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; | |
f3bc08c5 MD |
55 | unsigned long i; |
56 | ||
57 | num_pages = size >> PAGE_SHIFT; | |
58 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); | |
59 | subbuf_size = chanb->subbuf_size; | |
60 | num_subbuf_alloc = num_subbuf; | |
61 | ||
62 | if (extra_reader_sb) { | |
63 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ | |
64 | num_subbuf_alloc++; | |
65 | } | |
66 | ||
67 | pages = kmalloc_node(ALIGN(sizeof(*pages) * num_pages, | |
68 | 1 << INTERNODE_CACHE_SHIFT), | |
69 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
70 | if (unlikely(!pages)) | |
71 | goto pages_error; | |
72 | ||
f3bc08c5 MD |
73 | bufb->array = kmalloc_node(ALIGN(sizeof(*bufb->array) |
74 | * num_subbuf_alloc, | |
75 | 1 << INTERNODE_CACHE_SHIFT), | |
76 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
77 | if (unlikely(!bufb->array)) | |
78 | goto array_error; | |
79 | ||
80 | for (i = 0; i < num_pages; i++) { | |
81 | pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)), | |
82 | GFP_KERNEL | __GFP_ZERO, 0); | |
83 | if (unlikely(!pages[i])) | |
84 | goto depopulate; | |
f3bc08c5 MD |
85 | } |
86 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; | |
87 | ||
88 | /* Allocate backend pages array elements */ | |
89 | for (i = 0; i < num_subbuf_alloc; i++) { | |
90 | bufb->array[i] = | |
91 | kzalloc_node(ALIGN( | |
92 | sizeof(struct lib_ring_buffer_backend_pages) + | |
93 | sizeof(struct lib_ring_buffer_backend_page) | |
94 | * num_pages_per_subbuf, | |
95 | 1 << INTERNODE_CACHE_SHIFT), | |
96 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
97 | if (!bufb->array[i]) | |
98 | goto free_array; | |
99 | } | |
100 | ||
101 | /* Allocate write-side subbuffer table */ | |
102 | bufb->buf_wsb = kzalloc_node(ALIGN( | |
103 | sizeof(struct lib_ring_buffer_backend_subbuffer) | |
104 | * num_subbuf, | |
105 | 1 << INTERNODE_CACHE_SHIFT), | |
106 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
107 | if (unlikely(!bufb->buf_wsb)) | |
108 | goto free_array; | |
109 | ||
110 | for (i = 0; i < num_subbuf; i++) | |
111 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
112 | ||
113 | /* Assign read-side subbuffer table */ | |
114 | if (extra_reader_sb) | |
115 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
116 | num_subbuf_alloc - 1); | |
117 | else | |
118 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
119 | ||
5b3cf4f9 JD |
120 | /* Allocate subbuffer packet counter table */ |
121 | bufb->buf_cnt = kzalloc_node(ALIGN( | |
122 | sizeof(struct lib_ring_buffer_backend_counts) | |
123 | * num_subbuf, | |
124 | 1 << INTERNODE_CACHE_SHIFT), | |
125 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
126 | if (unlikely(!bufb->buf_cnt)) | |
127 | goto free_wsb; | |
128 | ||
f3bc08c5 MD |
129 | /* Assign pages to page index */ |
130 | for (i = 0; i < num_subbuf_alloc; i++) { | |
131 | for (j = 0; j < num_pages_per_subbuf; j++) { | |
132 | CHAN_WARN_ON(chanb, page_idx > num_pages); | |
0112cb7b MD |
133 | bufb->array[i]->p[j].virt = page_address(pages[page_idx]); |
134 | bufb->array[i]->p[j].pfn = page_to_pfn(pages[page_idx]); | |
f3bc08c5 MD |
135 | page_idx++; |
136 | } | |
137 | if (config->output == RING_BUFFER_MMAP) { | |
138 | bufb->array[i]->mmap_offset = mmap_offset; | |
139 | mmap_offset += subbuf_size; | |
140 | } | |
141 | } | |
142 | ||
143 | /* | |
144 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
145 | * will not fault. | |
146 | */ | |
6d2a620c | 147 | wrapper_vmalloc_sync_all(); |
f3bc08c5 MD |
148 | kfree(pages); |
149 | return 0; | |
150 | ||
5b3cf4f9 JD |
151 | free_wsb: |
152 | kfree(bufb->buf_wsb); | |
f3bc08c5 MD |
153 | free_array: |
154 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) | |
155 | kfree(bufb->array[i]); | |
156 | depopulate: | |
157 | /* Free all allocated pages */ | |
158 | for (i = 0; (i < num_pages && pages[i]); i++) | |
159 | __free_page(pages[i]); | |
160 | kfree(bufb->array); | |
161 | array_error: | |
f3bc08c5 MD |
162 | kfree(pages); |
163 | pages_error: | |
164 | return -ENOMEM; | |
165 | } | |
166 | ||
167 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
168 | struct channel_backend *chanb, int cpu) | |
169 | { | |
5a8fd222 | 170 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
171 | |
172 | bufb->chan = container_of(chanb, struct channel, backend); | |
173 | bufb->cpu = cpu; | |
174 | ||
175 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
176 | chanb->num_subbuf, | |
177 | chanb->extra_reader_sb); | |
178 | } | |
179 | ||
180 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) | |
181 | { | |
182 | struct channel_backend *chanb = &bufb->chan->backend; | |
183 | unsigned long i, j, num_subbuf_alloc; | |
184 | ||
185 | num_subbuf_alloc = chanb->num_subbuf; | |
186 | if (chanb->extra_reader_sb) | |
187 | num_subbuf_alloc++; | |
188 | ||
189 | kfree(bufb->buf_wsb); | |
5b3cf4f9 | 190 | kfree(bufb->buf_cnt); |
f3bc08c5 MD |
191 | for (i = 0; i < num_subbuf_alloc; i++) { |
192 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) | |
0112cb7b | 193 | __free_page(pfn_to_page(bufb->array[i]->p[j].pfn)); |
f3bc08c5 MD |
194 | kfree(bufb->array[i]); |
195 | } | |
196 | kfree(bufb->array); | |
197 | bufb->allocated = 0; | |
198 | } | |
199 | ||
200 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) | |
201 | { | |
202 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 203 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
204 | unsigned long num_subbuf_alloc; |
205 | unsigned int i; | |
206 | ||
207 | num_subbuf_alloc = chanb->num_subbuf; | |
208 | if (chanb->extra_reader_sb) | |
209 | num_subbuf_alloc++; | |
210 | ||
211 | for (i = 0; i < chanb->num_subbuf; i++) | |
212 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
213 | if (chanb->extra_reader_sb) | |
214 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
215 | num_subbuf_alloc - 1); | |
216 | else | |
217 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
218 | ||
219 | for (i = 0; i < num_subbuf_alloc; i++) { | |
220 | /* Don't reset mmap_offset */ | |
221 | v_set(config, &bufb->array[i]->records_commit, 0); | |
222 | v_set(config, &bufb->array[i]->records_unread, 0); | |
223 | bufb->array[i]->data_size = 0; | |
224 | /* Don't reset backend page and virt addresses */ | |
225 | } | |
226 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
227 | v_set(config, &bufb->records_read, 0); | |
228 | } | |
229 | ||
230 | /* | |
231 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
232 | * each buffer when calling channel_backend_reset. | |
233 | */ | |
234 | void channel_backend_reset(struct channel_backend *chanb) | |
235 | { | |
236 | struct channel *chan = container_of(chanb, struct channel, backend); | |
5a8fd222 | 237 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
238 | |
239 | /* | |
240 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
241 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
242 | * priv, notifiers, config, cpumask and name. | |
243 | */ | |
244 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
245 | } | |
246 | ||
247 | #ifdef CONFIG_HOTPLUG_CPU | |
248 | /** | |
249 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback | |
250 | * @nb: notifier block | |
251 | * @action: hotplug action to take | |
252 | * @hcpu: CPU number | |
253 | * | |
254 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
255 | */ | |
256 | static | |
e8f071d5 | 257 | int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, |
f3bc08c5 MD |
258 | unsigned long action, |
259 | void *hcpu) | |
260 | { | |
261 | unsigned int cpu = (unsigned long)hcpu; | |
262 | struct channel_backend *chanb = container_of(nb, struct channel_backend, | |
263 | cpu_hp_notifier); | |
5a8fd222 | 264 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
265 | struct lib_ring_buffer *buf; |
266 | int ret; | |
267 | ||
268 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
269 | ||
270 | switch (action) { | |
271 | case CPU_UP_PREPARE: | |
272 | case CPU_UP_PREPARE_FROZEN: | |
273 | buf = per_cpu_ptr(chanb->buf, cpu); | |
274 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
275 | if (ret) { | |
276 | printk(KERN_ERR | |
277 | "ring_buffer_cpu_hp_callback: cpu %d " | |
278 | "buffer creation failed\n", cpu); | |
279 | return NOTIFY_BAD; | |
280 | } | |
281 | break; | |
282 | case CPU_DEAD: | |
283 | case CPU_DEAD_FROZEN: | |
284 | /* No need to do a buffer switch here, because it will happen | |
285 | * when tracing is stopped, or will be done by switch timer CPU | |
286 | * DEAD callback. */ | |
287 | break; | |
288 | } | |
289 | return NOTIFY_OK; | |
290 | } | |
291 | #endif | |
292 | ||
293 | /** | |
294 | * channel_backend_init - initialize a channel backend | |
295 | * @chanb: channel backend | |
296 | * @name: channel name | |
297 | * @config: client ring buffer configuration | |
298 | * @priv: client private data | |
299 | * @parent: dentry of parent directory, %NULL for root directory | |
300 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
301 | * @num_subbuf: number of sub-buffers (power of 2) | |
302 | * | |
303 | * Returns channel pointer if successful, %NULL otherwise. | |
304 | * | |
305 | * Creates per-cpu channel buffers using the sizes and attributes | |
306 | * specified. The created channel buffer files will be named | |
307 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
308 | * | |
309 | * Called with CPU hotplug disabled. | |
310 | */ | |
311 | int channel_backend_init(struct channel_backend *chanb, | |
312 | const char *name, | |
313 | const struct lib_ring_buffer_config *config, | |
314 | void *priv, size_t subbuf_size, size_t num_subbuf) | |
315 | { | |
316 | struct channel *chan = container_of(chanb, struct channel, backend); | |
317 | unsigned int i; | |
318 | int ret; | |
319 | ||
320 | if (!name) | |
321 | return -EPERM; | |
322 | ||
f3bc08c5 | 323 | /* Check that the subbuffer size is larger than a page. */ |
2fb46300 MD |
324 | if (subbuf_size < PAGE_SIZE) |
325 | return -EINVAL; | |
f3bc08c5 MD |
326 | |
327 | /* | |
bbda3a00 MD |
328 | * Make sure the number of subbuffers and subbuffer size are |
329 | * power of 2 and nonzero. | |
f3bc08c5 | 330 | */ |
bbda3a00 | 331 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
863497fa | 332 | return -EINVAL; |
bbda3a00 | 333 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
863497fa | 334 | return -EINVAL; |
5140d2b3 MD |
335 | /* |
336 | * Overwrite mode buffers require at least 2 subbuffers per | |
337 | * buffer. | |
338 | */ | |
339 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
340 | return -EINVAL; | |
f3bc08c5 MD |
341 | |
342 | ret = subbuffer_id_check_index(config, num_subbuf); | |
343 | if (ret) | |
344 | return ret; | |
345 | ||
346 | chanb->priv = priv; | |
347 | chanb->buf_size = num_subbuf * subbuf_size; | |
348 | chanb->subbuf_size = subbuf_size; | |
349 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
350 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
351 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
352 | chanb->extra_reader_sb = | |
353 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
354 | chanb->num_subbuf = num_subbuf; | |
355 | strlcpy(chanb->name, name, NAME_MAX); | |
5a8fd222 | 356 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
f3bc08c5 MD |
357 | |
358 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
359 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) | |
360 | return -ENOMEM; | |
361 | } | |
362 | ||
363 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
364 | /* Allocating the buffer per-cpu structures */ | |
365 | chanb->buf = alloc_percpu(struct lib_ring_buffer); | |
366 | if (!chanb->buf) | |
367 | goto free_cpumask; | |
368 | ||
369 | /* | |
370 | * In case of non-hotplug cpu, if the ring-buffer is allocated | |
371 | * in early initcall, it will not be notified of secondary cpus. | |
372 | * In that off case, we need to allocate for all possible cpus. | |
373 | */ | |
374 | #ifdef CONFIG_HOTPLUG_CPU | |
375 | /* | |
376 | * buf->backend.allocated test takes care of concurrent CPU | |
377 | * hotplug. | |
378 | * Priority higher than frontend, so we create the ring buffer | |
379 | * before we start the timer. | |
380 | */ | |
381 | chanb->cpu_hp_notifier.notifier_call = | |
382 | lib_ring_buffer_cpu_hp_callback; | |
383 | chanb->cpu_hp_notifier.priority = 5; | |
384 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
385 | ||
386 | get_online_cpus(); | |
387 | for_each_online_cpu(i) { | |
388 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
389 | chanb, i); | |
390 | if (ret) | |
391 | goto free_bufs; /* cpu hotplug locked */ | |
392 | } | |
393 | put_online_cpus(); | |
394 | #else | |
395 | for_each_possible_cpu(i) { | |
396 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
397 | chanb, i); | |
398 | if (ret) | |
399 | goto free_bufs; /* cpu hotplug locked */ | |
400 | } | |
401 | #endif | |
402 | } else { | |
403 | chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL); | |
404 | if (!chanb->buf) | |
405 | goto free_cpumask; | |
406 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); | |
407 | if (ret) | |
408 | goto free_bufs; | |
409 | } | |
410 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
411 | ||
412 | return 0; | |
413 | ||
414 | free_bufs: | |
415 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
416 | for_each_possible_cpu(i) { | |
417 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
418 | ||
419 | if (!buf->backend.allocated) | |
420 | continue; | |
421 | lib_ring_buffer_free(buf); | |
422 | } | |
423 | #ifdef CONFIG_HOTPLUG_CPU | |
424 | put_online_cpus(); | |
425 | #endif | |
426 | free_percpu(chanb->buf); | |
427 | } else | |
428 | kfree(chanb->buf); | |
429 | free_cpumask: | |
430 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
431 | free_cpumask_var(chanb->cpumask); | |
432 | return -ENOMEM; | |
433 | } | |
434 | ||
435 | /** | |
436 | * channel_backend_unregister_notifiers - unregister notifiers | |
437 | * @chan: the channel | |
438 | * | |
439 | * Holds CPU hotplug. | |
440 | */ | |
441 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) | |
442 | { | |
5a8fd222 | 443 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
444 | |
445 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
446 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
447 | } | |
448 | ||
449 | /** | |
450 | * channel_backend_free - destroy the channel | |
451 | * @chan: the channel | |
452 | * | |
453 | * Destroy all channel buffers and frees the channel. | |
454 | */ | |
455 | void channel_backend_free(struct channel_backend *chanb) | |
456 | { | |
5a8fd222 | 457 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
458 | unsigned int i; |
459 | ||
460 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
461 | for_each_possible_cpu(i) { | |
462 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
463 | ||
464 | if (!buf->backend.allocated) | |
465 | continue; | |
466 | lib_ring_buffer_free(buf); | |
467 | } | |
468 | free_cpumask_var(chanb->cpumask); | |
469 | free_percpu(chanb->buf); | |
470 | } else { | |
471 | struct lib_ring_buffer *buf = chanb->buf; | |
472 | ||
473 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
474 | lib_ring_buffer_free(buf); | |
475 | kfree(buf); | |
476 | } | |
477 | } | |
478 | ||
479 | /** | |
480 | * lib_ring_buffer_write - write data to a ring_buffer buffer. | |
481 | * @bufb : buffer backend | |
482 | * @offset : offset within the buffer | |
483 | * @src : source address | |
484 | * @len : length to write | |
485 | * @pagecpy : page size copied so far | |
486 | */ | |
487 | void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, | |
bfe529f9 | 488 | const void *src, size_t len, size_t pagecpy) |
f3bc08c5 MD |
489 | { |
490 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 491 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
492 | size_t sbidx, index; |
493 | struct lib_ring_buffer_backend_pages *rpages; | |
494 | unsigned long sb_bindex, id; | |
495 | ||
496 | do { | |
497 | len -= pagecpy; | |
498 | src += pagecpy; | |
499 | offset += pagecpy; | |
500 | sbidx = offset >> chanb->subbuf_size_order; | |
501 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
502 | ||
503 | /* | |
504 | * Underlying layer should never ask for writes across | |
505 | * subbuffers. | |
506 | */ | |
507 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
508 | ||
509 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
510 | id = bufb->buf_wsb[sbidx].id; | |
511 | sb_bindex = subbuffer_id_get_index(config, id); | |
512 | rpages = bufb->array[sb_bindex]; | |
513 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
514 | && subbuffer_id_is_noref(config, id)); | |
515 | lib_ring_buffer_do_copy(config, | |
516 | rpages->p[index].virt | |
517 | + (offset & ~PAGE_MASK), | |
518 | src, pagecpy); | |
519 | } while (unlikely(len != pagecpy)); | |
520 | } | |
521 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); | |
522 | ||
4ea00e4f JD |
523 | |
524 | /** | |
525 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. | |
526 | * @bufb : buffer backend | |
527 | * @offset : offset within the buffer | |
528 | * @c : the byte to write | |
529 | * @len : length to write | |
530 | * @pagecpy : page size copied so far | |
531 | */ | |
532 | void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, | |
533 | size_t offset, | |
bfe529f9 | 534 | int c, size_t len, size_t pagecpy) |
4ea00e4f JD |
535 | { |
536 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 537 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
538 | size_t sbidx, index; |
539 | struct lib_ring_buffer_backend_pages *rpages; | |
540 | unsigned long sb_bindex, id; | |
541 | ||
542 | do { | |
543 | len -= pagecpy; | |
544 | offset += pagecpy; | |
545 | sbidx = offset >> chanb->subbuf_size_order; | |
546 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
547 | ||
548 | /* | |
549 | * Underlying layer should never ask for writes across | |
550 | * subbuffers. | |
551 | */ | |
552 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
553 | ||
554 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
555 | id = bufb->buf_wsb[sbidx].id; | |
556 | sb_bindex = subbuffer_id_get_index(config, id); | |
557 | rpages = bufb->array[sb_bindex]; | |
558 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
559 | && subbuffer_id_is_noref(config, id)); | |
560 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
561 | + (offset & ~PAGE_MASK), | |
562 | c, pagecpy); | |
563 | } while (unlikely(len != pagecpy)); | |
564 | } | |
565 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); | |
566 | ||
16f78f3a MD |
567 | /** |
568 | * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer. | |
569 | * @bufb : buffer backend | |
570 | * @offset : offset within the buffer | |
571 | * @src : source address | |
572 | * @len : length to write | |
573 | * @pagecpy : page size copied so far | |
574 | * @pad : character to use for padding | |
575 | */ | |
576 | void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb, | |
577 | size_t offset, const char *src, size_t len, | |
578 | size_t pagecpy, int pad) | |
579 | { | |
580 | struct channel_backend *chanb = &bufb->chan->backend; | |
581 | const struct lib_ring_buffer_config *config = &chanb->config; | |
582 | size_t sbidx, index; | |
583 | struct lib_ring_buffer_backend_pages *rpages; | |
584 | unsigned long sb_bindex, id; | |
585 | int src_terminated = 0; | |
586 | ||
587 | CHAN_WARN_ON(chanb, !len); | |
588 | offset += pagecpy; | |
589 | do { | |
590 | len -= pagecpy; | |
591 | if (!src_terminated) | |
592 | src += pagecpy; | |
593 | sbidx = offset >> chanb->subbuf_size_order; | |
594 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
595 | ||
596 | /* | |
597 | * Underlying layer should never ask for writes across | |
598 | * subbuffers. | |
599 | */ | |
600 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
601 | ||
602 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
603 | id = bufb->buf_wsb[sbidx].id; | |
604 | sb_bindex = subbuffer_id_get_index(config, id); | |
605 | rpages = bufb->array[sb_bindex]; | |
606 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
607 | && subbuffer_id_is_noref(config, id)); | |
608 | ||
609 | if (likely(!src_terminated)) { | |
610 | size_t count, to_copy; | |
611 | ||
612 | to_copy = pagecpy; | |
613 | if (pagecpy == len) | |
614 | to_copy--; /* Final '\0' */ | |
615 | count = lib_ring_buffer_do_strcpy(config, | |
616 | rpages->p[index].virt | |
617 | + (offset & ~PAGE_MASK), | |
618 | src, to_copy); | |
619 | offset += count; | |
620 | /* Padding */ | |
621 | if (unlikely(count < to_copy)) { | |
622 | size_t pad_len = to_copy - count; | |
623 | ||
624 | /* Next pages will have padding */ | |
625 | src_terminated = 1; | |
626 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
627 | + (offset & ~PAGE_MASK), | |
628 | pad, pad_len); | |
629 | offset += pad_len; | |
630 | } | |
631 | } else { | |
632 | size_t pad_len; | |
633 | ||
634 | pad_len = pagecpy; | |
635 | if (pagecpy == len) | |
636 | pad_len--; /* Final '\0' */ | |
637 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
638 | + (offset & ~PAGE_MASK), | |
639 | pad, pad_len); | |
640 | offset += pad_len; | |
641 | } | |
642 | } while (unlikely(len != pagecpy)); | |
643 | /* Ending '\0' */ | |
644 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
645 | '\0', 1); | |
646 | } | |
647 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy); | |
4ea00e4f JD |
648 | |
649 | /** | |
7b8ea3a5 | 650 | * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. |
4ea00e4f JD |
651 | * @bufb : buffer backend |
652 | * @offset : offset within the buffer | |
653 | * @src : source address | |
654 | * @len : length to write | |
655 | * @pagecpy : page size copied so far | |
656 | * | |
657 | * This function deals with userspace pointers, it should never be called | |
658 | * directly without having the src pointer checked with access_ok() | |
659 | * previously. | |
660 | */ | |
7b8ea3a5 | 661 | void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
4ea00e4f JD |
662 | size_t offset, |
663 | const void __user *src, size_t len, | |
bfe529f9 | 664 | size_t pagecpy) |
4ea00e4f JD |
665 | { |
666 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 667 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
668 | size_t sbidx, index; |
669 | struct lib_ring_buffer_backend_pages *rpages; | |
670 | unsigned long sb_bindex, id; | |
671 | int ret; | |
672 | ||
673 | do { | |
674 | len -= pagecpy; | |
675 | src += pagecpy; | |
676 | offset += pagecpy; | |
677 | sbidx = offset >> chanb->subbuf_size_order; | |
678 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
679 | ||
680 | /* | |
681 | * Underlying layer should never ask for writes across | |
682 | * subbuffers. | |
683 | */ | |
684 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
685 | ||
686 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
687 | id = bufb->buf_wsb[sbidx].id; | |
688 | sb_bindex = subbuffer_id_get_index(config, id); | |
689 | rpages = bufb->array[sb_bindex]; | |
690 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
691 | && subbuffer_id_is_noref(config, id)); | |
7b8ea3a5 | 692 | ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt |
4ea00e4f JD |
693 | + (offset & ~PAGE_MASK), |
694 | src, pagecpy) != 0; | |
695 | if (ret > 0) { | |
696 | offset += (pagecpy - ret); | |
697 | len -= (pagecpy - ret); | |
698 | _lib_ring_buffer_memset(bufb, offset, 0, len, 0); | |
699 | break; /* stop copy */ | |
700 | } | |
701 | } while (unlikely(len != pagecpy)); | |
702 | } | |
7b8ea3a5 | 703 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); |
4ea00e4f | 704 | |
16f78f3a MD |
705 | /** |
706 | * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer. | |
707 | * @bufb : buffer backend | |
708 | * @offset : offset within the buffer | |
709 | * @src : source address | |
710 | * @len : length to write | |
711 | * @pagecpy : page size copied so far | |
712 | * @pad : character to use for padding | |
713 | * | |
714 | * This function deals with userspace pointers, it should never be called | |
715 | * directly without having the src pointer checked with access_ok() | |
716 | * previously. | |
717 | */ | |
718 | void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, | |
719 | size_t offset, const char __user *src, size_t len, | |
720 | size_t pagecpy, int pad) | |
721 | { | |
722 | struct channel_backend *chanb = &bufb->chan->backend; | |
723 | const struct lib_ring_buffer_config *config = &chanb->config; | |
724 | size_t sbidx, index; | |
725 | struct lib_ring_buffer_backend_pages *rpages; | |
726 | unsigned long sb_bindex, id; | |
727 | int src_terminated = 0; | |
728 | ||
729 | offset += pagecpy; | |
730 | do { | |
731 | len -= pagecpy; | |
732 | if (!src_terminated) | |
733 | src += pagecpy; | |
734 | sbidx = offset >> chanb->subbuf_size_order; | |
735 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
736 | ||
737 | /* | |
738 | * Underlying layer should never ask for writes across | |
739 | * subbuffers. | |
740 | */ | |
741 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
742 | ||
743 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
744 | id = bufb->buf_wsb[sbidx].id; | |
745 | sb_bindex = subbuffer_id_get_index(config, id); | |
746 | rpages = bufb->array[sb_bindex]; | |
747 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
748 | && subbuffer_id_is_noref(config, id)); | |
749 | ||
750 | if (likely(!src_terminated)) { | |
751 | size_t count, to_copy; | |
752 | ||
753 | to_copy = pagecpy; | |
754 | if (pagecpy == len) | |
755 | to_copy--; /* Final '\0' */ | |
756 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, | |
757 | rpages->p[index].virt | |
758 | + (offset & ~PAGE_MASK), | |
759 | src, to_copy); | |
760 | offset += count; | |
761 | /* Padding */ | |
762 | if (unlikely(count < to_copy)) { | |
763 | size_t pad_len = to_copy - count; | |
764 | ||
765 | /* Next pages will have padding */ | |
766 | src_terminated = 1; | |
767 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
768 | + (offset & ~PAGE_MASK), | |
769 | pad, pad_len); | |
770 | offset += pad_len; | |
771 | } | |
772 | } else { | |
773 | size_t pad_len; | |
774 | ||
775 | pad_len = pagecpy; | |
776 | if (pagecpy == len) | |
777 | pad_len--; /* Final '\0' */ | |
778 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
779 | + (offset & ~PAGE_MASK), | |
780 | pad, pad_len); | |
781 | offset += pad_len; | |
782 | } | |
783 | } while (unlikely(len != pagecpy)); | |
784 | /* Ending '\0' */ | |
785 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
786 | '\0', 1); | |
787 | } | |
788 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic); | |
789 | ||
f3bc08c5 MD |
790 | /** |
791 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
792 | * @bufb : buffer backend | |
793 | * @offset : offset within the buffer | |
794 | * @dest : destination address | |
795 | * @len : length to copy to destination | |
796 | * | |
797 | * Should be protected by get_subbuf/put_subbuf. | |
798 | * Returns the length copied. | |
799 | */ | |
800 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, | |
801 | void *dest, size_t len) | |
802 | { | |
803 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 804 | const struct lib_ring_buffer_config *config = &chanb->config; |
bfe529f9 | 805 | size_t index, pagecpy, orig_len; |
f3bc08c5 MD |
806 | struct lib_ring_buffer_backend_pages *rpages; |
807 | unsigned long sb_bindex, id; | |
808 | ||
809 | orig_len = len; | |
810 | offset &= chanb->buf_size - 1; | |
811 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
812 | if (unlikely(!len)) | |
813 | return 0; | |
814 | for (;;) { | |
815 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
816 | id = bufb->buf_rsb.id; | |
817 | sb_bindex = subbuffer_id_get_index(config, id); | |
818 | rpages = bufb->array[sb_bindex]; | |
819 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
820 | && subbuffer_id_is_noref(config, id)); | |
821 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), | |
822 | pagecpy); | |
823 | len -= pagecpy; | |
824 | if (likely(!len)) | |
825 | break; | |
826 | dest += pagecpy; | |
827 | offset += pagecpy; | |
828 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
829 | /* | |
830 | * Underlying layer should never ask for reads across | |
831 | * subbuffers. | |
832 | */ | |
833 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
834 | } | |
835 | return orig_len; | |
836 | } | |
837 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); | |
838 | ||
839 | /** | |
840 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace | |
841 | * @bufb : buffer backend | |
842 | * @offset : offset within the buffer | |
843 | * @dest : destination userspace address | |
844 | * @len : length to copy to destination | |
845 | * | |
846 | * Should be protected by get_subbuf/put_subbuf. | |
847 | * access_ok() must have been performed on dest addresses prior to call this | |
848 | * function. | |
849 | * Returns -EFAULT on error, 0 if ok. | |
850 | */ | |
851 | int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, | |
852 | size_t offset, void __user *dest, size_t len) | |
853 | { | |
854 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 855 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 856 | size_t index; |
88dfd899 | 857 | ssize_t pagecpy; |
f3bc08c5 MD |
858 | struct lib_ring_buffer_backend_pages *rpages; |
859 | unsigned long sb_bindex, id; | |
860 | ||
f3bc08c5 MD |
861 | offset &= chanb->buf_size - 1; |
862 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
863 | if (unlikely(!len)) | |
864 | return 0; | |
865 | for (;;) { | |
866 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
867 | id = bufb->buf_rsb.id; | |
868 | sb_bindex = subbuffer_id_get_index(config, id); | |
869 | rpages = bufb->array[sb_bindex]; | |
870 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
871 | && subbuffer_id_is_noref(config, id)); | |
872 | if (__copy_to_user(dest, | |
873 | rpages->p[index].virt + (offset & ~PAGE_MASK), | |
874 | pagecpy)) | |
875 | return -EFAULT; | |
876 | len -= pagecpy; | |
877 | if (likely(!len)) | |
878 | break; | |
879 | dest += pagecpy; | |
880 | offset += pagecpy; | |
881 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
882 | /* | |
883 | * Underlying layer should never ask for reads across | |
884 | * subbuffers. | |
885 | */ | |
886 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
887 | } | |
888 | return 0; | |
889 | } | |
890 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); | |
891 | ||
892 | /** | |
893 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
894 | * @bufb : buffer backend | |
895 | * @offset : offset within the buffer | |
896 | * @dest : destination address | |
897 | * @len : destination's length | |
898 | * | |
61eb4c39 | 899 | * Return string's length, or -EINVAL on error. |
f3bc08c5 | 900 | * Should be protected by get_subbuf/put_subbuf. |
61eb4c39 | 901 | * Destination length should be at least 1 to hold '\0'. |
f3bc08c5 MD |
902 | */ |
903 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, | |
904 | void *dest, size_t len) | |
905 | { | |
906 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 907 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
908 | size_t index; |
909 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; | |
910 | char *str; | |
911 | struct lib_ring_buffer_backend_pages *rpages; | |
912 | unsigned long sb_bindex, id; | |
913 | ||
914 | offset &= chanb->buf_size - 1; | |
915 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
916 | orig_offset = offset; | |
61eb4c39 MD |
917 | if (unlikely(!len)) |
918 | return -EINVAL; | |
f3bc08c5 MD |
919 | for (;;) { |
920 | id = bufb->buf_rsb.id; | |
921 | sb_bindex = subbuffer_id_get_index(config, id); | |
922 | rpages = bufb->array[sb_bindex]; | |
923 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
924 | && subbuffer_id_is_noref(config, id)); | |
925 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); | |
926 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
927 | strpagelen = strnlen(str, pagelen); | |
928 | if (len) { | |
929 | pagecpy = min_t(size_t, len, strpagelen); | |
930 | if (dest) { | |
931 | memcpy(dest, str, pagecpy); | |
932 | dest += pagecpy; | |
933 | } | |
934 | len -= pagecpy; | |
935 | } | |
936 | offset += strpagelen; | |
937 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
938 | if (strpagelen < pagelen) | |
939 | break; | |
940 | /* | |
941 | * Underlying layer should never ask for reads across | |
942 | * subbuffers. | |
943 | */ | |
944 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
945 | } | |
946 | if (dest && len) | |
947 | ((char *)dest)[0] = 0; | |
948 | return offset - orig_offset; | |
949 | } | |
950 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); | |
951 | ||
952 | /** | |
0112cb7b | 953 | * lib_ring_buffer_read_get_pfn - Get a page frame number to read from |
f3bc08c5 MD |
954 | * @bufb : buffer backend |
955 | * @offset : offset within the buffer | |
956 | * @virt : pointer to page address (output) | |
957 | * | |
958 | * Should be protected by get_subbuf/put_subbuf. | |
0112cb7b | 959 | * Returns the pointer to the page frame number unsigned long. |
f3bc08c5 | 960 | */ |
0112cb7b | 961 | unsigned long *lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, |
f3bc08c5 MD |
962 | size_t offset, void ***virt) |
963 | { | |
964 | size_t index; | |
965 | struct lib_ring_buffer_backend_pages *rpages; | |
966 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 967 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
968 | unsigned long sb_bindex, id; |
969 | ||
970 | offset &= chanb->buf_size - 1; | |
971 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
972 | id = bufb->buf_rsb.id; | |
973 | sb_bindex = subbuffer_id_get_index(config, id); | |
974 | rpages = bufb->array[sb_bindex]; | |
975 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
976 | && subbuffer_id_is_noref(config, id)); | |
977 | *virt = &rpages->p[index].virt; | |
0112cb7b | 978 | return &rpages->p[index].pfn; |
f3bc08c5 | 979 | } |
0112cb7b | 980 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn); |
f3bc08c5 MD |
981 | |
982 | /** | |
983 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
984 | * @bufb : buffer backend | |
985 | * @offset : offset within the buffer. | |
986 | * | |
987 | * Return the address where a given offset is located (for read). | |
988 | * Should be used to get the current subbuffer header pointer. Given we know | |
759d02c1 MD |
989 | * it's never on a page boundary, it's safe to read/write directly |
990 | * from/to this address, as long as the read/write is never bigger than a | |
991 | * page size. | |
f3bc08c5 MD |
992 | */ |
993 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, | |
994 | size_t offset) | |
995 | { | |
996 | size_t index; | |
997 | struct lib_ring_buffer_backend_pages *rpages; | |
998 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 999 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1000 | unsigned long sb_bindex, id; |
1001 | ||
1002 | offset &= chanb->buf_size - 1; | |
1003 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1004 | id = bufb->buf_rsb.id; | |
1005 | sb_bindex = subbuffer_id_get_index(config, id); | |
1006 | rpages = bufb->array[sb_bindex]; | |
1007 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1008 | && subbuffer_id_is_noref(config, id)); | |
1009 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1010 | } | |
1011 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); | |
1012 | ||
1013 | /** | |
1014 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
1015 | * @bufb : buffer backend | |
1016 | * @offset : offset within the buffer. | |
1017 | * | |
1018 | * Return the address where a given offset is located. | |
1019 | * Should be used to get the current subbuffer header pointer. Given we know | |
1020 | * it's always at the beginning of a page, it's safe to write directly to this | |
1021 | * address, as long as the write is never bigger than a page size. | |
1022 | */ | |
1023 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, | |
1024 | size_t offset) | |
1025 | { | |
1026 | size_t sbidx, index; | |
1027 | struct lib_ring_buffer_backend_pages *rpages; | |
1028 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1029 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1030 | unsigned long sb_bindex, id; |
1031 | ||
1032 | offset &= chanb->buf_size - 1; | |
1033 | sbidx = offset >> chanb->subbuf_size_order; | |
1034 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1035 | id = bufb->buf_wsb[sbidx].id; | |
1036 | sb_bindex = subbuffer_id_get_index(config, id); | |
1037 | rpages = bufb->array[sb_bindex]; | |
1038 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1039 | && subbuffer_id_is_noref(config, id)); | |
1040 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1041 | } | |
1042 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |