/relayfs/buffers.c b/fs/relayfs/buffers.c
new file mode 100644
index 000000000000..2aa8e2719999
--- /dev/null
+++ b/fs/relayfs/buffers.c
@@ -0,0 +1,189 @@
1/*
2 * RelayFS buffer management code.
3 *
4 * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
5 * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
6 *
7 * This file is released under the GPL.
8 */
9
10#include <linux/module.h>
11#include <linux/vmalloc.h>
12#include <linux/mm.h>
13#include <linux/relayfs_fs.h>
14#include "relay.h"
15#include "buffers.h"
16
17/*
18 * close() vm_op implementation for relayfs file mapping.
19 */
20static void relay_file_mmap_close(struct vm_area_struct *vma)
21{
22 struct rchan_buf *buf = vma->vm_private_data;
23 buf->chan->cb->buf_unmapped(buf, vma->vm_file);
24}
25
26/*
27 * nopage() vm_op implementation for relayfs file mapping.
28 */
29static struct page *relay_buf_nopage(struct vm_area_struct *vma,
30 unsigned long address,
31 int *type)
32{
33 struct page *page;
34 struct rchan_buf *buf = vma->vm_private_data;
35 unsigned long offset = address - vma->vm_start;
36
37 if (address > vma->vm_end)
38 return NOPAGE_SIGBUS; /* Disallow mremap */
39 if (!buf)
40 return NOPAGE_OOM;
41
42 page = vmalloc_to_page(buf->start + offset);
43 if (!page)
44 return NOPAGE_OOM;
45 get_page(page);
46
47 if (type)
48 *type = VM_FAULT_MINOR;
49
50 return page;
51}
52
53/*
54 * vm_ops for relay file mappings.
55 */
56static struct vm_operations_struct relay_file_mmap_ops = {
57 .nopage = relay_buf_nopage,
58 .close = relay_file_mmap_close,
59};
60
61/**
62 * relay_mmap_buf: - mmap channel buffer to process address space
63 * @buf: relay channel buffer
64 * @vma: vm_area_struct describing memory to be mapped
65 *
66 * Returns 0 if ok, negative on error
67 *
68 * Caller should already have grabbed mmap_sem.
69 */
70int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
71{
72 unsigned long length = vma->vm_end - vma->vm_start;
73 struct file *filp = vma->vm_file;
74
75 if (!buf)
76 return -EBADF;
77
78 if (length != (unsigned long)buf->chan->alloc_size)
79 return -EINVAL;
80
81 vma->vm_ops = &relay_file_mmap_ops;
82 vma->vm_private_data = buf;
83 buf->chan->cb->buf_mapped(buf, filp);
84
85 return 0;
86}
87
88/**
89 * relay_alloc_buf - allocate a channel buffer
90 * @buf: the buffer struct
91 * @size: total size of the buffer
92 *
93 * Returns a pointer to the resulting buffer, NULL if unsuccessful
94 */
95static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
96{
97 void *mem;
98 unsigned int i, j, n_pages;
99
100 size = PAGE_ALIGN(size);
101 n_pages = size >> PAGE_SHIFT;
102
103 buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
104 if (!buf->page_array)
105 return NULL;
106
107 for (i = 0; i < n_pages; i++) {
108 buf->page_array[i] = alloc_page(GFP_KERNEL);
109 if (unlikely(!buf->page_array[i]))
110 goto depopulate;
111 }
112 mem = vmap(buf->page_array, n_pages, GFP_KERNEL, PAGE_KERNEL);
113 if (!mem)
114 goto depopulate;
115
116 memset(mem, 0, size);
117 buf->page_count = n_pages;
118 return mem;
119
120depopulate:
121 for (j = 0; j < i; j++)
122 __free_page(buf->page_array[j]);
123 kfree(buf->page_array);
124 return NULL;
125}
126
127/**
128 * relay_create_buf - allocate and initialize a channel buffer
129 * @alloc_size: size of the buffer to allocate
130 * @n_subbufs: number of sub-buffers in the channel
131 *
132 * Returns channel buffer if successful, NULL otherwise
133 */
134struct rchan_buf *relay_create_buf(struct rchan *chan)
135{
136 struct rchan_buf *buf = kcalloc(1, sizeof(struct rchan_buf), GFP_KERNEL);
137 if (!buf)
138 return NULL;
139
140 buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL);
141 if (!buf->padding)
142 goto free_buf;
143
144 buf->start = relay_alloc_buf(buf, chan->alloc_size);
145 if (!buf->start)
146 goto free_buf;
147
148 buf->chan = chan;
149 kref_get(&buf->chan->kref);
150 return buf;
151
152free_buf:
153 kfree(buf->padding);
154 kfree(buf);
155 return NULL;
156}
157
158/**
159 * relay_destroy_buf - destroy an rchan_buf struct and associated buffer
160 * @buf: the buffer struct
161 */
162void relay_destroy_buf(struct rchan_buf *buf)
163{
164 struct rchan *chan = buf->chan;
165 unsigned int i;
166
167 if (likely(buf->start)) {
168 vunmap(buf->start);
169 for (i = 0; i < buf->page_count; i++)
170 __free_page(buf->page_array[i]);
171 kfree(buf->page_array);
172 }
173 kfree(buf->padding);
174 kfree(buf);
175 kref_put(&chan->kref, relay_destroy_channel);
176}
177
178/**
179 * relay_remove_buf - remove a channel buffer
180 *
181 * Removes the file from the relayfs fileystem, which also frees the
182 * rchan_buf_struct and the channel buffer. Should only be called from
183 * kref_put().
184 */
185void relay_remove_buf(struct kref *kref)
186{
187 struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref);
188 relayfs_remove(buf->dentry);
189}
diff --git a/fs/relayfs/buffers.h b/fs/relayfs/buffers.h
new file mode 100644
index 000000000000..37a12493f641
--- /dev/null
+++ b/fs/relayfs/buffers.h
@@ -0,0 +1,12 @@
1#ifndef _BUFFERS_H
2#define _BUFFERS_H
3
4/* This inspired by rtai/shmem */
5#define FIX_SIZE(x) (((x) - 1) & PAGE_MASK) + PAGE_SIZE
6
7extern int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma);
8extern struct rchan_buf *relay_create_buf(struct rchan *chan);
9extern void relay_destroy_buf(struct rchan_buf *buf);
10extern void relay_remove_buf(struct kref *kref);
11
12#endif/* _BUFFERS_H */
diff --git a/fs/relayfs/inode.c b/fs/relayfs/inode.c
new file mode 100644
index 000000000000..0f7f88d067ad
--- /dev/null
+++ b/fs/relayfs/inode.c
@@ -0,0 +1,609 @@
1/*
2 * VFS-related code for RelayFS, a high-speed data relay filesystem.
3 *
4 * Copyright (C) 2003-2005 - Tom Zanussi <zanussi@us.ibm.com>, IBM Corp
5 * Copyright (C) 2003-2005 - Karim Yaghmour <karim@opersys.com>
6 *
7 * Based on ramfs, Copyright (C) 2002 - Linus Torvalds
8 *
9 * This file is released under the GPL.
10 */
11
12#include <linux/module.h>
13#include <linux/fs.h>
14#include <linux/mount.h>
15#include <linux/pagemap.h>
16#include <linux/init.h>
17#include <linux/string.h>
18#include <linux/backing-dev.h>
19#include <linux/namei.h>
20#include <linux/poll.h>
21#include <linux/relayfs_fs.h>
22#include "relay.h"
23#include "buffers.h"
24
25#define RELAYFS_MAGIC 0xF0B4A981
26
27static struct vfsmount * relayfs_mount;
28static int relayfs_mount_count;
29static kmem_cache_t * relayfs_inode_cachep;
30
31static struct backing_dev_info relayfs_backing_dev_info = {
32 .ra_pages = 0, /* No readahead */
33 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
34};
35
36static struct inode *relayfs_get_inode(struct super_block *sb, int mode,
37 struct rchan *chan)
38{
39 struct rchan_buf *buf = NULL;
40 struct inode *inode;
41
42 if (S_ISREG(mode)) {
43 BUG_ON(!chan);
44 buf = relay_create_buf(chan);
45 if (!buf)
46 return NULL;
47 }
48
49 inode = new_inode(sb);
50 if (!inode) {
51 relay_destroy_buf(buf);
52 return NULL;
53 }
54
55 inode->i_mode = mode;
56 inode->i_uid = 0;
57 inode->i_gid = 0;
58 inode->i_blksize = PAGE_CACHE_SIZE;
59 inode->i_blocks = 0;
60 inode->i_mapping->backing_dev_info = &relayfs_backing_dev_info;
61 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
62 switch (mode & S_IFMT) {
63 case S_IFREG:
64 inode->i_fop = &relayfs_file_operations;
65 RELAYFS_I(inode)->buf = buf;
66 break;
67 case S_IFDIR:
68 inode->i_op = &simple_dir_inode_operations;
69 inode->i_fop = &simple_dir_operations;
70
71 /* directory inodes start off with i_nlink == 2 (for "." entry) */
72 inode->i_nlink++;
73 break;
74 default:
75 break;
76 }
77
78 return inode;
79}
80
81/**
82 * relayfs_create_entry - create a relayfs directory or file
83 * @name: the name of the file to create
84 * @parent: parent directory
85 * @mode: mode
86 * @chan: relay channel associated with the file
87 *
88 * Returns the new dentry, NULL on failure
89 *
90 * Creates a file or directory with the specifed permissions.
91 */
92static struct dentry *relayfs_create_entry(const char *name,
93 struct dentry *parent,
94 int mode,
95 struct rchan *chan)
96{
97 struct dentry *d;
98 struct inode *inode;
99 int error = 0;
100
101 BUG_ON(!name || !(S_ISREG(mode) || S_ISDIR(mode)));
102
103 error = simple_pin_fs("relayfs", &relayfs_mount, &relayfs_mount_count);
104 if (error) {
105 printk(KERN_ERR "Couldn't mount relayfs: errcode %d\n", error);
106 return NULL;
107 }
108
109 if (!parent && relayfs_mount && relayfs_mount->mnt_sb)
110 parent = relayfs_mount->mnt_sb->s_root;
111
112 if (!parent) {
113 simple_release_fs(&relayfs_mount, &relayfs_mount_count);
114 return NULL;
115 }
116
117 parent = dget(parent);
118 down(&parent->d_inode->i_sem);
119 d = lookup_one_len(name, parent, strlen(name));
120 if (IS_ERR(d)) {
121 d = NULL;
122 goto release_mount;
123 }
124
125 if (d->d_inode) {
126 d = NULL;
127 goto release_mount;
128 }
129
130 inode = relayfs_get_inode(parent->d_inode->i_sb, mode, chan);
131 if (!inode) {
132 d = NULL;
133 goto release_mount;
134 }
135
136 d_instantiate(d, inode);
137 dget(d); /* Extra count - pin the dentry in core */
138
139 if (S_ISDIR(mode))
140 parent->d_inode->i_nlink++;
141
142 goto exit;
143
144release_mount:
145 simple_release_fs(&relayfs_mount, &relayfs_mount_count);
146
147exit:
148 up(&parent->d_inode->i_sem);
149 dput(parent);
150 return d;
151}
152
153/**
154 * relayfs_create_file - create a file in the relay filesystem
155 * @name: the name of the file to create
156 * @parent: parent directory
157 * @mode: mode, if not specied the default perms are used
158 * @chan: channel associated with the file
159 *
160 * Returns file dentry if successful, NULL otherwise.
161 *
162 * The file will be created user r on behalf of current user.
163 */
164struct dentry *relayfs_create_file(const char *name, struct dentry *parent,
165 int mode, struct rchan *chan)
166{
167 if (!mode)
168 mode = S_IRUSR;
169 mode = (mode & S_IALLUGO) | S_IFREG;
170
171 return relayfs_create_entry(name, parent, mode, chan);
172}
173
174/**
175 * relayfs_create_dir - create a directory in the relay filesystem
176 * @name: the name of the directory to create
177 * @parent: parent directory, NULL if parent should be fs root
178 *
179 * Returns directory dentry if successful, NULL otherwise.
180 *
181 * The directory will be created world rwx on behalf of current user.
182 */
183struct dentry *relayfs_create_dir(const char *name, struct dentry *parent)
184{
185 int mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
186 return relayfs_create_entry(name, parent, mode, NULL);
187}
188
189/**
190 * relayfs_remove - remove a file or directory in the relay filesystem
191 * @dentry: file or directory dentry
192 *
193 * Returns 0 if successful, negative otherwise.
194 */
195int relayfs_remove(struct dentry *dentry)
196{
197 struct dentry *parent;
198 int error = 0;
199
200 if (!dentry)
201 return -EINVAL;
202 parent = dentry->d_parent;
203 if (!parent)
204 return -EINVAL;
205
206 parent = dget(parent);
207 down(&parent->d_inode->i_sem);
208 if (dentry->d_inode) {
209 if (S_ISDIR(dentry->d_inode->i_mode))
210 error = simple_rmdir(parent->d_inode, dentry);
211 else
212 error = simple_unlink(parent->d_inode, dentry);
213 if (!error)
214 d_delete(dentry);
215 }
216 if (!error)
217 dput(dentry);
218 up(&parent->d_inode->i_sem);
219 dput(parent);
220
221 if (!error)
222 simple_release_fs(&relayfs_mount, &relayfs_mount_count);
223
224 return error;
225}
226
227/**
228 * relayfs_remove_dir - remove a directory in the relay filesystem
229 * @dentry: directory dentry
230 *
231 * Returns 0 if successful, negative otherwise.
232 */
233int relayfs_remove_dir(struct dentry *dentry)
234{
235 return relayfs_remove(dentry);
236}
237
238/**
239 * relayfs_open - open file op for relayfs files
240 * @inode: the inode
241 * @filp: the file
242 *
243 * Increments the channel buffer refcount.
244 */
245static int relayfs_open(struct inode *inode, struct file *filp)
246{
247 struct rchan_buf *buf = RELAYFS_I(inode)->buf;
248 kref_get(&buf->kref);
249
250 return 0;
251}
252
253/**
254 * relayfs_mmap - mmap file op for relayfs files
255 * @filp: the file
256 * @vma: the vma describing what to map
257 *
258 * Calls upon relay_mmap_buf to map the file into user space.
259 */
260static int relayfs_mmap(struct file *filp, struct vm_area_struct *vma)
261{
262 struct inode *inode = filp->f_dentry->d_inode;
263 return relay_mmap_buf(RELAYFS_I(inode)->buf, vma);
264}
265
266/**
267 * relayfs_poll - poll file op for relayfs files
268 * @filp: the file
269 * @wait: poll table
270 *
271 * Poll implemention.
272 */
273static unsigned int relayfs_poll(struct file *filp, poll_table *wait)
274{
275 unsigned int mask = 0;
276 struct inode *inode = filp->f_dentry->d_inode;
277 struct rchan_buf *buf = RELAYFS_I(inode)->buf;
278
279 if (buf->finalized)
280 return POLLERR;
281
282 if (filp->f_mode & FMODE_READ) {
283 poll_wait(filp, &buf->read_wait, wait);
284 if (!relay_buf_empty(buf))
285 mask |= POLLIN | POLLRDNORM;
286 }
287
288 return mask;
289}
290
291/**
292 * relayfs_release - release file op for relayfs files
293 * @inode: the inode
294 * @filp: the file
295 *
296 * Decrements the channel refcount, as the filesystem is
297 * no longer using it.
298 */
299static int relayfs_release(struct inode *inode, struct file *filp)
300{
301 struct rchan_buf *buf = RELAYFS_I(inode)->buf;
302 kref_put(&buf->kref, relay_remove_buf);
303
304 return 0;
305}
306
307/**
308 * relayfs_read_consume - update the consumed count for the buffer
309 */
310static void relayfs_read_consume(struct rchan_buf *buf,
311 size_t read_pos,
312 size_t bytes_consumed)
313{
314 size_t subbuf_size = buf->chan->subbuf_size;
315 size_t n_subbufs = buf->chan->n_subbufs;
316 size_t read_subbuf;
317
318 if (buf->bytes_consumed + bytes_consumed > subbuf_size) {
319 relay_subbufs_consumed(buf->chan, buf->cpu, 1);
320 buf->bytes_consumed = 0;
321 }
322
323 buf->bytes_consumed += bytes_consumed;
324 read_subbuf = read_pos / buf->chan->subbuf_size;
325 if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
326 if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
327 (buf->offset == subbuf_size))
328 return;
329 relay_subbufs_consumed(buf->chan, buf->cpu, 1);
330 buf->bytes_consumed = 0;
331 }
332}
333
334/**
335 * relayfs_read_avail - boolean, are there unconsumed bytes available?
336 */
337static int relayfs_read_avail(struct rchan_buf *buf, size_t read_pos)
338{
339 size_t bytes_produced, bytes_consumed, write_offset;
340 size_t subbuf_size = buf->chan->subbuf_size;
341 size_t n_subbufs = buf->chan->n_subbufs;
342 size_t produced = buf->subbufs_produced % n_subbufs;
343 size_t consumed = buf->subbufs_consumed % n_subbufs;
344
345 write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
346
347 if (consumed > produced) {
348 if ((produced > n_subbufs) &&
349 (produced + n_subbufs - consumed <= n_subbufs))
350 produced += n_subbufs;
351 } else if (consumed == produced) {
352 if (buf->offset > subbuf_size) {
353 produced += n_subbufs;
354 if (buf->subbufs_produced == buf->subbufs_consumed)
355 consumed += n_subbufs;
356 }
357 }
358
359 if (buf->offset > subbuf_size)
360 bytes_produced = (produced - 1) * subbuf_size + write_offset;
361 else
362 bytes_produced = produced * subbuf_size + write_offset;
363 bytes_consumed = consumed * subbuf_size + buf->bytes_consumed;
364
365 if (bytes_produced == bytes_consumed)
366 return 0;
367
368 relayfs_read_consume(buf, read_pos, 0);
369
370 return 1;
371}
372
373/**
374 * relayfs_read_subbuf_avail - return bytes available in sub-buffer
375 */
376static size_t relayfs_read_subbuf_avail(size_t read_pos,
377 struct rchan_buf *buf)
378{
379 size_t padding, avail = 0;
380 size_t read_subbuf, read_offset, write_subbuf, write_offset;
381 size_t subbuf_size = buf->chan->subbuf_size;
382
383 write_subbuf = (buf->data - buf->start) / subbuf_size;
384 write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
385 read_subbuf = read_pos / subbuf_size;
386 read_offset = read_pos % subbuf_size;
387 padding = buf->padding[read_subbuf];
388
389 if (read_subbuf == write_subbuf) {
390 if (read_offset + padding < write_offset)
391 avail = write_offset - (read_offset + padding);
392 } else
393 avail = (subbuf_size - padding) - read_offset;
394
395 return avail;
396}
397
398/**
399 * relayfs_read_start_pos - find the first available byte to read
400 *
401 * If the read_pos is in the middle of padding, return the
402 * position of the first actually available byte, otherwise
403 * return the original value.
404 */
405static size_t relayfs_read_start_pos(size_t read_pos,
406 struct rchan_buf *buf)
407{
408 size_t read_subbuf, padding, padding_start, padding_end;
409 size_t subbuf_size = buf->chan->subbuf_size;
410 size_t n_subbufs = buf->chan->n_subbufs;
411
412 read_subbuf = read_pos / subbuf_size;
413 padding = buf->padding[read_subbuf];
414 padding_start = (read_subbuf + 1) * subbuf_size - padding;
415 padding_end = (read_subbuf + 1) * subbuf_size;
416 if (read_pos >= padding_start && read_pos < padding_end) {
417 read_subbuf = (read_subbuf + 1) % n_subbufs;
418 read_pos = read_subbuf * subbuf_size;
419 }
420
421 return read_pos;
422}
423
424/**
425 * relayfs_read_end_pos - return the new read position
426 */
427static size_t relayfs_read_end_pos(struct rchan_buf *buf,
428 size_t read_pos,
429 size_t count)
430{
431 size_t read_subbuf, padding, end_pos;
432 size_t subbuf_size = buf->chan->subbuf_size;
433 size_t n_subbufs = buf->chan->n_subbufs;
434
435 read_subbuf = read_pos / subbuf_size;
436 padding = buf->padding[read_subbuf];
437 if (read_pos % subbuf_size + count + padding == subbuf_size)
438 end_pos = (read_subbuf + 1) * subbuf_size;
439 else
440 end_pos = read_pos + count;
441 if (end_pos >= subbuf_size * n_subbufs)
442 end_pos = 0;
443
444 return end_pos;
445}
446
447/**
448 * relayfs_read - read file op for relayfs files
449 * @filp: the file
450 * @buffer: the userspace buffer
451 * @count: number of bytes to read
452 * @ppos: position to read from
453 *
454 * Reads count bytes or the number of bytes available in the
455 * current sub-buffer being read, whichever is smaller.
456 */
457static ssize_t relayfs_read(struct file *filp,
458 char __user *buffer,
459 size_t count,
460 loff_t *ppos)
461{
462 struct inode *inode = filp->f_dentry->d_inode;
463 struct rchan_buf *buf = RELAYFS_I(inode)->buf;
464 size_t read_start, avail;
465 ssize_t ret = 0;
466 void *from;
467
468 down(&inode->i_sem);
469 if(!relayfs_read_avail(buf, *ppos))
470 goto out;
471
472 read_start = relayfs_read_start_pos(*ppos, buf);
473 avail = relayfs_read_subbuf_avail(read_start, buf);
474 if (!avail)
475 goto out;
476
477 from = buf->start + read_start;
478 ret = count = min(count, avail);
479 if (copy_to_user(buffer, from, count)) {
480 ret = -EFAULT;
481 goto out;
482 }
483 relayfs_read_consume(buf, read_start, count);
484 *ppos = relayfs_read_end_pos(buf, read_start, count);
485out:
486 up(&inode->i_sem);
487 return ret;
488}
489
490/**
491 * relayfs alloc_inode() implementation
492 */
493static struct inode *relayfs_alloc_inode(struct super_block *sb)
494{
495 struct relayfs_inode_info *p = kmem_cache_alloc(relayfs_inode_cachep, SLAB_KERNEL);
496 if (!p)
497 return NULL;
498 p->buf = NULL;
499
500 return &p->vfs_inode;
501}
502
503/**
504 * relayfs destroy_inode() implementation
505 */
506static void relayfs_destroy_inode(struct inode *inode)
507{
508 if (RELAYFS_I(inode)->buf)
509 relay_destroy_buf(RELAYFS_I(inode)->buf);
510
511 kmem_cache_free(relayfs_inode_cachep, RELAYFS_I(inode));
512}
513
514static void init_once(void *p, kmem_cache_t *cachep, unsigned long flags)
515{
516 struct relayfs_inode_info *i = p;
517 if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR)
518 inode_init_once(&i->vfs_inode);
519}
520
521struct file_operations relayfs_file_operations = {
522 .open = relayfs_open,
523 .poll = relayfs_poll,
524 .mmap = relayfs_mmap,
525 .read = relayfs_read,
526 .llseek = no_llseek,
527 .release = relayfs_release,
528};
529
530static struct super_operations relayfs_ops = {
531 .statfs = simple_statfs,
532 .drop_inode = generic_delete_inode,
533 .alloc_inode = relayfs_alloc_inode,
534 .destroy_inode = relayfs_destroy_inode,
535};
536
537static int relayfs_fill_super(struct super_block * sb, void * data, int silent)
538{
539 struct inode *inode;
540 struct dentry *root;
541 int mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
542
543 sb->s_blocksize = PAGE_CACHE_SIZE;
544 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
545 sb->s_magic = RELAYFS_MAGIC;
546 sb->s_op = &relayfs_ops;
547 inode = relayfs_get_inode(sb, mode, NULL);
548
549 if (!inode)
550 return -ENOMEM;
551
552 root = d_alloc_root(inode);
553 if (!root) {
554 iput(inode);
555 return -ENOMEM;
556 }
557 sb->s_root = root;
558
559 return 0;
560}
561
562static struct super_block * relayfs_get_sb(struct file_system_type *fs_type,
563 int flags, const char *dev_name,
564 void *data)
565{
566 return get_sb_single(fs_type, flags, data, relayfs_fill_super);
567}
568
569static struct file_system_type relayfs_fs_type = {
570 .owner = THIS_MODULE,
571 .name = "relayfs",
572 .get_sb = relayfs_get_sb,
573 .kill_sb = kill_litter_super,
574};
575
576static int __init init_relayfs_fs(void)
577{
578 int err;
579
580 relayfs_inode_cachep = kmem_cache_create("relayfs_inode_cache",
581 sizeof(struct relayfs_inode_info), 0,
582 0, init_once, NULL);
583 if (!relayfs_inode_cachep)
584 return -ENOMEM;
585
586 err = register_filesystem(&relayfs_fs_type);
587 if (err)
588 kmem_cache_destroy(relayfs_inode_cachep);
589
590 return err;
591}
592
593static void __exit exit_relayfs_fs(void)
594{
595 unregister_filesystem(&relayfs_fs_type);
596 kmem_cache_destroy(relayfs_inode_cachep);
597}
598
599module_init(init_relayfs_fs)
600module_exit(exit_relayfs_fs)
601
602EXPORT_SYMBOL_GPL(relayfs_file_operations);
603EXPORT_SYMBOL_GPL(relayfs_create_dir);
604EXPORT_SYMBOL_GPL(relayfs_remove_dir);
605
606MODULE_AUTHOR("Tom Zanussi <zanussi@us.ibm.com> and Karim Yaghmour <karim@opersys.com>");
607MODULE_DESCRIPTION("Relay Filesystem");
608MODULE_LICENSE("GPL");
609
diff --git a/fs/relayfs/relay.c b/fs/relayfs/relay.c
new file mode 100644
index 000000000000..16446a15c96d
--- /dev/null
+++ b/fs/relayfs/relay.c
@@ -0,0 +1,431 @@
1/*
2 * Public API and common code for RelayFS.
3 *
4 * See Documentation/filesystems/relayfs.txt for an overview of relayfs.
5 *
6 * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
7 * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
8 *
9 * This file is released under the GPL.
10 */
11
12#include <linux/errno.h>
13#include <linux/stddef.h>
14#include <linux/slab.h>
15#include <linux/module.h>
16#include <linux/string.h>
17#include <linux/relayfs_fs.h>
18#include "relay.h"
19#include "buffers.h"
20
21/**
22 * relay_buf_empty - boolean, is the channel buffer empty?
23 * @buf: channel buffer
24 *
25 * Returns 1 if the buffer is empty, 0 otherwise.
26 */
27int relay_buf_empty(struct rchan_buf *buf)
28{
29 return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1;
30}
31
32/**
33 * relay_buf_full - boolean, is the channel buffer full?
34 * @buf: channel buffer
35 *
36 * Returns 1 if the buffer is full, 0 otherwise.
37 */
38int relay_buf_full(struct rchan_buf *buf)
39{
40 size_t ready = buf->subbufs_produced - buf->subbufs_consumed;
41 return (ready >= buf->chan->n_subbufs) ? 1 : 0;
42}
43
44/*
45 * High-level relayfs kernel API and associated functions.
46 */
47
48/*
49 * rchan_callback implementations defining default channel behavior. Used
50 * in place of corresponding NULL values in client callback struct.
51 */
52
53/*
54 * subbuf_start() default callback. Does nothing.
55 */
56static int subbuf_start_default_callback (struct rchan_buf *buf,
57 void *subbuf,
58 void *prev_subbuf,
59 size_t prev_padding)
60{
61 if (relay_buf_full(buf))
62 return 0;
63
64 return 1;
65}
66
67/*
68 * buf_mapped() default callback. Does nothing.
69 */
70static void buf_mapped_default_callback(struct rchan_buf *buf,
71 struct file *filp)
72{
73}
74
75/*
76 * buf_unmapped() default callback. Does nothing.
77 */
78static void buf_unmapped_default_callback(struct rchan_buf *buf,
79 struct file *filp)
80{
81}
82
83/* relay channel default callbacks */
84static struct rchan_callbacks default_channel_callbacks = {
85 .subbuf_start = subbuf_start_default_callback,
86 .buf_mapped = buf_mapped_default_callback,
87 .buf_unmapped = buf_unmapped_default_callback,
88};
89
90/**
91 * wakeup_readers - wake up readers waiting on a channel
92 * @private: the channel buffer
93 *
94 * This is the work function used to defer reader waking. The
95 * reason waking is deferred is that calling directly from write
96 * causes problems if you're writing from say the scheduler.
97 */
98static void wakeup_readers(void *private)
99{
100 struct rchan_buf *buf = private;
101 wake_up_interruptible(&buf->read_wait);
102}
103
104/**
105 * __relay_reset - reset a channel buffer
106 * @buf: the channel buffer
107 * @init: 1 if this is a first-time initialization
108 *
109 * See relay_reset for description of effect.
110 */
111static inline void __relay_reset(struct rchan_buf *buf, unsigned int init)
112{
113 size_t i;
114
115 if (init) {
116 init_waitqueue_head(&buf->read_wait);
117 kref_init(&buf->kref);
118 INIT_WORK(&buf->wake_readers, NULL, NULL);
119 } else {
120 cancel_delayed_work(&buf->wake_readers);
121 flush_scheduled_work();
122 }
123
124 buf->subbufs_produced = 0;
125 buf->subbufs_consumed = 0;
126 buf->bytes_consumed = 0;
127 buf->finalized = 0;
128 buf->data = buf->start;
129 buf->offset = 0;
130
131 for (i = 0; i < buf->chan->n_subbufs; i++)
132 buf->padding[i] = 0;
133
134 buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0);
135}
136
137/**
138 * relay_reset - reset the channel
139 * @chan: the channel
140 *
141 * This has the effect of erasing all data from all channel buffers
142 * and restarting the channel in its initial state. The buffers
143 * are not freed, so any mappings are still in effect.
144 *
145 * NOTE: Care should be taken that the channel isn't actually
146 * being used by anything when this call is made.
147 */
148void relay_reset(struct rchan *chan)
149{
150 unsigned int i;
151
152 if (!chan)
153 return;
154
155 for (i = 0; i < NR_CPUS; i++) {
156 if (!chan->buf[i])
157 continue;
158 __relay_reset(chan->buf[i], 0);
159 }
160}
161
162/**
163 * relay_open_buf - create a new channel buffer in relayfs
164 *
165 * Internal - used by relay_open().
166 */
167static struct rchan_buf *relay_open_buf(struct rchan *chan,
168 const char *filename,
169 struct dentry *parent)
170{
171 struct rchan_buf *buf;
172 struct dentry *dentry;
173
174 /* Create file in fs */
175 dentry = relayfs_create_file(filename, parent, S_IRUSR, chan);
176 if (!dentry)
177 return NULL;
178
179 buf = RELAYFS_I(dentry->d_inode)->buf;
180 buf->dentry = dentry;
181 __relay_reset(buf, 1);
182
183 return buf;
184}
185
186/**
187 * relay_close_buf - close a channel buffer
188 * @buf: channel buffer
189 *
190 * Marks the buffer finalized and restores the default callbacks.
191 * The channel buffer and channel buffer data structure are then freed
192 * automatically when the last reference is given up.
193 */
194static inline void relay_close_buf(struct rchan_buf *buf)
195{
196 buf->finalized = 1;
197 buf->chan->cb = &default_channel_callbacks;
198 cancel_delayed_work(&buf->wake_readers);
199 flush_scheduled_work();
200 kref_put(&buf->kref, relay_remove_buf);
201}
202
203static inline void setup_callbacks(struct rchan *chan,
204 struct rchan_callbacks *cb)
205{
206 if (!cb) {
207 chan->cb = &default_channel_callbacks;
208 return;
209 }
210
211 if (!cb->subbuf_start)
212 cb->subbuf_start = subbuf_start_default_callback;
213 if (!cb->buf_mapped)
214 cb->buf_mapped = buf_mapped_default_callback;
215 if (!cb->buf_unmapped)
216 cb->buf_unmapped = buf_unmapped_default_callback;
217 chan->cb = cb;
218}
219
220/**
221 * relay_open - create a new relayfs channel
222 * @base_filename: base name of files to create
223 * @parent: dentry of parent directory, NULL for root directory
224 * @subbuf_size: size of sub-buffers
225 * @n_subbufs: number of sub-buffers
226 * @cb: client callback functions
227 *
228 * Returns channel pointer if successful, NULL otherwise.
229 *
230 * Creates a channel buffer for each cpu using the sizes and
231 * attributes specified. The created channel buffer files
232 * will be named base_filename0...base_filenameN-1. File
233 * permissions will be S_IRUSR.
234 */
235struct rchan *relay_open(const char *base_filename,
236 struct dentry *parent,
237 size_t subbuf_size,
238 size_t n_subbufs,
239 struct rchan_callbacks *cb)
240{
241 unsigned int i;
242 struct rchan *chan;
243 char *tmpname;
244
245 if (!base_filename)
246 return NULL;
247
248 if (!(subbuf_size && n_subbufs))
249 return NULL;
250
251 chan = kcalloc(1, sizeof(struct rchan), GFP_KERNEL);
252 if (!chan)
253 return NULL;
254
255 chan->version = RELAYFS_CHANNEL_VERSION;
256 chan->n_subbufs = n_subbufs;
257 chan->subbuf_size = subbuf_size;
258 chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
259 setup_callbacks(chan, cb);
260 kref_init(&chan->kref);
261
262 tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL);
263 if (!tmpname)
264 goto free_chan;
265
266 for_each_online_cpu(i) {
267 sprintf(tmpname, "%s%d", base_filename, i);
268 chan->buf[i] = relay_open_buf(chan, tmpname, parent);
269 chan->buf[i]->cpu = i;
270 if (!chan->buf[i])
271 goto free_bufs;
272 }
273
274 kfree(tmpname);
275 return chan;
276
277free_bufs:
278 for (i = 0; i < NR_CPUS; i++) {
279 if (!chan->buf[i])
280 break;
281 relay_close_buf(chan->buf[i]);
282 }
283 kfree(tmpname);
284
285free_chan:
286 kref_put(&chan->kref, relay_destroy_channel);
287 return NULL;
288}
289
290/**
291 * relay_switch_subbuf - switch to a new sub-buffer
292 * @buf: channel buffer
293 * @length: size of current event
294 *
295 * Returns either the length passed in or 0 if full.
296
297 * Performs sub-buffer-switch tasks such as invoking callbacks,
298 * updating padding counts, waking up readers, etc.
299 */
300size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
301{
302 void *old, *new;
303 size_t old_subbuf, new_subbuf;
304
305 if (unlikely(length > buf->chan->subbuf_size))
306 goto toobig;
307
308 if (buf->offset != buf->chan->subbuf_size + 1) {
309 buf->prev_padding = buf->chan->subbuf_size - buf->offset;
310 old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
311 buf->padding[old_subbuf] = buf->prev_padding;
312 buf->subbufs_produced++;
313 if (waitqueue_active(&buf->read_wait)) {
314 PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf);
315 schedule_delayed_work(&buf->wake_readers, 1);
316 }
317 }
318
319 old = buf->data;
320 new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
321 new = buf->start + new_subbuf * buf->chan->subbuf_size;
322 buf->offset = 0;
323 if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) {
324 buf->offset = buf->chan->subbuf_size + 1;
325 return 0;
326 }
327 buf->data = new;
328 buf->padding[new_subbuf] = 0;
329
330 if (unlikely(length + buf->offset > buf->chan->subbuf_size))
331 goto toobig;
332
333 return length;
334
335toobig:
336 printk(KERN_WARNING "relayfs: event too large (%Zd)\n", length);
337 WARN_ON(1);
338 return 0;
339}
340
341/**
342 * relay_subbufs_consumed - update the buffer's sub-buffers-consumed count
343 * @chan: the channel
344 * @cpu: the cpu associated with the channel buffer to update
345 * @subbufs_consumed: number of sub-buffers to add to current buf's count
346 *
347 * Adds to the channel buffer's consumed sub-buffer count.
348 * subbufs_consumed should be the number of sub-buffers newly consumed,
349 * not the total consumed.
350 *
351 * NOTE: kernel clients don't need to call this function if the channel
352 * mode is 'overwrite'.
353 */
354void relay_subbufs_consumed(struct rchan *chan,
355 unsigned int cpu,
356 size_t subbufs_consumed)
357{
358 struct rchan_buf *buf;
359
360 if (!chan)
361 return;
362
363 if (cpu >= NR_CPUS || !chan->buf[cpu])
364 return;
365
366 buf = chan->buf[cpu];
367 buf->subbufs_consumed += subbufs_consumed;
368 if (buf->subbufs_consumed > buf->subbufs_produced)
369 buf->subbufs_consumed = buf->subbufs_produced;
370}
371
372/**
373 * relay_destroy_channel - free the channel struct
374 *
375 * Should only be called from kref_put().
376 */
377void relay_destroy_channel(struct kref *kref)
378{
379 struct rchan *chan = container_of(kref, struct rchan, kref);
380 kfree(chan);
381}
382
383/**
384 * relay_close - close the channel
385 * @chan: the channel
386 *
387 * Closes all channel buffers and frees the channel.
388 */
389void relay_close(struct rchan *chan)
390{
391 unsigned int i;
392
393 if (!chan)
394 return;
395
396 for (i = 0; i < NR_CPUS; i++) {
397 if (!chan->buf[i])
398 continue;
399 relay_close_buf(chan->buf[i]);
400 }
401
402 kref_put(&chan->kref, relay_destroy_channel);
403}
404
405/**
406 * relay_flush - close the channel
407 * @chan: the channel
408 *
409 * Flushes all channel buffers i.e. forces buffer switch.
410 */
411void relay_flush(struct rchan *chan)
412{
413 unsigned int i;
414
415 if (!chan)
416 return;
417
418 for (i = 0; i < NR_CPUS; i++) {
419 if (!chan->buf[i])
420 continue;
421 relay_switch_subbuf(chan->buf[i], 0);
422 }
423}
424
425EXPORT_SYMBOL_GPL(relay_open);
426EXPORT_SYMBOL_GPL(relay_close);
427EXPORT_SYMBOL_GPL(relay_flush);
428EXPORT_SYMBOL_GPL(relay_reset);
429EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
430EXPORT_SYMBOL_GPL(relay_switch_subbuf);
431EXPORT_SYMBOL_GPL(relay_buf_full);
diff --git a/fs/relayfs/relay.h b/fs/relayfs/relay.h
new file mode 100644
index 000000000000..703503fa22b6
--- /dev/null
+++ b/fs/relayfs/relay.h
@@ -0,0 +1,12 @@
1#ifndef _RELAY_H
2#define _RELAY_H
3
4struct dentry *relayfs_create_file(const char *name,
5 struct dentry *parent,
6 int mode,
7 struct rchan *chan);
8extern int relayfs_remove(struct dentry *dentry);
9extern int relay_buf_empty(struct rchan_buf *buf);
10extern void relay_destroy_channel(struct kref *kref);
11
12#endif /* _RELAY_H */
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-29 20:36:24 -0400