Commit | Line | Data |
---|---|---|
f3bc08c5 MD |
1 | /* |
2 | * ring_buffer_backend.c | |
3 | * | |
886d51a3 | 4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 | 5 | * |
886d51a3 MD |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; only | |
9 | * version 2.1 of the License. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
f3bc08c5 MD |
19 | */ |
20 | ||
f3bc08c5 MD |
21 | #include <linux/stddef.h> |
22 | #include <linux/module.h> | |
23 | #include <linux/string.h> | |
24 | #include <linux/bitops.h> | |
25 | #include <linux/delay.h> | |
26 | #include <linux/errno.h> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/cpu.h> | |
29 | #include <linux/mm.h> | |
30 | ||
b13f3ebe | 31 | #include "../../wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ |
f3bc08c5 MD |
32 | #include "../../wrapper/ringbuffer/config.h" |
33 | #include "../../wrapper/ringbuffer/backend.h" | |
34 | #include "../../wrapper/ringbuffer/frontend.h" | |
35 | ||
36 | /** | |
37 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
38 | * @config: ring buffer instance configuration | |
39 | * @buf: the buffer struct | |
40 | * @size: total size of the buffer | |
41 | * @num_subbuf: number of subbuffers | |
42 | * @extra_reader_sb: need extra subbuffer for reader | |
43 | */ | |
44 | static | |
45 | int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config, | |
46 | struct lib_ring_buffer_backend *bufb, | |
47 | size_t size, size_t num_subbuf, | |
48 | int extra_reader_sb) | |
49 | { | |
50 | struct channel_backend *chanb = &bufb->chan->backend; | |
51 | unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0; | |
52 | unsigned long subbuf_size, mmap_offset = 0; | |
53 | unsigned long num_subbuf_alloc; | |
54 | struct page **pages; | |
55 | void **virt; | |
56 | unsigned long i; | |
57 | ||
58 | num_pages = size >> PAGE_SHIFT; | |
59 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); | |
60 | subbuf_size = chanb->subbuf_size; | |
61 | num_subbuf_alloc = num_subbuf; | |
62 | ||
63 | if (extra_reader_sb) { | |
64 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ | |
65 | num_subbuf_alloc++; | |
66 | } | |
67 | ||
68 | pages = kmalloc_node(ALIGN(sizeof(*pages) * num_pages, | |
69 | 1 << INTERNODE_CACHE_SHIFT), | |
70 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
71 | if (unlikely(!pages)) | |
72 | goto pages_error; | |
73 | ||
74 | virt = kmalloc_node(ALIGN(sizeof(*virt) * num_pages, | |
75 | 1 << INTERNODE_CACHE_SHIFT), | |
76 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
77 | if (unlikely(!virt)) | |
78 | goto virt_error; | |
79 | ||
80 | bufb->array = kmalloc_node(ALIGN(sizeof(*bufb->array) | |
81 | * num_subbuf_alloc, | |
82 | 1 << INTERNODE_CACHE_SHIFT), | |
83 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
84 | if (unlikely(!bufb->array)) | |
85 | goto array_error; | |
86 | ||
87 | for (i = 0; i < num_pages; i++) { | |
88 | pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)), | |
89 | GFP_KERNEL | __GFP_ZERO, 0); | |
90 | if (unlikely(!pages[i])) | |
91 | goto depopulate; | |
92 | virt[i] = page_address(pages[i]); | |
93 | } | |
94 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; | |
95 | ||
96 | /* Allocate backend pages array elements */ | |
97 | for (i = 0; i < num_subbuf_alloc; i++) { | |
98 | bufb->array[i] = | |
99 | kzalloc_node(ALIGN( | |
100 | sizeof(struct lib_ring_buffer_backend_pages) + | |
101 | sizeof(struct lib_ring_buffer_backend_page) | |
102 | * num_pages_per_subbuf, | |
103 | 1 << INTERNODE_CACHE_SHIFT), | |
104 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
105 | if (!bufb->array[i]) | |
106 | goto free_array; | |
107 | } | |
108 | ||
109 | /* Allocate write-side subbuffer table */ | |
110 | bufb->buf_wsb = kzalloc_node(ALIGN( | |
111 | sizeof(struct lib_ring_buffer_backend_subbuffer) | |
112 | * num_subbuf, | |
113 | 1 << INTERNODE_CACHE_SHIFT), | |
114 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
115 | if (unlikely(!bufb->buf_wsb)) | |
116 | goto free_array; | |
117 | ||
118 | for (i = 0; i < num_subbuf; i++) | |
119 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
120 | ||
121 | /* Assign read-side subbuffer table */ | |
122 | if (extra_reader_sb) | |
123 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
124 | num_subbuf_alloc - 1); | |
125 | else | |
126 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
127 | ||
5b3cf4f9 JD |
128 | /* Allocate subbuffer packet counter table */ |
129 | bufb->buf_cnt = kzalloc_node(ALIGN( | |
130 | sizeof(struct lib_ring_buffer_backend_counts) | |
131 | * num_subbuf, | |
132 | 1 << INTERNODE_CACHE_SHIFT), | |
133 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
134 | if (unlikely(!bufb->buf_cnt)) | |
135 | goto free_wsb; | |
136 | ||
f3bc08c5 MD |
137 | /* Assign pages to page index */ |
138 | for (i = 0; i < num_subbuf_alloc; i++) { | |
139 | for (j = 0; j < num_pages_per_subbuf; j++) { | |
140 | CHAN_WARN_ON(chanb, page_idx > num_pages); | |
141 | bufb->array[i]->p[j].virt = virt[page_idx]; | |
142 | bufb->array[i]->p[j].page = pages[page_idx]; | |
143 | page_idx++; | |
144 | } | |
145 | if (config->output == RING_BUFFER_MMAP) { | |
146 | bufb->array[i]->mmap_offset = mmap_offset; | |
147 | mmap_offset += subbuf_size; | |
148 | } | |
149 | } | |
150 | ||
151 | /* | |
152 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
153 | * will not fault. | |
154 | */ | |
6d2a620c | 155 | wrapper_vmalloc_sync_all(); |
f3bc08c5 MD |
156 | kfree(virt); |
157 | kfree(pages); | |
158 | return 0; | |
159 | ||
5b3cf4f9 JD |
160 | free_wsb: |
161 | kfree(bufb->buf_wsb); | |
f3bc08c5 MD |
162 | free_array: |
163 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) | |
164 | kfree(bufb->array[i]); | |
165 | depopulate: | |
166 | /* Free all allocated pages */ | |
167 | for (i = 0; (i < num_pages && pages[i]); i++) | |
168 | __free_page(pages[i]); | |
169 | kfree(bufb->array); | |
170 | array_error: | |
171 | kfree(virt); | |
172 | virt_error: | |
173 | kfree(pages); | |
174 | pages_error: | |
175 | return -ENOMEM; | |
176 | } | |
177 | ||
178 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
179 | struct channel_backend *chanb, int cpu) | |
180 | { | |
5a8fd222 | 181 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
182 | |
183 | bufb->chan = container_of(chanb, struct channel, backend); | |
184 | bufb->cpu = cpu; | |
185 | ||
186 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
187 | chanb->num_subbuf, | |
188 | chanb->extra_reader_sb); | |
189 | } | |
190 | ||
191 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) | |
192 | { | |
193 | struct channel_backend *chanb = &bufb->chan->backend; | |
194 | unsigned long i, j, num_subbuf_alloc; | |
195 | ||
196 | num_subbuf_alloc = chanb->num_subbuf; | |
197 | if (chanb->extra_reader_sb) | |
198 | num_subbuf_alloc++; | |
199 | ||
200 | kfree(bufb->buf_wsb); | |
5b3cf4f9 | 201 | kfree(bufb->buf_cnt); |
f3bc08c5 MD |
202 | for (i = 0; i < num_subbuf_alloc; i++) { |
203 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) | |
204 | __free_page(bufb->array[i]->p[j].page); | |
205 | kfree(bufb->array[i]); | |
206 | } | |
207 | kfree(bufb->array); | |
208 | bufb->allocated = 0; | |
209 | } | |
210 | ||
211 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) | |
212 | { | |
213 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 214 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
215 | unsigned long num_subbuf_alloc; |
216 | unsigned int i; | |
217 | ||
218 | num_subbuf_alloc = chanb->num_subbuf; | |
219 | if (chanb->extra_reader_sb) | |
220 | num_subbuf_alloc++; | |
221 | ||
222 | for (i = 0; i < chanb->num_subbuf; i++) | |
223 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
224 | if (chanb->extra_reader_sb) | |
225 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
226 | num_subbuf_alloc - 1); | |
227 | else | |
228 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
229 | ||
230 | for (i = 0; i < num_subbuf_alloc; i++) { | |
231 | /* Don't reset mmap_offset */ | |
232 | v_set(config, &bufb->array[i]->records_commit, 0); | |
233 | v_set(config, &bufb->array[i]->records_unread, 0); | |
234 | bufb->array[i]->data_size = 0; | |
235 | /* Don't reset backend page and virt addresses */ | |
236 | } | |
237 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
238 | v_set(config, &bufb->records_read, 0); | |
239 | } | |
240 | ||
241 | /* | |
242 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
243 | * each buffer when calling channel_backend_reset. | |
244 | */ | |
245 | void channel_backend_reset(struct channel_backend *chanb) | |
246 | { | |
247 | struct channel *chan = container_of(chanb, struct channel, backend); | |
5a8fd222 | 248 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
249 | |
250 | /* | |
251 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
252 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
253 | * priv, notifiers, config, cpumask and name. | |
254 | */ | |
255 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
256 | } | |
257 | ||
258 | #ifdef CONFIG_HOTPLUG_CPU | |
259 | /** | |
260 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback | |
261 | * @nb: notifier block | |
262 | * @action: hotplug action to take | |
263 | * @hcpu: CPU number | |
264 | * | |
265 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
266 | */ | |
267 | static | |
e8f071d5 | 268 | int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, |
f3bc08c5 MD |
269 | unsigned long action, |
270 | void *hcpu) | |
271 | { | |
272 | unsigned int cpu = (unsigned long)hcpu; | |
273 | struct channel_backend *chanb = container_of(nb, struct channel_backend, | |
274 | cpu_hp_notifier); | |
5a8fd222 | 275 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
276 | struct lib_ring_buffer *buf; |
277 | int ret; | |
278 | ||
279 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
280 | ||
281 | switch (action) { | |
282 | case CPU_UP_PREPARE: | |
283 | case CPU_UP_PREPARE_FROZEN: | |
284 | buf = per_cpu_ptr(chanb->buf, cpu); | |
285 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
286 | if (ret) { | |
287 | printk(KERN_ERR | |
288 | "ring_buffer_cpu_hp_callback: cpu %d " | |
289 | "buffer creation failed\n", cpu); | |
290 | return NOTIFY_BAD; | |
291 | } | |
292 | break; | |
293 | case CPU_DEAD: | |
294 | case CPU_DEAD_FROZEN: | |
295 | /* No need to do a buffer switch here, because it will happen | |
296 | * when tracing is stopped, or will be done by switch timer CPU | |
297 | * DEAD callback. */ | |
298 | break; | |
299 | } | |
300 | return NOTIFY_OK; | |
301 | } | |
302 | #endif | |
303 | ||
304 | /** | |
305 | * channel_backend_init - initialize a channel backend | |
306 | * @chanb: channel backend | |
307 | * @name: channel name | |
308 | * @config: client ring buffer configuration | |
309 | * @priv: client private data | |
310 | * @parent: dentry of parent directory, %NULL for root directory | |
311 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
312 | * @num_subbuf: number of sub-buffers (power of 2) | |
313 | * | |
314 | * Returns channel pointer if successful, %NULL otherwise. | |
315 | * | |
316 | * Creates per-cpu channel buffers using the sizes and attributes | |
317 | * specified. The created channel buffer files will be named | |
318 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
319 | * | |
320 | * Called with CPU hotplug disabled. | |
321 | */ | |
322 | int channel_backend_init(struct channel_backend *chanb, | |
323 | const char *name, | |
324 | const struct lib_ring_buffer_config *config, | |
325 | void *priv, size_t subbuf_size, size_t num_subbuf) | |
326 | { | |
327 | struct channel *chan = container_of(chanb, struct channel, backend); | |
328 | unsigned int i; | |
329 | int ret; | |
330 | ||
331 | if (!name) | |
332 | return -EPERM; | |
333 | ||
f3bc08c5 | 334 | /* Check that the subbuffer size is larger than a page. */ |
2fb46300 MD |
335 | if (subbuf_size < PAGE_SIZE) |
336 | return -EINVAL; | |
f3bc08c5 MD |
337 | |
338 | /* | |
bbda3a00 MD |
339 | * Make sure the number of subbuffers and subbuffer size are |
340 | * power of 2 and nonzero. | |
f3bc08c5 | 341 | */ |
bbda3a00 | 342 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
863497fa | 343 | return -EINVAL; |
bbda3a00 | 344 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
863497fa | 345 | return -EINVAL; |
5140d2b3 MD |
346 | /* |
347 | * Overwrite mode buffers require at least 2 subbuffers per | |
348 | * buffer. | |
349 | */ | |
350 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
351 | return -EINVAL; | |
f3bc08c5 MD |
352 | |
353 | ret = subbuffer_id_check_index(config, num_subbuf); | |
354 | if (ret) | |
355 | return ret; | |
356 | ||
357 | chanb->priv = priv; | |
358 | chanb->buf_size = num_subbuf * subbuf_size; | |
359 | chanb->subbuf_size = subbuf_size; | |
360 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
361 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
362 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
363 | chanb->extra_reader_sb = | |
364 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
365 | chanb->num_subbuf = num_subbuf; | |
366 | strlcpy(chanb->name, name, NAME_MAX); | |
5a8fd222 | 367 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
f3bc08c5 MD |
368 | |
369 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
370 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) | |
371 | return -ENOMEM; | |
372 | } | |
373 | ||
374 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
375 | /* Allocating the buffer per-cpu structures */ | |
376 | chanb->buf = alloc_percpu(struct lib_ring_buffer); | |
377 | if (!chanb->buf) | |
378 | goto free_cpumask; | |
379 | ||
380 | /* | |
381 | * In case of non-hotplug cpu, if the ring-buffer is allocated | |
382 | * in early initcall, it will not be notified of secondary cpus. | |
383 | * In that off case, we need to allocate for all possible cpus. | |
384 | */ | |
385 | #ifdef CONFIG_HOTPLUG_CPU | |
386 | /* | |
387 | * buf->backend.allocated test takes care of concurrent CPU | |
388 | * hotplug. | |
389 | * Priority higher than frontend, so we create the ring buffer | |
390 | * before we start the timer. | |
391 | */ | |
392 | chanb->cpu_hp_notifier.notifier_call = | |
393 | lib_ring_buffer_cpu_hp_callback; | |
394 | chanb->cpu_hp_notifier.priority = 5; | |
395 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
396 | ||
397 | get_online_cpus(); | |
398 | for_each_online_cpu(i) { | |
399 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
400 | chanb, i); | |
401 | if (ret) | |
402 | goto free_bufs; /* cpu hotplug locked */ | |
403 | } | |
404 | put_online_cpus(); | |
405 | #else | |
406 | for_each_possible_cpu(i) { | |
407 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
408 | chanb, i); | |
409 | if (ret) | |
410 | goto free_bufs; /* cpu hotplug locked */ | |
411 | } | |
412 | #endif | |
413 | } else { | |
414 | chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL); | |
415 | if (!chanb->buf) | |
416 | goto free_cpumask; | |
417 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); | |
418 | if (ret) | |
419 | goto free_bufs; | |
420 | } | |
421 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
422 | ||
423 | return 0; | |
424 | ||
425 | free_bufs: | |
426 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
427 | for_each_possible_cpu(i) { | |
428 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
429 | ||
430 | if (!buf->backend.allocated) | |
431 | continue; | |
432 | lib_ring_buffer_free(buf); | |
433 | } | |
434 | #ifdef CONFIG_HOTPLUG_CPU | |
435 | put_online_cpus(); | |
436 | #endif | |
437 | free_percpu(chanb->buf); | |
438 | } else | |
439 | kfree(chanb->buf); | |
440 | free_cpumask: | |
441 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
442 | free_cpumask_var(chanb->cpumask); | |
443 | return -ENOMEM; | |
444 | } | |
445 | ||
446 | /** | |
447 | * channel_backend_unregister_notifiers - unregister notifiers | |
448 | * @chan: the channel | |
449 | * | |
450 | * Holds CPU hotplug. | |
451 | */ | |
452 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) | |
453 | { | |
5a8fd222 | 454 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
455 | |
456 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
457 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
458 | } | |
459 | ||
460 | /** | |
461 | * channel_backend_free - destroy the channel | |
462 | * @chan: the channel | |
463 | * | |
464 | * Destroy all channel buffers and frees the channel. | |
465 | */ | |
466 | void channel_backend_free(struct channel_backend *chanb) | |
467 | { | |
5a8fd222 | 468 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
469 | unsigned int i; |
470 | ||
471 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
472 | for_each_possible_cpu(i) { | |
473 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
474 | ||
475 | if (!buf->backend.allocated) | |
476 | continue; | |
477 | lib_ring_buffer_free(buf); | |
478 | } | |
479 | free_cpumask_var(chanb->cpumask); | |
480 | free_percpu(chanb->buf); | |
481 | } else { | |
482 | struct lib_ring_buffer *buf = chanb->buf; | |
483 | ||
484 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
485 | lib_ring_buffer_free(buf); | |
486 | kfree(buf); | |
487 | } | |
488 | } | |
489 | ||
490 | /** | |
491 | * lib_ring_buffer_write - write data to a ring_buffer buffer. | |
492 | * @bufb : buffer backend | |
493 | * @offset : offset within the buffer | |
494 | * @src : source address | |
495 | * @len : length to write | |
496 | * @pagecpy : page size copied so far | |
497 | */ | |
498 | void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, | |
bfe529f9 | 499 | const void *src, size_t len, size_t pagecpy) |
f3bc08c5 MD |
500 | { |
501 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 502 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
503 | size_t sbidx, index; |
504 | struct lib_ring_buffer_backend_pages *rpages; | |
505 | unsigned long sb_bindex, id; | |
506 | ||
507 | do { | |
508 | len -= pagecpy; | |
509 | src += pagecpy; | |
510 | offset += pagecpy; | |
511 | sbidx = offset >> chanb->subbuf_size_order; | |
512 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
513 | ||
514 | /* | |
515 | * Underlying layer should never ask for writes across | |
516 | * subbuffers. | |
517 | */ | |
518 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
519 | ||
520 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
521 | id = bufb->buf_wsb[sbidx].id; | |
522 | sb_bindex = subbuffer_id_get_index(config, id); | |
523 | rpages = bufb->array[sb_bindex]; | |
524 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
525 | && subbuffer_id_is_noref(config, id)); | |
526 | lib_ring_buffer_do_copy(config, | |
527 | rpages->p[index].virt | |
528 | + (offset & ~PAGE_MASK), | |
529 | src, pagecpy); | |
530 | } while (unlikely(len != pagecpy)); | |
531 | } | |
532 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); | |
533 | ||
4ea00e4f JD |
534 | |
535 | /** | |
536 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. | |
537 | * @bufb : buffer backend | |
538 | * @offset : offset within the buffer | |
539 | * @c : the byte to write | |
540 | * @len : length to write | |
541 | * @pagecpy : page size copied so far | |
542 | */ | |
543 | void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, | |
544 | size_t offset, | |
bfe529f9 | 545 | int c, size_t len, size_t pagecpy) |
4ea00e4f JD |
546 | { |
547 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 548 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
549 | size_t sbidx, index; |
550 | struct lib_ring_buffer_backend_pages *rpages; | |
551 | unsigned long sb_bindex, id; | |
552 | ||
553 | do { | |
554 | len -= pagecpy; | |
555 | offset += pagecpy; | |
556 | sbidx = offset >> chanb->subbuf_size_order; | |
557 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
558 | ||
559 | /* | |
560 | * Underlying layer should never ask for writes across | |
561 | * subbuffers. | |
562 | */ | |
563 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
564 | ||
565 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
566 | id = bufb->buf_wsb[sbidx].id; | |
567 | sb_bindex = subbuffer_id_get_index(config, id); | |
568 | rpages = bufb->array[sb_bindex]; | |
569 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
570 | && subbuffer_id_is_noref(config, id)); | |
571 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
572 | + (offset & ~PAGE_MASK), | |
573 | c, pagecpy); | |
574 | } while (unlikely(len != pagecpy)); | |
575 | } | |
576 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); | |
577 | ||
16f78f3a MD |
578 | /** |
579 | * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer. | |
580 | * @bufb : buffer backend | |
581 | * @offset : offset within the buffer | |
582 | * @src : source address | |
583 | * @len : length to write | |
584 | * @pagecpy : page size copied so far | |
585 | * @pad : character to use for padding | |
586 | */ | |
587 | void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb, | |
588 | size_t offset, const char *src, size_t len, | |
589 | size_t pagecpy, int pad) | |
590 | { | |
591 | struct channel_backend *chanb = &bufb->chan->backend; | |
592 | const struct lib_ring_buffer_config *config = &chanb->config; | |
593 | size_t sbidx, index; | |
594 | struct lib_ring_buffer_backend_pages *rpages; | |
595 | unsigned long sb_bindex, id; | |
596 | int src_terminated = 0; | |
597 | ||
598 | CHAN_WARN_ON(chanb, !len); | |
599 | offset += pagecpy; | |
600 | do { | |
601 | len -= pagecpy; | |
602 | if (!src_terminated) | |
603 | src += pagecpy; | |
604 | sbidx = offset >> chanb->subbuf_size_order; | |
605 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
606 | ||
607 | /* | |
608 | * Underlying layer should never ask for writes across | |
609 | * subbuffers. | |
610 | */ | |
611 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
612 | ||
613 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
614 | id = bufb->buf_wsb[sbidx].id; | |
615 | sb_bindex = subbuffer_id_get_index(config, id); | |
616 | rpages = bufb->array[sb_bindex]; | |
617 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
618 | && subbuffer_id_is_noref(config, id)); | |
619 | ||
620 | if (likely(!src_terminated)) { | |
621 | size_t count, to_copy; | |
622 | ||
623 | to_copy = pagecpy; | |
624 | if (pagecpy == len) | |
625 | to_copy--; /* Final '\0' */ | |
626 | count = lib_ring_buffer_do_strcpy(config, | |
627 | rpages->p[index].virt | |
628 | + (offset & ~PAGE_MASK), | |
629 | src, to_copy); | |
630 | offset += count; | |
631 | /* Padding */ | |
632 | if (unlikely(count < to_copy)) { | |
633 | size_t pad_len = to_copy - count; | |
634 | ||
635 | /* Next pages will have padding */ | |
636 | src_terminated = 1; | |
637 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
638 | + (offset & ~PAGE_MASK), | |
639 | pad, pad_len); | |
640 | offset += pad_len; | |
641 | } | |
642 | } else { | |
643 | size_t pad_len; | |
644 | ||
645 | pad_len = pagecpy; | |
646 | if (pagecpy == len) | |
647 | pad_len--; /* Final '\0' */ | |
648 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
649 | + (offset & ~PAGE_MASK), | |
650 | pad, pad_len); | |
651 | offset += pad_len; | |
652 | } | |
653 | } while (unlikely(len != pagecpy)); | |
654 | /* Ending '\0' */ | |
655 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
656 | '\0', 1); | |
657 | } | |
658 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy); | |
4ea00e4f JD |
659 | |
660 | /** | |
7b8ea3a5 | 661 | * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. |
4ea00e4f JD |
662 | * @bufb : buffer backend |
663 | * @offset : offset within the buffer | |
664 | * @src : source address | |
665 | * @len : length to write | |
666 | * @pagecpy : page size copied so far | |
667 | * | |
668 | * This function deals with userspace pointers, it should never be called | |
669 | * directly without having the src pointer checked with access_ok() | |
670 | * previously. | |
671 | */ | |
7b8ea3a5 | 672 | void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
4ea00e4f JD |
673 | size_t offset, |
674 | const void __user *src, size_t len, | |
bfe529f9 | 675 | size_t pagecpy) |
4ea00e4f JD |
676 | { |
677 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 678 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
679 | size_t sbidx, index; |
680 | struct lib_ring_buffer_backend_pages *rpages; | |
681 | unsigned long sb_bindex, id; | |
682 | int ret; | |
683 | ||
684 | do { | |
685 | len -= pagecpy; | |
686 | src += pagecpy; | |
687 | offset += pagecpy; | |
688 | sbidx = offset >> chanb->subbuf_size_order; | |
689 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
690 | ||
691 | /* | |
692 | * Underlying layer should never ask for writes across | |
693 | * subbuffers. | |
694 | */ | |
695 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
696 | ||
697 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
698 | id = bufb->buf_wsb[sbidx].id; | |
699 | sb_bindex = subbuffer_id_get_index(config, id); | |
700 | rpages = bufb->array[sb_bindex]; | |
701 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
702 | && subbuffer_id_is_noref(config, id)); | |
7b8ea3a5 | 703 | ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt |
4ea00e4f JD |
704 | + (offset & ~PAGE_MASK), |
705 | src, pagecpy) != 0; | |
706 | if (ret > 0) { | |
707 | offset += (pagecpy - ret); | |
708 | len -= (pagecpy - ret); | |
709 | _lib_ring_buffer_memset(bufb, offset, 0, len, 0); | |
710 | break; /* stop copy */ | |
711 | } | |
712 | } while (unlikely(len != pagecpy)); | |
713 | } | |
7b8ea3a5 | 714 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); |
4ea00e4f | 715 | |
16f78f3a MD |
716 | /** |
717 | * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer. | |
718 | * @bufb : buffer backend | |
719 | * @offset : offset within the buffer | |
720 | * @src : source address | |
721 | * @len : length to write | |
722 | * @pagecpy : page size copied so far | |
723 | * @pad : character to use for padding | |
724 | * | |
725 | * This function deals with userspace pointers, it should never be called | |
726 | * directly without having the src pointer checked with access_ok() | |
727 | * previously. | |
728 | */ | |
729 | void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, | |
730 | size_t offset, const char __user *src, size_t len, | |
731 | size_t pagecpy, int pad) | |
732 | { | |
733 | struct channel_backend *chanb = &bufb->chan->backend; | |
734 | const struct lib_ring_buffer_config *config = &chanb->config; | |
735 | size_t sbidx, index; | |
736 | struct lib_ring_buffer_backend_pages *rpages; | |
737 | unsigned long sb_bindex, id; | |
738 | int src_terminated = 0; | |
739 | ||
740 | offset += pagecpy; | |
741 | do { | |
742 | len -= pagecpy; | |
743 | if (!src_terminated) | |
744 | src += pagecpy; | |
745 | sbidx = offset >> chanb->subbuf_size_order; | |
746 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
747 | ||
748 | /* | |
749 | * Underlying layer should never ask for writes across | |
750 | * subbuffers. | |
751 | */ | |
752 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
753 | ||
754 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
755 | id = bufb->buf_wsb[sbidx].id; | |
756 | sb_bindex = subbuffer_id_get_index(config, id); | |
757 | rpages = bufb->array[sb_bindex]; | |
758 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
759 | && subbuffer_id_is_noref(config, id)); | |
760 | ||
761 | if (likely(!src_terminated)) { | |
762 | size_t count, to_copy; | |
763 | ||
764 | to_copy = pagecpy; | |
765 | if (pagecpy == len) | |
766 | to_copy--; /* Final '\0' */ | |
767 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, | |
768 | rpages->p[index].virt | |
769 | + (offset & ~PAGE_MASK), | |
770 | src, to_copy); | |
771 | offset += count; | |
772 | /* Padding */ | |
773 | if (unlikely(count < to_copy)) { | |
774 | size_t pad_len = to_copy - count; | |
775 | ||
776 | /* Next pages will have padding */ | |
777 | src_terminated = 1; | |
778 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
779 | + (offset & ~PAGE_MASK), | |
780 | pad, pad_len); | |
781 | offset += pad_len; | |
782 | } | |
783 | } else { | |
784 | size_t pad_len; | |
785 | ||
786 | pad_len = pagecpy; | |
787 | if (pagecpy == len) | |
788 | pad_len--; /* Final '\0' */ | |
789 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
790 | + (offset & ~PAGE_MASK), | |
791 | pad, pad_len); | |
792 | offset += pad_len; | |
793 | } | |
794 | } while (unlikely(len != pagecpy)); | |
795 | /* Ending '\0' */ | |
796 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
797 | '\0', 1); | |
798 | } | |
799 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic); | |
800 | ||
f3bc08c5 MD |
801 | /** |
802 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
803 | * @bufb : buffer backend | |
804 | * @offset : offset within the buffer | |
805 | * @dest : destination address | |
806 | * @len : length to copy to destination | |
807 | * | |
808 | * Should be protected by get_subbuf/put_subbuf. | |
809 | * Returns the length copied. | |
810 | */ | |
811 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, | |
812 | void *dest, size_t len) | |
813 | { | |
814 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 815 | const struct lib_ring_buffer_config *config = &chanb->config; |
bfe529f9 | 816 | size_t index, pagecpy, orig_len; |
f3bc08c5 MD |
817 | struct lib_ring_buffer_backend_pages *rpages; |
818 | unsigned long sb_bindex, id; | |
819 | ||
820 | orig_len = len; | |
821 | offset &= chanb->buf_size - 1; | |
822 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
823 | if (unlikely(!len)) | |
824 | return 0; | |
825 | for (;;) { | |
826 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
827 | id = bufb->buf_rsb.id; | |
828 | sb_bindex = subbuffer_id_get_index(config, id); | |
829 | rpages = bufb->array[sb_bindex]; | |
830 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
831 | && subbuffer_id_is_noref(config, id)); | |
832 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), | |
833 | pagecpy); | |
834 | len -= pagecpy; | |
835 | if (likely(!len)) | |
836 | break; | |
837 | dest += pagecpy; | |
838 | offset += pagecpy; | |
839 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
840 | /* | |
841 | * Underlying layer should never ask for reads across | |
842 | * subbuffers. | |
843 | */ | |
844 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
845 | } | |
846 | return orig_len; | |
847 | } | |
848 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); | |
849 | ||
850 | /** | |
851 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace | |
852 | * @bufb : buffer backend | |
853 | * @offset : offset within the buffer | |
854 | * @dest : destination userspace address | |
855 | * @len : length to copy to destination | |
856 | * | |
857 | * Should be protected by get_subbuf/put_subbuf. | |
858 | * access_ok() must have been performed on dest addresses prior to call this | |
859 | * function. | |
860 | * Returns -EFAULT on error, 0 if ok. | |
861 | */ | |
862 | int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, | |
863 | size_t offset, void __user *dest, size_t len) | |
864 | { | |
865 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 866 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 867 | size_t index; |
88dfd899 | 868 | ssize_t pagecpy; |
f3bc08c5 MD |
869 | struct lib_ring_buffer_backend_pages *rpages; |
870 | unsigned long sb_bindex, id; | |
871 | ||
f3bc08c5 MD |
872 | offset &= chanb->buf_size - 1; |
873 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
874 | if (unlikely(!len)) | |
875 | return 0; | |
876 | for (;;) { | |
877 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
878 | id = bufb->buf_rsb.id; | |
879 | sb_bindex = subbuffer_id_get_index(config, id); | |
880 | rpages = bufb->array[sb_bindex]; | |
881 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
882 | && subbuffer_id_is_noref(config, id)); | |
883 | if (__copy_to_user(dest, | |
884 | rpages->p[index].virt + (offset & ~PAGE_MASK), | |
885 | pagecpy)) | |
886 | return -EFAULT; | |
887 | len -= pagecpy; | |
888 | if (likely(!len)) | |
889 | break; | |
890 | dest += pagecpy; | |
891 | offset += pagecpy; | |
892 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
893 | /* | |
894 | * Underlying layer should never ask for reads across | |
895 | * subbuffers. | |
896 | */ | |
897 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
898 | } | |
899 | return 0; | |
900 | } | |
901 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); | |
902 | ||
903 | /** | |
904 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
905 | * @bufb : buffer backend | |
906 | * @offset : offset within the buffer | |
907 | * @dest : destination address | |
908 | * @len : destination's length | |
909 | * | |
61eb4c39 | 910 | * Return string's length, or -EINVAL on error. |
f3bc08c5 | 911 | * Should be protected by get_subbuf/put_subbuf. |
61eb4c39 | 912 | * Destination length should be at least 1 to hold '\0'. |
f3bc08c5 MD |
913 | */ |
914 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, | |
915 | void *dest, size_t len) | |
916 | { | |
917 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 918 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
919 | size_t index; |
920 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; | |
921 | char *str; | |
922 | struct lib_ring_buffer_backend_pages *rpages; | |
923 | unsigned long sb_bindex, id; | |
924 | ||
925 | offset &= chanb->buf_size - 1; | |
926 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
927 | orig_offset = offset; | |
61eb4c39 MD |
928 | if (unlikely(!len)) |
929 | return -EINVAL; | |
f3bc08c5 MD |
930 | for (;;) { |
931 | id = bufb->buf_rsb.id; | |
932 | sb_bindex = subbuffer_id_get_index(config, id); | |
933 | rpages = bufb->array[sb_bindex]; | |
934 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
935 | && subbuffer_id_is_noref(config, id)); | |
936 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); | |
937 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
938 | strpagelen = strnlen(str, pagelen); | |
939 | if (len) { | |
940 | pagecpy = min_t(size_t, len, strpagelen); | |
941 | if (dest) { | |
942 | memcpy(dest, str, pagecpy); | |
943 | dest += pagecpy; | |
944 | } | |
945 | len -= pagecpy; | |
946 | } | |
947 | offset += strpagelen; | |
948 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
949 | if (strpagelen < pagelen) | |
950 | break; | |
951 | /* | |
952 | * Underlying layer should never ask for reads across | |
953 | * subbuffers. | |
954 | */ | |
955 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
956 | } | |
957 | if (dest && len) | |
958 | ((char *)dest)[0] = 0; | |
959 | return offset - orig_offset; | |
960 | } | |
961 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); | |
962 | ||
963 | /** | |
964 | * lib_ring_buffer_read_get_page - Get a whole page to read from | |
965 | * @bufb : buffer backend | |
966 | * @offset : offset within the buffer | |
967 | * @virt : pointer to page address (output) | |
968 | * | |
969 | * Should be protected by get_subbuf/put_subbuf. | |
970 | * Returns the pointer to the page struct pointer. | |
971 | */ | |
972 | struct page **lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb, | |
973 | size_t offset, void ***virt) | |
974 | { | |
975 | size_t index; | |
976 | struct lib_ring_buffer_backend_pages *rpages; | |
977 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 978 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
979 | unsigned long sb_bindex, id; |
980 | ||
981 | offset &= chanb->buf_size - 1; | |
982 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
983 | id = bufb->buf_rsb.id; | |
984 | sb_bindex = subbuffer_id_get_index(config, id); | |
985 | rpages = bufb->array[sb_bindex]; | |
986 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
987 | && subbuffer_id_is_noref(config, id)); | |
988 | *virt = &rpages->p[index].virt; | |
989 | return &rpages->p[index].page; | |
990 | } | |
991 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_page); | |
992 | ||
993 | /** | |
994 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
995 | * @bufb : buffer backend | |
996 | * @offset : offset within the buffer. | |
997 | * | |
998 | * Return the address where a given offset is located (for read). | |
999 | * Should be used to get the current subbuffer header pointer. Given we know | |
759d02c1 MD |
1000 | * it's never on a page boundary, it's safe to read/write directly |
1001 | * from/to this address, as long as the read/write is never bigger than a | |
1002 | * page size. | |
f3bc08c5 MD |
1003 | */ |
1004 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, | |
1005 | size_t offset) | |
1006 | { | |
1007 | size_t index; | |
1008 | struct lib_ring_buffer_backend_pages *rpages; | |
1009 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1010 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1011 | unsigned long sb_bindex, id; |
1012 | ||
1013 | offset &= chanb->buf_size - 1; | |
1014 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1015 | id = bufb->buf_rsb.id; | |
1016 | sb_bindex = subbuffer_id_get_index(config, id); | |
1017 | rpages = bufb->array[sb_bindex]; | |
1018 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1019 | && subbuffer_id_is_noref(config, id)); | |
1020 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1021 | } | |
1022 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); | |
1023 | ||
1024 | /** | |
1025 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
1026 | * @bufb : buffer backend | |
1027 | * @offset : offset within the buffer. | |
1028 | * | |
1029 | * Return the address where a given offset is located. | |
1030 | * Should be used to get the current subbuffer header pointer. Given we know | |
1031 | * it's always at the beginning of a page, it's safe to write directly to this | |
1032 | * address, as long as the write is never bigger than a page size. | |
1033 | */ | |
1034 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, | |
1035 | size_t offset) | |
1036 | { | |
1037 | size_t sbidx, index; | |
1038 | struct lib_ring_buffer_backend_pages *rpages; | |
1039 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1040 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1041 | unsigned long sb_bindex, id; |
1042 | ||
1043 | offset &= chanb->buf_size - 1; | |
1044 | sbidx = offset >> chanb->subbuf_size_order; | |
1045 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1046 | id = bufb->buf_wsb[sbidx].id; | |
1047 | sb_bindex = subbuffer_id_get_index(config, id); | |
1048 | rpages = bufb->array[sb_bindex]; | |
1049 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1050 | && subbuffer_id_is_noref(config, id)); | |
1051 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1052 | } | |
1053 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |