Rename struct lib_ring_buffer* to struct lttng_ust_lib_ring_buffer*
[lttng-ust.git] / libringbuffer / ring_buffer_abi.c
CommitLineData
852c2936 1/*
9f3fdbc6 2 * ring_buffer_abi.c
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3 *
4 * Copyright (C) 2009-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
5 *
8b62831e 6 * Ring Buffer ABI operations.
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7 *
8 * Dual LGPL v2.1/GPL v2 license.
9 */
10
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11#include "backend.h"
12#include "frontend.h"
9f3fdbc6 13#include <ust/ring-buffer-abi.h>
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14
15static int put_ulong(unsigned long val, unsigned long arg)
16{
17 return put_user(val, (unsigned long __user *)arg);
18}
19
20#ifdef CONFIG_COMPAT
21static int compat_put_ulong(compat_ulong_t val, unsigned long arg)
22{
23 return put_user(val, (compat_ulong_t __user *)compat_ptr(arg));
24}
25#endif
26
27/**
28 * lib_ring_buffer_open - ring buffer open file operation
29 * @inode: opened inode
30 * @file: opened file
31 *
32 * Open implementation. Makes sure only one open instance of a buffer is
33 * done at a given moment.
34 */
35int lib_ring_buffer_open(struct inode *inode, struct file *file)
36{
4cfec15c 37 struct lttng_ust_lib_ring_buffer *buf = inode->i_private;
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38 int ret;
39
40 ret = lib_ring_buffer_open_read(buf);
41 if (ret)
42 return ret;
43
44 file->private_data = buf;
45 ret = nonseekable_open(inode, file);
46 if (ret)
47 goto release_read;
48 return 0;
49
50release_read:
51 lib_ring_buffer_release_read(buf);
52 return ret;
53}
54
55/**
56 * lib_ring_buffer_release - ring buffer release file operation
57 * @inode: opened inode
58 * @file: opened file
59 *
60 * Release implementation.
61 */
62int lib_ring_buffer_release(struct inode *inode, struct file *file)
63{
4cfec15c 64 struct lttng_ust_lib_ring_buffer *buf = file->private_data;
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65
66 lib_ring_buffer_release_read(buf);
67
68 return 0;
69}
70
71/**
72 * lib_ring_buffer_poll - ring buffer poll file operation
73 * @filp: the file
74 * @wait: poll table
75 *
76 * Poll implementation.
77 */
78unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait)
79{
80 unsigned int mask = 0;
4cfec15c 81 struct lttng_ust_lib_ring_buffer *buf = filp->private_data;
852c2936 82 struct channel *chan = buf->backend.chan;
4cfec15c 83 const struct lttng_ust_lib_ring_buffer_config *config = chan->backend.config;
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84 int finalized, disabled;
85
86 if (filp->f_mode & FMODE_READ) {
87 poll_wait_set_exclusive(wait);
88 poll_wait(filp, &buf->read_wait, wait);
89
90 finalized = lib_ring_buffer_is_finalized(config, buf);
91 disabled = lib_ring_buffer_channel_is_disabled(chan);
92
93 /*
94 * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering
95 * finalized load before offsets loads.
96 */
97 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
98retry:
99 if (disabled)
100 return POLLERR;
101
102 if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan)
103 - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan)
104 == 0) {
105 if (finalized)
106 return POLLHUP;
107 else {
108 /*
109 * The memory barriers
110 * __wait_event()/wake_up_interruptible() take
111 * care of "raw_spin_is_locked" memory ordering.
112 */
113 if (raw_spin_is_locked(&buf->raw_tick_nohz_spinlock))
114 goto retry;
115 else
116 return 0;
117 }
118 } else {
119 if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf),
120 chan)
121 - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf),
122 chan)
123 >= chan->backend.buf_size)
124 return POLLPRI | POLLRDBAND;
125 else
126 return POLLIN | POLLRDNORM;
127 }
128 }
129 return mask;
130}
131
132/**
133 * lib_ring_buffer_ioctl - control ring buffer reader synchronization
134 *
135 * @filp: the file
136 * @cmd: the command
137 * @arg: command arg
138 *
139 * This ioctl implements commands necessary for producer/consumer
140 * and flight recorder reader interaction :
141 * RING_BUFFER_GET_NEXT_SUBBUF
142 * Get the next sub-buffer that can be read. It never blocks.
143 * RING_BUFFER_PUT_NEXT_SUBBUF
144 * Release the currently read sub-buffer.
145 * RING_BUFFER_GET_SUBBUF_SIZE
146 * returns the size of the current sub-buffer.
147 * RING_BUFFER_GET_MAX_SUBBUF_SIZE
148 * returns the maximum size for sub-buffers.
149 * RING_BUFFER_GET_NUM_SUBBUF
150 * returns the number of reader-visible sub-buffers in the per cpu
151 * channel (for mmap).
152 * RING_BUFFER_GET_MMAP_READ_OFFSET
153 * returns the offset of the subbuffer belonging to the reader.
154 * Should only be used for mmap clients.
155 */
156long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
157{
4cfec15c 158 struct lttng_ust_lib_ring_buffer *buf = filp->private_data;
852c2936 159 struct channel *chan = buf->backend.chan;
4cfec15c 160 const struct lttng_ust_lib_ring_buffer_config *config = chan->backend.config;
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161
162 if (lib_ring_buffer_channel_is_disabled(chan))
163 return -EIO;
164
165 switch (cmd) {
166 case RING_BUFFER_SNAPSHOT:
167 return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
168 &buf->prod_snapshot);
169 case RING_BUFFER_SNAPSHOT_GET_CONSUMED:
170 return put_ulong(buf->cons_snapshot, arg);
171 case RING_BUFFER_SNAPSHOT_GET_PRODUCED:
172 return put_ulong(buf->prod_snapshot, arg);
173 case RING_BUFFER_GET_SUBBUF:
174 {
175 unsigned long uconsume;
176 long ret;
177
178 ret = get_user(uconsume, (unsigned long __user *) arg);
179 if (ret)
180 return ret; /* will return -EFAULT */
181 ret = lib_ring_buffer_get_subbuf(buf, uconsume);
182 if (!ret) {
183 /* Set file position to zero at each successful "get" */
184 filp->f_pos = 0;
185 }
186 return ret;
187 }
188 case RING_BUFFER_PUT_SUBBUF:
189 lib_ring_buffer_put_subbuf(buf);
190 return 0;
191
192 case RING_BUFFER_GET_NEXT_SUBBUF:
193 {
194 long ret;
195
196 ret = lib_ring_buffer_get_next_subbuf(buf);
197 if (!ret) {
198 /* Set file position to zero at each successful "get" */
199 filp->f_pos = 0;
200 }
201 return ret;
202 }
203 case RING_BUFFER_PUT_NEXT_SUBBUF:
204 lib_ring_buffer_put_next_subbuf(buf);
205 return 0;
206 case RING_BUFFER_GET_SUBBUF_SIZE:
207 return put_ulong(lib_ring_buffer_get_read_data_size(config, buf),
208 arg);
209 case RING_BUFFER_GET_PADDED_SUBBUF_SIZE:
210 {
211 unsigned long size;
212
213 size = lib_ring_buffer_get_read_data_size(config, buf);
214 size = PAGE_ALIGN(size);
215 return put_ulong(size, arg);
216 }
217 case RING_BUFFER_GET_MAX_SUBBUF_SIZE:
218 return put_ulong(chan->backend.subbuf_size, arg);
219 case RING_BUFFER_GET_MMAP_LEN:
220 {
221 unsigned long mmap_buf_len;
222
223 if (config->output != RING_BUFFER_MMAP)
224 return -EINVAL;
225 mmap_buf_len = chan->backend.buf_size;
226 if (chan->backend.extra_reader_sb)
227 mmap_buf_len += chan->backend.subbuf_size;
228 if (mmap_buf_len > INT_MAX)
229 return -EFBIG;
230 return put_ulong(mmap_buf_len, arg);
231 }
232 case RING_BUFFER_GET_MMAP_READ_OFFSET:
233 {
234 unsigned long sb_bindex;
235
236 if (config->output != RING_BUFFER_MMAP)
237 return -EINVAL;
238 sb_bindex = subbuffer_id_get_index(config,
239 buf->backend.buf_rsb.id);
240 return put_ulong(buf->backend.array[sb_bindex]->mmap_offset,
241 arg);
242 }
529b552a 243 case RING_BUFFER_FLUSH:
1d498196 244 lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE, handle);
529b552a 245 return 0;
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246 default:
247 return -ENOIOCTLCMD;
248 }
249}
250
251#ifdef CONFIG_COMPAT
252long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
253 unsigned long arg)
254{
4cfec15c 255 struct lttng_ust_lib_ring_buffer *buf = filp->private_data;
852c2936 256 struct channel *chan = buf->backend.chan;
4cfec15c 257 const struct lttng_ust_lib_ring_buffer_config *config = chan->backend.config;
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258
259 if (lib_ring_buffer_channel_is_disabled(chan))
260 return -EIO;
261
262 switch (cmd) {
263 case RING_BUFFER_SNAPSHOT:
264 return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
265 &buf->prod_snapshot);
266 case RING_BUFFER_SNAPSHOT_GET_CONSUMED:
267 return compat_put_ulong(buf->cons_snapshot, arg);
268 case RING_BUFFER_SNAPSHOT_GET_PRODUCED:
269 return compat_put_ulong(buf->prod_snapshot, arg);
270 case RING_BUFFER_GET_SUBBUF:
271 {
272 __u32 uconsume;
273 unsigned long consume;
274 long ret;
275
276 ret = get_user(uconsume, (__u32 __user *) arg);
277 if (ret)
278 return ret; /* will return -EFAULT */
279 consume = buf->cons_snapshot;
280 consume &= ~0xFFFFFFFFL;
281 consume |= uconsume;
282 ret = lib_ring_buffer_get_subbuf(buf, consume);
283 if (!ret) {
284 /* Set file position to zero at each successful "get" */
285 filp->f_pos = 0;
286 }
287 return ret;
288 }
289 case RING_BUFFER_PUT_SUBBUF:
290 lib_ring_buffer_put_subbuf(buf);
291 return 0;
292
293 case RING_BUFFER_GET_NEXT_SUBBUF:
294 {
295 long ret;
296
297 ret = lib_ring_buffer_get_next_subbuf(buf);
298 if (!ret) {
299 /* Set file position to zero at each successful "get" */
300 filp->f_pos = 0;
301 }
302 return ret;
303 }
304 case RING_BUFFER_PUT_NEXT_SUBBUF:
305 lib_ring_buffer_put_next_subbuf(buf);
306 return 0;
307 case RING_BUFFER_GET_SUBBUF_SIZE:
308 {
309 unsigned long data_size;
310
311 data_size = lib_ring_buffer_get_read_data_size(config, buf);
312 if (data_size > UINT_MAX)
313 return -EFBIG;
314 return put_ulong(data_size, arg);
315 }
316 case RING_BUFFER_GET_PADDED_SUBBUF_SIZE:
317 {
318 unsigned long size;
319
320 size = lib_ring_buffer_get_read_data_size(config, buf);
321 size = PAGE_ALIGN(size);
322 if (size > UINT_MAX)
323 return -EFBIG;
324 return put_ulong(size, arg);
325 }
326 case RING_BUFFER_GET_MAX_SUBBUF_SIZE:
327 if (chan->backend.subbuf_size > UINT_MAX)
328 return -EFBIG;
329 return put_ulong(chan->backend.subbuf_size, arg);
330 case RING_BUFFER_GET_MMAP_LEN:
331 {
332 unsigned long mmap_buf_len;
333
334 if (config->output != RING_BUFFER_MMAP)
335 return -EINVAL;
336 mmap_buf_len = chan->backend.buf_size;
337 if (chan->backend.extra_reader_sb)
338 mmap_buf_len += chan->backend.subbuf_size;
339 if (mmap_buf_len > UINT_MAX)
340 return -EFBIG;
341 return put_ulong(mmap_buf_len, arg);
342 }
343 case RING_BUFFER_GET_MMAP_READ_OFFSET:
344 {
345 unsigned long sb_bindex, read_offset;
346
347 if (config->output != RING_BUFFER_MMAP)
348 return -EINVAL;
349 sb_bindex = subbuffer_id_get_index(config,
350 buf->backend.buf_rsb.id);
351 read_offset = buf->backend.array[sb_bindex]->mmap_offset;
352 if (read_offset > UINT_MAX)
353 return -EINVAL;
354 return put_ulong(read_offset, arg);
355 }
529b552a 356 case RING_BUFFER_FLUSH:
1d498196 357 lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE, handle);
529b552a 358 return 0;
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359 default:
360 return -ENOIOCTLCMD;
361 }
362}
363#endif
364
365const struct file_operations lib_ring_buffer_file_operations = {
366 .open = lib_ring_buffer_open,
367 .release = lib_ring_buffer_release,
368 .poll = lib_ring_buffer_poll,
369 .splice_read = lib_ring_buffer_splice_read,
370 .mmap = lib_ring_buffer_mmap,
371 .unlocked_ioctl = lib_ring_buffer_ioctl,
372 .llseek = lib_ring_buffer_no_llseek,
373#ifdef CONFIG_COMPAT
374 .compat_ioctl = lib_ring_buffer_compat_ioctl,
375#endif
376};
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