| 1 | /* SPDX-License-Identifier: (GPL-2.0 OR LGPL-2.1) |
| 2 | * |
| 3 | * ring_buffer_backend.c |
| 4 | * |
| 5 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 6 | */ |
| 7 | |
| 8 | #include <linux/stddef.h> |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/string.h> |
| 11 | #include <linux/bitops.h> |
| 12 | #include <linux/delay.h> |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/cpu.h> |
| 16 | #include <linux/mm.h> |
| 17 | #include <linux/vmalloc.h> |
| 18 | |
| 19 | #include <wrapper/mm.h> |
| 20 | #include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_all() */ |
| 21 | #include <wrapper/ringbuffer/config.h> |
| 22 | #include <wrapper/ringbuffer/backend.h> |
| 23 | #include <wrapper/ringbuffer/frontend.h> |
| 24 | |
| 25 | /** |
| 26 | * lib_ring_buffer_backend_allocate - allocate a channel buffer |
| 27 | * @config: ring buffer instance configuration |
| 28 | * @buf: the buffer struct |
| 29 | * @size: total size of the buffer |
| 30 | * @num_subbuf: number of subbuffers |
| 31 | * @extra_reader_sb: need extra subbuffer for reader |
| 32 | */ |
| 33 | static |
| 34 | int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config, |
| 35 | struct lib_ring_buffer_backend *bufb, |
| 36 | size_t size, size_t num_subbuf, |
| 37 | int extra_reader_sb) |
| 38 | { |
| 39 | struct channel_backend *chanb = &bufb->chan->backend; |
| 40 | unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0; |
| 41 | unsigned long subbuf_size, mmap_offset = 0; |
| 42 | unsigned long num_subbuf_alloc; |
| 43 | struct page **pages; |
| 44 | unsigned long i; |
| 45 | |
| 46 | num_pages = size >> PAGE_SHIFT; |
| 47 | |
| 48 | /* |
| 49 | * Verify that there is enough free pages available on the system for |
| 50 | * the current allocation request. |
| 51 | * wrapper_check_enough_free_pages uses si_mem_available() if available |
| 52 | * and returns if there should be enough free pages based on the |
| 53 | * current estimate. |
| 54 | */ |
| 55 | if (!wrapper_check_enough_free_pages(num_pages)) |
| 56 | goto not_enough_pages; |
| 57 | |
| 58 | /* |
| 59 | * Set the current user thread as the first target of the OOM killer. |
| 60 | * If the estimate received by si_mem_available() was off, and we do |
| 61 | * end up running out of memory because of this buffer allocation, we |
| 62 | * want to kill the offending app first. |
| 63 | */ |
| 64 | wrapper_set_current_oom_origin(); |
| 65 | |
| 66 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); |
| 67 | subbuf_size = chanb->subbuf_size; |
| 68 | num_subbuf_alloc = num_subbuf; |
| 69 | |
| 70 | if (extra_reader_sb) { |
| 71 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ |
| 72 | num_subbuf_alloc++; |
| 73 | } |
| 74 | |
| 75 | pages = vmalloc_node(ALIGN(sizeof(*pages) * num_pages, |
| 76 | 1 << INTERNODE_CACHE_SHIFT), |
| 77 | cpu_to_node(max(bufb->cpu, 0))); |
| 78 | if (unlikely(!pages)) |
| 79 | goto pages_error; |
| 80 | |
| 81 | bufb->array = lttng_kvmalloc_node(ALIGN(sizeof(*bufb->array) |
| 82 | * num_subbuf_alloc, |
| 83 | 1 << INTERNODE_CACHE_SHIFT), |
| 84 | GFP_KERNEL | __GFP_NOWARN, |
| 85 | cpu_to_node(max(bufb->cpu, 0))); |
| 86 | if (unlikely(!bufb->array)) |
| 87 | goto array_error; |
| 88 | |
| 89 | for (i = 0; i < num_pages; i++) { |
| 90 | pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)), |
| 91 | GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 0); |
| 92 | if (unlikely(!pages[i])) |
| 93 | goto depopulate; |
| 94 | } |
| 95 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; |
| 96 | |
| 97 | /* Allocate backend pages array elements */ |
| 98 | for (i = 0; i < num_subbuf_alloc; i++) { |
| 99 | bufb->array[i] = |
| 100 | lttng_kvzalloc_node(ALIGN( |
| 101 | sizeof(struct lib_ring_buffer_backend_pages) + |
| 102 | sizeof(struct lib_ring_buffer_backend_page) |
| 103 | * num_pages_per_subbuf, |
| 104 | 1 << INTERNODE_CACHE_SHIFT), |
| 105 | GFP_KERNEL | __GFP_NOWARN, |
| 106 | cpu_to_node(max(bufb->cpu, 0))); |
| 107 | if (!bufb->array[i]) |
| 108 | goto free_array; |
| 109 | } |
| 110 | |
| 111 | /* Allocate write-side subbuffer table */ |
| 112 | bufb->buf_wsb = lttng_kvzalloc_node(ALIGN( |
| 113 | sizeof(struct lib_ring_buffer_backend_subbuffer) |
| 114 | * num_subbuf, |
| 115 | 1 << INTERNODE_CACHE_SHIFT), |
| 116 | GFP_KERNEL | __GFP_NOWARN, |
| 117 | cpu_to_node(max(bufb->cpu, 0))); |
| 118 | if (unlikely(!bufb->buf_wsb)) |
| 119 | goto free_array; |
| 120 | |
| 121 | for (i = 0; i < num_subbuf; i++) |
| 122 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); |
| 123 | |
| 124 | /* Assign read-side subbuffer table */ |
| 125 | if (extra_reader_sb) |
| 126 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, |
| 127 | num_subbuf_alloc - 1); |
| 128 | else |
| 129 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); |
| 130 | |
| 131 | /* Allocate subbuffer packet counter table */ |
| 132 | bufb->buf_cnt = lttng_kvzalloc_node(ALIGN( |
| 133 | sizeof(struct lib_ring_buffer_backend_counts) |
| 134 | * num_subbuf, |
| 135 | 1 << INTERNODE_CACHE_SHIFT), |
| 136 | GFP_KERNEL | __GFP_NOWARN, |
| 137 | cpu_to_node(max(bufb->cpu, 0))); |
| 138 | if (unlikely(!bufb->buf_cnt)) |
| 139 | goto free_wsb; |
| 140 | |
| 141 | /* Assign pages to page index */ |
| 142 | for (i = 0; i < num_subbuf_alloc; i++) { |
| 143 | for (j = 0; j < num_pages_per_subbuf; j++) { |
| 144 | CHAN_WARN_ON(chanb, page_idx > num_pages); |
| 145 | bufb->array[i]->p[j].virt = page_address(pages[page_idx]); |
| 146 | bufb->array[i]->p[j].pfn = page_to_pfn(pages[page_idx]); |
| 147 | page_idx++; |
| 148 | } |
| 149 | if (config->output == RING_BUFFER_MMAP) { |
| 150 | bufb->array[i]->mmap_offset = mmap_offset; |
| 151 | mmap_offset += subbuf_size; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | /* |
| 156 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages |
| 157 | * will not fault. |
| 158 | */ |
| 159 | wrapper_vmalloc_sync_all(); |
| 160 | wrapper_clear_current_oom_origin(); |
| 161 | vfree(pages); |
| 162 | return 0; |
| 163 | |
| 164 | free_wsb: |
| 165 | lttng_kvfree(bufb->buf_wsb); |
| 166 | free_array: |
| 167 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) |
| 168 | lttng_kvfree(bufb->array[i]); |
| 169 | depopulate: |
| 170 | /* Free all allocated pages */ |
| 171 | for (i = 0; (i < num_pages && pages[i]); i++) |
| 172 | __free_page(pages[i]); |
| 173 | lttng_kvfree(bufb->array); |
| 174 | array_error: |
| 175 | vfree(pages); |
| 176 | pages_error: |
| 177 | wrapper_clear_current_oom_origin(); |
| 178 | not_enough_pages: |
| 179 | return -ENOMEM; |
| 180 | } |
| 181 | |
| 182 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, |
| 183 | struct channel_backend *chanb, int cpu) |
| 184 | { |
| 185 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 186 | |
| 187 | bufb->chan = container_of(chanb, struct channel, backend); |
| 188 | bufb->cpu = cpu; |
| 189 | |
| 190 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, |
| 191 | chanb->num_subbuf, |
| 192 | chanb->extra_reader_sb); |
| 193 | } |
| 194 | |
| 195 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) |
| 196 | { |
| 197 | struct channel_backend *chanb = &bufb->chan->backend; |
| 198 | unsigned long i, j, num_subbuf_alloc; |
| 199 | |
| 200 | num_subbuf_alloc = chanb->num_subbuf; |
| 201 | if (chanb->extra_reader_sb) |
| 202 | num_subbuf_alloc++; |
| 203 | |
| 204 | lttng_kvfree(bufb->buf_wsb); |
| 205 | lttng_kvfree(bufb->buf_cnt); |
| 206 | for (i = 0; i < num_subbuf_alloc; i++) { |
| 207 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) |
| 208 | __free_page(pfn_to_page(bufb->array[i]->p[j].pfn)); |
| 209 | lttng_kvfree(bufb->array[i]); |
| 210 | } |
| 211 | lttng_kvfree(bufb->array); |
| 212 | bufb->allocated = 0; |
| 213 | } |
| 214 | |
| 215 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) |
| 216 | { |
| 217 | struct channel_backend *chanb = &bufb->chan->backend; |
| 218 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 219 | unsigned long num_subbuf_alloc; |
| 220 | unsigned int i; |
| 221 | |
| 222 | num_subbuf_alloc = chanb->num_subbuf; |
| 223 | if (chanb->extra_reader_sb) |
| 224 | num_subbuf_alloc++; |
| 225 | |
| 226 | for (i = 0; i < chanb->num_subbuf; i++) |
| 227 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); |
| 228 | if (chanb->extra_reader_sb) |
| 229 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, |
| 230 | num_subbuf_alloc - 1); |
| 231 | else |
| 232 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); |
| 233 | |
| 234 | for (i = 0; i < num_subbuf_alloc; i++) { |
| 235 | /* Don't reset mmap_offset */ |
| 236 | v_set(config, &bufb->array[i]->records_commit, 0); |
| 237 | v_set(config, &bufb->array[i]->records_unread, 0); |
| 238 | bufb->array[i]->data_size = 0; |
| 239 | /* Don't reset backend page and virt addresses */ |
| 240 | } |
| 241 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ |
| 242 | v_set(config, &bufb->records_read, 0); |
| 243 | } |
| 244 | |
| 245 | /* |
| 246 | * The frontend is responsible for also calling ring_buffer_backend_reset for |
| 247 | * each buffer when calling channel_backend_reset. |
| 248 | */ |
| 249 | void channel_backend_reset(struct channel_backend *chanb) |
| 250 | { |
| 251 | struct channel *chan = container_of(chanb, struct channel, backend); |
| 252 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 253 | |
| 254 | /* |
| 255 | * Don't reset buf_size, subbuf_size, subbuf_size_order, |
| 256 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, |
| 257 | * priv, notifiers, config, cpumask and name. |
| 258 | */ |
| 259 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); |
| 260 | } |
| 261 | |
| 262 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
| 263 | |
| 264 | /* |
| 265 | * No need to implement a "dead" callback to do a buffer switch here, |
| 266 | * because it will happen when tracing is stopped, or will be done by |
| 267 | * switch timer CPU DEAD callback. |
| 268 | * We don't free buffers when CPU go away, because it would make trace |
| 269 | * data vanish, which is unwanted. |
| 270 | */ |
| 271 | int lttng_cpuhp_rb_backend_prepare(unsigned int cpu, |
| 272 | struct lttng_cpuhp_node *node) |
| 273 | { |
| 274 | struct channel_backend *chanb = container_of(node, |
| 275 | struct channel_backend, cpuhp_prepare); |
| 276 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 277 | struct lib_ring_buffer *buf; |
| 278 | int ret; |
| 279 | |
| 280 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); |
| 281 | |
| 282 | buf = per_cpu_ptr(chanb->buf, cpu); |
| 283 | ret = lib_ring_buffer_create(buf, chanb, cpu); |
| 284 | if (ret) { |
| 285 | printk(KERN_ERR |
| 286 | "ring_buffer_cpu_hp_callback: cpu %d " |
| 287 | "buffer creation failed\n", cpu); |
| 288 | return ret; |
| 289 | } |
| 290 | return 0; |
| 291 | } |
| 292 | EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_backend_prepare); |
| 293 | |
| 294 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
| 295 | |
| 296 | #ifdef CONFIG_HOTPLUG_CPU |
| 297 | |
| 298 | /** |
| 299 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback |
| 300 | * @nb: notifier block |
| 301 | * @action: hotplug action to take |
| 302 | * @hcpu: CPU number |
| 303 | * |
| 304 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) |
| 305 | */ |
| 306 | static |
| 307 | int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, |
| 308 | unsigned long action, |
| 309 | void *hcpu) |
| 310 | { |
| 311 | unsigned int cpu = (unsigned long)hcpu; |
| 312 | struct channel_backend *chanb = container_of(nb, struct channel_backend, |
| 313 | cpu_hp_notifier); |
| 314 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 315 | struct lib_ring_buffer *buf; |
| 316 | int ret; |
| 317 | |
| 318 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); |
| 319 | |
| 320 | switch (action) { |
| 321 | case CPU_UP_PREPARE: |
| 322 | case CPU_UP_PREPARE_FROZEN: |
| 323 | buf = per_cpu_ptr(chanb->buf, cpu); |
| 324 | ret = lib_ring_buffer_create(buf, chanb, cpu); |
| 325 | if (ret) { |
| 326 | printk(KERN_ERR |
| 327 | "ring_buffer_cpu_hp_callback: cpu %d " |
| 328 | "buffer creation failed\n", cpu); |
| 329 | return NOTIFY_BAD; |
| 330 | } |
| 331 | break; |
| 332 | case CPU_DEAD: |
| 333 | case CPU_DEAD_FROZEN: |
| 334 | /* No need to do a buffer switch here, because it will happen |
| 335 | * when tracing is stopped, or will be done by switch timer CPU |
| 336 | * DEAD callback. */ |
| 337 | break; |
| 338 | } |
| 339 | return NOTIFY_OK; |
| 340 | } |
| 341 | |
| 342 | #endif |
| 343 | |
| 344 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
| 345 | |
| 346 | /** |
| 347 | * channel_backend_init - initialize a channel backend |
| 348 | * @chanb: channel backend |
| 349 | * @name: channel name |
| 350 | * @config: client ring buffer configuration |
| 351 | * @priv: client private data |
| 352 | * @parent: dentry of parent directory, %NULL for root directory |
| 353 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) |
| 354 | * @num_subbuf: number of sub-buffers (power of 2) |
| 355 | * |
| 356 | * Returns channel pointer if successful, %NULL otherwise. |
| 357 | * |
| 358 | * Creates per-cpu channel buffers using the sizes and attributes |
| 359 | * specified. The created channel buffer files will be named |
| 360 | * name_0...name_N-1. File permissions will be %S_IRUSR. |
| 361 | * |
| 362 | * Called with CPU hotplug disabled. |
| 363 | */ |
| 364 | int channel_backend_init(struct channel_backend *chanb, |
| 365 | const char *name, |
| 366 | const struct lib_ring_buffer_config *config, |
| 367 | void *priv, size_t subbuf_size, size_t num_subbuf) |
| 368 | { |
| 369 | struct channel *chan = container_of(chanb, struct channel, backend); |
| 370 | unsigned int i; |
| 371 | int ret; |
| 372 | |
| 373 | if (!name) |
| 374 | return -EPERM; |
| 375 | |
| 376 | /* Check that the subbuffer size is larger than a page. */ |
| 377 | if (subbuf_size < PAGE_SIZE) |
| 378 | return -EINVAL; |
| 379 | |
| 380 | /* |
| 381 | * Make sure the number of subbuffers and subbuffer size are |
| 382 | * power of 2 and nonzero. |
| 383 | */ |
| 384 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
| 385 | return -EINVAL; |
| 386 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
| 387 | return -EINVAL; |
| 388 | /* |
| 389 | * Overwrite mode buffers require at least 2 subbuffers per |
| 390 | * buffer. |
| 391 | */ |
| 392 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) |
| 393 | return -EINVAL; |
| 394 | |
| 395 | ret = subbuffer_id_check_index(config, num_subbuf); |
| 396 | if (ret) |
| 397 | return ret; |
| 398 | |
| 399 | chanb->priv = priv; |
| 400 | chanb->buf_size = num_subbuf * subbuf_size; |
| 401 | chanb->subbuf_size = subbuf_size; |
| 402 | chanb->buf_size_order = get_count_order(chanb->buf_size); |
| 403 | chanb->subbuf_size_order = get_count_order(subbuf_size); |
| 404 | chanb->num_subbuf_order = get_count_order(num_subbuf); |
| 405 | chanb->extra_reader_sb = |
| 406 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; |
| 407 | chanb->num_subbuf = num_subbuf; |
| 408 | strlcpy(chanb->name, name, NAME_MAX); |
| 409 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
| 410 | |
| 411 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
| 412 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) |
| 413 | return -ENOMEM; |
| 414 | } |
| 415 | |
| 416 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
| 417 | /* Allocating the buffer per-cpu structures */ |
| 418 | chanb->buf = alloc_percpu(struct lib_ring_buffer); |
| 419 | if (!chanb->buf) |
| 420 | goto free_cpumask; |
| 421 | |
| 422 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
| 423 | chanb->cpuhp_prepare.component = LTTNG_RING_BUFFER_BACKEND; |
| 424 | ret = cpuhp_state_add_instance(lttng_rb_hp_prepare, |
| 425 | &chanb->cpuhp_prepare.node); |
| 426 | if (ret) |
| 427 | goto free_bufs; |
| 428 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
| 429 | |
| 430 | { |
| 431 | /* |
| 432 | * In case of non-hotplug cpu, if the ring-buffer is allocated |
| 433 | * in early initcall, it will not be notified of secondary cpus. |
| 434 | * In that off case, we need to allocate for all possible cpus. |
| 435 | */ |
| 436 | #ifdef CONFIG_HOTPLUG_CPU |
| 437 | /* |
| 438 | * buf->backend.allocated test takes care of concurrent CPU |
| 439 | * hotplug. |
| 440 | * Priority higher than frontend, so we create the ring buffer |
| 441 | * before we start the timer. |
| 442 | */ |
| 443 | chanb->cpu_hp_notifier.notifier_call = |
| 444 | lib_ring_buffer_cpu_hp_callback; |
| 445 | chanb->cpu_hp_notifier.priority = 5; |
| 446 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); |
| 447 | |
| 448 | get_online_cpus(); |
| 449 | for_each_online_cpu(i) { |
| 450 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), |
| 451 | chanb, i); |
| 452 | if (ret) |
| 453 | goto free_bufs; /* cpu hotplug locked */ |
| 454 | } |
| 455 | put_online_cpus(); |
| 456 | #else |
| 457 | for_each_possible_cpu(i) { |
| 458 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), |
| 459 | chanb, i); |
| 460 | if (ret) |
| 461 | goto free_bufs; |
| 462 | } |
| 463 | #endif |
| 464 | } |
| 465 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
| 466 | } else { |
| 467 | chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL); |
| 468 | if (!chanb->buf) |
| 469 | goto free_cpumask; |
| 470 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); |
| 471 | if (ret) |
| 472 | goto free_bufs; |
| 473 | } |
| 474 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); |
| 475 | |
| 476 | return 0; |
| 477 | |
| 478 | free_bufs: |
| 479 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
| 480 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
| 481 | /* |
| 482 | * Teardown of lttng_rb_hp_prepare instance |
| 483 | * on "add" error is handled within cpu hotplug, |
| 484 | * no teardown to do from the caller. |
| 485 | */ |
| 486 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
| 487 | #ifdef CONFIG_HOTPLUG_CPU |
| 488 | put_online_cpus(); |
| 489 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); |
| 490 | #endif |
| 491 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
| 492 | for_each_possible_cpu(i) { |
| 493 | struct lib_ring_buffer *buf = |
| 494 | per_cpu_ptr(chanb->buf, i); |
| 495 | |
| 496 | if (!buf->backend.allocated) |
| 497 | continue; |
| 498 | lib_ring_buffer_free(buf); |
| 499 | } |
| 500 | free_percpu(chanb->buf); |
| 501 | } else |
| 502 | kfree(chanb->buf); |
| 503 | free_cpumask: |
| 504 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) |
| 505 | free_cpumask_var(chanb->cpumask); |
| 506 | return -ENOMEM; |
| 507 | } |
| 508 | |
| 509 | /** |
| 510 | * channel_backend_unregister_notifiers - unregister notifiers |
| 511 | * @chan: the channel |
| 512 | * |
| 513 | * Holds CPU hotplug. |
| 514 | */ |
| 515 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) |
| 516 | { |
| 517 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 518 | |
| 519 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
| 520 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
| 521 | int ret; |
| 522 | |
| 523 | ret = cpuhp_state_remove_instance(lttng_rb_hp_prepare, |
| 524 | &chanb->cpuhp_prepare.node); |
| 525 | WARN_ON(ret); |
| 526 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
| 527 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); |
| 528 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
| 529 | } |
| 530 | } |
| 531 | |
| 532 | /** |
| 533 | * channel_backend_free - destroy the channel |
| 534 | * @chan: the channel |
| 535 | * |
| 536 | * Destroy all channel buffers and frees the channel. |
| 537 | */ |
| 538 | void channel_backend_free(struct channel_backend *chanb) |
| 539 | { |
| 540 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 541 | unsigned int i; |
| 542 | |
| 543 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
| 544 | for_each_possible_cpu(i) { |
| 545 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); |
| 546 | |
| 547 | if (!buf->backend.allocated) |
| 548 | continue; |
| 549 | lib_ring_buffer_free(buf); |
| 550 | } |
| 551 | free_cpumask_var(chanb->cpumask); |
| 552 | free_percpu(chanb->buf); |
| 553 | } else { |
| 554 | struct lib_ring_buffer *buf = chanb->buf; |
| 555 | |
| 556 | CHAN_WARN_ON(chanb, !buf->backend.allocated); |
| 557 | lib_ring_buffer_free(buf); |
| 558 | kfree(buf); |
| 559 | } |
| 560 | } |
| 561 | |
| 562 | /** |
| 563 | * lib_ring_buffer_write - write data to a ring_buffer buffer. |
| 564 | * @bufb : buffer backend |
| 565 | * @offset : offset within the buffer |
| 566 | * @src : source address |
| 567 | * @len : length to write |
| 568 | * @pagecpy : page size copied so far |
| 569 | */ |
| 570 | void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, |
| 571 | const void *src, size_t len, size_t pagecpy) |
| 572 | { |
| 573 | struct channel_backend *chanb = &bufb->chan->backend; |
| 574 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 575 | size_t sbidx, index; |
| 576 | struct lib_ring_buffer_backend_pages *rpages; |
| 577 | unsigned long sb_bindex, id; |
| 578 | |
| 579 | do { |
| 580 | len -= pagecpy; |
| 581 | src += pagecpy; |
| 582 | offset += pagecpy; |
| 583 | sbidx = offset >> chanb->subbuf_size_order; |
| 584 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 585 | |
| 586 | /* |
| 587 | * Underlying layer should never ask for writes across |
| 588 | * subbuffers. |
| 589 | */ |
| 590 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); |
| 591 | |
| 592 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
| 593 | id = bufb->buf_wsb[sbidx].id; |
| 594 | sb_bindex = subbuffer_id_get_index(config, id); |
| 595 | rpages = bufb->array[sb_bindex]; |
| 596 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 597 | && subbuffer_id_is_noref(config, id)); |
| 598 | lib_ring_buffer_do_copy(config, |
| 599 | rpages->p[index].virt |
| 600 | + (offset & ~PAGE_MASK), |
| 601 | src, pagecpy); |
| 602 | } while (unlikely(len != pagecpy)); |
| 603 | } |
| 604 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); |
| 605 | |
| 606 | |
| 607 | /** |
| 608 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. |
| 609 | * @bufb : buffer backend |
| 610 | * @offset : offset within the buffer |
| 611 | * @c : the byte to write |
| 612 | * @len : length to write |
| 613 | * @pagecpy : page size copied so far |
| 614 | */ |
| 615 | void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, |
| 616 | size_t offset, |
| 617 | int c, size_t len, size_t pagecpy) |
| 618 | { |
| 619 | struct channel_backend *chanb = &bufb->chan->backend; |
| 620 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 621 | size_t sbidx, index; |
| 622 | struct lib_ring_buffer_backend_pages *rpages; |
| 623 | unsigned long sb_bindex, id; |
| 624 | |
| 625 | do { |
| 626 | len -= pagecpy; |
| 627 | offset += pagecpy; |
| 628 | sbidx = offset >> chanb->subbuf_size_order; |
| 629 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 630 | |
| 631 | /* |
| 632 | * Underlying layer should never ask for writes across |
| 633 | * subbuffers. |
| 634 | */ |
| 635 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); |
| 636 | |
| 637 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
| 638 | id = bufb->buf_wsb[sbidx].id; |
| 639 | sb_bindex = subbuffer_id_get_index(config, id); |
| 640 | rpages = bufb->array[sb_bindex]; |
| 641 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 642 | && subbuffer_id_is_noref(config, id)); |
| 643 | lib_ring_buffer_do_memset(rpages->p[index].virt |
| 644 | + (offset & ~PAGE_MASK), |
| 645 | c, pagecpy); |
| 646 | } while (unlikely(len != pagecpy)); |
| 647 | } |
| 648 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); |
| 649 | |
| 650 | /** |
| 651 | * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer. |
| 652 | * @bufb : buffer backend |
| 653 | * @offset : offset within the buffer |
| 654 | * @src : source address |
| 655 | * @len : length to write |
| 656 | * @pagecpy : page size copied so far |
| 657 | * @pad : character to use for padding |
| 658 | */ |
| 659 | void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb, |
| 660 | size_t offset, const char *src, size_t len, |
| 661 | size_t pagecpy, int pad) |
| 662 | { |
| 663 | struct channel_backend *chanb = &bufb->chan->backend; |
| 664 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 665 | size_t sbidx, index; |
| 666 | struct lib_ring_buffer_backend_pages *rpages; |
| 667 | unsigned long sb_bindex, id; |
| 668 | int src_terminated = 0; |
| 669 | |
| 670 | CHAN_WARN_ON(chanb, !len); |
| 671 | offset += pagecpy; |
| 672 | do { |
| 673 | len -= pagecpy; |
| 674 | if (!src_terminated) |
| 675 | src += pagecpy; |
| 676 | sbidx = offset >> chanb->subbuf_size_order; |
| 677 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 678 | |
| 679 | /* |
| 680 | * Underlying layer should never ask for writes across |
| 681 | * subbuffers. |
| 682 | */ |
| 683 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); |
| 684 | |
| 685 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
| 686 | id = bufb->buf_wsb[sbidx].id; |
| 687 | sb_bindex = subbuffer_id_get_index(config, id); |
| 688 | rpages = bufb->array[sb_bindex]; |
| 689 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 690 | && subbuffer_id_is_noref(config, id)); |
| 691 | |
| 692 | if (likely(!src_terminated)) { |
| 693 | size_t count, to_copy; |
| 694 | |
| 695 | to_copy = pagecpy; |
| 696 | if (pagecpy == len) |
| 697 | to_copy--; /* Final '\0' */ |
| 698 | count = lib_ring_buffer_do_strcpy(config, |
| 699 | rpages->p[index].virt |
| 700 | + (offset & ~PAGE_MASK), |
| 701 | src, to_copy); |
| 702 | offset += count; |
| 703 | /* Padding */ |
| 704 | if (unlikely(count < to_copy)) { |
| 705 | size_t pad_len = to_copy - count; |
| 706 | |
| 707 | /* Next pages will have padding */ |
| 708 | src_terminated = 1; |
| 709 | lib_ring_buffer_do_memset(rpages->p[index].virt |
| 710 | + (offset & ~PAGE_MASK), |
| 711 | pad, pad_len); |
| 712 | offset += pad_len; |
| 713 | } |
| 714 | } else { |
| 715 | size_t pad_len; |
| 716 | |
| 717 | pad_len = pagecpy; |
| 718 | if (pagecpy == len) |
| 719 | pad_len--; /* Final '\0' */ |
| 720 | lib_ring_buffer_do_memset(rpages->p[index].virt |
| 721 | + (offset & ~PAGE_MASK), |
| 722 | pad, pad_len); |
| 723 | offset += pad_len; |
| 724 | } |
| 725 | } while (unlikely(len != pagecpy)); |
| 726 | /* Ending '\0' */ |
| 727 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), |
| 728 | '\0', 1); |
| 729 | } |
| 730 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy); |
| 731 | |
| 732 | /** |
| 733 | * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. |
| 734 | * @bufb : buffer backend |
| 735 | * @offset : offset within the buffer |
| 736 | * @src : source address |
| 737 | * @len : length to write |
| 738 | * @pagecpy : page size copied so far |
| 739 | * |
| 740 | * This function deals with userspace pointers, it should never be called |
| 741 | * directly without having the src pointer checked with access_ok() |
| 742 | * previously. |
| 743 | */ |
| 744 | void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
| 745 | size_t offset, |
| 746 | const void __user *src, size_t len, |
| 747 | size_t pagecpy) |
| 748 | { |
| 749 | struct channel_backend *chanb = &bufb->chan->backend; |
| 750 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 751 | size_t sbidx, index; |
| 752 | struct lib_ring_buffer_backend_pages *rpages; |
| 753 | unsigned long sb_bindex, id; |
| 754 | int ret; |
| 755 | |
| 756 | do { |
| 757 | len -= pagecpy; |
| 758 | src += pagecpy; |
| 759 | offset += pagecpy; |
| 760 | sbidx = offset >> chanb->subbuf_size_order; |
| 761 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 762 | |
| 763 | /* |
| 764 | * Underlying layer should never ask for writes across |
| 765 | * subbuffers. |
| 766 | */ |
| 767 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); |
| 768 | |
| 769 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
| 770 | id = bufb->buf_wsb[sbidx].id; |
| 771 | sb_bindex = subbuffer_id_get_index(config, id); |
| 772 | rpages = bufb->array[sb_bindex]; |
| 773 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 774 | && subbuffer_id_is_noref(config, id)); |
| 775 | ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt |
| 776 | + (offset & ~PAGE_MASK), |
| 777 | src, pagecpy) != 0; |
| 778 | if (ret > 0) { |
| 779 | /* Copy failed. */ |
| 780 | _lib_ring_buffer_memset(bufb, offset, 0, len, 0); |
| 781 | break; /* stop copy */ |
| 782 | } |
| 783 | } while (unlikely(len != pagecpy)); |
| 784 | } |
| 785 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); |
| 786 | |
| 787 | /** |
| 788 | * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer. |
| 789 | * @bufb : buffer backend |
| 790 | * @offset : offset within the buffer |
| 791 | * @src : source address |
| 792 | * @len : length to write |
| 793 | * @pagecpy : page size copied so far |
| 794 | * @pad : character to use for padding |
| 795 | * |
| 796 | * This function deals with userspace pointers, it should never be called |
| 797 | * directly without having the src pointer checked with access_ok() |
| 798 | * previously. |
| 799 | */ |
| 800 | void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
| 801 | size_t offset, const char __user *src, size_t len, |
| 802 | size_t pagecpy, int pad) |
| 803 | { |
| 804 | struct channel_backend *chanb = &bufb->chan->backend; |
| 805 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 806 | size_t sbidx, index; |
| 807 | struct lib_ring_buffer_backend_pages *rpages; |
| 808 | unsigned long sb_bindex, id; |
| 809 | int src_terminated = 0; |
| 810 | |
| 811 | offset += pagecpy; |
| 812 | do { |
| 813 | len -= pagecpy; |
| 814 | if (!src_terminated) |
| 815 | src += pagecpy; |
| 816 | sbidx = offset >> chanb->subbuf_size_order; |
| 817 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 818 | |
| 819 | /* |
| 820 | * Underlying layer should never ask for writes across |
| 821 | * subbuffers. |
| 822 | */ |
| 823 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); |
| 824 | |
| 825 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
| 826 | id = bufb->buf_wsb[sbidx].id; |
| 827 | sb_bindex = subbuffer_id_get_index(config, id); |
| 828 | rpages = bufb->array[sb_bindex]; |
| 829 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 830 | && subbuffer_id_is_noref(config, id)); |
| 831 | |
| 832 | if (likely(!src_terminated)) { |
| 833 | size_t count, to_copy; |
| 834 | |
| 835 | to_copy = pagecpy; |
| 836 | if (pagecpy == len) |
| 837 | to_copy--; /* Final '\0' */ |
| 838 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, |
| 839 | rpages->p[index].virt |
| 840 | + (offset & ~PAGE_MASK), |
| 841 | src, to_copy); |
| 842 | offset += count; |
| 843 | /* Padding */ |
| 844 | if (unlikely(count < to_copy)) { |
| 845 | size_t pad_len = to_copy - count; |
| 846 | |
| 847 | /* Next pages will have padding */ |
| 848 | src_terminated = 1; |
| 849 | lib_ring_buffer_do_memset(rpages->p[index].virt |
| 850 | + (offset & ~PAGE_MASK), |
| 851 | pad, pad_len); |
| 852 | offset += pad_len; |
| 853 | } |
| 854 | } else { |
| 855 | size_t pad_len; |
| 856 | |
| 857 | pad_len = pagecpy; |
| 858 | if (pagecpy == len) |
| 859 | pad_len--; /* Final '\0' */ |
| 860 | lib_ring_buffer_do_memset(rpages->p[index].virt |
| 861 | + (offset & ~PAGE_MASK), |
| 862 | pad, pad_len); |
| 863 | offset += pad_len; |
| 864 | } |
| 865 | } while (unlikely(len != pagecpy)); |
| 866 | /* Ending '\0' */ |
| 867 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), |
| 868 | '\0', 1); |
| 869 | } |
| 870 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic); |
| 871 | |
| 872 | /** |
| 873 | * lib_ring_buffer_read - read data from ring_buffer_buffer. |
| 874 | * @bufb : buffer backend |
| 875 | * @offset : offset within the buffer |
| 876 | * @dest : destination address |
| 877 | * @len : length to copy to destination |
| 878 | * |
| 879 | * Should be protected by get_subbuf/put_subbuf. |
| 880 | * Returns the length copied. |
| 881 | */ |
| 882 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, |
| 883 | void *dest, size_t len) |
| 884 | { |
| 885 | struct channel_backend *chanb = &bufb->chan->backend; |
| 886 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 887 | size_t index, pagecpy, orig_len; |
| 888 | struct lib_ring_buffer_backend_pages *rpages; |
| 889 | unsigned long sb_bindex, id; |
| 890 | |
| 891 | orig_len = len; |
| 892 | offset &= chanb->buf_size - 1; |
| 893 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 894 | if (unlikely(!len)) |
| 895 | return 0; |
| 896 | for (;;) { |
| 897 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
| 898 | id = bufb->buf_rsb.id; |
| 899 | sb_bindex = subbuffer_id_get_index(config, id); |
| 900 | rpages = bufb->array[sb_bindex]; |
| 901 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 902 | && subbuffer_id_is_noref(config, id)); |
| 903 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), |
| 904 | pagecpy); |
| 905 | len -= pagecpy; |
| 906 | if (likely(!len)) |
| 907 | break; |
| 908 | dest += pagecpy; |
| 909 | offset += pagecpy; |
| 910 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 911 | /* |
| 912 | * Underlying layer should never ask for reads across |
| 913 | * subbuffers. |
| 914 | */ |
| 915 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); |
| 916 | } |
| 917 | return orig_len; |
| 918 | } |
| 919 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); |
| 920 | |
| 921 | /** |
| 922 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace |
| 923 | * @bufb : buffer backend |
| 924 | * @offset : offset within the buffer |
| 925 | * @dest : destination userspace address |
| 926 | * @len : length to copy to destination |
| 927 | * |
| 928 | * Should be protected by get_subbuf/put_subbuf. |
| 929 | * access_ok() must have been performed on dest addresses prior to call this |
| 930 | * function. |
| 931 | * Returns -EFAULT on error, 0 if ok. |
| 932 | */ |
| 933 | int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, |
| 934 | size_t offset, void __user *dest, size_t len) |
| 935 | { |
| 936 | struct channel_backend *chanb = &bufb->chan->backend; |
| 937 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 938 | size_t index; |
| 939 | ssize_t pagecpy; |
| 940 | struct lib_ring_buffer_backend_pages *rpages; |
| 941 | unsigned long sb_bindex, id; |
| 942 | |
| 943 | offset &= chanb->buf_size - 1; |
| 944 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 945 | if (unlikely(!len)) |
| 946 | return 0; |
| 947 | for (;;) { |
| 948 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); |
| 949 | id = bufb->buf_rsb.id; |
| 950 | sb_bindex = subbuffer_id_get_index(config, id); |
| 951 | rpages = bufb->array[sb_bindex]; |
| 952 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 953 | && subbuffer_id_is_noref(config, id)); |
| 954 | if (__copy_to_user(dest, |
| 955 | rpages->p[index].virt + (offset & ~PAGE_MASK), |
| 956 | pagecpy)) |
| 957 | return -EFAULT; |
| 958 | len -= pagecpy; |
| 959 | if (likely(!len)) |
| 960 | break; |
| 961 | dest += pagecpy; |
| 962 | offset += pagecpy; |
| 963 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 964 | /* |
| 965 | * Underlying layer should never ask for reads across |
| 966 | * subbuffers. |
| 967 | */ |
| 968 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); |
| 969 | } |
| 970 | return 0; |
| 971 | } |
| 972 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); |
| 973 | |
| 974 | /** |
| 975 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. |
| 976 | * @bufb : buffer backend |
| 977 | * @offset : offset within the buffer |
| 978 | * @dest : destination address |
| 979 | * @len : destination's length |
| 980 | * |
| 981 | * Return string's length, or -EINVAL on error. |
| 982 | * Should be protected by get_subbuf/put_subbuf. |
| 983 | * Destination length should be at least 1 to hold '\0'. |
| 984 | */ |
| 985 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, |
| 986 | void *dest, size_t len) |
| 987 | { |
| 988 | struct channel_backend *chanb = &bufb->chan->backend; |
| 989 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 990 | size_t index; |
| 991 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; |
| 992 | char *str; |
| 993 | struct lib_ring_buffer_backend_pages *rpages; |
| 994 | unsigned long sb_bindex, id; |
| 995 | |
| 996 | offset &= chanb->buf_size - 1; |
| 997 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 998 | orig_offset = offset; |
| 999 | if (unlikely(!len)) |
| 1000 | return -EINVAL; |
| 1001 | for (;;) { |
| 1002 | id = bufb->buf_rsb.id; |
| 1003 | sb_bindex = subbuffer_id_get_index(config, id); |
| 1004 | rpages = bufb->array[sb_bindex]; |
| 1005 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 1006 | && subbuffer_id_is_noref(config, id)); |
| 1007 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); |
| 1008 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); |
| 1009 | strpagelen = strnlen(str, pagelen); |
| 1010 | if (len) { |
| 1011 | pagecpy = min_t(size_t, len, strpagelen); |
| 1012 | if (dest) { |
| 1013 | memcpy(dest, str, pagecpy); |
| 1014 | dest += pagecpy; |
| 1015 | } |
| 1016 | len -= pagecpy; |
| 1017 | } |
| 1018 | offset += strpagelen; |
| 1019 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 1020 | if (strpagelen < pagelen) |
| 1021 | break; |
| 1022 | /* |
| 1023 | * Underlying layer should never ask for reads across |
| 1024 | * subbuffers. |
| 1025 | */ |
| 1026 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); |
| 1027 | } |
| 1028 | if (dest && len) |
| 1029 | ((char *)dest)[0] = 0; |
| 1030 | return offset - orig_offset; |
| 1031 | } |
| 1032 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); |
| 1033 | |
| 1034 | /** |
| 1035 | * lib_ring_buffer_read_get_pfn - Get a page frame number to read from |
| 1036 | * @bufb : buffer backend |
| 1037 | * @offset : offset within the buffer |
| 1038 | * @virt : pointer to page address (output) |
| 1039 | * |
| 1040 | * Should be protected by get_subbuf/put_subbuf. |
| 1041 | * Returns the pointer to the page frame number unsigned long. |
| 1042 | */ |
| 1043 | unsigned long *lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, |
| 1044 | size_t offset, void ***virt) |
| 1045 | { |
| 1046 | size_t index; |
| 1047 | struct lib_ring_buffer_backend_pages *rpages; |
| 1048 | struct channel_backend *chanb = &bufb->chan->backend; |
| 1049 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 1050 | unsigned long sb_bindex, id; |
| 1051 | |
| 1052 | offset &= chanb->buf_size - 1; |
| 1053 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 1054 | id = bufb->buf_rsb.id; |
| 1055 | sb_bindex = subbuffer_id_get_index(config, id); |
| 1056 | rpages = bufb->array[sb_bindex]; |
| 1057 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 1058 | && subbuffer_id_is_noref(config, id)); |
| 1059 | *virt = &rpages->p[index].virt; |
| 1060 | return &rpages->p[index].pfn; |
| 1061 | } |
| 1062 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn); |
| 1063 | |
| 1064 | /** |
| 1065 | * lib_ring_buffer_read_offset_address - get address of a buffer location |
| 1066 | * @bufb : buffer backend |
| 1067 | * @offset : offset within the buffer. |
| 1068 | * |
| 1069 | * Return the address where a given offset is located (for read). |
| 1070 | * Should be used to get the current subbuffer header pointer. Given we know |
| 1071 | * it's never on a page boundary, it's safe to read/write directly |
| 1072 | * from/to this address, as long as the read/write is never bigger than a |
| 1073 | * page size. |
| 1074 | */ |
| 1075 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, |
| 1076 | size_t offset) |
| 1077 | { |
| 1078 | size_t index; |
| 1079 | struct lib_ring_buffer_backend_pages *rpages; |
| 1080 | struct channel_backend *chanb = &bufb->chan->backend; |
| 1081 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 1082 | unsigned long sb_bindex, id; |
| 1083 | |
| 1084 | offset &= chanb->buf_size - 1; |
| 1085 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 1086 | id = bufb->buf_rsb.id; |
| 1087 | sb_bindex = subbuffer_id_get_index(config, id); |
| 1088 | rpages = bufb->array[sb_bindex]; |
| 1089 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 1090 | && subbuffer_id_is_noref(config, id)); |
| 1091 | return rpages->p[index].virt + (offset & ~PAGE_MASK); |
| 1092 | } |
| 1093 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); |
| 1094 | |
| 1095 | /** |
| 1096 | * lib_ring_buffer_offset_address - get address of a location within the buffer |
| 1097 | * @bufb : buffer backend |
| 1098 | * @offset : offset within the buffer. |
| 1099 | * |
| 1100 | * Return the address where a given offset is located. |
| 1101 | * Should be used to get the current subbuffer header pointer. Given we know |
| 1102 | * it's always at the beginning of a page, it's safe to write directly to this |
| 1103 | * address, as long as the write is never bigger than a page size. |
| 1104 | */ |
| 1105 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, |
| 1106 | size_t offset) |
| 1107 | { |
| 1108 | size_t sbidx, index; |
| 1109 | struct lib_ring_buffer_backend_pages *rpages; |
| 1110 | struct channel_backend *chanb = &bufb->chan->backend; |
| 1111 | const struct lib_ring_buffer_config *config = &chanb->config; |
| 1112 | unsigned long sb_bindex, id; |
| 1113 | |
| 1114 | offset &= chanb->buf_size - 1; |
| 1115 | sbidx = offset >> chanb->subbuf_size_order; |
| 1116 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; |
| 1117 | id = bufb->buf_wsb[sbidx].id; |
| 1118 | sb_bindex = subbuffer_id_get_index(config, id); |
| 1119 | rpages = bufb->array[sb_bindex]; |
| 1120 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
| 1121 | && subbuffer_id_is_noref(config, id)); |
| 1122 | return rpages->p[index].virt + (offset & ~PAGE_MASK); |
| 1123 | } |
| 1124 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |