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> | |
9778aa3c | 30 | #include <linux/vmalloc.h> |
f3bc08c5 | 31 | |
b13f3ebe | 32 | #include "../../wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ |
f3bc08c5 MD |
33 | #include "../../wrapper/ringbuffer/config.h" |
34 | #include "../../wrapper/ringbuffer/backend.h" | |
35 | #include "../../wrapper/ringbuffer/frontend.h" | |
36 | ||
37 | /** | |
38 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
39 | * @config: ring buffer instance configuration | |
40 | * @buf: the buffer struct | |
41 | * @size: total size of the buffer | |
42 | * @num_subbuf: number of subbuffers | |
43 | * @extra_reader_sb: need extra subbuffer for reader | |
44 | */ | |
45 | static | |
46 | int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config, | |
47 | struct lib_ring_buffer_backend *bufb, | |
48 | size_t size, size_t num_subbuf, | |
49 | int extra_reader_sb) | |
50 | { | |
51 | struct channel_backend *chanb = &bufb->chan->backend; | |
52 | unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0; | |
53 | unsigned long subbuf_size, mmap_offset = 0; | |
54 | unsigned long num_subbuf_alloc; | |
55 | struct page **pages; | |
56 | void **virt; | |
57 | unsigned long i; | |
58 | ||
59 | num_pages = size >> PAGE_SHIFT; | |
60 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); | |
61 | subbuf_size = chanb->subbuf_size; | |
62 | num_subbuf_alloc = num_subbuf; | |
63 | ||
64 | if (extra_reader_sb) { | |
65 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ | |
66 | num_subbuf_alloc++; | |
67 | } | |
68 | ||
9778aa3c | 69 | pages = vmalloc_node(ALIGN(sizeof(*pages) * num_pages, |
f3bc08c5 | 70 | 1 << INTERNODE_CACHE_SHIFT), |
9778aa3c | 71 | cpu_to_node(max(bufb->cpu, 0))); |
f3bc08c5 MD |
72 | if (unlikely(!pages)) |
73 | goto pages_error; | |
74 | ||
9778aa3c | 75 | virt = vmalloc_node(ALIGN(sizeof(*virt) * num_pages, |
f3bc08c5 | 76 | 1 << INTERNODE_CACHE_SHIFT), |
9778aa3c | 77 | cpu_to_node(max(bufb->cpu, 0))); |
f3bc08c5 MD |
78 | if (unlikely(!virt)) |
79 | goto virt_error; | |
80 | ||
81 | bufb->array = kmalloc_node(ALIGN(sizeof(*bufb->array) | |
82 | * num_subbuf_alloc, | |
83 | 1 << INTERNODE_CACHE_SHIFT), | |
9778aa3c MD |
84 | GFP_KERNEL | __GFP_NOWARN, |
85 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
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)), | |
9778aa3c | 91 | GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 0); |
f3bc08c5 MD |
92 | if (unlikely(!pages[i])) |
93 | goto depopulate; | |
94 | virt[i] = page_address(pages[i]); | |
95 | } | |
96 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; | |
97 | ||
98 | /* Allocate backend pages array elements */ | |
99 | for (i = 0; i < num_subbuf_alloc; i++) { | |
100 | bufb->array[i] = | |
101 | kzalloc_node(ALIGN( | |
102 | sizeof(struct lib_ring_buffer_backend_pages) + | |
103 | sizeof(struct lib_ring_buffer_backend_page) | |
104 | * num_pages_per_subbuf, | |
105 | 1 << INTERNODE_CACHE_SHIFT), | |
9778aa3c MD |
106 | GFP_KERNEL | __GFP_NOWARN, |
107 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
108 | if (!bufb->array[i]) |
109 | goto free_array; | |
110 | } | |
111 | ||
112 | /* Allocate write-side subbuffer table */ | |
113 | bufb->buf_wsb = kzalloc_node(ALIGN( | |
114 | sizeof(struct lib_ring_buffer_backend_subbuffer) | |
115 | * num_subbuf, | |
116 | 1 << INTERNODE_CACHE_SHIFT), | |
9778aa3c MD |
117 | GFP_KERNEL | __GFP_NOWARN, |
118 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
119 | if (unlikely(!bufb->buf_wsb)) |
120 | goto free_array; | |
121 | ||
122 | for (i = 0; i < num_subbuf; i++) | |
123 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
124 | ||
125 | /* Assign read-side subbuffer table */ | |
126 | if (extra_reader_sb) | |
127 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
128 | num_subbuf_alloc - 1); | |
129 | else | |
130 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
131 | ||
132 | /* Assign pages to page index */ | |
133 | for (i = 0; i < num_subbuf_alloc; i++) { | |
134 | for (j = 0; j < num_pages_per_subbuf; j++) { | |
135 | CHAN_WARN_ON(chanb, page_idx > num_pages); | |
136 | bufb->array[i]->p[j].virt = virt[page_idx]; | |
137 | bufb->array[i]->p[j].page = pages[page_idx]; | |
138 | page_idx++; | |
139 | } | |
140 | if (config->output == RING_BUFFER_MMAP) { | |
141 | bufb->array[i]->mmap_offset = mmap_offset; | |
142 | mmap_offset += subbuf_size; | |
143 | } | |
144 | } | |
145 | ||
146 | /* | |
147 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
148 | * will not fault. | |
149 | */ | |
6d2a620c | 150 | wrapper_vmalloc_sync_all(); |
9778aa3c MD |
151 | vfree(virt); |
152 | vfree(pages); | |
f3bc08c5 MD |
153 | return 0; |
154 | ||
155 | free_array: | |
156 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) | |
157 | kfree(bufb->array[i]); | |
158 | depopulate: | |
159 | /* Free all allocated pages */ | |
160 | for (i = 0; (i < num_pages && pages[i]); i++) | |
161 | __free_page(pages[i]); | |
162 | kfree(bufb->array); | |
163 | array_error: | |
9778aa3c | 164 | vfree(virt); |
f3bc08c5 | 165 | virt_error: |
9778aa3c | 166 | vfree(pages); |
f3bc08c5 MD |
167 | pages_error: |
168 | return -ENOMEM; | |
169 | } | |
170 | ||
171 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
172 | struct channel_backend *chanb, int cpu) | |
173 | { | |
5a8fd222 | 174 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
175 | |
176 | bufb->chan = container_of(chanb, struct channel, backend); | |
177 | bufb->cpu = cpu; | |
178 | ||
179 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
180 | chanb->num_subbuf, | |
181 | chanb->extra_reader_sb); | |
182 | } | |
183 | ||
184 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) | |
185 | { | |
186 | struct channel_backend *chanb = &bufb->chan->backend; | |
187 | unsigned long i, j, num_subbuf_alloc; | |
188 | ||
189 | num_subbuf_alloc = chanb->num_subbuf; | |
190 | if (chanb->extra_reader_sb) | |
191 | num_subbuf_alloc++; | |
192 | ||
193 | kfree(bufb->buf_wsb); | |
194 | for (i = 0; i < num_subbuf_alloc; i++) { | |
195 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) | |
196 | __free_page(bufb->array[i]->p[j].page); | |
197 | kfree(bufb->array[i]); | |
198 | } | |
199 | kfree(bufb->array); | |
200 | bufb->allocated = 0; | |
201 | } | |
202 | ||
203 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) | |
204 | { | |
205 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 206 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
207 | unsigned long num_subbuf_alloc; |
208 | unsigned int i; | |
209 | ||
210 | num_subbuf_alloc = chanb->num_subbuf; | |
211 | if (chanb->extra_reader_sb) | |
212 | num_subbuf_alloc++; | |
213 | ||
214 | for (i = 0; i < chanb->num_subbuf; i++) | |
215 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
216 | if (chanb->extra_reader_sb) | |
217 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
218 | num_subbuf_alloc - 1); | |
219 | else | |
220 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
221 | ||
222 | for (i = 0; i < num_subbuf_alloc; i++) { | |
223 | /* Don't reset mmap_offset */ | |
224 | v_set(config, &bufb->array[i]->records_commit, 0); | |
225 | v_set(config, &bufb->array[i]->records_unread, 0); | |
226 | bufb->array[i]->data_size = 0; | |
227 | /* Don't reset backend page and virt addresses */ | |
228 | } | |
229 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
230 | v_set(config, &bufb->records_read, 0); | |
231 | } | |
232 | ||
233 | /* | |
234 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
235 | * each buffer when calling channel_backend_reset. | |
236 | */ | |
237 | void channel_backend_reset(struct channel_backend *chanb) | |
238 | { | |
239 | struct channel *chan = container_of(chanb, struct channel, backend); | |
5a8fd222 | 240 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
241 | |
242 | /* | |
243 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
244 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
245 | * priv, notifiers, config, cpumask and name. | |
246 | */ | |
247 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
248 | } | |
249 | ||
250 | #ifdef CONFIG_HOTPLUG_CPU | |
251 | /** | |
252 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback | |
253 | * @nb: notifier block | |
254 | * @action: hotplug action to take | |
255 | * @hcpu: CPU number | |
256 | * | |
257 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
258 | */ | |
259 | static | |
e8f071d5 | 260 | int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, |
f3bc08c5 MD |
261 | unsigned long action, |
262 | void *hcpu) | |
263 | { | |
264 | unsigned int cpu = (unsigned long)hcpu; | |
265 | struct channel_backend *chanb = container_of(nb, struct channel_backend, | |
266 | cpu_hp_notifier); | |
5a8fd222 | 267 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
268 | struct lib_ring_buffer *buf; |
269 | int ret; | |
270 | ||
271 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
272 | ||
273 | switch (action) { | |
274 | case CPU_UP_PREPARE: | |
275 | case CPU_UP_PREPARE_FROZEN: | |
276 | buf = per_cpu_ptr(chanb->buf, cpu); | |
277 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
278 | if (ret) { | |
279 | printk(KERN_ERR | |
280 | "ring_buffer_cpu_hp_callback: cpu %d " | |
281 | "buffer creation failed\n", cpu); | |
282 | return NOTIFY_BAD; | |
283 | } | |
284 | break; | |
285 | case CPU_DEAD: | |
286 | case CPU_DEAD_FROZEN: | |
287 | /* No need to do a buffer switch here, because it will happen | |
288 | * when tracing is stopped, or will be done by switch timer CPU | |
289 | * DEAD callback. */ | |
290 | break; | |
291 | } | |
292 | return NOTIFY_OK; | |
293 | } | |
294 | #endif | |
295 | ||
296 | /** | |
297 | * channel_backend_init - initialize a channel backend | |
298 | * @chanb: channel backend | |
299 | * @name: channel name | |
300 | * @config: client ring buffer configuration | |
301 | * @priv: client private data | |
302 | * @parent: dentry of parent directory, %NULL for root directory | |
303 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
304 | * @num_subbuf: number of sub-buffers (power of 2) | |
305 | * | |
306 | * Returns channel pointer if successful, %NULL otherwise. | |
307 | * | |
308 | * Creates per-cpu channel buffers using the sizes and attributes | |
309 | * specified. The created channel buffer files will be named | |
310 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
311 | * | |
312 | * Called with CPU hotplug disabled. | |
313 | */ | |
314 | int channel_backend_init(struct channel_backend *chanb, | |
315 | const char *name, | |
316 | const struct lib_ring_buffer_config *config, | |
317 | void *priv, size_t subbuf_size, size_t num_subbuf) | |
318 | { | |
319 | struct channel *chan = container_of(chanb, struct channel, backend); | |
320 | unsigned int i; | |
321 | int ret; | |
322 | ||
323 | if (!name) | |
324 | return -EPERM; | |
325 | ||
f3bc08c5 | 326 | /* Check that the subbuffer size is larger than a page. */ |
2fb46300 MD |
327 | if (subbuf_size < PAGE_SIZE) |
328 | return -EINVAL; | |
f3bc08c5 MD |
329 | |
330 | /* | |
bbda3a00 MD |
331 | * Make sure the number of subbuffers and subbuffer size are |
332 | * power of 2 and nonzero. | |
f3bc08c5 | 333 | */ |
bbda3a00 | 334 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
863497fa | 335 | return -EINVAL; |
bbda3a00 | 336 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
863497fa | 337 | return -EINVAL; |
5140d2b3 MD |
338 | /* |
339 | * Overwrite mode buffers require at least 2 subbuffers per | |
340 | * buffer. | |
341 | */ | |
342 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
343 | return -EINVAL; | |
f3bc08c5 MD |
344 | |
345 | ret = subbuffer_id_check_index(config, num_subbuf); | |
346 | if (ret) | |
347 | return ret; | |
348 | ||
349 | chanb->priv = priv; | |
350 | chanb->buf_size = num_subbuf * subbuf_size; | |
351 | chanb->subbuf_size = subbuf_size; | |
352 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
353 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
354 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
355 | chanb->extra_reader_sb = | |
356 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
357 | chanb->num_subbuf = num_subbuf; | |
358 | strlcpy(chanb->name, name, NAME_MAX); | |
5a8fd222 | 359 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
f3bc08c5 MD |
360 | |
361 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
362 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) | |
363 | return -ENOMEM; | |
364 | } | |
365 | ||
366 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
367 | /* Allocating the buffer per-cpu structures */ | |
368 | chanb->buf = alloc_percpu(struct lib_ring_buffer); | |
369 | if (!chanb->buf) | |
370 | goto free_cpumask; | |
371 | ||
372 | /* | |
373 | * In case of non-hotplug cpu, if the ring-buffer is allocated | |
374 | * in early initcall, it will not be notified of secondary cpus. | |
375 | * In that off case, we need to allocate for all possible cpus. | |
376 | */ | |
377 | #ifdef CONFIG_HOTPLUG_CPU | |
378 | /* | |
379 | * buf->backend.allocated test takes care of concurrent CPU | |
380 | * hotplug. | |
381 | * Priority higher than frontend, so we create the ring buffer | |
382 | * before we start the timer. | |
383 | */ | |
384 | chanb->cpu_hp_notifier.notifier_call = | |
385 | lib_ring_buffer_cpu_hp_callback; | |
386 | chanb->cpu_hp_notifier.priority = 5; | |
387 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
388 | ||
389 | get_online_cpus(); | |
390 | for_each_online_cpu(i) { | |
391 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
392 | chanb, i); | |
393 | if (ret) | |
394 | goto free_bufs; /* cpu hotplug locked */ | |
395 | } | |
396 | put_online_cpus(); | |
397 | #else | |
398 | for_each_possible_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 | #endif | |
405 | } else { | |
406 | chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL); | |
407 | if (!chanb->buf) | |
408 | goto free_cpumask; | |
409 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); | |
410 | if (ret) | |
411 | goto free_bufs; | |
412 | } | |
413 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
414 | ||
415 | return 0; | |
416 | ||
417 | free_bufs: | |
418 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
419 | for_each_possible_cpu(i) { | |
420 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
421 | ||
422 | if (!buf->backend.allocated) | |
423 | continue; | |
424 | lib_ring_buffer_free(buf); | |
425 | } | |
426 | #ifdef CONFIG_HOTPLUG_CPU | |
427 | put_online_cpus(); | |
364754c1 | 428 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); |
f3bc08c5 MD |
429 | #endif |
430 | free_percpu(chanb->buf); | |
431 | } else | |
432 | kfree(chanb->buf); | |
433 | free_cpumask: | |
434 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
435 | free_cpumask_var(chanb->cpumask); | |
436 | return -ENOMEM; | |
437 | } | |
438 | ||
439 | /** | |
440 | * channel_backend_unregister_notifiers - unregister notifiers | |
441 | * @chan: the channel | |
442 | * | |
443 | * Holds CPU hotplug. | |
444 | */ | |
445 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) | |
446 | { | |
5a8fd222 | 447 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
448 | |
449 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
450 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
451 | } | |
452 | ||
453 | /** | |
454 | * channel_backend_free - destroy the channel | |
455 | * @chan: the channel | |
456 | * | |
457 | * Destroy all channel buffers and frees the channel. | |
458 | */ | |
459 | void channel_backend_free(struct channel_backend *chanb) | |
460 | { | |
5a8fd222 | 461 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
462 | unsigned int i; |
463 | ||
464 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
465 | for_each_possible_cpu(i) { | |
466 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
467 | ||
468 | if (!buf->backend.allocated) | |
469 | continue; | |
470 | lib_ring_buffer_free(buf); | |
471 | } | |
472 | free_cpumask_var(chanb->cpumask); | |
473 | free_percpu(chanb->buf); | |
474 | } else { | |
475 | struct lib_ring_buffer *buf = chanb->buf; | |
476 | ||
477 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
478 | lib_ring_buffer_free(buf); | |
479 | kfree(buf); | |
480 | } | |
481 | } | |
482 | ||
483 | /** | |
484 | * lib_ring_buffer_write - write data to a ring_buffer buffer. | |
485 | * @bufb : buffer backend | |
486 | * @offset : offset within the buffer | |
487 | * @src : source address | |
488 | * @len : length to write | |
489 | * @pagecpy : page size copied so far | |
490 | */ | |
491 | void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, | |
bfe529f9 | 492 | const void *src, size_t len, size_t pagecpy) |
f3bc08c5 MD |
493 | { |
494 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 495 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
496 | size_t sbidx, index; |
497 | struct lib_ring_buffer_backend_pages *rpages; | |
498 | unsigned long sb_bindex, id; | |
499 | ||
500 | do { | |
501 | len -= pagecpy; | |
502 | src += pagecpy; | |
503 | offset += pagecpy; | |
504 | sbidx = offset >> chanb->subbuf_size_order; | |
505 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
506 | ||
507 | /* | |
508 | * Underlying layer should never ask for writes across | |
509 | * subbuffers. | |
510 | */ | |
511 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
512 | ||
513 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
514 | id = bufb->buf_wsb[sbidx].id; | |
515 | sb_bindex = subbuffer_id_get_index(config, id); | |
516 | rpages = bufb->array[sb_bindex]; | |
517 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
518 | && subbuffer_id_is_noref(config, id)); | |
519 | lib_ring_buffer_do_copy(config, | |
520 | rpages->p[index].virt | |
521 | + (offset & ~PAGE_MASK), | |
522 | src, pagecpy); | |
523 | } while (unlikely(len != pagecpy)); | |
524 | } | |
525 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); | |
526 | ||
4ea00e4f JD |
527 | |
528 | /** | |
529 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. | |
530 | * @bufb : buffer backend | |
531 | * @offset : offset within the buffer | |
532 | * @c : the byte to write | |
533 | * @len : length to write | |
534 | * @pagecpy : page size copied so far | |
535 | */ | |
536 | void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, | |
537 | size_t offset, | |
bfe529f9 | 538 | int c, size_t len, size_t pagecpy) |
4ea00e4f JD |
539 | { |
540 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 541 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
542 | size_t sbidx, index; |
543 | struct lib_ring_buffer_backend_pages *rpages; | |
544 | unsigned long sb_bindex, id; | |
545 | ||
546 | do { | |
547 | len -= pagecpy; | |
548 | offset += pagecpy; | |
549 | sbidx = offset >> chanb->subbuf_size_order; | |
550 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
551 | ||
552 | /* | |
553 | * Underlying layer should never ask for writes across | |
554 | * subbuffers. | |
555 | */ | |
556 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
557 | ||
558 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
559 | id = bufb->buf_wsb[sbidx].id; | |
560 | sb_bindex = subbuffer_id_get_index(config, id); | |
561 | rpages = bufb->array[sb_bindex]; | |
562 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
563 | && subbuffer_id_is_noref(config, id)); | |
564 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
565 | + (offset & ~PAGE_MASK), | |
566 | c, pagecpy); | |
567 | } while (unlikely(len != pagecpy)); | |
568 | } | |
569 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); | |
570 | ||
16f78f3a MD |
571 | /** |
572 | * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer. | |
573 | * @bufb : buffer backend | |
574 | * @offset : offset within the buffer | |
575 | * @src : source address | |
576 | * @len : length to write | |
577 | * @pagecpy : page size copied so far | |
578 | * @pad : character to use for padding | |
579 | */ | |
580 | void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb, | |
581 | size_t offset, const char *src, size_t len, | |
582 | size_t pagecpy, int pad) | |
583 | { | |
584 | struct channel_backend *chanb = &bufb->chan->backend; | |
585 | const struct lib_ring_buffer_config *config = &chanb->config; | |
586 | size_t sbidx, index; | |
587 | struct lib_ring_buffer_backend_pages *rpages; | |
588 | unsigned long sb_bindex, id; | |
589 | int src_terminated = 0; | |
590 | ||
591 | CHAN_WARN_ON(chanb, !len); | |
592 | offset += pagecpy; | |
593 | do { | |
594 | len -= pagecpy; | |
595 | if (!src_terminated) | |
596 | src += pagecpy; | |
597 | sbidx = offset >> chanb->subbuf_size_order; | |
598 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
599 | ||
600 | /* | |
601 | * Underlying layer should never ask for writes across | |
602 | * subbuffers. | |
603 | */ | |
604 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
605 | ||
606 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
607 | id = bufb->buf_wsb[sbidx].id; | |
608 | sb_bindex = subbuffer_id_get_index(config, id); | |
609 | rpages = bufb->array[sb_bindex]; | |
610 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
611 | && subbuffer_id_is_noref(config, id)); | |
612 | ||
613 | if (likely(!src_terminated)) { | |
614 | size_t count, to_copy; | |
615 | ||
616 | to_copy = pagecpy; | |
617 | if (pagecpy == len) | |
618 | to_copy--; /* Final '\0' */ | |
619 | count = lib_ring_buffer_do_strcpy(config, | |
620 | rpages->p[index].virt | |
621 | + (offset & ~PAGE_MASK), | |
622 | src, to_copy); | |
623 | offset += count; | |
624 | /* Padding */ | |
625 | if (unlikely(count < to_copy)) { | |
626 | size_t pad_len = to_copy - count; | |
627 | ||
628 | /* Next pages will have padding */ | |
629 | src_terminated = 1; | |
630 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
631 | + (offset & ~PAGE_MASK), | |
632 | pad, pad_len); | |
633 | offset += pad_len; | |
634 | } | |
635 | } else { | |
636 | size_t pad_len; | |
637 | ||
638 | pad_len = pagecpy; | |
639 | if (pagecpy == len) | |
640 | pad_len--; /* Final '\0' */ | |
641 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
642 | + (offset & ~PAGE_MASK), | |
643 | pad, pad_len); | |
644 | offset += pad_len; | |
645 | } | |
646 | } while (unlikely(len != pagecpy)); | |
647 | /* Ending '\0' */ | |
648 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
649 | '\0', 1); | |
650 | } | |
651 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy); | |
4ea00e4f JD |
652 | |
653 | /** | |
7b8ea3a5 | 654 | * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. |
4ea00e4f JD |
655 | * @bufb : buffer backend |
656 | * @offset : offset within the buffer | |
657 | * @src : source address | |
658 | * @len : length to write | |
659 | * @pagecpy : page size copied so far | |
660 | * | |
661 | * This function deals with userspace pointers, it should never be called | |
662 | * directly without having the src pointer checked with access_ok() | |
663 | * previously. | |
664 | */ | |
7b8ea3a5 | 665 | void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
4ea00e4f JD |
666 | size_t offset, |
667 | const void __user *src, size_t len, | |
bfe529f9 | 668 | size_t pagecpy) |
4ea00e4f JD |
669 | { |
670 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 671 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
672 | size_t sbidx, index; |
673 | struct lib_ring_buffer_backend_pages *rpages; | |
674 | unsigned long sb_bindex, id; | |
675 | int ret; | |
676 | ||
677 | do { | |
678 | len -= pagecpy; | |
679 | src += pagecpy; | |
680 | offset += pagecpy; | |
681 | sbidx = offset >> chanb->subbuf_size_order; | |
682 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
683 | ||
684 | /* | |
685 | * Underlying layer should never ask for writes across | |
686 | * subbuffers. | |
687 | */ | |
688 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
689 | ||
690 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
691 | id = bufb->buf_wsb[sbidx].id; | |
692 | sb_bindex = subbuffer_id_get_index(config, id); | |
693 | rpages = bufb->array[sb_bindex]; | |
694 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
695 | && subbuffer_id_is_noref(config, id)); | |
7b8ea3a5 | 696 | ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt |
4ea00e4f JD |
697 | + (offset & ~PAGE_MASK), |
698 | src, pagecpy) != 0; | |
699 | if (ret > 0) { | |
6115dd20 | 700 | /* Copy failed. */ |
4ea00e4f JD |
701 | _lib_ring_buffer_memset(bufb, offset, 0, len, 0); |
702 | break; /* stop copy */ | |
703 | } | |
704 | } while (unlikely(len != pagecpy)); | |
705 | } | |
7b8ea3a5 | 706 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); |
4ea00e4f | 707 | |
16f78f3a MD |
708 | /** |
709 | * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer. | |
710 | * @bufb : buffer backend | |
711 | * @offset : offset within the buffer | |
712 | * @src : source address | |
713 | * @len : length to write | |
714 | * @pagecpy : page size copied so far | |
715 | * @pad : character to use for padding | |
716 | * | |
717 | * This function deals with userspace pointers, it should never be called | |
718 | * directly without having the src pointer checked with access_ok() | |
719 | * previously. | |
720 | */ | |
721 | void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, | |
722 | size_t offset, const char __user *src, size_t len, | |
723 | size_t pagecpy, int pad) | |
724 | { | |
725 | struct channel_backend *chanb = &bufb->chan->backend; | |
726 | const struct lib_ring_buffer_config *config = &chanb->config; | |
727 | size_t sbidx, index; | |
728 | struct lib_ring_buffer_backend_pages *rpages; | |
729 | unsigned long sb_bindex, id; | |
730 | int src_terminated = 0; | |
731 | ||
732 | offset += pagecpy; | |
733 | do { | |
734 | len -= pagecpy; | |
735 | if (!src_terminated) | |
736 | src += pagecpy; | |
737 | sbidx = offset >> chanb->subbuf_size_order; | |
738 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
739 | ||
740 | /* | |
741 | * Underlying layer should never ask for writes across | |
742 | * subbuffers. | |
743 | */ | |
744 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
745 | ||
746 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
747 | id = bufb->buf_wsb[sbidx].id; | |
748 | sb_bindex = subbuffer_id_get_index(config, id); | |
749 | rpages = bufb->array[sb_bindex]; | |
750 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
751 | && subbuffer_id_is_noref(config, id)); | |
752 | ||
753 | if (likely(!src_terminated)) { | |
754 | size_t count, to_copy; | |
755 | ||
756 | to_copy = pagecpy; | |
757 | if (pagecpy == len) | |
758 | to_copy--; /* Final '\0' */ | |
759 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, | |
760 | rpages->p[index].virt | |
761 | + (offset & ~PAGE_MASK), | |
762 | src, to_copy); | |
763 | offset += count; | |
764 | /* Padding */ | |
765 | if (unlikely(count < to_copy)) { | |
766 | size_t pad_len = to_copy - count; | |
767 | ||
768 | /* Next pages will have padding */ | |
769 | src_terminated = 1; | |
770 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
771 | + (offset & ~PAGE_MASK), | |
772 | pad, pad_len); | |
773 | offset += pad_len; | |
774 | } | |
775 | } else { | |
776 | size_t pad_len; | |
777 | ||
778 | pad_len = pagecpy; | |
779 | if (pagecpy == len) | |
780 | pad_len--; /* Final '\0' */ | |
781 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
782 | + (offset & ~PAGE_MASK), | |
783 | pad, pad_len); | |
784 | offset += pad_len; | |
785 | } | |
786 | } while (unlikely(len != pagecpy)); | |
787 | /* Ending '\0' */ | |
788 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
789 | '\0', 1); | |
790 | } | |
791 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic); | |
792 | ||
f3bc08c5 MD |
793 | /** |
794 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
795 | * @bufb : buffer backend | |
796 | * @offset : offset within the buffer | |
797 | * @dest : destination address | |
798 | * @len : length to copy to destination | |
799 | * | |
800 | * Should be protected by get_subbuf/put_subbuf. | |
801 | * Returns the length copied. | |
802 | */ | |
803 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, | |
804 | void *dest, size_t len) | |
805 | { | |
806 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 807 | const struct lib_ring_buffer_config *config = &chanb->config; |
bfe529f9 | 808 | size_t index, pagecpy, orig_len; |
f3bc08c5 MD |
809 | struct lib_ring_buffer_backend_pages *rpages; |
810 | unsigned long sb_bindex, id; | |
811 | ||
812 | orig_len = len; | |
813 | offset &= chanb->buf_size - 1; | |
814 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
815 | if (unlikely(!len)) | |
816 | return 0; | |
817 | for (;;) { | |
818 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
819 | id = bufb->buf_rsb.id; | |
820 | sb_bindex = subbuffer_id_get_index(config, id); | |
821 | rpages = bufb->array[sb_bindex]; | |
822 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
823 | && subbuffer_id_is_noref(config, id)); | |
824 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), | |
825 | pagecpy); | |
826 | len -= pagecpy; | |
827 | if (likely(!len)) | |
828 | break; | |
829 | dest += pagecpy; | |
830 | offset += pagecpy; | |
831 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
832 | /* | |
833 | * Underlying layer should never ask for reads across | |
834 | * subbuffers. | |
835 | */ | |
836 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
837 | } | |
838 | return orig_len; | |
839 | } | |
840 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); | |
841 | ||
842 | /** | |
843 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace | |
844 | * @bufb : buffer backend | |
845 | * @offset : offset within the buffer | |
846 | * @dest : destination userspace address | |
847 | * @len : length to copy to destination | |
848 | * | |
849 | * Should be protected by get_subbuf/put_subbuf. | |
850 | * access_ok() must have been performed on dest addresses prior to call this | |
851 | * function. | |
852 | * Returns -EFAULT on error, 0 if ok. | |
853 | */ | |
854 | int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, | |
855 | size_t offset, void __user *dest, size_t len) | |
856 | { | |
857 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 858 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 859 | size_t index; |
88dfd899 | 860 | ssize_t pagecpy; |
f3bc08c5 MD |
861 | struct lib_ring_buffer_backend_pages *rpages; |
862 | unsigned long sb_bindex, id; | |
863 | ||
f3bc08c5 MD |
864 | offset &= chanb->buf_size - 1; |
865 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
866 | if (unlikely(!len)) | |
867 | return 0; | |
868 | for (;;) { | |
869 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
870 | id = bufb->buf_rsb.id; | |
871 | sb_bindex = subbuffer_id_get_index(config, id); | |
872 | rpages = bufb->array[sb_bindex]; | |
873 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
874 | && subbuffer_id_is_noref(config, id)); | |
875 | if (__copy_to_user(dest, | |
876 | rpages->p[index].virt + (offset & ~PAGE_MASK), | |
877 | pagecpy)) | |
878 | return -EFAULT; | |
879 | len -= pagecpy; | |
880 | if (likely(!len)) | |
881 | break; | |
882 | dest += pagecpy; | |
883 | offset += pagecpy; | |
884 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
885 | /* | |
886 | * Underlying layer should never ask for reads across | |
887 | * subbuffers. | |
888 | */ | |
889 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
890 | } | |
891 | return 0; | |
892 | } | |
893 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); | |
894 | ||
895 | /** | |
896 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
897 | * @bufb : buffer backend | |
898 | * @offset : offset within the buffer | |
899 | * @dest : destination address | |
900 | * @len : destination's length | |
901 | * | |
61eb4c39 | 902 | * Return string's length, or -EINVAL on error. |
f3bc08c5 | 903 | * Should be protected by get_subbuf/put_subbuf. |
61eb4c39 | 904 | * Destination length should be at least 1 to hold '\0'. |
f3bc08c5 MD |
905 | */ |
906 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, | |
907 | void *dest, size_t len) | |
908 | { | |
909 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 910 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
911 | size_t index; |
912 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; | |
913 | char *str; | |
914 | struct lib_ring_buffer_backend_pages *rpages; | |
915 | unsigned long sb_bindex, id; | |
916 | ||
917 | offset &= chanb->buf_size - 1; | |
918 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
919 | orig_offset = offset; | |
61eb4c39 MD |
920 | if (unlikely(!len)) |
921 | return -EINVAL; | |
f3bc08c5 MD |
922 | for (;;) { |
923 | id = bufb->buf_rsb.id; | |
924 | sb_bindex = subbuffer_id_get_index(config, id); | |
925 | rpages = bufb->array[sb_bindex]; | |
926 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
927 | && subbuffer_id_is_noref(config, id)); | |
928 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); | |
929 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
930 | strpagelen = strnlen(str, pagelen); | |
931 | if (len) { | |
932 | pagecpy = min_t(size_t, len, strpagelen); | |
933 | if (dest) { | |
934 | memcpy(dest, str, pagecpy); | |
935 | dest += pagecpy; | |
936 | } | |
937 | len -= pagecpy; | |
938 | } | |
939 | offset += strpagelen; | |
940 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
941 | if (strpagelen < pagelen) | |
942 | break; | |
943 | /* | |
944 | * Underlying layer should never ask for reads across | |
945 | * subbuffers. | |
946 | */ | |
947 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
948 | } | |
949 | if (dest && len) | |
950 | ((char *)dest)[0] = 0; | |
951 | return offset - orig_offset; | |
952 | } | |
953 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); | |
954 | ||
955 | /** | |
956 | * lib_ring_buffer_read_get_page - Get a whole page to read from | |
957 | * @bufb : buffer backend | |
958 | * @offset : offset within the buffer | |
959 | * @virt : pointer to page address (output) | |
960 | * | |
961 | * Should be protected by get_subbuf/put_subbuf. | |
962 | * Returns the pointer to the page struct pointer. | |
963 | */ | |
964 | struct page **lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb, | |
965 | size_t offset, void ***virt) | |
966 | { | |
967 | size_t index; | |
968 | struct lib_ring_buffer_backend_pages *rpages; | |
969 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 970 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
971 | unsigned long sb_bindex, id; |
972 | ||
973 | offset &= chanb->buf_size - 1; | |
974 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
975 | id = bufb->buf_rsb.id; | |
976 | sb_bindex = subbuffer_id_get_index(config, id); | |
977 | rpages = bufb->array[sb_bindex]; | |
978 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
979 | && subbuffer_id_is_noref(config, id)); | |
980 | *virt = &rpages->p[index].virt; | |
981 | return &rpages->p[index].page; | |
982 | } | |
983 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_page); | |
984 | ||
985 | /** | |
986 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
987 | * @bufb : buffer backend | |
988 | * @offset : offset within the buffer. | |
989 | * | |
990 | * Return the address where a given offset is located (for read). | |
991 | * Should be used to get the current subbuffer header pointer. Given we know | |
759d02c1 MD |
992 | * it's never on a page boundary, it's safe to read/write directly |
993 | * from/to this address, as long as the read/write is never bigger than a | |
994 | * page size. | |
f3bc08c5 MD |
995 | */ |
996 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, | |
997 | size_t offset) | |
998 | { | |
999 | size_t index; | |
1000 | struct lib_ring_buffer_backend_pages *rpages; | |
1001 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1002 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1003 | unsigned long sb_bindex, id; |
1004 | ||
1005 | offset &= chanb->buf_size - 1; | |
1006 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1007 | id = bufb->buf_rsb.id; | |
1008 | sb_bindex = subbuffer_id_get_index(config, id); | |
1009 | rpages = bufb->array[sb_bindex]; | |
1010 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1011 | && subbuffer_id_is_noref(config, id)); | |
1012 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1013 | } | |
1014 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); | |
1015 | ||
1016 | /** | |
1017 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
1018 | * @bufb : buffer backend | |
1019 | * @offset : offset within the buffer. | |
1020 | * | |
1021 | * Return the address where a given offset is located. | |
1022 | * Should be used to get the current subbuffer header pointer. Given we know | |
1023 | * it's always at the beginning of a page, it's safe to write directly to this | |
1024 | * address, as long as the write is never bigger than a page size. | |
1025 | */ | |
1026 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, | |
1027 | size_t offset) | |
1028 | { | |
1029 | size_t sbidx, index; | |
1030 | struct lib_ring_buffer_backend_pages *rpages; | |
1031 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1032 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1033 | unsigned long sb_bindex, id; |
1034 | ||
1035 | offset &= chanb->buf_size - 1; | |
1036 | sbidx = offset >> chanb->subbuf_size_order; | |
1037 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1038 | id = bufb->buf_wsb[sbidx].id; | |
1039 | sb_bindex = subbuffer_id_get_index(config, id); | |
1040 | rpages = bufb->array[sb_bindex]; | |
1041 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1042 | && subbuffer_id_is_noref(config, id)); | |
1043 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1044 | } | |
1045 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |