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f3bc08c5 MD |
1 | /* |
2 | * ring_buffer_vfs.c | |
3 | * | |
f3bc08c5 MD |
4 | * Ring Buffer VFS file operations. |
5 | * | |
886d51a3 MD |
6 | * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; only | |
11 | * version 2.1 of the License. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
f3bc08c5 MD |
21 | */ |
22 | ||
23 | #include <linux/module.h> | |
24 | #include <linux/fs.h> | |
25 | #include <linux/compat.h> | |
26 | ||
27 | #include "../../wrapper/ringbuffer/backend.h" | |
28 | #include "../../wrapper/ringbuffer/frontend.h" | |
29 | #include "../../wrapper/ringbuffer/vfs.h" | |
30 | #include "../../wrapper/poll.h" | |
31 | ||
32 | static int put_ulong(unsigned long val, unsigned long arg) | |
33 | { | |
34 | return put_user(val, (unsigned long __user *)arg); | |
35 | } | |
36 | ||
37 | #ifdef CONFIG_COMPAT | |
38 | static int compat_put_ulong(compat_ulong_t val, unsigned long arg) | |
39 | { | |
40 | return put_user(val, (compat_ulong_t __user *)compat_ptr(arg)); | |
41 | } | |
42 | #endif | |
43 | ||
44 | /** | |
45 | * lib_ring_buffer_open - ring buffer open file operation | |
46 | * @inode: opened inode | |
47 | * @file: opened file | |
48 | * | |
49 | * Open implementation. Makes sure only one open instance of a buffer is | |
50 | * done at a given moment. | |
51 | */ | |
52 | int lib_ring_buffer_open(struct inode *inode, struct file *file) | |
53 | { | |
54 | struct lib_ring_buffer *buf = inode->i_private; | |
55 | int ret; | |
56 | ||
733ce41d MD |
57 | if (!buf) |
58 | return -EINVAL; | |
59 | ||
f3bc08c5 MD |
60 | ret = lib_ring_buffer_open_read(buf); |
61 | if (ret) | |
62 | return ret; | |
63 | ||
64 | file->private_data = buf; | |
65 | ret = nonseekable_open(inode, file); | |
66 | if (ret) | |
67 | goto release_read; | |
68 | return 0; | |
69 | ||
70 | release_read: | |
71 | lib_ring_buffer_release_read(buf); | |
72 | return ret; | |
73 | } | |
74 | ||
75 | /** | |
76 | * lib_ring_buffer_release - ring buffer release file operation | |
77 | * @inode: opened inode | |
78 | * @file: opened file | |
79 | * | |
80 | * Release implementation. | |
81 | */ | |
82 | int lib_ring_buffer_release(struct inode *inode, struct file *file) | |
83 | { | |
84 | struct lib_ring_buffer *buf = file->private_data; | |
85 | ||
86 | lib_ring_buffer_release_read(buf); | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | /** | |
92 | * lib_ring_buffer_poll - ring buffer poll file operation | |
93 | * @filp: the file | |
94 | * @wait: poll table | |
95 | * | |
96 | * Poll implementation. | |
97 | */ | |
98 | unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait) | |
99 | { | |
100 | unsigned int mask = 0; | |
101 | struct lib_ring_buffer *buf = filp->private_data; | |
102 | struct channel *chan = buf->backend.chan; | |
5a8fd222 | 103 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
254ec7bc | 104 | int finalized, disabled; |
f3bc08c5 MD |
105 | |
106 | if (filp->f_mode & FMODE_READ) { | |
a33e44a6 | 107 | poll_wait_set_exclusive(wait); |
f3bc08c5 MD |
108 | poll_wait(filp, &buf->read_wait, wait); |
109 | ||
110 | finalized = lib_ring_buffer_is_finalized(config, buf); | |
254ec7bc MD |
111 | disabled = lib_ring_buffer_channel_is_disabled(chan); |
112 | ||
f3bc08c5 MD |
113 | /* |
114 | * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering | |
115 | * finalized load before offsets loads. | |
116 | */ | |
117 | WARN_ON(atomic_long_read(&buf->active_readers) != 1); | |
118 | retry: | |
254ec7bc MD |
119 | if (disabled) |
120 | return POLLERR; | |
121 | ||
f3bc08c5 MD |
122 | if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan) |
123 | - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan) | |
124 | == 0) { | |
125 | if (finalized) | |
126 | return POLLHUP; | |
127 | else { | |
128 | /* | |
129 | * The memory barriers | |
130 | * __wait_event()/wake_up_interruptible() take | |
131 | * care of "raw_spin_is_locked" memory ordering. | |
132 | */ | |
133 | if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock)) | |
134 | goto retry; | |
135 | else | |
136 | return 0; | |
137 | } | |
138 | } else { | |
139 | if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), | |
140 | chan) | |
141 | - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), | |
142 | chan) | |
143 | >= chan->backend.buf_size) | |
144 | return POLLPRI | POLLRDBAND; | |
145 | else | |
146 | return POLLIN | POLLRDNORM; | |
147 | } | |
148 | } | |
149 | return mask; | |
150 | } | |
151 | ||
152 | /** | |
153 | * lib_ring_buffer_ioctl - control ring buffer reader synchronization | |
154 | * | |
155 | * @filp: the file | |
156 | * @cmd: the command | |
157 | * @arg: command arg | |
158 | * | |
159 | * This ioctl implements commands necessary for producer/consumer | |
160 | * and flight recorder reader interaction : | |
161 | * RING_BUFFER_GET_NEXT_SUBBUF | |
162 | * Get the next sub-buffer that can be read. It never blocks. | |
163 | * RING_BUFFER_PUT_NEXT_SUBBUF | |
164 | * Release the currently read sub-buffer. | |
165 | * RING_BUFFER_GET_SUBBUF_SIZE | |
166 | * returns the size of the current sub-buffer. | |
167 | * RING_BUFFER_GET_MAX_SUBBUF_SIZE | |
168 | * returns the maximum size for sub-buffers. | |
169 | * RING_BUFFER_GET_NUM_SUBBUF | |
170 | * returns the number of reader-visible sub-buffers in the per cpu | |
171 | * channel (for mmap). | |
172 | * RING_BUFFER_GET_MMAP_READ_OFFSET | |
173 | * returns the offset of the subbuffer belonging to the reader. | |
174 | * Should only be used for mmap clients. | |
175 | */ | |
176 | long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
177 | { | |
178 | struct lib_ring_buffer *buf = filp->private_data; | |
179 | struct channel *chan = buf->backend.chan; | |
5a8fd222 | 180 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
f3bc08c5 | 181 | |
254ec7bc MD |
182 | if (lib_ring_buffer_channel_is_disabled(chan)) |
183 | return -EIO; | |
184 | ||
f3bc08c5 MD |
185 | switch (cmd) { |
186 | case RING_BUFFER_SNAPSHOT: | |
187 | return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, | |
188 | &buf->prod_snapshot); | |
189 | case RING_BUFFER_SNAPSHOT_GET_CONSUMED: | |
190 | return put_ulong(buf->cons_snapshot, arg); | |
191 | case RING_BUFFER_SNAPSHOT_GET_PRODUCED: | |
192 | return put_ulong(buf->prod_snapshot, arg); | |
193 | case RING_BUFFER_GET_SUBBUF: | |
194 | { | |
195 | unsigned long uconsume; | |
196 | long ret; | |
197 | ||
198 | ret = get_user(uconsume, (unsigned long __user *) arg); | |
199 | if (ret) | |
200 | return ret; /* will return -EFAULT */ | |
201 | ret = lib_ring_buffer_get_subbuf(buf, uconsume); | |
202 | if (!ret) { | |
203 | /* Set file position to zero at each successful "get" */ | |
204 | filp->f_pos = 0; | |
205 | } | |
206 | return ret; | |
207 | } | |
208 | case RING_BUFFER_PUT_SUBBUF: | |
209 | lib_ring_buffer_put_subbuf(buf); | |
210 | return 0; | |
211 | ||
212 | case RING_BUFFER_GET_NEXT_SUBBUF: | |
213 | { | |
214 | long ret; | |
215 | ||
216 | ret = lib_ring_buffer_get_next_subbuf(buf); | |
217 | if (!ret) { | |
218 | /* Set file position to zero at each successful "get" */ | |
219 | filp->f_pos = 0; | |
220 | } | |
221 | return ret; | |
222 | } | |
223 | case RING_BUFFER_PUT_NEXT_SUBBUF: | |
224 | lib_ring_buffer_put_next_subbuf(buf); | |
225 | return 0; | |
226 | case RING_BUFFER_GET_SUBBUF_SIZE: | |
227 | return put_ulong(lib_ring_buffer_get_read_data_size(config, buf), | |
228 | arg); | |
229 | case RING_BUFFER_GET_PADDED_SUBBUF_SIZE: | |
230 | { | |
231 | unsigned long size; | |
232 | ||
233 | size = lib_ring_buffer_get_read_data_size(config, buf); | |
234 | size = PAGE_ALIGN(size); | |
235 | return put_ulong(size, arg); | |
236 | } | |
237 | case RING_BUFFER_GET_MAX_SUBBUF_SIZE: | |
238 | return put_ulong(chan->backend.subbuf_size, arg); | |
239 | case RING_BUFFER_GET_MMAP_LEN: | |
240 | { | |
241 | unsigned long mmap_buf_len; | |
242 | ||
243 | if (config->output != RING_BUFFER_MMAP) | |
244 | return -EINVAL; | |
245 | mmap_buf_len = chan->backend.buf_size; | |
246 | if (chan->backend.extra_reader_sb) | |
247 | mmap_buf_len += chan->backend.subbuf_size; | |
248 | if (mmap_buf_len > INT_MAX) | |
249 | return -EFBIG; | |
250 | return put_ulong(mmap_buf_len, arg); | |
251 | } | |
252 | case RING_BUFFER_GET_MMAP_READ_OFFSET: | |
253 | { | |
254 | unsigned long sb_bindex; | |
255 | ||
256 | if (config->output != RING_BUFFER_MMAP) | |
257 | return -EINVAL; | |
258 | sb_bindex = subbuffer_id_get_index(config, | |
259 | buf->backend.buf_rsb.id); | |
260 | return put_ulong(buf->backend.array[sb_bindex]->mmap_offset, | |
261 | arg); | |
262 | } | |
5c055266 MD |
263 | case RING_BUFFER_FLUSH: |
264 | lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE); | |
265 | return 0; | |
f3bc08c5 MD |
266 | default: |
267 | return -ENOIOCTLCMD; | |
268 | } | |
269 | } | |
270 | ||
271 | #ifdef CONFIG_COMPAT | |
272 | long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd, | |
273 | unsigned long arg) | |
274 | { | |
275 | struct lib_ring_buffer *buf = filp->private_data; | |
276 | struct channel *chan = buf->backend.chan; | |
5a8fd222 | 277 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
254ec7bc MD |
278 | |
279 | if (lib_ring_buffer_channel_is_disabled(chan)) | |
280 | return -EIO; | |
f3bc08c5 MD |
281 | |
282 | switch (cmd) { | |
216f7feb | 283 | case RING_BUFFER_COMPAT_SNAPSHOT: |
f3bc08c5 MD |
284 | return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, |
285 | &buf->prod_snapshot); | |
216f7feb | 286 | case RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED: |
f3bc08c5 | 287 | return compat_put_ulong(buf->cons_snapshot, arg); |
216f7feb | 288 | case RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED: |
f3bc08c5 | 289 | return compat_put_ulong(buf->prod_snapshot, arg); |
216f7feb | 290 | case RING_BUFFER_COMPAT_GET_SUBBUF: |
f3bc08c5 MD |
291 | { |
292 | __u32 uconsume; | |
293 | unsigned long consume; | |
294 | long ret; | |
295 | ||
296 | ret = get_user(uconsume, (__u32 __user *) arg); | |
297 | if (ret) | |
298 | return ret; /* will return -EFAULT */ | |
299 | consume = buf->cons_snapshot; | |
300 | consume &= ~0xFFFFFFFFL; | |
301 | consume |= uconsume; | |
302 | ret = lib_ring_buffer_get_subbuf(buf, consume); | |
303 | if (!ret) { | |
304 | /* Set file position to zero at each successful "get" */ | |
305 | filp->f_pos = 0; | |
306 | } | |
307 | return ret; | |
308 | } | |
216f7feb | 309 | case RING_BUFFER_COMPAT_PUT_SUBBUF: |
f3bc08c5 MD |
310 | lib_ring_buffer_put_subbuf(buf); |
311 | return 0; | |
312 | ||
216f7feb | 313 | case RING_BUFFER_COMPAT_GET_NEXT_SUBBUF: |
f3bc08c5 MD |
314 | { |
315 | long ret; | |
316 | ||
317 | ret = lib_ring_buffer_get_next_subbuf(buf); | |
318 | if (!ret) { | |
319 | /* Set file position to zero at each successful "get" */ | |
320 | filp->f_pos = 0; | |
321 | } | |
322 | return ret; | |
323 | } | |
216f7feb | 324 | case RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF: |
f3bc08c5 MD |
325 | lib_ring_buffer_put_next_subbuf(buf); |
326 | return 0; | |
216f7feb | 327 | case RING_BUFFER_COMPAT_GET_SUBBUF_SIZE: |
f3bc08c5 MD |
328 | { |
329 | unsigned long data_size; | |
330 | ||
331 | data_size = lib_ring_buffer_get_read_data_size(config, buf); | |
332 | if (data_size > UINT_MAX) | |
333 | return -EFBIG; | |
334 | return put_ulong(data_size, arg); | |
335 | } | |
216f7feb | 336 | case RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE: |
f3bc08c5 MD |
337 | { |
338 | unsigned long size; | |
339 | ||
340 | size = lib_ring_buffer_get_read_data_size(config, buf); | |
341 | size = PAGE_ALIGN(size); | |
342 | if (size > UINT_MAX) | |
343 | return -EFBIG; | |
344 | return put_ulong(size, arg); | |
345 | } | |
216f7feb | 346 | case RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE: |
f3bc08c5 MD |
347 | if (chan->backend.subbuf_size > UINT_MAX) |
348 | return -EFBIG; | |
349 | return put_ulong(chan->backend.subbuf_size, arg); | |
216f7feb | 350 | case RING_BUFFER_COMPAT_GET_MMAP_LEN: |
f3bc08c5 MD |
351 | { |
352 | unsigned long mmap_buf_len; | |
353 | ||
354 | if (config->output != RING_BUFFER_MMAP) | |
355 | return -EINVAL; | |
356 | mmap_buf_len = chan->backend.buf_size; | |
357 | if (chan->backend.extra_reader_sb) | |
358 | mmap_buf_len += chan->backend.subbuf_size; | |
359 | if (mmap_buf_len > UINT_MAX) | |
360 | return -EFBIG; | |
361 | return put_ulong(mmap_buf_len, arg); | |
362 | } | |
216f7feb | 363 | case RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET: |
f3bc08c5 MD |
364 | { |
365 | unsigned long sb_bindex, read_offset; | |
366 | ||
367 | if (config->output != RING_BUFFER_MMAP) | |
368 | return -EINVAL; | |
369 | sb_bindex = subbuffer_id_get_index(config, | |
370 | buf->backend.buf_rsb.id); | |
371 | read_offset = buf->backend.array[sb_bindex]->mmap_offset; | |
372 | if (read_offset > UINT_MAX) | |
373 | return -EINVAL; | |
374 | return put_ulong(read_offset, arg); | |
375 | } | |
216f7feb | 376 | case RING_BUFFER_COMPAT_FLUSH: |
5c055266 MD |
377 | lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE); |
378 | return 0; | |
f3bc08c5 MD |
379 | default: |
380 | return -ENOIOCTLCMD; | |
381 | } | |
382 | } | |
383 | #endif | |
384 | ||
385 | const struct file_operations lib_ring_buffer_file_operations = { | |
a33c9927 | 386 | .owner = THIS_MODULE, |
f3bc08c5 MD |
387 | .open = lib_ring_buffer_open, |
388 | .release = lib_ring_buffer_release, | |
389 | .poll = lib_ring_buffer_poll, | |
390 | .splice_read = lib_ring_buffer_splice_read, | |
391 | .mmap = lib_ring_buffer_mmap, | |
392 | .unlocked_ioctl = lib_ring_buffer_ioctl, | |
393 | .llseek = lib_ring_buffer_no_llseek, | |
394 | #ifdef CONFIG_COMPAT | |
395 | .compat_ioctl = lib_ring_buffer_compat_ioctl, | |
396 | #endif | |
397 | }; | |
398 | EXPORT_SYMBOL_GPL(lib_ring_buffer_file_operations); | |
399 | ||
400 | MODULE_LICENSE("GPL and additional rights"); | |
401 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
402 | MODULE_DESCRIPTION("Ring Buffer Library VFS"); |