4 * Ring Buffer VFS file operations.
6 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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.
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.
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
23 #include <linux/module.h>
25 #include <linux/compat.h>
27 #include <wrapper/ringbuffer/backend.h>
28 #include <wrapper/ringbuffer/frontend.h>
29 #include <wrapper/ringbuffer/vfs.h>
30 #include <wrapper/poll.h>
31 #include <lttng-tracer.h>
33 static int put_ulong(unsigned long val
, unsigned long arg
)
35 return put_user(val
, (unsigned long __user
*)arg
);
39 static int compat_put_ulong(compat_ulong_t val
, unsigned long arg
)
41 return put_user(val
, (compat_ulong_t __user
*)compat_ptr(arg
));
46 * This is not used by anonymous file descriptors. This code is left
47 * there if we ever want to implement an inode with open() operation.
49 int lib_ring_buffer_open(struct inode
*inode
, struct file
*file
,
50 struct lib_ring_buffer
*buf
)
57 ret
= lib_ring_buffer_open_read(buf
);
61 ret
= nonseekable_open(inode
, file
);
67 lib_ring_buffer_release_read(buf
);
70 EXPORT_SYMBOL_GPL(lib_ring_buffer_open
);
73 * vfs_lib_ring_buffer_open - ring buffer open file operation
74 * @inode: opened inode
77 * Open implementation. Makes sure only one open instance of a buffer is
78 * done at a given moment.
81 int vfs_lib_ring_buffer_open(struct inode
*inode
, struct file
*file
)
83 struct lib_ring_buffer
*buf
= inode
->i_private
;
85 file
->private_data
= buf
;
86 return lib_ring_buffer_open(inode
, file
, buf
);
89 int lib_ring_buffer_release(struct inode
*inode
, struct file
*file
,
90 struct lib_ring_buffer
*buf
)
92 lib_ring_buffer_release_read(buf
);
96 EXPORT_SYMBOL_GPL(lib_ring_buffer_release
);
99 * vfs_lib_ring_buffer_release - ring buffer release file operation
100 * @inode: opened inode
103 * Release implementation.
106 int vfs_lib_ring_buffer_release(struct inode
*inode
, struct file
*file
)
108 struct lib_ring_buffer
*buf
= file
->private_data
;
110 return lib_ring_buffer_release(inode
, file
, buf
);
113 unsigned int lib_ring_buffer_poll(struct file
*filp
, poll_table
*wait
,
114 struct lib_ring_buffer
*buf
)
116 unsigned int mask
= 0;
117 struct channel
*chan
= buf
->backend
.chan
;
118 const struct lib_ring_buffer_config
*config
= &chan
->backend
.config
;
119 int finalized
, disabled
;
121 if (filp
->f_mode
& FMODE_READ
) {
122 poll_wait_set_exclusive(wait
);
123 poll_wait(filp
, &buf
->read_wait
, wait
);
125 finalized
= lib_ring_buffer_is_finalized(config
, buf
);
126 disabled
= lib_ring_buffer_channel_is_disabled(chan
);
129 * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering
130 * finalized load before offsets loads.
132 WARN_ON(atomic_long_read(&buf
->active_readers
) != 1);
137 if (subbuf_trunc(lib_ring_buffer_get_offset(config
, buf
), chan
)
138 - subbuf_trunc(lib_ring_buffer_get_consumed(config
, buf
), chan
)
144 * The memory barriers
145 * __wait_event()/wake_up_interruptible() take
146 * care of "raw_spin_is_locked" memory ordering.
148 if (raw_spin_is_locked(&buf
->raw_tick_nohz_spinlock
))
154 if (subbuf_trunc(lib_ring_buffer_get_offset(config
, buf
),
156 - subbuf_trunc(lib_ring_buffer_get_consumed(config
, buf
),
158 >= chan
->backend
.buf_size
)
159 return POLLPRI
| POLLRDBAND
;
161 return POLLIN
| POLLRDNORM
;
166 EXPORT_SYMBOL_GPL(lib_ring_buffer_poll
);
169 * vfs_lib_ring_buffer_poll - ring buffer poll file operation
173 * Poll implementation.
176 unsigned int vfs_lib_ring_buffer_poll(struct file
*filp
, poll_table
*wait
)
178 struct lib_ring_buffer
*buf
= filp
->private_data
;
180 return lib_ring_buffer_poll(filp
, wait
, buf
);
183 long lib_ring_buffer_ioctl(struct file
*filp
, unsigned int cmd
,
184 unsigned long arg
, struct lib_ring_buffer
*buf
)
186 struct channel
*chan
= buf
->backend
.chan
;
187 const struct lib_ring_buffer_config
*config
= &chan
->backend
.config
;
189 if (lib_ring_buffer_channel_is_disabled(chan
))
193 case RING_BUFFER_SNAPSHOT
:
195 * First, ensure we perform a "final" flush onto the
196 * stream. This will ensure we create a packet of
197 * padding if we encounter an empty packet. This ensures
198 * the time-stamps right before the snapshot is used as
199 * end of packet timestamp.
202 lib_ring_buffer_switch_remote_empty(buf
);
203 return lib_ring_buffer_snapshot(buf
, &buf
->cons_snapshot
,
204 &buf
->prod_snapshot
);
205 case RING_BUFFER_SNAPSHOT_GET_CONSUMED
:
206 return put_ulong(buf
->cons_snapshot
, arg
);
207 case RING_BUFFER_SNAPSHOT_GET_PRODUCED
:
208 return put_ulong(buf
->prod_snapshot
, arg
);
209 case RING_BUFFER_GET_SUBBUF
:
211 unsigned long uconsume
;
214 ret
= get_user(uconsume
, (unsigned long __user
*) arg
);
216 return ret
; /* will return -EFAULT */
217 ret
= lib_ring_buffer_get_subbuf(buf
, uconsume
);
219 /* Set file position to zero at each successful "get" */
224 case RING_BUFFER_PUT_SUBBUF
:
225 lib_ring_buffer_put_subbuf(buf
);
228 case RING_BUFFER_GET_NEXT_SUBBUF
:
232 ret
= lib_ring_buffer_get_next_subbuf(buf
);
234 /* Set file position to zero at each successful "get" */
239 case RING_BUFFER_PUT_NEXT_SUBBUF
:
240 lib_ring_buffer_put_next_subbuf(buf
);
242 case RING_BUFFER_GET_SUBBUF_SIZE
:
243 return put_ulong(lib_ring_buffer_get_read_data_size(config
, buf
),
245 case RING_BUFFER_GET_PADDED_SUBBUF_SIZE
:
249 size
= lib_ring_buffer_get_read_data_size(config
, buf
);
250 size
= PAGE_ALIGN(size
);
251 return put_ulong(size
, arg
);
253 case RING_BUFFER_GET_MAX_SUBBUF_SIZE
:
254 return put_ulong(chan
->backend
.subbuf_size
, arg
);
255 case RING_BUFFER_GET_MMAP_LEN
:
257 unsigned long mmap_buf_len
;
259 if (config
->output
!= RING_BUFFER_MMAP
)
261 mmap_buf_len
= chan
->backend
.buf_size
;
262 if (chan
->backend
.extra_reader_sb
)
263 mmap_buf_len
+= chan
->backend
.subbuf_size
;
264 if (mmap_buf_len
> INT_MAX
)
266 return put_ulong(mmap_buf_len
, arg
);
268 case RING_BUFFER_GET_MMAP_READ_OFFSET
:
270 unsigned long sb_bindex
;
272 if (config
->output
!= RING_BUFFER_MMAP
)
274 sb_bindex
= subbuffer_id_get_index(config
,
275 buf
->backend
.buf_rsb
.id
);
276 return put_ulong(buf
->backend
.array
[sb_bindex
]->mmap_offset
,
279 case RING_BUFFER_FLUSH
:
280 lib_ring_buffer_switch_remote(buf
);
286 EXPORT_SYMBOL_GPL(lib_ring_buffer_ioctl
);
289 * vfs_lib_ring_buffer_ioctl - control ring buffer reader synchronization
295 * This ioctl implements commands necessary for producer/consumer
296 * and flight recorder reader interaction :
297 * RING_BUFFER_GET_NEXT_SUBBUF
298 * Get the next sub-buffer that can be read. It never blocks.
299 * RING_BUFFER_PUT_NEXT_SUBBUF
300 * Release the currently read sub-buffer.
301 * RING_BUFFER_GET_SUBBUF_SIZE
302 * returns the size of the current sub-buffer.
303 * RING_BUFFER_GET_MAX_SUBBUF_SIZE
304 * returns the maximum size for sub-buffers.
305 * RING_BUFFER_GET_NUM_SUBBUF
306 * returns the number of reader-visible sub-buffers in the per cpu
307 * channel (for mmap).
308 * RING_BUFFER_GET_MMAP_READ_OFFSET
309 * returns the offset of the subbuffer belonging to the reader.
310 * Should only be used for mmap clients.
313 long vfs_lib_ring_buffer_ioctl(struct file
*filp
, unsigned int cmd
, unsigned long arg
)
315 struct lib_ring_buffer
*buf
= filp
->private_data
;
317 return lib_ring_buffer_ioctl(filp
, cmd
, arg
, buf
);
321 long lib_ring_buffer_compat_ioctl(struct file
*filp
, unsigned int cmd
,
322 unsigned long arg
, struct lib_ring_buffer
*buf
)
324 struct channel
*chan
= buf
->backend
.chan
;
325 const struct lib_ring_buffer_config
*config
= &chan
->backend
.config
;
327 if (lib_ring_buffer_channel_is_disabled(chan
))
331 case RING_BUFFER_COMPAT_SNAPSHOT
:
333 * First, ensure we perform a "final" flush onto the
334 * stream. This will ensure we create a packet of
335 * padding if we encounter an empty packet. This ensures
336 * the time-stamps right before the snapshot is used as
337 * end of packet timestamp.
340 lib_ring_buffer_switch_remote_empty(buf
);
341 return lib_ring_buffer_snapshot(buf
, &buf
->cons_snapshot
,
342 &buf
->prod_snapshot
);
343 case RING_BUFFER_COMPAT_SNAPSHOT_GET_CONSUMED
:
344 return compat_put_ulong(buf
->cons_snapshot
, arg
);
345 case RING_BUFFER_COMPAT_SNAPSHOT_GET_PRODUCED
:
346 return compat_put_ulong(buf
->prod_snapshot
, arg
);
347 case RING_BUFFER_COMPAT_GET_SUBBUF
:
350 unsigned long consume
;
353 ret
= get_user(uconsume
, (__u32 __user
*) arg
);
355 return ret
; /* will return -EFAULT */
356 consume
= buf
->cons_snapshot
;
357 consume
&= ~0xFFFFFFFFL
;
359 ret
= lib_ring_buffer_get_subbuf(buf
, consume
);
361 /* Set file position to zero at each successful "get" */
366 case RING_BUFFER_COMPAT_PUT_SUBBUF
:
367 lib_ring_buffer_put_subbuf(buf
);
370 case RING_BUFFER_COMPAT_GET_NEXT_SUBBUF
:
374 ret
= lib_ring_buffer_get_next_subbuf(buf
);
376 /* Set file position to zero at each successful "get" */
381 case RING_BUFFER_COMPAT_PUT_NEXT_SUBBUF
:
382 lib_ring_buffer_put_next_subbuf(buf
);
384 case RING_BUFFER_COMPAT_GET_SUBBUF_SIZE
:
386 unsigned long data_size
;
388 data_size
= lib_ring_buffer_get_read_data_size(config
, buf
);
389 if (data_size
> UINT_MAX
)
391 return compat_put_ulong(data_size
, arg
);
393 case RING_BUFFER_COMPAT_GET_PADDED_SUBBUF_SIZE
:
397 size
= lib_ring_buffer_get_read_data_size(config
, buf
);
398 size
= PAGE_ALIGN(size
);
401 return compat_put_ulong(size
, arg
);
403 case RING_BUFFER_COMPAT_GET_MAX_SUBBUF_SIZE
:
404 if (chan
->backend
.subbuf_size
> UINT_MAX
)
406 return compat_put_ulong(chan
->backend
.subbuf_size
, arg
);
407 case RING_BUFFER_COMPAT_GET_MMAP_LEN
:
409 unsigned long mmap_buf_len
;
411 if (config
->output
!= RING_BUFFER_MMAP
)
413 mmap_buf_len
= chan
->backend
.buf_size
;
414 if (chan
->backend
.extra_reader_sb
)
415 mmap_buf_len
+= chan
->backend
.subbuf_size
;
416 if (mmap_buf_len
> UINT_MAX
)
418 return compat_put_ulong(mmap_buf_len
, arg
);
420 case RING_BUFFER_COMPAT_GET_MMAP_READ_OFFSET
:
422 unsigned long sb_bindex
, read_offset
;
424 if (config
->output
!= RING_BUFFER_MMAP
)
426 sb_bindex
= subbuffer_id_get_index(config
,
427 buf
->backend
.buf_rsb
.id
);
428 read_offset
= buf
->backend
.array
[sb_bindex
]->mmap_offset
;
429 if (read_offset
> UINT_MAX
)
431 return compat_put_ulong(read_offset
, arg
);
433 case RING_BUFFER_COMPAT_FLUSH
:
434 lib_ring_buffer_switch_remote(buf
);
440 EXPORT_SYMBOL_GPL(lib_ring_buffer_compat_ioctl
);
443 long vfs_lib_ring_buffer_compat_ioctl(struct file
*filp
, unsigned int cmd
,
446 struct lib_ring_buffer
*buf
= filp
->private_data
;
448 return lib_ring_buffer_compat_ioctl(filp
, cmd
, arg
, buf
);
452 const struct file_operations lib_ring_buffer_file_operations
= {
453 .owner
= THIS_MODULE
,
454 .open
= vfs_lib_ring_buffer_open
,
455 .release
= vfs_lib_ring_buffer_release
,
456 .poll
= vfs_lib_ring_buffer_poll
,
457 .splice_read
= vfs_lib_ring_buffer_splice_read
,
458 .mmap
= vfs_lib_ring_buffer_mmap
,
459 .unlocked_ioctl
= vfs_lib_ring_buffer_ioctl
,
460 .llseek
= vfs_lib_ring_buffer_no_llseek
,
462 .compat_ioctl
= vfs_lib_ring_buffer_compat_ioctl
,
465 EXPORT_SYMBOL_GPL(lib_ring_buffer_file_operations
);
467 MODULE_LICENSE("GPL and additional rights");
468 MODULE_AUTHOR("Mathieu Desnoyers");
469 MODULE_DESCRIPTION("Ring Buffer Library VFS");
470 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION
) "."
471 __stringify(LTTNG_MODULES_MINOR_VERSION
) "."
472 __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION
)
473 LTTNG_MODULES_EXTRAVERSION
);