Commit | Line | Data |
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b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only) |
9f36eaed | 2 | * |
24591303 | 3 | * ringbuffer/backend_internal.h |
f3bc08c5 MD |
4 | * |
5 | * Ring buffer backend (internal helpers). | |
6 | * | |
886d51a3 | 7 | * Copyright (C) 2008-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 MD |
8 | */ |
9 | ||
9f36eaed MJ |
10 | #ifndef _LIB_RING_BUFFER_BACKEND_INTERNAL_H |
11 | #define _LIB_RING_BUFFER_BACKEND_INTERNAL_H | |
12 | ||
a8f2d0c7 | 13 | #include <wrapper/compiler.h> |
24591303 MD |
14 | #include <wrapper/inline_memcpy.h> |
15 | #include <ringbuffer/config.h> | |
16 | #include <ringbuffer/backend_types.h> | |
17 | #include <ringbuffer/frontend_types.h> | |
f3bc08c5 | 18 | #include <linux/string.h> |
4ea00e4f | 19 | #include <linux/uaccess.h> |
f3bc08c5 MD |
20 | |
21 | /* Ring buffer backend API presented to the frontend */ | |
22 | ||
23 | /* Ring buffer and channel backend create/free */ | |
24 | ||
25 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
26 | struct channel_backend *chan, int cpu); | |
27 | void channel_backend_unregister_notifiers(struct channel_backend *chanb); | |
28 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb); | |
29 | int channel_backend_init(struct channel_backend *chanb, | |
30 | const char *name, | |
31 | const struct lib_ring_buffer_config *config, | |
32 | void *priv, size_t subbuf_size, | |
33 | size_t num_subbuf); | |
34 | void channel_backend_free(struct channel_backend *chanb); | |
35 | ||
36 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb); | |
37 | void channel_backend_reset(struct channel_backend *chanb); | |
38 | ||
39 | int lib_ring_buffer_backend_init(void); | |
40 | void lib_ring_buffer_backend_exit(void); | |
41 | ||
42 | extern void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, | |
43 | size_t offset, const void *src, size_t len, | |
bfe529f9 | 44 | size_t pagecpy); |
4ea00e4f JD |
45 | extern void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, |
46 | size_t offset, int c, size_t len, | |
bfe529f9 | 47 | size_t pagecpy); |
16f78f3a MD |
48 | extern void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb, |
49 | size_t offset, const char *src, size_t len, | |
50 | size_t pagecpy, int pad); | |
7b8ea3a5 | 51 | extern void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
4ea00e4f | 52 | size_t offset, const void *src, |
bfe529f9 | 53 | size_t len, size_t pagecpy); |
16f78f3a MD |
54 | extern void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
55 | size_t offset, const char __user *src, size_t len, | |
56 | size_t pagecpy, int pad); | |
f3bc08c5 MD |
57 | |
58 | /* | |
59 | * Subbuffer ID bits for overwrite mode. Need to fit within a single word to be | |
60 | * exchanged atomically. | |
61 | * | |
62 | * Top half word, except lowest bit, belongs to "offset", which is used to keep | |
63 | * to count the produced buffers. For overwrite mode, this provides the | |
64 | * consumer with the capacity to read subbuffers in order, handling the | |
65 | * situation where producers would write up to 2^15 buffers (or 2^31 for 64-bit | |
66 | * systems) concurrently with a single execution of get_subbuf (between offset | |
67 | * sampling and subbuffer ID exchange). | |
68 | */ | |
69 | ||
70 | #define HALF_ULONG_BITS (BITS_PER_LONG >> 1) | |
71 | ||
72 | #define SB_ID_OFFSET_SHIFT (HALF_ULONG_BITS + 1) | |
73 | #define SB_ID_OFFSET_COUNT (1UL << SB_ID_OFFSET_SHIFT) | |
74 | #define SB_ID_OFFSET_MASK (~(SB_ID_OFFSET_COUNT - 1)) | |
75 | /* | |
76 | * Lowest bit of top word half belongs to noref. Used only for overwrite mode. | |
77 | */ | |
78 | #define SB_ID_NOREF_SHIFT (SB_ID_OFFSET_SHIFT - 1) | |
79 | #define SB_ID_NOREF_COUNT (1UL << SB_ID_NOREF_SHIFT) | |
80 | #define SB_ID_NOREF_MASK SB_ID_NOREF_COUNT | |
81 | /* | |
82 | * In overwrite mode: lowest half of word is used for index. | |
83 | * Limit of 2^16 subbuffers per buffer on 32-bit, 2^32 on 64-bit. | |
84 | * In producer-consumer mode: whole word used for index. | |
85 | */ | |
86 | #define SB_ID_INDEX_SHIFT 0 | |
87 | #define SB_ID_INDEX_COUNT (1UL << SB_ID_INDEX_SHIFT) | |
88 | #define SB_ID_INDEX_MASK (SB_ID_NOREF_COUNT - 1) | |
89 | ||
90 | /* | |
91 | * Construct the subbuffer id from offset, index and noref. Use only the index | |
92 | * for producer-consumer mode (offset and noref are only used in overwrite | |
93 | * mode). | |
94 | */ | |
95 | static inline | |
96 | unsigned long subbuffer_id(const struct lib_ring_buffer_config *config, | |
97 | unsigned long offset, unsigned long noref, | |
98 | unsigned long index) | |
99 | { | |
100 | if (config->mode == RING_BUFFER_OVERWRITE) | |
101 | return (offset << SB_ID_OFFSET_SHIFT) | |
102 | | (noref << SB_ID_NOREF_SHIFT) | |
103 | | index; | |
104 | else | |
105 | return index; | |
106 | } | |
107 | ||
108 | /* | |
109 | * Compare offset with the offset contained within id. Return 1 if the offset | |
110 | * bits are identical, else 0. | |
111 | */ | |
112 | static inline | |
113 | int subbuffer_id_compare_offset(const struct lib_ring_buffer_config *config, | |
114 | unsigned long id, unsigned long offset) | |
115 | { | |
116 | return (id & SB_ID_OFFSET_MASK) == (offset << SB_ID_OFFSET_SHIFT); | |
117 | } | |
118 | ||
119 | static inline | |
120 | unsigned long subbuffer_id_get_index(const struct lib_ring_buffer_config *config, | |
121 | unsigned long id) | |
122 | { | |
123 | if (config->mode == RING_BUFFER_OVERWRITE) | |
124 | return id & SB_ID_INDEX_MASK; | |
125 | else | |
126 | return id; | |
127 | } | |
128 | ||
129 | static inline | |
130 | unsigned long subbuffer_id_is_noref(const struct lib_ring_buffer_config *config, | |
131 | unsigned long id) | |
132 | { | |
133 | if (config->mode == RING_BUFFER_OVERWRITE) | |
134 | return !!(id & SB_ID_NOREF_MASK); | |
135 | else | |
136 | return 1; | |
137 | } | |
138 | ||
139 | /* | |
140 | * Only used by reader on subbuffer ID it has exclusive access to. No volatile | |
141 | * needed. | |
142 | */ | |
143 | static inline | |
144 | void subbuffer_id_set_noref(const struct lib_ring_buffer_config *config, | |
145 | unsigned long *id) | |
146 | { | |
147 | if (config->mode == RING_BUFFER_OVERWRITE) | |
148 | *id |= SB_ID_NOREF_MASK; | |
149 | } | |
150 | ||
151 | static inline | |
152 | void subbuffer_id_set_noref_offset(const struct lib_ring_buffer_config *config, | |
153 | unsigned long *id, unsigned long offset) | |
154 | { | |
155 | unsigned long tmp; | |
156 | ||
157 | if (config->mode == RING_BUFFER_OVERWRITE) { | |
158 | tmp = *id; | |
159 | tmp &= ~SB_ID_OFFSET_MASK; | |
160 | tmp |= offset << SB_ID_OFFSET_SHIFT; | |
161 | tmp |= SB_ID_NOREF_MASK; | |
162 | /* Volatile store, read concurrently by readers. */ | |
a8f2d0c7 | 163 | WRITE_ONCE(*id, tmp); |
f3bc08c5 MD |
164 | } |
165 | } | |
166 | ||
167 | /* No volatile access, since already used locally */ | |
168 | static inline | |
169 | void subbuffer_id_clear_noref(const struct lib_ring_buffer_config *config, | |
170 | unsigned long *id) | |
171 | { | |
172 | if (config->mode == RING_BUFFER_OVERWRITE) | |
173 | *id &= ~SB_ID_NOREF_MASK; | |
174 | } | |
175 | ||
176 | /* | |
177 | * For overwrite mode, cap the number of subbuffers per buffer to: | |
178 | * 2^16 on 32-bit architectures | |
179 | * 2^32 on 64-bit architectures | |
180 | * This is required to fit in the index part of the ID. Return 0 on success, | |
181 | * -EPERM on failure. | |
182 | */ | |
183 | static inline | |
184 | int subbuffer_id_check_index(const struct lib_ring_buffer_config *config, | |
185 | unsigned long num_subbuf) | |
186 | { | |
187 | if (config->mode == RING_BUFFER_OVERWRITE) | |
188 | return (num_subbuf > (1UL << HALF_ULONG_BITS)) ? -EPERM : 0; | |
189 | else | |
190 | return 0; | |
191 | } | |
192 | ||
85a07c33 MD |
193 | static inline |
194 | void lib_ring_buffer_backend_get_pages(const struct lib_ring_buffer_config *config, | |
195 | struct lib_ring_buffer_ctx *ctx, | |
196 | struct lib_ring_buffer_backend_pages **backend_pages) | |
197 | { | |
c7d9db61 MD |
198 | struct lib_ring_buffer_backend *bufb = &ctx->priv.buf->backend; |
199 | struct channel_backend *chanb = &ctx->priv.chan->backend; | |
200 | size_t sbidx, offset = ctx->priv.buf_offset; | |
85a07c33 MD |
201 | unsigned long sb_bindex, id; |
202 | struct lib_ring_buffer_backend_pages *rpages; | |
203 | ||
204 | offset &= chanb->buf_size - 1; | |
205 | sbidx = offset >> chanb->subbuf_size_order; | |
206 | id = bufb->buf_wsb[sbidx].id; | |
207 | sb_bindex = subbuffer_id_get_index(config, id); | |
208 | rpages = bufb->array[sb_bindex]; | |
c7d9db61 | 209 | CHAN_WARN_ON(ctx->priv.chan, |
85a07c33 MD |
210 | config->mode == RING_BUFFER_OVERWRITE |
211 | && subbuffer_id_is_noref(config, id)); | |
212 | *backend_pages = rpages; | |
213 | } | |
214 | ||
215 | /* Get backend pages from cache. */ | |
216 | static inline | |
217 | struct lib_ring_buffer_backend_pages * | |
218 | lib_ring_buffer_get_backend_pages_from_ctx(const struct lib_ring_buffer_config *config, | |
219 | struct lib_ring_buffer_ctx *ctx) | |
220 | { | |
c7d9db61 | 221 | return ctx->priv.backend_pages; |
85a07c33 MD |
222 | } |
223 | ||
25337cb5 MD |
224 | /* |
225 | * The ring buffer can count events recorded and overwritten per buffer, | |
226 | * but it is disabled by default due to its performance overhead. | |
227 | */ | |
228 | #ifdef LTTNG_RING_BUFFER_COUNT_EVENTS | |
f3bc08c5 MD |
229 | static inline |
230 | void subbuffer_count_record(const struct lib_ring_buffer_config *config, | |
231 | struct lib_ring_buffer_backend *bufb, | |
232 | unsigned long idx) | |
233 | { | |
234 | unsigned long sb_bindex; | |
235 | ||
236 | sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id); | |
237 | v_inc(config, &bufb->array[sb_bindex]->records_commit); | |
238 | } | |
239 | ||
240 | /* | |
241 | * Reader has exclusive subbuffer access for record consumption. No need to | |
242 | * perform the decrement atomically. | |
243 | */ | |
244 | static inline | |
245 | void subbuffer_consume_record(const struct lib_ring_buffer_config *config, | |
246 | struct lib_ring_buffer_backend *bufb) | |
247 | { | |
248 | unsigned long sb_bindex; | |
249 | ||
250 | sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id); | |
251 | CHAN_WARN_ON(bufb->chan, | |
252 | !v_read(config, &bufb->array[sb_bindex]->records_unread)); | |
253 | /* Non-atomic decrement protected by exclusive subbuffer access */ | |
254 | _v_dec(config, &bufb->array[sb_bindex]->records_unread); | |
255 | v_inc(config, &bufb->records_read); | |
256 | } | |
935150de MD |
257 | #else /* LTTNG_RING_BUFFER_COUNT_EVENTS */ |
258 | static inline | |
259 | void subbuffer_count_record(const struct lib_ring_buffer_config *config, | |
260 | struct lib_ring_buffer_backend *bufb, | |
261 | unsigned long idx) | |
262 | { | |
263 | } | |
264 | static inline | |
265 | void subbuffer_consume_record(const struct lib_ring_buffer_config *config, | |
266 | struct lib_ring_buffer_backend *bufb) | |
267 | { | |
268 | } | |
269 | #endif /* #else LTTNG_RING_BUFFER_COUNT_EVENTS */ | |
f3bc08c5 MD |
270 | |
271 | static inline | |
272 | unsigned long subbuffer_get_records_count( | |
273 | const struct lib_ring_buffer_config *config, | |
274 | struct lib_ring_buffer_backend *bufb, | |
275 | unsigned long idx) | |
276 | { | |
277 | unsigned long sb_bindex; | |
278 | ||
279 | sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id); | |
280 | return v_read(config, &bufb->array[sb_bindex]->records_commit); | |
281 | } | |
282 | ||
283 | /* | |
284 | * Must be executed at subbuffer delivery when the writer has _exclusive_ | |
c68be968 MD |
285 | * subbuffer access. See lib_ring_buffer_check_deliver() for details. |
286 | * lib_ring_buffer_get_records_count() must be called to get the records | |
287 | * count before this function, because it resets the records_commit | |
288 | * count. | |
f3bc08c5 MD |
289 | */ |
290 | static inline | |
291 | unsigned long subbuffer_count_records_overrun( | |
292 | const struct lib_ring_buffer_config *config, | |
293 | struct lib_ring_buffer_backend *bufb, | |
294 | unsigned long idx) | |
295 | { | |
296 | struct lib_ring_buffer_backend_pages *pages; | |
297 | unsigned long overruns, sb_bindex; | |
298 | ||
299 | sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id); | |
300 | pages = bufb->array[sb_bindex]; | |
301 | overruns = v_read(config, &pages->records_unread); | |
302 | v_set(config, &pages->records_unread, | |
303 | v_read(config, &pages->records_commit)); | |
304 | v_set(config, &pages->records_commit, 0); | |
305 | ||
306 | return overruns; | |
307 | } | |
308 | ||
309 | static inline | |
310 | void subbuffer_set_data_size(const struct lib_ring_buffer_config *config, | |
311 | struct lib_ring_buffer_backend *bufb, | |
312 | unsigned long idx, | |
313 | unsigned long data_size) | |
314 | { | |
315 | struct lib_ring_buffer_backend_pages *pages; | |
316 | unsigned long sb_bindex; | |
317 | ||
318 | sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id); | |
319 | pages = bufb->array[sb_bindex]; | |
320 | pages->data_size = data_size; | |
321 | } | |
322 | ||
323 | static inline | |
324 | unsigned long subbuffer_get_read_data_size( | |
325 | const struct lib_ring_buffer_config *config, | |
326 | struct lib_ring_buffer_backend *bufb) | |
327 | { | |
328 | struct lib_ring_buffer_backend_pages *pages; | |
329 | unsigned long sb_bindex; | |
330 | ||
331 | sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id); | |
332 | pages = bufb->array[sb_bindex]; | |
333 | return pages->data_size; | |
334 | } | |
335 | ||
336 | static inline | |
337 | unsigned long subbuffer_get_data_size( | |
338 | const struct lib_ring_buffer_config *config, | |
339 | struct lib_ring_buffer_backend *bufb, | |
340 | unsigned long idx) | |
341 | { | |
342 | struct lib_ring_buffer_backend_pages *pages; | |
343 | unsigned long sb_bindex; | |
344 | ||
345 | sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id); | |
346 | pages = bufb->array[sb_bindex]; | |
347 | return pages->data_size; | |
348 | } | |
349 | ||
5b3cf4f9 JD |
350 | static inline |
351 | void subbuffer_inc_packet_count(const struct lib_ring_buffer_config *config, | |
352 | struct lib_ring_buffer_backend *bufb, | |
353 | unsigned long idx) | |
354 | { | |
355 | bufb->buf_cnt[idx].seq_cnt++; | |
356 | } | |
357 | ||
f3bc08c5 MD |
358 | /** |
359 | * lib_ring_buffer_clear_noref - Clear the noref subbuffer flag, called by | |
360 | * writer. | |
361 | */ | |
362 | static inline | |
363 | void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config, | |
364 | struct lib_ring_buffer_backend *bufb, | |
365 | unsigned long idx) | |
366 | { | |
367 | unsigned long id, new_id; | |
368 | ||
369 | if (config->mode != RING_BUFFER_OVERWRITE) | |
370 | return; | |
371 | ||
372 | /* | |
373 | * Performing a volatile access to read the sb_pages, because we want to | |
374 | * read a coherent version of the pointer and the associated noref flag. | |
375 | */ | |
585e5dcc | 376 | id = LTTNG_READ_ONCE(bufb->buf_wsb[idx].id); |
f3bc08c5 MD |
377 | for (;;) { |
378 | /* This check is called on the fast path for each record. */ | |
379 | if (likely(!subbuffer_id_is_noref(config, id))) { | |
380 | /* | |
381 | * Store after load dependency ordering the writes to | |
382 | * the subbuffer after load and test of the noref flag | |
383 | * matches the memory barrier implied by the cmpxchg() | |
384 | * in update_read_sb_index(). | |
385 | */ | |
386 | return; /* Already writing to this buffer */ | |
387 | } | |
388 | new_id = id; | |
389 | subbuffer_id_clear_noref(config, &new_id); | |
390 | new_id = cmpxchg(&bufb->buf_wsb[idx].id, id, new_id); | |
391 | if (likely(new_id == id)) | |
392 | break; | |
393 | id = new_id; | |
394 | } | |
395 | } | |
396 | ||
397 | /** | |
398 | * lib_ring_buffer_set_noref_offset - Set the noref subbuffer flag and offset, | |
399 | * called by writer. | |
400 | */ | |
401 | static inline | |
402 | void lib_ring_buffer_set_noref_offset(const struct lib_ring_buffer_config *config, | |
403 | struct lib_ring_buffer_backend *bufb, | |
404 | unsigned long idx, unsigned long offset) | |
405 | { | |
406 | if (config->mode != RING_BUFFER_OVERWRITE) | |
407 | return; | |
408 | ||
409 | /* | |
410 | * Because ring_buffer_set_noref() is only called by a single thread | |
411 | * (the one which updated the cc_sb value), there are no concurrent | |
412 | * updates to take care of: other writers have not updated cc_sb, so | |
413 | * they cannot set the noref flag, and concurrent readers cannot modify | |
414 | * the pointer because the noref flag is not set yet. | |
415 | * The smp_wmb() in ring_buffer_commit() takes care of ordering writes | |
416 | * to the subbuffer before this set noref operation. | |
417 | * subbuffer_set_noref() uses a volatile store to deal with concurrent | |
418 | * readers of the noref flag. | |
419 | */ | |
420 | CHAN_WARN_ON(bufb->chan, | |
421 | subbuffer_id_is_noref(config, bufb->buf_wsb[idx].id)); | |
422 | /* | |
423 | * Memory barrier that ensures counter stores are ordered before set | |
424 | * noref and offset. | |
425 | */ | |
426 | smp_mb(); | |
427 | subbuffer_id_set_noref_offset(config, &bufb->buf_wsb[idx].id, offset); | |
428 | } | |
429 | ||
430 | /** | |
431 | * update_read_sb_index - Read-side subbuffer index update. | |
432 | */ | |
433 | static inline | |
434 | int update_read_sb_index(const struct lib_ring_buffer_config *config, | |
435 | struct lib_ring_buffer_backend *bufb, | |
436 | struct channel_backend *chanb, | |
437 | unsigned long consumed_idx, | |
438 | unsigned long consumed_count) | |
439 | { | |
440 | unsigned long old_id, new_id; | |
441 | ||
442 | if (config->mode == RING_BUFFER_OVERWRITE) { | |
443 | /* | |
444 | * Exchange the target writer subbuffer with our own unused | |
a8f2d0c7 | 445 | * subbuffer. No need to use READ_ONCE() here to read the |
f3bc08c5 MD |
446 | * old_wpage, because the value read will be confirmed by the |
447 | * following cmpxchg(). | |
448 | */ | |
449 | old_id = bufb->buf_wsb[consumed_idx].id; | |
450 | if (unlikely(!subbuffer_id_is_noref(config, old_id))) | |
451 | return -EAGAIN; | |
452 | /* | |
453 | * Make sure the offset count we are expecting matches the one | |
454 | * indicated by the writer. | |
455 | */ | |
456 | if (unlikely(!subbuffer_id_compare_offset(config, old_id, | |
457 | consumed_count))) | |
458 | return -EAGAIN; | |
459 | CHAN_WARN_ON(bufb->chan, | |
460 | !subbuffer_id_is_noref(config, bufb->buf_rsb.id)); | |
461 | subbuffer_id_set_noref_offset(config, &bufb->buf_rsb.id, | |
462 | consumed_count); | |
463 | new_id = cmpxchg(&bufb->buf_wsb[consumed_idx].id, old_id, | |
464 | bufb->buf_rsb.id); | |
465 | if (unlikely(old_id != new_id)) | |
466 | return -EAGAIN; | |
467 | bufb->buf_rsb.id = new_id; | |
468 | } else { | |
469 | /* No page exchange, use the writer page directly */ | |
470 | bufb->buf_rsb.id = bufb->buf_wsb[consumed_idx].id; | |
471 | } | |
472 | return 0; | |
473 | } | |
474 | ||
327177e6 | 475 | static inline __attribute__((always_inline)) |
04707312 | 476 | void lttng_inline_memcpy(void *dest, const void *src, |
327177e6 MD |
477 | unsigned long len) |
478 | { | |
479 | switch (len) { | |
480 | case 1: | |
481 | *(uint8_t *) dest = *(const uint8_t *) src; | |
482 | break; | |
483 | case 2: | |
484 | *(uint16_t *) dest = *(const uint16_t *) src; | |
485 | break; | |
486 | case 4: | |
487 | *(uint32_t *) dest = *(const uint32_t *) src; | |
488 | break; | |
489 | case 8: | |
490 | *(uint64_t *) dest = *(const uint64_t *) src; | |
491 | break; | |
492 | default: | |
493 | inline_memcpy(dest, src, len); | |
494 | } | |
495 | } | |
496 | ||
f3bc08c5 MD |
497 | /* |
498 | * Use the architecture-specific memcpy implementation for constant-sized | |
499 | * inputs, but rely on an inline memcpy for length statically unknown. | |
500 | * The function call to memcpy is just way too expensive for a fast path. | |
501 | */ | |
502 | #define lib_ring_buffer_do_copy(config, dest, src, len) \ | |
503 | do { \ | |
504 | size_t __len = (len); \ | |
505 | if (__builtin_constant_p(len)) \ | |
506 | memcpy(dest, src, __len); \ | |
507 | else \ | |
327177e6 | 508 | lttng_inline_memcpy(dest, src, __len); \ |
f3bc08c5 MD |
509 | } while (0) |
510 | ||
4ea00e4f | 511 | /* |
7b8ea3a5 | 512 | * We use __copy_from_user_inatomic to copy userspace data since we already |
4ea00e4f | 513 | * did the access_ok for the whole range. |
d87a9f03 MD |
514 | * |
515 | * Return 0 if OK, nonzero on error. | |
4ea00e4f JD |
516 | */ |
517 | static inline | |
7b8ea3a5 | 518 | unsigned long lib_ring_buffer_do_copy_from_user_inatomic(void *dest, |
4ea00e4f JD |
519 | const void __user *src, |
520 | unsigned long len) | |
521 | { | |
7b8ea3a5 | 522 | return __copy_from_user_inatomic(dest, src, len); |
4ea00e4f JD |
523 | } |
524 | ||
525 | /* | |
526 | * write len bytes to dest with c | |
527 | */ | |
528 | static inline | |
529 | void lib_ring_buffer_do_memset(char *dest, int c, | |
530 | unsigned long len) | |
531 | { | |
532 | unsigned long i; | |
533 | ||
534 | for (i = 0; i < len; i++) | |
535 | dest[i] = c; | |
536 | } | |
537 | ||
886d51a3 | 538 | #endif /* _LIB_RING_BUFFER_BACKEND_INTERNAL_H */ |