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f3bc08c5 MD |
1 | /* |
2 | * ring_buffer_vfs.c | |
3 | * | |
4 | * Copyright (C) 2009-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Ring Buffer VFS file operations. | |
7 | * | |
8 | * Dual LGPL v2.1/GPL v2 license. | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/fs.h> | |
13 | #include <linux/compat.h> | |
14 | ||
15 | #include "../../wrapper/ringbuffer/backend.h" | |
16 | #include "../../wrapper/ringbuffer/frontend.h" | |
17 | #include "../../wrapper/ringbuffer/vfs.h" | |
18 | #include "../../wrapper/poll.h" | |
19 | ||
20 | static int put_ulong(unsigned long val, unsigned long arg) | |
21 | { | |
22 | return put_user(val, (unsigned long __user *)arg); | |
23 | } | |
24 | ||
25 | #ifdef CONFIG_COMPAT | |
26 | static int compat_put_ulong(compat_ulong_t val, unsigned long arg) | |
27 | { | |
28 | return put_user(val, (compat_ulong_t __user *)compat_ptr(arg)); | |
29 | } | |
30 | #endif | |
31 | ||
32 | /** | |
33 | * lib_ring_buffer_open - ring buffer open file operation | |
34 | * @inode: opened inode | |
35 | * @file: opened file | |
36 | * | |
37 | * Open implementation. Makes sure only one open instance of a buffer is | |
38 | * done at a given moment. | |
39 | */ | |
40 | int lib_ring_buffer_open(struct inode *inode, struct file *file) | |
41 | { | |
42 | struct lib_ring_buffer *buf = inode->i_private; | |
43 | int ret; | |
44 | ||
733ce41d MD |
45 | if (!buf) |
46 | return -EINVAL; | |
47 | ||
f3bc08c5 MD |
48 | ret = lib_ring_buffer_open_read(buf); |
49 | if (ret) | |
50 | return ret; | |
51 | ||
52 | file->private_data = buf; | |
53 | ret = nonseekable_open(inode, file); | |
54 | if (ret) | |
55 | goto release_read; | |
56 | return 0; | |
57 | ||
58 | release_read: | |
59 | lib_ring_buffer_release_read(buf); | |
60 | return ret; | |
61 | } | |
62 | ||
63 | /** | |
64 | * lib_ring_buffer_release - ring buffer release file operation | |
65 | * @inode: opened inode | |
66 | * @file: opened file | |
67 | * | |
68 | * Release implementation. | |
69 | */ | |
70 | int lib_ring_buffer_release(struct inode *inode, struct file *file) | |
71 | { | |
72 | struct lib_ring_buffer *buf = file->private_data; | |
73 | ||
74 | lib_ring_buffer_release_read(buf); | |
75 | ||
76 | return 0; | |
77 | } | |
78 | ||
79 | /** | |
80 | * lib_ring_buffer_poll - ring buffer poll file operation | |
81 | * @filp: the file | |
82 | * @wait: poll table | |
83 | * | |
84 | * Poll implementation. | |
85 | */ | |
86 | unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait) | |
87 | { | |
88 | unsigned int mask = 0; | |
89 | struct lib_ring_buffer *buf = filp->private_data; | |
90 | struct channel *chan = buf->backend.chan; | |
91 | const struct lib_ring_buffer_config *config = chan->backend.config; | |
254ec7bc | 92 | int finalized, disabled; |
f3bc08c5 MD |
93 | |
94 | if (filp->f_mode & FMODE_READ) { | |
a33e44a6 | 95 | poll_wait_set_exclusive(wait); |
f3bc08c5 MD |
96 | poll_wait(filp, &buf->read_wait, wait); |
97 | ||
98 | finalized = lib_ring_buffer_is_finalized(config, buf); | |
254ec7bc MD |
99 | disabled = lib_ring_buffer_channel_is_disabled(chan); |
100 | ||
f3bc08c5 MD |
101 | /* |
102 | * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering | |
103 | * finalized load before offsets loads. | |
104 | */ | |
105 | WARN_ON(atomic_long_read(&buf->active_readers) != 1); | |
106 | retry: | |
254ec7bc MD |
107 | if (disabled) |
108 | return POLLERR; | |
109 | ||
f3bc08c5 MD |
110 | if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan) |
111 | - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan) | |
112 | == 0) { | |
113 | if (finalized) | |
114 | return POLLHUP; | |
115 | else { | |
116 | /* | |
117 | * The memory barriers | |
118 | * __wait_event()/wake_up_interruptible() take | |
119 | * care of "raw_spin_is_locked" memory ordering. | |
120 | */ | |
121 | if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock)) | |
122 | goto retry; | |
123 | else | |
124 | return 0; | |
125 | } | |
126 | } else { | |
127 | if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), | |
128 | chan) | |
129 | - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), | |
130 | chan) | |
131 | >= chan->backend.buf_size) | |
132 | return POLLPRI | POLLRDBAND; | |
133 | else | |
134 | return POLLIN | POLLRDNORM; | |
135 | } | |
136 | } | |
137 | return mask; | |
138 | } | |
139 | ||
140 | /** | |
141 | * lib_ring_buffer_ioctl - control ring buffer reader synchronization | |
142 | * | |
143 | * @filp: the file | |
144 | * @cmd: the command | |
145 | * @arg: command arg | |
146 | * | |
147 | * This ioctl implements commands necessary for producer/consumer | |
148 | * and flight recorder reader interaction : | |
149 | * RING_BUFFER_GET_NEXT_SUBBUF | |
150 | * Get the next sub-buffer that can be read. It never blocks. | |
151 | * RING_BUFFER_PUT_NEXT_SUBBUF | |
152 | * Release the currently read sub-buffer. | |
153 | * RING_BUFFER_GET_SUBBUF_SIZE | |
154 | * returns the size of the current sub-buffer. | |
155 | * RING_BUFFER_GET_MAX_SUBBUF_SIZE | |
156 | * returns the maximum size for sub-buffers. | |
157 | * RING_BUFFER_GET_NUM_SUBBUF | |
158 | * returns the number of reader-visible sub-buffers in the per cpu | |
159 | * channel (for mmap). | |
160 | * RING_BUFFER_GET_MMAP_READ_OFFSET | |
161 | * returns the offset of the subbuffer belonging to the reader. | |
162 | * Should only be used for mmap clients. | |
163 | */ | |
164 | long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
165 | { | |
166 | struct lib_ring_buffer *buf = filp->private_data; | |
167 | struct channel *chan = buf->backend.chan; | |
168 | const struct lib_ring_buffer_config *config = chan->backend.config; | |
169 | ||
254ec7bc MD |
170 | if (lib_ring_buffer_channel_is_disabled(chan)) |
171 | return -EIO; | |
172 | ||
f3bc08c5 MD |
173 | switch (cmd) { |
174 | case RING_BUFFER_SNAPSHOT: | |
175 | return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, | |
176 | &buf->prod_snapshot); | |
177 | case RING_BUFFER_SNAPSHOT_GET_CONSUMED: | |
178 | return put_ulong(buf->cons_snapshot, arg); | |
179 | case RING_BUFFER_SNAPSHOT_GET_PRODUCED: | |
180 | return put_ulong(buf->prod_snapshot, arg); | |
181 | case RING_BUFFER_GET_SUBBUF: | |
182 | { | |
183 | unsigned long uconsume; | |
184 | long ret; | |
185 | ||
186 | ret = get_user(uconsume, (unsigned long __user *) arg); | |
187 | if (ret) | |
188 | return ret; /* will return -EFAULT */ | |
189 | ret = lib_ring_buffer_get_subbuf(buf, uconsume); | |
190 | if (!ret) { | |
191 | /* Set file position to zero at each successful "get" */ | |
192 | filp->f_pos = 0; | |
193 | } | |
194 | return ret; | |
195 | } | |
196 | case RING_BUFFER_PUT_SUBBUF: | |
197 | lib_ring_buffer_put_subbuf(buf); | |
198 | return 0; | |
199 | ||
200 | case RING_BUFFER_GET_NEXT_SUBBUF: | |
201 | { | |
202 | long ret; | |
203 | ||
204 | ret = lib_ring_buffer_get_next_subbuf(buf); | |
205 | if (!ret) { | |
206 | /* Set file position to zero at each successful "get" */ | |
207 | filp->f_pos = 0; | |
208 | } | |
209 | return ret; | |
210 | } | |
211 | case RING_BUFFER_PUT_NEXT_SUBBUF: | |
212 | lib_ring_buffer_put_next_subbuf(buf); | |
213 | return 0; | |
214 | case RING_BUFFER_GET_SUBBUF_SIZE: | |
215 | return put_ulong(lib_ring_buffer_get_read_data_size(config, buf), | |
216 | arg); | |
217 | case RING_BUFFER_GET_PADDED_SUBBUF_SIZE: | |
218 | { | |
219 | unsigned long size; | |
220 | ||
221 | size = lib_ring_buffer_get_read_data_size(config, buf); | |
222 | size = PAGE_ALIGN(size); | |
223 | return put_ulong(size, arg); | |
224 | } | |
225 | case RING_BUFFER_GET_MAX_SUBBUF_SIZE: | |
226 | return put_ulong(chan->backend.subbuf_size, arg); | |
227 | case RING_BUFFER_GET_MMAP_LEN: | |
228 | { | |
229 | unsigned long mmap_buf_len; | |
230 | ||
231 | if (config->output != RING_BUFFER_MMAP) | |
232 | return -EINVAL; | |
233 | mmap_buf_len = chan->backend.buf_size; | |
234 | if (chan->backend.extra_reader_sb) | |
235 | mmap_buf_len += chan->backend.subbuf_size; | |
236 | if (mmap_buf_len > INT_MAX) | |
237 | return -EFBIG; | |
238 | return put_ulong(mmap_buf_len, arg); | |
239 | } | |
240 | case RING_BUFFER_GET_MMAP_READ_OFFSET: | |
241 | { | |
242 | unsigned long sb_bindex; | |
243 | ||
244 | if (config->output != RING_BUFFER_MMAP) | |
245 | return -EINVAL; | |
246 | sb_bindex = subbuffer_id_get_index(config, | |
247 | buf->backend.buf_rsb.id); | |
248 | return put_ulong(buf->backend.array[sb_bindex]->mmap_offset, | |
249 | arg); | |
250 | } | |
5c055266 MD |
251 | case RING_BUFFER_FLUSH: |
252 | lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE); | |
253 | return 0; | |
f3bc08c5 MD |
254 | default: |
255 | return -ENOIOCTLCMD; | |
256 | } | |
257 | } | |
258 | ||
259 | #ifdef CONFIG_COMPAT | |
260 | long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd, | |
261 | unsigned long arg) | |
262 | { | |
263 | struct lib_ring_buffer *buf = filp->private_data; | |
264 | struct channel *chan = buf->backend.chan; | |
265 | const struct lib_ring_buffer_config *config = chan->backend.config; | |
254ec7bc MD |
266 | |
267 | if (lib_ring_buffer_channel_is_disabled(chan)) | |
268 | return -EIO; | |
f3bc08c5 MD |
269 | |
270 | switch (cmd) { | |
271 | case RING_BUFFER_SNAPSHOT: | |
272 | return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, | |
273 | &buf->prod_snapshot); | |
274 | case RING_BUFFER_SNAPSHOT_GET_CONSUMED: | |
275 | return compat_put_ulong(buf->cons_snapshot, arg); | |
276 | case RING_BUFFER_SNAPSHOT_GET_PRODUCED: | |
277 | return compat_put_ulong(buf->prod_snapshot, arg); | |
278 | case RING_BUFFER_GET_SUBBUF: | |
279 | { | |
280 | __u32 uconsume; | |
281 | unsigned long consume; | |
282 | long ret; | |
283 | ||
284 | ret = get_user(uconsume, (__u32 __user *) arg); | |
285 | if (ret) | |
286 | return ret; /* will return -EFAULT */ | |
287 | consume = buf->cons_snapshot; | |
288 | consume &= ~0xFFFFFFFFL; | |
289 | consume |= uconsume; | |
290 | ret = lib_ring_buffer_get_subbuf(buf, consume); | |
291 | if (!ret) { | |
292 | /* Set file position to zero at each successful "get" */ | |
293 | filp->f_pos = 0; | |
294 | } | |
295 | return ret; | |
296 | } | |
297 | case RING_BUFFER_PUT_SUBBUF: | |
298 | lib_ring_buffer_put_subbuf(buf); | |
299 | return 0; | |
300 | ||
301 | case RING_BUFFER_GET_NEXT_SUBBUF: | |
302 | { | |
303 | long ret; | |
304 | ||
305 | ret = lib_ring_buffer_get_next_subbuf(buf); | |
306 | if (!ret) { | |
307 | /* Set file position to zero at each successful "get" */ | |
308 | filp->f_pos = 0; | |
309 | } | |
310 | return ret; | |
311 | } | |
312 | case RING_BUFFER_PUT_NEXT_SUBBUF: | |
313 | lib_ring_buffer_put_next_subbuf(buf); | |
314 | return 0; | |
315 | case RING_BUFFER_GET_SUBBUF_SIZE: | |
316 | { | |
317 | unsigned long data_size; | |
318 | ||
319 | data_size = lib_ring_buffer_get_read_data_size(config, buf); | |
320 | if (data_size > UINT_MAX) | |
321 | return -EFBIG; | |
322 | return put_ulong(data_size, arg); | |
323 | } | |
324 | case RING_BUFFER_GET_PADDED_SUBBUF_SIZE: | |
325 | { | |
326 | unsigned long size; | |
327 | ||
328 | size = lib_ring_buffer_get_read_data_size(config, buf); | |
329 | size = PAGE_ALIGN(size); | |
330 | if (size > UINT_MAX) | |
331 | return -EFBIG; | |
332 | return put_ulong(size, arg); | |
333 | } | |
334 | case RING_BUFFER_GET_MAX_SUBBUF_SIZE: | |
335 | if (chan->backend.subbuf_size > UINT_MAX) | |
336 | return -EFBIG; | |
337 | return put_ulong(chan->backend.subbuf_size, arg); | |
338 | case RING_BUFFER_GET_MMAP_LEN: | |
339 | { | |
340 | unsigned long mmap_buf_len; | |
341 | ||
342 | if (config->output != RING_BUFFER_MMAP) | |
343 | return -EINVAL; | |
344 | mmap_buf_len = chan->backend.buf_size; | |
345 | if (chan->backend.extra_reader_sb) | |
346 | mmap_buf_len += chan->backend.subbuf_size; | |
347 | if (mmap_buf_len > UINT_MAX) | |
348 | return -EFBIG; | |
349 | return put_ulong(mmap_buf_len, arg); | |
350 | } | |
351 | case RING_BUFFER_GET_MMAP_READ_OFFSET: | |
352 | { | |
353 | unsigned long sb_bindex, read_offset; | |
354 | ||
355 | if (config->output != RING_BUFFER_MMAP) | |
356 | return -EINVAL; | |
357 | sb_bindex = subbuffer_id_get_index(config, | |
358 | buf->backend.buf_rsb.id); | |
359 | read_offset = buf->backend.array[sb_bindex]->mmap_offset; | |
360 | if (read_offset > UINT_MAX) | |
361 | return -EINVAL; | |
362 | return put_ulong(read_offset, arg); | |
363 | } | |
5c055266 MD |
364 | case RING_BUFFER_FLUSH: |
365 | lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE); | |
366 | return 0; | |
f3bc08c5 MD |
367 | default: |
368 | return -ENOIOCTLCMD; | |
369 | } | |
370 | } | |
371 | #endif | |
372 | ||
373 | const struct file_operations lib_ring_buffer_file_operations = { | |
a33c9927 | 374 | .owner = THIS_MODULE, |
f3bc08c5 MD |
375 | .open = lib_ring_buffer_open, |
376 | .release = lib_ring_buffer_release, | |
377 | .poll = lib_ring_buffer_poll, | |
378 | .splice_read = lib_ring_buffer_splice_read, | |
379 | .mmap = lib_ring_buffer_mmap, | |
380 | .unlocked_ioctl = lib_ring_buffer_ioctl, | |
381 | .llseek = lib_ring_buffer_no_llseek, | |
382 | #ifdef CONFIG_COMPAT | |
383 | .compat_ioctl = lib_ring_buffer_compat_ioctl, | |
384 | #endif | |
385 | }; | |
386 | EXPORT_SYMBOL_GPL(lib_ring_buffer_file_operations); | |
387 | ||
388 | MODULE_LICENSE("GPL and additional rights"); | |
389 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
390 | MODULE_DESCRIPTION("Ring Buffer Library VFS"); |