Commit | Line | Data |
---|---|---|
f3bc08c5 MD |
1 | /* |
2 | * ring_buffer_backend.c | |
3 | * | |
4 | * Copyright (C) 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Dual LGPL v2.1/GPL v2 license. | |
7 | */ | |
8 | ||
f3bc08c5 MD |
9 | #include <linux/stddef.h> |
10 | #include <linux/module.h> | |
11 | #include <linux/string.h> | |
12 | #include <linux/bitops.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/errno.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/cpu.h> | |
17 | #include <linux/mm.h> | |
18 | ||
b13f3ebe | 19 | #include "../../wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ |
f3bc08c5 MD |
20 | #include "../../wrapper/ringbuffer/config.h" |
21 | #include "../../wrapper/ringbuffer/backend.h" | |
22 | #include "../../wrapper/ringbuffer/frontend.h" | |
23 | ||
24 | /** | |
25 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
26 | * @config: ring buffer instance configuration | |
27 | * @buf: the buffer struct | |
28 | * @size: total size of the buffer | |
29 | * @num_subbuf: number of subbuffers | |
30 | * @extra_reader_sb: need extra subbuffer for reader | |
31 | */ | |
32 | static | |
33 | int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config, | |
34 | struct lib_ring_buffer_backend *bufb, | |
35 | size_t size, size_t num_subbuf, | |
36 | int extra_reader_sb) | |
37 | { | |
38 | struct channel_backend *chanb = &bufb->chan->backend; | |
39 | unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0; | |
40 | unsigned long subbuf_size, mmap_offset = 0; | |
41 | unsigned long num_subbuf_alloc; | |
42 | struct page **pages; | |
43 | void **virt; | |
44 | unsigned long i; | |
45 | ||
46 | num_pages = size >> PAGE_SHIFT; | |
47 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); | |
48 | subbuf_size = chanb->subbuf_size; | |
49 | num_subbuf_alloc = num_subbuf; | |
50 | ||
51 | if (extra_reader_sb) { | |
52 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ | |
53 | num_subbuf_alloc++; | |
54 | } | |
55 | ||
56 | pages = kmalloc_node(ALIGN(sizeof(*pages) * num_pages, | |
57 | 1 << INTERNODE_CACHE_SHIFT), | |
58 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
59 | if (unlikely(!pages)) | |
60 | goto pages_error; | |
61 | ||
62 | virt = kmalloc_node(ALIGN(sizeof(*virt) * num_pages, | |
63 | 1 << INTERNODE_CACHE_SHIFT), | |
64 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
65 | if (unlikely(!virt)) | |
66 | goto virt_error; | |
67 | ||
68 | bufb->array = kmalloc_node(ALIGN(sizeof(*bufb->array) | |
69 | * num_subbuf_alloc, | |
70 | 1 << INTERNODE_CACHE_SHIFT), | |
71 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
72 | if (unlikely(!bufb->array)) | |
73 | goto array_error; | |
74 | ||
75 | for (i = 0; i < num_pages; i++) { | |
76 | pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)), | |
77 | GFP_KERNEL | __GFP_ZERO, 0); | |
78 | if (unlikely(!pages[i])) | |
79 | goto depopulate; | |
80 | virt[i] = page_address(pages[i]); | |
81 | } | |
82 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; | |
83 | ||
84 | /* Allocate backend pages array elements */ | |
85 | for (i = 0; i < num_subbuf_alloc; i++) { | |
86 | bufb->array[i] = | |
87 | kzalloc_node(ALIGN( | |
88 | sizeof(struct lib_ring_buffer_backend_pages) + | |
89 | sizeof(struct lib_ring_buffer_backend_page) | |
90 | * num_pages_per_subbuf, | |
91 | 1 << INTERNODE_CACHE_SHIFT), | |
92 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
93 | if (!bufb->array[i]) | |
94 | goto free_array; | |
95 | } | |
96 | ||
97 | /* Allocate write-side subbuffer table */ | |
98 | bufb->buf_wsb = kzalloc_node(ALIGN( | |
99 | sizeof(struct lib_ring_buffer_backend_subbuffer) | |
100 | * num_subbuf, | |
101 | 1 << INTERNODE_CACHE_SHIFT), | |
102 | GFP_KERNEL, cpu_to_node(max(bufb->cpu, 0))); | |
103 | if (unlikely(!bufb->buf_wsb)) | |
104 | goto free_array; | |
105 | ||
106 | for (i = 0; i < num_subbuf; i++) | |
107 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
108 | ||
109 | /* Assign read-side subbuffer table */ | |
110 | if (extra_reader_sb) | |
111 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
112 | num_subbuf_alloc - 1); | |
113 | else | |
114 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
115 | ||
116 | /* Assign pages to page index */ | |
117 | for (i = 0; i < num_subbuf_alloc; i++) { | |
118 | for (j = 0; j < num_pages_per_subbuf; j++) { | |
119 | CHAN_WARN_ON(chanb, page_idx > num_pages); | |
120 | bufb->array[i]->p[j].virt = virt[page_idx]; | |
121 | bufb->array[i]->p[j].page = pages[page_idx]; | |
122 | page_idx++; | |
123 | } | |
124 | if (config->output == RING_BUFFER_MMAP) { | |
125 | bufb->array[i]->mmap_offset = mmap_offset; | |
126 | mmap_offset += subbuf_size; | |
127 | } | |
128 | } | |
129 | ||
130 | /* | |
131 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
132 | * will not fault. | |
133 | */ | |
6d2a620c | 134 | wrapper_vmalloc_sync_all(); |
f3bc08c5 MD |
135 | kfree(virt); |
136 | kfree(pages); | |
137 | return 0; | |
138 | ||
139 | free_array: | |
140 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) | |
141 | kfree(bufb->array[i]); | |
142 | depopulate: | |
143 | /* Free all allocated pages */ | |
144 | for (i = 0; (i < num_pages && pages[i]); i++) | |
145 | __free_page(pages[i]); | |
146 | kfree(bufb->array); | |
147 | array_error: | |
148 | kfree(virt); | |
149 | virt_error: | |
150 | kfree(pages); | |
151 | pages_error: | |
152 | return -ENOMEM; | |
153 | } | |
154 | ||
155 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
156 | struct channel_backend *chanb, int cpu) | |
157 | { | |
5a8fd222 | 158 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
159 | |
160 | bufb->chan = container_of(chanb, struct channel, backend); | |
161 | bufb->cpu = cpu; | |
162 | ||
163 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
164 | chanb->num_subbuf, | |
165 | chanb->extra_reader_sb); | |
166 | } | |
167 | ||
168 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) | |
169 | { | |
170 | struct channel_backend *chanb = &bufb->chan->backend; | |
171 | unsigned long i, j, num_subbuf_alloc; | |
172 | ||
173 | num_subbuf_alloc = chanb->num_subbuf; | |
174 | if (chanb->extra_reader_sb) | |
175 | num_subbuf_alloc++; | |
176 | ||
177 | kfree(bufb->buf_wsb); | |
178 | for (i = 0; i < num_subbuf_alloc; i++) { | |
179 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) | |
180 | __free_page(bufb->array[i]->p[j].page); | |
181 | kfree(bufb->array[i]); | |
182 | } | |
183 | kfree(bufb->array); | |
184 | bufb->allocated = 0; | |
185 | } | |
186 | ||
187 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) | |
188 | { | |
189 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 190 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
191 | unsigned long num_subbuf_alloc; |
192 | unsigned int i; | |
193 | ||
194 | num_subbuf_alloc = chanb->num_subbuf; | |
195 | if (chanb->extra_reader_sb) | |
196 | num_subbuf_alloc++; | |
197 | ||
198 | for (i = 0; i < chanb->num_subbuf; i++) | |
199 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
200 | if (chanb->extra_reader_sb) | |
201 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
202 | num_subbuf_alloc - 1); | |
203 | else | |
204 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
205 | ||
206 | for (i = 0; i < num_subbuf_alloc; i++) { | |
207 | /* Don't reset mmap_offset */ | |
208 | v_set(config, &bufb->array[i]->records_commit, 0); | |
209 | v_set(config, &bufb->array[i]->records_unread, 0); | |
210 | bufb->array[i]->data_size = 0; | |
211 | /* Don't reset backend page and virt addresses */ | |
212 | } | |
213 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
214 | v_set(config, &bufb->records_read, 0); | |
215 | } | |
216 | ||
217 | /* | |
218 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
219 | * each buffer when calling channel_backend_reset. | |
220 | */ | |
221 | void channel_backend_reset(struct channel_backend *chanb) | |
222 | { | |
223 | struct channel *chan = container_of(chanb, struct channel, backend); | |
5a8fd222 | 224 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
225 | |
226 | /* | |
227 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
228 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
229 | * priv, notifiers, config, cpumask and name. | |
230 | */ | |
231 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
232 | } | |
233 | ||
234 | #ifdef CONFIG_HOTPLUG_CPU | |
235 | /** | |
236 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback | |
237 | * @nb: notifier block | |
238 | * @action: hotplug action to take | |
239 | * @hcpu: CPU number | |
240 | * | |
241 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
242 | */ | |
243 | static | |
244 | int __cpuinit lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, | |
245 | unsigned long action, | |
246 | void *hcpu) | |
247 | { | |
248 | unsigned int cpu = (unsigned long)hcpu; | |
249 | struct channel_backend *chanb = container_of(nb, struct channel_backend, | |
250 | cpu_hp_notifier); | |
5a8fd222 | 251 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
252 | struct lib_ring_buffer *buf; |
253 | int ret; | |
254 | ||
255 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
256 | ||
257 | switch (action) { | |
258 | case CPU_UP_PREPARE: | |
259 | case CPU_UP_PREPARE_FROZEN: | |
260 | buf = per_cpu_ptr(chanb->buf, cpu); | |
261 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
262 | if (ret) { | |
263 | printk(KERN_ERR | |
264 | "ring_buffer_cpu_hp_callback: cpu %d " | |
265 | "buffer creation failed\n", cpu); | |
266 | return NOTIFY_BAD; | |
267 | } | |
268 | break; | |
269 | case CPU_DEAD: | |
270 | case CPU_DEAD_FROZEN: | |
271 | /* No need to do a buffer switch here, because it will happen | |
272 | * when tracing is stopped, or will be done by switch timer CPU | |
273 | * DEAD callback. */ | |
274 | break; | |
275 | } | |
276 | return NOTIFY_OK; | |
277 | } | |
278 | #endif | |
279 | ||
280 | /** | |
281 | * channel_backend_init - initialize a channel backend | |
282 | * @chanb: channel backend | |
283 | * @name: channel name | |
284 | * @config: client ring buffer configuration | |
285 | * @priv: client private data | |
286 | * @parent: dentry of parent directory, %NULL for root directory | |
287 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
288 | * @num_subbuf: number of sub-buffers (power of 2) | |
289 | * | |
290 | * Returns channel pointer if successful, %NULL otherwise. | |
291 | * | |
292 | * Creates per-cpu channel buffers using the sizes and attributes | |
293 | * specified. The created channel buffer files will be named | |
294 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
295 | * | |
296 | * Called with CPU hotplug disabled. | |
297 | */ | |
298 | int channel_backend_init(struct channel_backend *chanb, | |
299 | const char *name, | |
300 | const struct lib_ring_buffer_config *config, | |
301 | void *priv, size_t subbuf_size, size_t num_subbuf) | |
302 | { | |
303 | struct channel *chan = container_of(chanb, struct channel, backend); | |
304 | unsigned int i; | |
305 | int ret; | |
306 | ||
307 | if (!name) | |
308 | return -EPERM; | |
309 | ||
310 | if (!(subbuf_size && num_subbuf)) | |
311 | return -EPERM; | |
312 | ||
313 | /* Check that the subbuffer size is larger than a page. */ | |
2fb46300 MD |
314 | if (subbuf_size < PAGE_SIZE) |
315 | return -EINVAL; | |
f3bc08c5 MD |
316 | |
317 | /* | |
318 | * Make sure the number of subbuffers and subbuffer size are power of 2. | |
319 | */ | |
863497fa MD |
320 | if (hweight32(subbuf_size) != 1) |
321 | return -EINVAL; | |
322 | if (hweight32(num_subbuf) != 1) | |
323 | return -EINVAL; | |
f3bc08c5 MD |
324 | |
325 | ret = subbuffer_id_check_index(config, num_subbuf); | |
326 | if (ret) | |
327 | return ret; | |
328 | ||
329 | chanb->priv = priv; | |
330 | chanb->buf_size = num_subbuf * subbuf_size; | |
331 | chanb->subbuf_size = subbuf_size; | |
332 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
333 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
334 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
335 | chanb->extra_reader_sb = | |
336 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
337 | chanb->num_subbuf = num_subbuf; | |
338 | strlcpy(chanb->name, name, NAME_MAX); | |
5a8fd222 | 339 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
f3bc08c5 MD |
340 | |
341 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
342 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) | |
343 | return -ENOMEM; | |
344 | } | |
345 | ||
346 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
347 | /* Allocating the buffer per-cpu structures */ | |
348 | chanb->buf = alloc_percpu(struct lib_ring_buffer); | |
349 | if (!chanb->buf) | |
350 | goto free_cpumask; | |
351 | ||
352 | /* | |
353 | * In case of non-hotplug cpu, if the ring-buffer is allocated | |
354 | * in early initcall, it will not be notified of secondary cpus. | |
355 | * In that off case, we need to allocate for all possible cpus. | |
356 | */ | |
357 | #ifdef CONFIG_HOTPLUG_CPU | |
358 | /* | |
359 | * buf->backend.allocated test takes care of concurrent CPU | |
360 | * hotplug. | |
361 | * Priority higher than frontend, so we create the ring buffer | |
362 | * before we start the timer. | |
363 | */ | |
364 | chanb->cpu_hp_notifier.notifier_call = | |
365 | lib_ring_buffer_cpu_hp_callback; | |
366 | chanb->cpu_hp_notifier.priority = 5; | |
367 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
368 | ||
369 | get_online_cpus(); | |
370 | for_each_online_cpu(i) { | |
371 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
372 | chanb, i); | |
373 | if (ret) | |
374 | goto free_bufs; /* cpu hotplug locked */ | |
375 | } | |
376 | put_online_cpus(); | |
377 | #else | |
378 | for_each_possible_cpu(i) { | |
379 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
380 | chanb, i); | |
381 | if (ret) | |
382 | goto free_bufs; /* cpu hotplug locked */ | |
383 | } | |
384 | #endif | |
385 | } else { | |
386 | chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL); | |
387 | if (!chanb->buf) | |
388 | goto free_cpumask; | |
389 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); | |
390 | if (ret) | |
391 | goto free_bufs; | |
392 | } | |
393 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
394 | ||
395 | return 0; | |
396 | ||
397 | free_bufs: | |
398 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
399 | for_each_possible_cpu(i) { | |
400 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
401 | ||
402 | if (!buf->backend.allocated) | |
403 | continue; | |
404 | lib_ring_buffer_free(buf); | |
405 | } | |
406 | #ifdef CONFIG_HOTPLUG_CPU | |
407 | put_online_cpus(); | |
408 | #endif | |
409 | free_percpu(chanb->buf); | |
410 | } else | |
411 | kfree(chanb->buf); | |
412 | free_cpumask: | |
413 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
414 | free_cpumask_var(chanb->cpumask); | |
415 | return -ENOMEM; | |
416 | } | |
417 | ||
418 | /** | |
419 | * channel_backend_unregister_notifiers - unregister notifiers | |
420 | * @chan: the channel | |
421 | * | |
422 | * Holds CPU hotplug. | |
423 | */ | |
424 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) | |
425 | { | |
5a8fd222 | 426 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
427 | |
428 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
429 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
430 | } | |
431 | ||
432 | /** | |
433 | * channel_backend_free - destroy the channel | |
434 | * @chan: the channel | |
435 | * | |
436 | * Destroy all channel buffers and frees the channel. | |
437 | */ | |
438 | void channel_backend_free(struct channel_backend *chanb) | |
439 | { | |
5a8fd222 | 440 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
441 | unsigned int i; |
442 | ||
443 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
444 | for_each_possible_cpu(i) { | |
445 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
446 | ||
447 | if (!buf->backend.allocated) | |
448 | continue; | |
449 | lib_ring_buffer_free(buf); | |
450 | } | |
451 | free_cpumask_var(chanb->cpumask); | |
452 | free_percpu(chanb->buf); | |
453 | } else { | |
454 | struct lib_ring_buffer *buf = chanb->buf; | |
455 | ||
456 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
457 | lib_ring_buffer_free(buf); | |
458 | kfree(buf); | |
459 | } | |
460 | } | |
461 | ||
462 | /** | |
463 | * lib_ring_buffer_write - write data to a ring_buffer buffer. | |
464 | * @bufb : buffer backend | |
465 | * @offset : offset within the buffer | |
466 | * @src : source address | |
467 | * @len : length to write | |
468 | * @pagecpy : page size copied so far | |
469 | */ | |
470 | void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, | |
471 | const void *src, size_t len, ssize_t pagecpy) | |
472 | { | |
473 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 474 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
475 | size_t sbidx, index; |
476 | struct lib_ring_buffer_backend_pages *rpages; | |
477 | unsigned long sb_bindex, id; | |
478 | ||
479 | do { | |
480 | len -= pagecpy; | |
481 | src += pagecpy; | |
482 | offset += pagecpy; | |
483 | sbidx = offset >> chanb->subbuf_size_order; | |
484 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
485 | ||
486 | /* | |
487 | * Underlying layer should never ask for writes across | |
488 | * subbuffers. | |
489 | */ | |
490 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
491 | ||
492 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
493 | id = bufb->buf_wsb[sbidx].id; | |
494 | sb_bindex = subbuffer_id_get_index(config, id); | |
495 | rpages = bufb->array[sb_bindex]; | |
496 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
497 | && subbuffer_id_is_noref(config, id)); | |
498 | lib_ring_buffer_do_copy(config, | |
499 | rpages->p[index].virt | |
500 | + (offset & ~PAGE_MASK), | |
501 | src, pagecpy); | |
502 | } while (unlikely(len != pagecpy)); | |
503 | } | |
504 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); | |
505 | ||
4ea00e4f JD |
506 | |
507 | /** | |
508 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. | |
509 | * @bufb : buffer backend | |
510 | * @offset : offset within the buffer | |
511 | * @c : the byte to write | |
512 | * @len : length to write | |
513 | * @pagecpy : page size copied so far | |
514 | */ | |
515 | void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, | |
516 | size_t offset, | |
517 | int c, size_t len, ssize_t pagecpy) | |
518 | { | |
519 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 520 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
521 | size_t sbidx, index; |
522 | struct lib_ring_buffer_backend_pages *rpages; | |
523 | unsigned long sb_bindex, id; | |
524 | ||
525 | do { | |
526 | len -= pagecpy; | |
527 | offset += pagecpy; | |
528 | sbidx = offset >> chanb->subbuf_size_order; | |
529 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
530 | ||
531 | /* | |
532 | * Underlying layer should never ask for writes across | |
533 | * subbuffers. | |
534 | */ | |
535 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
536 | ||
537 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
538 | id = bufb->buf_wsb[sbidx].id; | |
539 | sb_bindex = subbuffer_id_get_index(config, id); | |
540 | rpages = bufb->array[sb_bindex]; | |
541 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
542 | && subbuffer_id_is_noref(config, id)); | |
543 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
544 | + (offset & ~PAGE_MASK), | |
545 | c, pagecpy); | |
546 | } while (unlikely(len != pagecpy)); | |
547 | } | |
548 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); | |
549 | ||
550 | ||
551 | /** | |
552 | * lib_ring_buffer_copy_from_user - write user data to a ring_buffer buffer. | |
553 | * @bufb : buffer backend | |
554 | * @offset : offset within the buffer | |
555 | * @src : source address | |
556 | * @len : length to write | |
557 | * @pagecpy : page size copied so far | |
558 | * | |
559 | * This function deals with userspace pointers, it should never be called | |
560 | * directly without having the src pointer checked with access_ok() | |
561 | * previously. | |
562 | */ | |
563 | void _lib_ring_buffer_copy_from_user(struct lib_ring_buffer_backend *bufb, | |
564 | size_t offset, | |
565 | const void __user *src, size_t len, | |
566 | ssize_t pagecpy) | |
567 | { | |
568 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 569 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
570 | size_t sbidx, index; |
571 | struct lib_ring_buffer_backend_pages *rpages; | |
572 | unsigned long sb_bindex, id; | |
573 | int ret; | |
574 | ||
575 | do { | |
576 | len -= pagecpy; | |
577 | src += pagecpy; | |
578 | offset += pagecpy; | |
579 | sbidx = offset >> chanb->subbuf_size_order; | |
580 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
581 | ||
582 | /* | |
583 | * Underlying layer should never ask for writes across | |
584 | * subbuffers. | |
585 | */ | |
586 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
587 | ||
588 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
589 | id = bufb->buf_wsb[sbidx].id; | |
590 | sb_bindex = subbuffer_id_get_index(config, id); | |
591 | rpages = bufb->array[sb_bindex]; | |
592 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
593 | && subbuffer_id_is_noref(config, id)); | |
594 | ret = lib_ring_buffer_do_copy_from_user(rpages->p[index].virt | |
595 | + (offset & ~PAGE_MASK), | |
596 | src, pagecpy) != 0; | |
597 | if (ret > 0) { | |
598 | offset += (pagecpy - ret); | |
599 | len -= (pagecpy - ret); | |
600 | _lib_ring_buffer_memset(bufb, offset, 0, len, 0); | |
601 | break; /* stop copy */ | |
602 | } | |
603 | } while (unlikely(len != pagecpy)); | |
604 | } | |
605 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user); | |
606 | ||
f3bc08c5 MD |
607 | /** |
608 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
609 | * @bufb : buffer backend | |
610 | * @offset : offset within the buffer | |
611 | * @dest : destination address | |
612 | * @len : length to copy to destination | |
613 | * | |
614 | * Should be protected by get_subbuf/put_subbuf. | |
615 | * Returns the length copied. | |
616 | */ | |
617 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, | |
618 | void *dest, size_t len) | |
619 | { | |
620 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 621 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
622 | size_t index; |
623 | ssize_t pagecpy, orig_len; | |
624 | struct lib_ring_buffer_backend_pages *rpages; | |
625 | unsigned long sb_bindex, id; | |
626 | ||
627 | orig_len = len; | |
628 | offset &= chanb->buf_size - 1; | |
629 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
630 | if (unlikely(!len)) | |
631 | return 0; | |
632 | for (;;) { | |
633 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
634 | id = bufb->buf_rsb.id; | |
635 | sb_bindex = subbuffer_id_get_index(config, id); | |
636 | rpages = bufb->array[sb_bindex]; | |
637 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
638 | && subbuffer_id_is_noref(config, id)); | |
639 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), | |
640 | pagecpy); | |
641 | len -= pagecpy; | |
642 | if (likely(!len)) | |
643 | break; | |
644 | dest += pagecpy; | |
645 | offset += pagecpy; | |
646 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
647 | /* | |
648 | * Underlying layer should never ask for reads across | |
649 | * subbuffers. | |
650 | */ | |
651 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
652 | } | |
653 | return orig_len; | |
654 | } | |
655 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); | |
656 | ||
657 | /** | |
658 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace | |
659 | * @bufb : buffer backend | |
660 | * @offset : offset within the buffer | |
661 | * @dest : destination userspace address | |
662 | * @len : length to copy to destination | |
663 | * | |
664 | * Should be protected by get_subbuf/put_subbuf. | |
665 | * access_ok() must have been performed on dest addresses prior to call this | |
666 | * function. | |
667 | * Returns -EFAULT on error, 0 if ok. | |
668 | */ | |
669 | int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, | |
670 | size_t offset, void __user *dest, size_t len) | |
671 | { | |
672 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 673 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 674 | size_t index; |
88dfd899 | 675 | ssize_t pagecpy; |
f3bc08c5 MD |
676 | struct lib_ring_buffer_backend_pages *rpages; |
677 | unsigned long sb_bindex, id; | |
678 | ||
f3bc08c5 MD |
679 | offset &= chanb->buf_size - 1; |
680 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
681 | if (unlikely(!len)) | |
682 | return 0; | |
683 | for (;;) { | |
684 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
685 | id = bufb->buf_rsb.id; | |
686 | sb_bindex = subbuffer_id_get_index(config, id); | |
687 | rpages = bufb->array[sb_bindex]; | |
688 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
689 | && subbuffer_id_is_noref(config, id)); | |
690 | if (__copy_to_user(dest, | |
691 | rpages->p[index].virt + (offset & ~PAGE_MASK), | |
692 | pagecpy)) | |
693 | return -EFAULT; | |
694 | len -= pagecpy; | |
695 | if (likely(!len)) | |
696 | break; | |
697 | dest += pagecpy; | |
698 | offset += pagecpy; | |
699 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
700 | /* | |
701 | * Underlying layer should never ask for reads across | |
702 | * subbuffers. | |
703 | */ | |
704 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
705 | } | |
706 | return 0; | |
707 | } | |
708 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); | |
709 | ||
710 | /** | |
711 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
712 | * @bufb : buffer backend | |
713 | * @offset : offset within the buffer | |
714 | * @dest : destination address | |
715 | * @len : destination's length | |
716 | * | |
717 | * return string's length | |
718 | * Should be protected by get_subbuf/put_subbuf. | |
719 | */ | |
720 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, | |
721 | void *dest, size_t len) | |
722 | { | |
723 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 724 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
725 | size_t index; |
726 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; | |
727 | char *str; | |
728 | struct lib_ring_buffer_backend_pages *rpages; | |
729 | unsigned long sb_bindex, id; | |
730 | ||
731 | offset &= chanb->buf_size - 1; | |
732 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
733 | orig_offset = offset; | |
734 | for (;;) { | |
735 | id = bufb->buf_rsb.id; | |
736 | sb_bindex = subbuffer_id_get_index(config, id); | |
737 | rpages = bufb->array[sb_bindex]; | |
738 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
739 | && subbuffer_id_is_noref(config, id)); | |
740 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); | |
741 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
742 | strpagelen = strnlen(str, pagelen); | |
743 | if (len) { | |
744 | pagecpy = min_t(size_t, len, strpagelen); | |
745 | if (dest) { | |
746 | memcpy(dest, str, pagecpy); | |
747 | dest += pagecpy; | |
748 | } | |
749 | len -= pagecpy; | |
750 | } | |
751 | offset += strpagelen; | |
752 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
753 | if (strpagelen < pagelen) | |
754 | break; | |
755 | /* | |
756 | * Underlying layer should never ask for reads across | |
757 | * subbuffers. | |
758 | */ | |
759 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
760 | } | |
761 | if (dest && len) | |
762 | ((char *)dest)[0] = 0; | |
763 | return offset - orig_offset; | |
764 | } | |
765 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); | |
766 | ||
767 | /** | |
768 | * lib_ring_buffer_read_get_page - Get a whole page to read from | |
769 | * @bufb : buffer backend | |
770 | * @offset : offset within the buffer | |
771 | * @virt : pointer to page address (output) | |
772 | * | |
773 | * Should be protected by get_subbuf/put_subbuf. | |
774 | * Returns the pointer to the page struct pointer. | |
775 | */ | |
776 | struct page **lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb, | |
777 | size_t offset, void ***virt) | |
778 | { | |
779 | size_t index; | |
780 | struct lib_ring_buffer_backend_pages *rpages; | |
781 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 782 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
783 | unsigned long sb_bindex, id; |
784 | ||
785 | offset &= chanb->buf_size - 1; | |
786 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
787 | id = bufb->buf_rsb.id; | |
788 | sb_bindex = subbuffer_id_get_index(config, id); | |
789 | rpages = bufb->array[sb_bindex]; | |
790 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
791 | && subbuffer_id_is_noref(config, id)); | |
792 | *virt = &rpages->p[index].virt; | |
793 | return &rpages->p[index].page; | |
794 | } | |
795 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_page); | |
796 | ||
797 | /** | |
798 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
799 | * @bufb : buffer backend | |
800 | * @offset : offset within the buffer. | |
801 | * | |
802 | * Return the address where a given offset is located (for read). | |
803 | * Should be used to get the current subbuffer header pointer. Given we know | |
804 | * it's never on a page boundary, it's safe to write directly to this address, | |
805 | * as long as the write is never bigger than a page size. | |
806 | */ | |
807 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, | |
808 | size_t offset) | |
809 | { | |
810 | size_t index; | |
811 | struct lib_ring_buffer_backend_pages *rpages; | |
812 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 813 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
814 | unsigned long sb_bindex, id; |
815 | ||
816 | offset &= chanb->buf_size - 1; | |
817 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
818 | id = bufb->buf_rsb.id; | |
819 | sb_bindex = subbuffer_id_get_index(config, id); | |
820 | rpages = bufb->array[sb_bindex]; | |
821 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
822 | && subbuffer_id_is_noref(config, id)); | |
823 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
824 | } | |
825 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); | |
826 | ||
827 | /** | |
828 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
829 | * @bufb : buffer backend | |
830 | * @offset : offset within the buffer. | |
831 | * | |
832 | * Return the address where a given offset is located. | |
833 | * Should be used to get the current subbuffer header pointer. Given we know | |
834 | * it's always at the beginning of a page, it's safe to write directly to this | |
835 | * address, as long as the write is never bigger than a page size. | |
836 | */ | |
837 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, | |
838 | size_t offset) | |
839 | { | |
840 | size_t sbidx, index; | |
841 | struct lib_ring_buffer_backend_pages *rpages; | |
842 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 843 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
844 | unsigned long sb_bindex, id; |
845 | ||
846 | offset &= chanb->buf_size - 1; | |
847 | sbidx = offset >> chanb->subbuf_size_order; | |
848 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
849 | id = bufb->buf_wsb[sbidx].id; | |
850 | sb_bindex = subbuffer_id_get_index(config, id); | |
851 | rpages = bufb->array[sb_bindex]; | |
852 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
853 | && subbuffer_id_is_noref(config, id)); | |
854 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
855 | } | |
856 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |