Commit | Line | Data |
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852c2936 | 1 | /* |
c0c0989a | 2 | * SPDX-License-Identifier: LGPL-2.1-only |
852c2936 | 3 | * |
e92f3e28 | 4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
852c2936 MD |
5 | */ |
6 | ||
3fbec7dc | 7 | #define _LGPL_SOURCE |
b4051ad8 | 8 | #include <stddef.h> |
fb31eb73 | 9 | #include <stdint.h> |
2657d1ba | 10 | #include <unistd.h> |
14641deb | 11 | #include <urcu/arch.h> |
96e80018 | 12 | #include <limits.h> |
14641deb | 13 | |
b72687b8 | 14 | #include <lttng/align.h> |
4318ae1b | 15 | #include <lttng/ringbuffer-config.h> |
2fed87ae | 16 | #include "vatomic.h" |
4931a13e MD |
17 | #include "backend.h" |
18 | #include "frontend.h" | |
a6352fd4 | 19 | #include "smp.h" |
431d5cf0 | 20 | #include "shm.h" |
852c2936 MD |
21 | |
22 | /** | |
23 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
24 | * @config: ring buffer instance configuration | |
25 | * @buf: the buffer struct | |
26 | * @size: total size of the buffer | |
27 | * @num_subbuf: number of subbuffers | |
28 | * @extra_reader_sb: need extra subbuffer for reader | |
29 | */ | |
30 | static | |
4cfec15c MD |
31 | int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_config *config, |
32 | struct lttng_ust_lib_ring_buffer_backend *bufb, | |
852c2936 | 33 | size_t size, size_t num_subbuf, |
a6352fd4 | 34 | int extra_reader_sb, |
38fae1d3 | 35 | struct lttng_ust_shm_handle *handle, |
1d498196 | 36 | struct shm_object *shmobj) |
852c2936 | 37 | { |
34daae3e | 38 | struct channel_backend *chanb; |
852c2936 MD |
39 | unsigned long subbuf_size, mmap_offset = 0; |
40 | unsigned long num_subbuf_alloc; | |
852c2936 | 41 | unsigned long i; |
2657d1ba | 42 | long page_size; |
852c2936 | 43 | |
34daae3e MD |
44 | chanb = &shmp(handle, bufb->chan)->backend; |
45 | if (!chanb) | |
46 | return -EINVAL; | |
47 | ||
852c2936 MD |
48 | subbuf_size = chanb->subbuf_size; |
49 | num_subbuf_alloc = num_subbuf; | |
50 | ||
a6352fd4 | 51 | if (extra_reader_sb) |
852c2936 | 52 | num_subbuf_alloc++; |
852c2936 | 53 | |
b72687b8 | 54 | page_size = LTTNG_UST_PAGE_SIZE; |
2657d1ba MD |
55 | if (page_size <= 0) { |
56 | goto page_size_error; | |
57 | } | |
58 | ||
4cfec15c | 59 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
1d498196 | 60 | set_shmp(bufb->array, zalloc_shm(shmobj, |
4cfec15c | 61 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc)); |
b5a3dfa5 | 62 | if (caa_unlikely(!shmp(handle, bufb->array))) |
852c2936 MD |
63 | goto array_error; |
64 | ||
431d5cf0 MD |
65 | /* |
66 | * This is the largest element (the buffer pages) which needs to | |
2657d1ba | 67 | * be aligned on page size. |
431d5cf0 | 68 | */ |
2657d1ba | 69 | align_shm(shmobj, page_size); |
1d498196 | 70 | set_shmp(bufb->memory_map, zalloc_shm(shmobj, |
a6352fd4 | 71 | subbuf_size * num_subbuf_alloc)); |
b5a3dfa5 | 72 | if (caa_unlikely(!shmp(handle, bufb->memory_map))) |
a6352fd4 | 73 | goto memory_map_error; |
852c2936 MD |
74 | |
75 | /* Allocate backend pages array elements */ | |
76 | for (i = 0; i < num_subbuf_alloc; i++) { | |
4cfec15c | 77 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
aead2025 | 78 | set_shmp(shmp_index(handle, bufb->array, i)->shmp, |
1d498196 | 79 | zalloc_shm(shmobj, |
4cfec15c | 80 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages))); |
4746ae29 | 81 | if (!shmp(handle, shmp_index(handle, bufb->array, i)->shmp)) |
852c2936 MD |
82 | goto free_array; |
83 | } | |
84 | ||
85 | /* Allocate write-side subbuffer table */ | |
4cfec15c | 86 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
1d498196 | 87 | set_shmp(bufb->buf_wsb, zalloc_shm(shmobj, |
4cfec15c | 88 | sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) |
1d498196 | 89 | * num_subbuf)); |
b5a3dfa5 | 90 | if (caa_unlikely(!shmp(handle, bufb->buf_wsb))) |
852c2936 MD |
91 | goto free_array; |
92 | ||
34daae3e MD |
93 | for (i = 0; i < num_subbuf; i++) { |
94 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
95 | ||
96 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
97 | if (!sb) | |
98 | goto free_array; | |
99 | sb->id = subbuffer_id(config, 0, 1, i); | |
100 | } | |
852c2936 MD |
101 | |
102 | /* Assign read-side subbuffer table */ | |
103 | if (extra_reader_sb) | |
104 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
105 | num_subbuf_alloc - 1); | |
106 | else | |
107 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
108 | ||
1ff31389 | 109 | /* Allocate subbuffer packet counter table */ |
bf8f2ef2 | 110 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_counts)); |
1ff31389 JD |
111 | set_shmp(bufb->buf_cnt, zalloc_shm(shmobj, |
112 | sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) | |
113 | * num_subbuf)); | |
114 | if (caa_unlikely(!shmp(handle, bufb->buf_cnt))) | |
115 | goto free_wsb; | |
116 | ||
852c2936 MD |
117 | /* Assign pages to page index */ |
118 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
119 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
120 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
1d498196 MD |
121 | struct shm_ref ref; |
122 | ||
123 | ref.index = bufb->memory_map._ref.index; | |
124 | ref.offset = bufb->memory_map._ref.offset; | |
125 | ref.offset += i * subbuf_size; | |
126 | ||
34daae3e MD |
127 | sbp = shmp_index(handle, bufb->array, i); |
128 | if (!sbp) | |
129 | goto free_array; | |
130 | pages = shmp(handle, sbp->shmp); | |
131 | if (!pages) | |
132 | goto free_array; | |
133 | set_shmp(pages->p, ref); | |
852c2936 | 134 | if (config->output == RING_BUFFER_MMAP) { |
34daae3e | 135 | pages->mmap_offset = mmap_offset; |
852c2936 MD |
136 | mmap_offset += subbuf_size; |
137 | } | |
138 | } | |
852c2936 MD |
139 | return 0; |
140 | ||
1ff31389 JD |
141 | free_wsb: |
142 | /* bufb->buf_wsb will be freed by shm teardown */ | |
852c2936 | 143 | free_array: |
a6352fd4 MD |
144 | /* bufb->array[i] will be freed by shm teardown */ |
145 | memory_map_error: | |
146 | /* bufb->array will be freed by shm teardown */ | |
852c2936 | 147 | array_error: |
2657d1ba | 148 | page_size_error: |
852c2936 MD |
149 | return -ENOMEM; |
150 | } | |
151 | ||
4cfec15c | 152 | int lib_ring_buffer_backend_create(struct lttng_ust_lib_ring_buffer_backend *bufb, |
a6352fd4 | 153 | struct channel_backend *chanb, int cpu, |
38fae1d3 | 154 | struct lttng_ust_shm_handle *handle, |
1d498196 | 155 | struct shm_object *shmobj) |
852c2936 | 156 | { |
4cfec15c | 157 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 | 158 | |
1d498196 | 159 | set_shmp(bufb->chan, handle->chan._ref); |
852c2936 MD |
160 | bufb->cpu = cpu; |
161 | ||
162 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
163 | chanb->num_subbuf, | |
a6352fd4 | 164 | chanb->extra_reader_sb, |
1d498196 | 165 | handle, shmobj); |
852c2936 MD |
166 | } |
167 | ||
4cfec15c | 168 | void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb, |
38fae1d3 | 169 | struct lttng_ust_shm_handle *handle) |
852c2936 | 170 | { |
34daae3e MD |
171 | struct channel_backend *chanb; |
172 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
173 | unsigned long num_subbuf_alloc; |
174 | unsigned int i; | |
175 | ||
34daae3e MD |
176 | chanb = &shmp(handle, bufb->chan)->backend; |
177 | if (!chanb) | |
15500a1b | 178 | return; |
34daae3e MD |
179 | config = &chanb->config; |
180 | ||
852c2936 MD |
181 | num_subbuf_alloc = chanb->num_subbuf; |
182 | if (chanb->extra_reader_sb) | |
183 | num_subbuf_alloc++; | |
184 | ||
34daae3e MD |
185 | for (i = 0; i < chanb->num_subbuf; i++) { |
186 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
187 | ||
188 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
189 | if (!sb) | |
15500a1b | 190 | return; |
34daae3e MD |
191 | sb->id = subbuffer_id(config, 0, 1, i); |
192 | } | |
852c2936 MD |
193 | if (chanb->extra_reader_sb) |
194 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
195 | num_subbuf_alloc - 1); | |
196 | else | |
197 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
198 | ||
199 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
200 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
201 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
202 | ||
203 | sbp = shmp_index(handle, bufb->array, i); | |
204 | if (!sbp) | |
15500a1b | 205 | return; |
34daae3e MD |
206 | pages = shmp(handle, sbp->shmp); |
207 | if (!pages) | |
15500a1b | 208 | return; |
852c2936 | 209 | /* Don't reset mmap_offset */ |
34daae3e MD |
210 | v_set(config, &pages->records_commit, 0); |
211 | v_set(config, &pages->records_unread, 0); | |
212 | pages->data_size = 0; | |
852c2936 MD |
213 | /* Don't reset backend page and virt addresses */ |
214 | } | |
215 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
216 | v_set(config, &bufb->records_read, 0); | |
217 | } | |
218 | ||
219 | /* | |
220 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
221 | * each buffer when calling channel_backend_reset. | |
222 | */ | |
223 | void channel_backend_reset(struct channel_backend *chanb) | |
224 | { | |
14641deb | 225 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
4cfec15c | 226 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 MD |
227 | |
228 | /* | |
229 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
230 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
231 | * priv, notifiers, config, cpumask and name. | |
232 | */ | |
233 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
234 | } | |
235 | ||
852c2936 MD |
236 | /** |
237 | * channel_backend_init - initialize a channel backend | |
238 | * @chanb: channel backend | |
239 | * @name: channel name | |
240 | * @config: client ring buffer configuration | |
852c2936 | 241 | * @parent: dentry of parent directory, %NULL for root directory |
2657d1ba | 242 | * @subbuf_size: size of sub-buffers (> page size, power of 2) |
852c2936 | 243 | * @num_subbuf: number of sub-buffers (power of 2) |
38fae1d3 | 244 | * @lttng_ust_shm_handle: shared memory handle |
5ea386c3 | 245 | * @stream_fds: stream file descriptors. |
852c2936 MD |
246 | * |
247 | * Returns channel pointer if successful, %NULL otherwise. | |
248 | * | |
249 | * Creates per-cpu channel buffers using the sizes and attributes | |
250 | * specified. The created channel buffer files will be named | |
251 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
252 | * | |
253 | * Called with CPU hotplug disabled. | |
254 | */ | |
255 | int channel_backend_init(struct channel_backend *chanb, | |
256 | const char *name, | |
4cfec15c | 257 | const struct lttng_ust_lib_ring_buffer_config *config, |
a3f61e7f | 258 | size_t subbuf_size, size_t num_subbuf, |
a9ff648c | 259 | struct lttng_ust_shm_handle *handle, |
5ea386c3 | 260 | const int *stream_fds) |
852c2936 | 261 | { |
14641deb | 262 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
852c2936 MD |
263 | unsigned int i; |
264 | int ret; | |
6c1f7d8b | 265 | size_t shmsize = 0, num_subbuf_alloc; |
2657d1ba | 266 | long page_size; |
852c2936 MD |
267 | |
268 | if (!name) | |
269 | return -EPERM; | |
270 | ||
b72687b8 | 271 | page_size = LTTNG_UST_PAGE_SIZE; |
2657d1ba MD |
272 | if (page_size <= 0) { |
273 | return -ENOMEM; | |
274 | } | |
852c2936 | 275 | /* Check that the subbuffer size is larger than a page. */ |
2657d1ba | 276 | if (subbuf_size < page_size) |
852c2936 MD |
277 | return -EINVAL; |
278 | ||
279 | /* | |
12bcbbdb MD |
280 | * Make sure the number of subbuffers and subbuffer size are |
281 | * power of 2, and nonzero. | |
852c2936 | 282 | */ |
12bcbbdb | 283 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
e52b0723 | 284 | return -EINVAL; |
12bcbbdb | 285 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
e52b0723 | 286 | return -EINVAL; |
3d8e9399 MD |
287 | /* |
288 | * Overwrite mode buffers require at least 2 subbuffers per | |
289 | * buffer. | |
290 | */ | |
291 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
292 | return -EINVAL; | |
852c2936 MD |
293 | |
294 | ret = subbuffer_id_check_index(config, num_subbuf); | |
295 | if (ret) | |
296 | return ret; | |
297 | ||
852c2936 MD |
298 | chanb->buf_size = num_subbuf * subbuf_size; |
299 | chanb->subbuf_size = subbuf_size; | |
300 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
301 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
302 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
303 | chanb->extra_reader_sb = | |
304 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
305 | chanb->num_subbuf = num_subbuf; | |
a6352fd4 MD |
306 | strncpy(chanb->name, name, NAME_MAX); |
307 | chanb->name[NAME_MAX - 1] = '\0'; | |
193183fb | 308 | memcpy(&chanb->config, config, sizeof(*config)); |
852c2936 | 309 | |
1d498196 | 310 | /* Per-cpu buffer size: control (prior to backend) */ |
b72687b8 | 311 | shmsize = lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer)); |
4cfec15c | 312 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer); |
b72687b8 | 313 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct commit_counters_hot)); |
d2f09c1c | 314 | shmsize += sizeof(struct commit_counters_hot) * num_subbuf; |
b72687b8 | 315 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct commit_counters_cold)); |
d2f09c1c MD |
316 | shmsize += sizeof(struct commit_counters_cold) * num_subbuf; |
317 | /* Sampled timestamp end */ | |
b72687b8 | 318 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(uint64_t)); |
d2f09c1c | 319 | shmsize += sizeof(uint64_t) * num_subbuf; |
1d498196 MD |
320 | |
321 | /* Per-cpu buffer size: backend */ | |
322 | /* num_subbuf + 1 is the worse case */ | |
323 | num_subbuf_alloc = num_subbuf + 1; | |
b72687b8 | 324 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
4cfec15c | 325 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc; |
b72687b8 | 326 | shmsize += lttng_ust_offset_align(shmsize, page_size); |
1d498196 | 327 | shmsize += subbuf_size * num_subbuf_alloc; |
b72687b8 | 328 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
4cfec15c | 329 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages) * num_subbuf_alloc; |
b72687b8 | 330 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
4cfec15c | 331 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) * num_subbuf; |
b72687b8 | 332 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_counts)); |
bf8f2ef2 | 333 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) * num_subbuf; |
1d498196 | 334 | |
852c2936 | 335 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
4cfec15c | 336 | struct lttng_ust_lib_ring_buffer *buf; |
852c2936 | 337 | /* |
a6352fd4 | 338 | * We need to allocate for all possible cpus. |
852c2936 | 339 | */ |
852c2936 | 340 | for_each_possible_cpu(i) { |
1d498196 | 341 | struct shm_object *shmobj; |
5ea386c3 | 342 | |
74d81a6c | 343 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
4b68c31f | 344 | SHM_OBJECT_SHM, stream_fds[i], i); |
afdf9825 MD |
345 | if (!shmobj) |
346 | goto end; | |
4cfec15c MD |
347 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
348 | set_shmp(chanb->buf[i].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 MD |
349 | buf = shmp(handle, chanb->buf[i].shmp); |
350 | if (!buf) | |
351 | goto end; | |
5d61a504 | 352 | set_shmp(buf->self, chanb->buf[i].shmp._ref); |
1d498196 MD |
353 | ret = lib_ring_buffer_create(buf, chanb, i, |
354 | handle, shmobj); | |
852c2936 MD |
355 | if (ret) |
356 | goto free_bufs; /* cpu hotplug locked */ | |
357 | } | |
852c2936 | 358 | } else { |
1d498196 | 359 | struct shm_object *shmobj; |
4cfec15c | 360 | struct lttng_ust_lib_ring_buffer *buf; |
a6352fd4 | 361 | |
74d81a6c | 362 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
4b68c31f | 363 | SHM_OBJECT_SHM, stream_fds[0], -1); |
afdf9825 MD |
364 | if (!shmobj) |
365 | goto end; | |
4cfec15c MD |
366 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
367 | set_shmp(chanb->buf[0].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 | 368 | buf = shmp(handle, chanb->buf[0].shmp); |
a6352fd4 MD |
369 | if (!buf) |
370 | goto end; | |
cb14bae9 | 371 | set_shmp(buf->self, chanb->buf[0].shmp._ref); |
1d498196 MD |
372 | ret = lib_ring_buffer_create(buf, chanb, -1, |
373 | handle, shmobj); | |
852c2936 MD |
374 | if (ret) |
375 | goto free_bufs; | |
376 | } | |
377 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
378 | ||
379 | return 0; | |
380 | ||
381 | free_bufs: | |
a6352fd4 MD |
382 | /* We only free the buffer data upon shm teardown */ |
383 | end: | |
852c2936 MD |
384 | return -ENOMEM; |
385 | } | |
386 | ||
852c2936 MD |
387 | /** |
388 | * channel_backend_free - destroy the channel | |
389 | * @chan: the channel | |
390 | * | |
391 | * Destroy all channel buffers and frees the channel. | |
392 | */ | |
1d498196 | 393 | void channel_backend_free(struct channel_backend *chanb, |
38fae1d3 | 394 | struct lttng_ust_shm_handle *handle) |
852c2936 | 395 | { |
45e9e699 | 396 | /* SHM teardown takes care of everything */ |
852c2936 MD |
397 | } |
398 | ||
852c2936 MD |
399 | /** |
400 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
401 | * @bufb : buffer backend | |
402 | * @offset : offset within the buffer | |
403 | * @dest : destination address | |
404 | * @len : length to copy to destination | |
405 | * | |
406 | * Should be protected by get_subbuf/put_subbuf. | |
407 | * Returns the length copied. | |
408 | */ | |
4cfec15c | 409 | size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 410 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 411 | { |
34daae3e MD |
412 | struct channel_backend *chanb; |
413 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 414 | ssize_t orig_len; |
4cfec15c | 415 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 416 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
852c2936 | 417 | unsigned long sb_bindex, id; |
99b99b47 | 418 | void *src; |
852c2936 | 419 | |
34daae3e MD |
420 | chanb = &shmp(handle, bufb->chan)->backend; |
421 | if (!chanb) | |
422 | return 0; | |
423 | config = &chanb->config; | |
852c2936 MD |
424 | orig_len = len; |
425 | offset &= chanb->buf_size - 1; | |
a6352fd4 | 426 | |
b5a3dfa5 | 427 | if (caa_unlikely(!len)) |
852c2936 | 428 | return 0; |
a6352fd4 MD |
429 | id = bufb->buf_rsb.id; |
430 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 431 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
432 | if (!rpages) |
433 | return 0; | |
a6352fd4 MD |
434 | /* |
435 | * Underlying layer should never ask for reads across | |
436 | * subbuffers. | |
437 | */ | |
438 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
439 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
440 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
441 | backend_pages = shmp(handle, rpages->shmp); |
442 | if (!backend_pages) | |
443 | return 0; | |
444 | src = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
99b99b47 MD |
445 | if (caa_unlikely(!src)) |
446 | return 0; | |
447 | memcpy(dest, src, len); | |
852c2936 MD |
448 | return orig_len; |
449 | } | |
852c2936 | 450 | |
852c2936 MD |
451 | /** |
452 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
453 | * @bufb : buffer backend | |
454 | * @offset : offset within the buffer | |
455 | * @dest : destination address | |
456 | * @len : destination's length | |
457 | * | |
0bf3c920 | 458 | * Return string's length, or -EINVAL on error. |
852c2936 | 459 | * Should be protected by get_subbuf/put_subbuf. |
0bf3c920 | 460 | * Destination length should be at least 1 to hold '\0'. |
852c2936 | 461 | */ |
4cfec15c | 462 | int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 463 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 464 | { |
34daae3e MD |
465 | struct channel_backend *chanb; |
466 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 467 | ssize_t string_len, orig_offset; |
852c2936 | 468 | char *str; |
4cfec15c | 469 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 470 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
852c2936 MD |
471 | unsigned long sb_bindex, id; |
472 | ||
34daae3e MD |
473 | chanb = &shmp(handle, bufb->chan)->backend; |
474 | if (!chanb) | |
475 | return -EINVAL; | |
476 | config = &chanb->config; | |
0bf3c920 MD |
477 | if (caa_unlikely(!len)) |
478 | return -EINVAL; | |
852c2936 | 479 | offset &= chanb->buf_size - 1; |
852c2936 | 480 | orig_offset = offset; |
852c2936 MD |
481 | id = bufb->buf_rsb.id; |
482 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 483 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
484 | if (!rpages) |
485 | return -EINVAL; | |
a6352fd4 MD |
486 | /* |
487 | * Underlying layer should never ask for reads across | |
488 | * subbuffers. | |
489 | */ | |
490 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
852c2936 MD |
491 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
492 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
493 | backend_pages = shmp(handle, rpages->shmp); |
494 | if (!backend_pages) | |
495 | return -EINVAL; | |
496 | str = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
99b99b47 MD |
497 | if (caa_unlikely(!str)) |
498 | return -EINVAL; | |
a6352fd4 MD |
499 | string_len = strnlen(str, len); |
500 | if (dest && len) { | |
501 | memcpy(dest, str, string_len); | |
502 | ((char *)dest)[0] = 0; | |
503 | } | |
504 | return offset - orig_offset; | |
852c2936 | 505 | } |
852c2936 MD |
506 | |
507 | /** | |
508 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
509 | * @bufb : buffer backend | |
510 | * @offset : offset within the buffer. | |
511 | * | |
512 | * Return the address where a given offset is located (for read). | |
513 | * Should be used to get the current subbuffer header pointer. Given we know | |
22b22ce9 MD |
514 | * it's never on a page boundary, it's safe to read/write directly |
515 | * from/to this address, as long as the read/write is never bigger than | |
516 | * a page size. | |
852c2936 | 517 | */ |
4cfec15c | 518 | void *lib_ring_buffer_read_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 519 | size_t offset, |
38fae1d3 | 520 | struct lttng_ust_shm_handle *handle) |
852c2936 | 521 | { |
4cfec15c | 522 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 523 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
34daae3e MD |
524 | struct channel_backend *chanb; |
525 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
526 | unsigned long sb_bindex, id; |
527 | ||
34daae3e MD |
528 | chanb = &shmp(handle, bufb->chan)->backend; |
529 | if (!chanb) | |
530 | return NULL; | |
531 | config = &chanb->config; | |
852c2936 | 532 | offset &= chanb->buf_size - 1; |
852c2936 MD |
533 | id = bufb->buf_rsb.id; |
534 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 535 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
536 | if (!rpages) |
537 | return NULL; | |
852c2936 MD |
538 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
539 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
540 | backend_pages = shmp(handle, rpages->shmp); |
541 | if (!backend_pages) | |
542 | return NULL; | |
543 | return shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
852c2936 | 544 | } |
852c2936 MD |
545 | |
546 | /** | |
547 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
548 | * @bufb : buffer backend | |
549 | * @offset : offset within the buffer. | |
550 | * | |
551 | * Return the address where a given offset is located. | |
552 | * Should be used to get the current subbuffer header pointer. Given we know | |
553 | * it's always at the beginning of a page, it's safe to write directly to this | |
554 | * address, as long as the write is never bigger than a page size. | |
555 | */ | |
4cfec15c | 556 | void *lib_ring_buffer_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 557 | size_t offset, |
38fae1d3 | 558 | struct lttng_ust_shm_handle *handle) |
852c2936 | 559 | { |
a6352fd4 | 560 | size_t sbidx; |
4cfec15c | 561 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 562 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
34daae3e MD |
563 | struct channel_backend *chanb; |
564 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 | 565 | unsigned long sb_bindex, id; |
34daae3e | 566 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; |
852c2936 | 567 | |
34daae3e MD |
568 | chanb = &shmp(handle, bufb->chan)->backend; |
569 | if (!chanb) | |
570 | return NULL; | |
571 | config = &chanb->config; | |
852c2936 MD |
572 | offset &= chanb->buf_size - 1; |
573 | sbidx = offset >> chanb->subbuf_size_order; | |
34daae3e MD |
574 | sb = shmp_index(handle, bufb->buf_wsb, sbidx); |
575 | if (!sb) | |
576 | return NULL; | |
577 | id = sb->id; | |
852c2936 | 578 | sb_bindex = subbuffer_id_get_index(config, id); |
4746ae29 | 579 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
580 | if (!rpages) |
581 | return NULL; | |
852c2936 MD |
582 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
583 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
584 | backend_pages = shmp(handle, rpages->shmp); |
585 | if (!backend_pages) | |
586 | return NULL; | |
587 | return shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
852c2936 | 588 | } |