Commit | Line | Data |
---|---|---|
9f36eaed MJ |
1 | /* SPDX-License-Identifier: (GPL-2.0 OR LGPL-2.1) |
2 | * | |
f3bc08c5 MD |
3 | * ring_buffer_backend.c |
4 | * | |
886d51a3 | 5 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 MD |
6 | */ |
7 | ||
f3bc08c5 MD |
8 | #include <linux/stddef.h> |
9 | #include <linux/module.h> | |
10 | #include <linux/string.h> | |
11 | #include <linux/bitops.h> | |
12 | #include <linux/delay.h> | |
13 | #include <linux/errno.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/cpu.h> | |
16 | #include <linux/mm.h> | |
df388b78 | 17 | #include <linux/vmalloc.h> |
f3bc08c5 | 18 | |
c075712b MD |
19 | #include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_all() */ |
20 | #include <wrapper/ringbuffer/config.h> | |
21 | #include <wrapper/ringbuffer/backend.h> | |
22 | #include <wrapper/ringbuffer/frontend.h> | |
f3bc08c5 MD |
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; | |
f3bc08c5 MD |
43 | unsigned long i; |
44 | ||
45 | num_pages = size >> PAGE_SHIFT; | |
46 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); | |
47 | subbuf_size = chanb->subbuf_size; | |
48 | num_subbuf_alloc = num_subbuf; | |
49 | ||
50 | if (extra_reader_sb) { | |
51 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ | |
52 | num_subbuf_alloc++; | |
53 | } | |
54 | ||
df388b78 | 55 | pages = vmalloc_node(ALIGN(sizeof(*pages) * num_pages, |
f3bc08c5 | 56 | 1 << INTERNODE_CACHE_SHIFT), |
df388b78 | 57 | cpu_to_node(max(bufb->cpu, 0))); |
f3bc08c5 MD |
58 | if (unlikely(!pages)) |
59 | goto pages_error; | |
60 | ||
48f5e0b5 | 61 | bufb->array = lttng_kvmalloc_node(ALIGN(sizeof(*bufb->array) |
f3bc08c5 MD |
62 | * num_subbuf_alloc, |
63 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
64 | GFP_KERNEL | __GFP_NOWARN, |
65 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
66 | if (unlikely(!bufb->array)) |
67 | goto array_error; | |
68 | ||
69 | for (i = 0; i < num_pages; i++) { | |
70 | pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)), | |
df388b78 | 71 | GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 0); |
f3bc08c5 MD |
72 | if (unlikely(!pages[i])) |
73 | goto depopulate; | |
f3bc08c5 MD |
74 | } |
75 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; | |
76 | ||
77 | /* Allocate backend pages array elements */ | |
78 | for (i = 0; i < num_subbuf_alloc; i++) { | |
79 | bufb->array[i] = | |
48f5e0b5 | 80 | lttng_kvzalloc_node(ALIGN( |
f3bc08c5 MD |
81 | sizeof(struct lib_ring_buffer_backend_pages) + |
82 | sizeof(struct lib_ring_buffer_backend_page) | |
83 | * num_pages_per_subbuf, | |
84 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
85 | GFP_KERNEL | __GFP_NOWARN, |
86 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
87 | if (!bufb->array[i]) |
88 | goto free_array; | |
89 | } | |
90 | ||
91 | /* Allocate write-side subbuffer table */ | |
48f5e0b5 | 92 | bufb->buf_wsb = lttng_kvzalloc_node(ALIGN( |
f3bc08c5 MD |
93 | sizeof(struct lib_ring_buffer_backend_subbuffer) |
94 | * num_subbuf, | |
95 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
96 | GFP_KERNEL | __GFP_NOWARN, |
97 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
98 | if (unlikely(!bufb->buf_wsb)) |
99 | goto free_array; | |
100 | ||
101 | for (i = 0; i < num_subbuf; i++) | |
102 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
103 | ||
104 | /* Assign read-side subbuffer table */ | |
105 | if (extra_reader_sb) | |
106 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
107 | num_subbuf_alloc - 1); | |
108 | else | |
109 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
110 | ||
5b3cf4f9 | 111 | /* Allocate subbuffer packet counter table */ |
48f5e0b5 | 112 | bufb->buf_cnt = lttng_kvzalloc_node(ALIGN( |
5b3cf4f9 JD |
113 | sizeof(struct lib_ring_buffer_backend_counts) |
114 | * num_subbuf, | |
115 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
116 | GFP_KERNEL | __GFP_NOWARN, |
117 | cpu_to_node(max(bufb->cpu, 0))); | |
5b3cf4f9 JD |
118 | if (unlikely(!bufb->buf_cnt)) |
119 | goto free_wsb; | |
120 | ||
f3bc08c5 MD |
121 | /* Assign pages to page index */ |
122 | for (i = 0; i < num_subbuf_alloc; i++) { | |
123 | for (j = 0; j < num_pages_per_subbuf; j++) { | |
124 | CHAN_WARN_ON(chanb, page_idx > num_pages); | |
0112cb7b MD |
125 | bufb->array[i]->p[j].virt = page_address(pages[page_idx]); |
126 | bufb->array[i]->p[j].pfn = page_to_pfn(pages[page_idx]); | |
f3bc08c5 MD |
127 | page_idx++; |
128 | } | |
129 | if (config->output == RING_BUFFER_MMAP) { | |
130 | bufb->array[i]->mmap_offset = mmap_offset; | |
131 | mmap_offset += subbuf_size; | |
132 | } | |
133 | } | |
134 | ||
135 | /* | |
136 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
137 | * will not fault. | |
138 | */ | |
6d2a620c | 139 | wrapper_vmalloc_sync_all(); |
df388b78 | 140 | vfree(pages); |
f3bc08c5 MD |
141 | return 0; |
142 | ||
5b3cf4f9 | 143 | free_wsb: |
48f5e0b5 | 144 | lttng_kvfree(bufb->buf_wsb); |
f3bc08c5 MD |
145 | free_array: |
146 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) | |
48f5e0b5 | 147 | lttng_kvfree(bufb->array[i]); |
f3bc08c5 MD |
148 | depopulate: |
149 | /* Free all allocated pages */ | |
150 | for (i = 0; (i < num_pages && pages[i]); i++) | |
151 | __free_page(pages[i]); | |
48f5e0b5 | 152 | lttng_kvfree(bufb->array); |
f3bc08c5 | 153 | array_error: |
df388b78 | 154 | vfree(pages); |
f3bc08c5 MD |
155 | pages_error: |
156 | return -ENOMEM; | |
157 | } | |
158 | ||
159 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
160 | struct channel_backend *chanb, int cpu) | |
161 | { | |
5a8fd222 | 162 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
163 | |
164 | bufb->chan = container_of(chanb, struct channel, backend); | |
165 | bufb->cpu = cpu; | |
166 | ||
167 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
168 | chanb->num_subbuf, | |
169 | chanb->extra_reader_sb); | |
170 | } | |
171 | ||
172 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) | |
173 | { | |
174 | struct channel_backend *chanb = &bufb->chan->backend; | |
175 | unsigned long i, j, num_subbuf_alloc; | |
176 | ||
177 | num_subbuf_alloc = chanb->num_subbuf; | |
178 | if (chanb->extra_reader_sb) | |
179 | num_subbuf_alloc++; | |
180 | ||
48f5e0b5 MJ |
181 | lttng_kvfree(bufb->buf_wsb); |
182 | lttng_kvfree(bufb->buf_cnt); | |
f3bc08c5 MD |
183 | for (i = 0; i < num_subbuf_alloc; i++) { |
184 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) | |
0112cb7b | 185 | __free_page(pfn_to_page(bufb->array[i]->p[j].pfn)); |
48f5e0b5 | 186 | lttng_kvfree(bufb->array[i]); |
f3bc08c5 | 187 | } |
48f5e0b5 | 188 | lttng_kvfree(bufb->array); |
f3bc08c5 MD |
189 | bufb->allocated = 0; |
190 | } | |
191 | ||
192 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) | |
193 | { | |
194 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 195 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
196 | unsigned long num_subbuf_alloc; |
197 | unsigned int i; | |
198 | ||
199 | num_subbuf_alloc = chanb->num_subbuf; | |
200 | if (chanb->extra_reader_sb) | |
201 | num_subbuf_alloc++; | |
202 | ||
203 | for (i = 0; i < chanb->num_subbuf; i++) | |
204 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
205 | if (chanb->extra_reader_sb) | |
206 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
207 | num_subbuf_alloc - 1); | |
208 | else | |
209 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
210 | ||
211 | for (i = 0; i < num_subbuf_alloc; i++) { | |
212 | /* Don't reset mmap_offset */ | |
213 | v_set(config, &bufb->array[i]->records_commit, 0); | |
214 | v_set(config, &bufb->array[i]->records_unread, 0); | |
215 | bufb->array[i]->data_size = 0; | |
216 | /* Don't reset backend page and virt addresses */ | |
217 | } | |
218 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
219 | v_set(config, &bufb->records_read, 0); | |
220 | } | |
221 | ||
222 | /* | |
223 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
224 | * each buffer when calling channel_backend_reset. | |
225 | */ | |
226 | void channel_backend_reset(struct channel_backend *chanb) | |
227 | { | |
228 | struct channel *chan = container_of(chanb, struct channel, backend); | |
5a8fd222 | 229 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
230 | |
231 | /* | |
232 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
233 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
234 | * priv, notifiers, config, cpumask and name. | |
235 | */ | |
236 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
237 | } | |
238 | ||
1e367326 MD |
239 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
240 | ||
241 | /* | |
242 | * No need to implement a "dead" callback to do a buffer switch here, | |
243 | * because it will happen when tracing is stopped, or will be done by | |
244 | * switch timer CPU DEAD callback. | |
245 | * We don't free buffers when CPU go away, because it would make trace | |
246 | * data vanish, which is unwanted. | |
247 | */ | |
248 | int lttng_cpuhp_rb_backend_prepare(unsigned int cpu, | |
249 | struct lttng_cpuhp_node *node) | |
250 | { | |
251 | struct channel_backend *chanb = container_of(node, | |
252 | struct channel_backend, cpuhp_prepare); | |
253 | const struct lib_ring_buffer_config *config = &chanb->config; | |
254 | struct lib_ring_buffer *buf; | |
255 | int ret; | |
256 | ||
257 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
258 | ||
259 | buf = per_cpu_ptr(chanb->buf, cpu); | |
260 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
261 | if (ret) { | |
262 | printk(KERN_ERR | |
263 | "ring_buffer_cpu_hp_callback: cpu %d " | |
264 | "buffer creation failed\n", cpu); | |
265 | return ret; | |
266 | } | |
267 | return 0; | |
268 | } | |
269 | EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_backend_prepare); | |
270 | ||
271 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
272 | ||
f3bc08c5 | 273 | #ifdef CONFIG_HOTPLUG_CPU |
1e367326 | 274 | |
f3bc08c5 MD |
275 | /** |
276 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback | |
277 | * @nb: notifier block | |
278 | * @action: hotplug action to take | |
279 | * @hcpu: CPU number | |
280 | * | |
281 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
282 | */ | |
283 | static | |
e8f071d5 | 284 | int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, |
f3bc08c5 MD |
285 | unsigned long action, |
286 | void *hcpu) | |
287 | { | |
288 | unsigned int cpu = (unsigned long)hcpu; | |
289 | struct channel_backend *chanb = container_of(nb, struct channel_backend, | |
290 | cpu_hp_notifier); | |
5a8fd222 | 291 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
292 | struct lib_ring_buffer *buf; |
293 | int ret; | |
294 | ||
295 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
296 | ||
297 | switch (action) { | |
298 | case CPU_UP_PREPARE: | |
299 | case CPU_UP_PREPARE_FROZEN: | |
300 | buf = per_cpu_ptr(chanb->buf, cpu); | |
301 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
302 | if (ret) { | |
303 | printk(KERN_ERR | |
304 | "ring_buffer_cpu_hp_callback: cpu %d " | |
305 | "buffer creation failed\n", cpu); | |
306 | return NOTIFY_BAD; | |
307 | } | |
308 | break; | |
309 | case CPU_DEAD: | |
310 | case CPU_DEAD_FROZEN: | |
311 | /* No need to do a buffer switch here, because it will happen | |
312 | * when tracing is stopped, or will be done by switch timer CPU | |
313 | * DEAD callback. */ | |
314 | break; | |
315 | } | |
316 | return NOTIFY_OK; | |
317 | } | |
1e367326 | 318 | |
f3bc08c5 MD |
319 | #endif |
320 | ||
1e367326 MD |
321 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
322 | ||
f3bc08c5 MD |
323 | /** |
324 | * channel_backend_init - initialize a channel backend | |
325 | * @chanb: channel backend | |
326 | * @name: channel name | |
327 | * @config: client ring buffer configuration | |
328 | * @priv: client private data | |
329 | * @parent: dentry of parent directory, %NULL for root directory | |
330 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
331 | * @num_subbuf: number of sub-buffers (power of 2) | |
332 | * | |
333 | * Returns channel pointer if successful, %NULL otherwise. | |
334 | * | |
335 | * Creates per-cpu channel buffers using the sizes and attributes | |
336 | * specified. The created channel buffer files will be named | |
337 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
338 | * | |
339 | * Called with CPU hotplug disabled. | |
340 | */ | |
341 | int channel_backend_init(struct channel_backend *chanb, | |
342 | const char *name, | |
343 | const struct lib_ring_buffer_config *config, | |
344 | void *priv, size_t subbuf_size, size_t num_subbuf) | |
345 | { | |
346 | struct channel *chan = container_of(chanb, struct channel, backend); | |
347 | unsigned int i; | |
348 | int ret; | |
349 | ||
350 | if (!name) | |
351 | return -EPERM; | |
352 | ||
f3bc08c5 | 353 | /* Check that the subbuffer size is larger than a page. */ |
2fb46300 MD |
354 | if (subbuf_size < PAGE_SIZE) |
355 | return -EINVAL; | |
f3bc08c5 MD |
356 | |
357 | /* | |
bbda3a00 MD |
358 | * Make sure the number of subbuffers and subbuffer size are |
359 | * power of 2 and nonzero. | |
f3bc08c5 | 360 | */ |
bbda3a00 | 361 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
863497fa | 362 | return -EINVAL; |
bbda3a00 | 363 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
863497fa | 364 | return -EINVAL; |
5140d2b3 MD |
365 | /* |
366 | * Overwrite mode buffers require at least 2 subbuffers per | |
367 | * buffer. | |
368 | */ | |
369 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
370 | return -EINVAL; | |
f3bc08c5 MD |
371 | |
372 | ret = subbuffer_id_check_index(config, num_subbuf); | |
373 | if (ret) | |
374 | return ret; | |
375 | ||
376 | chanb->priv = priv; | |
377 | chanb->buf_size = num_subbuf * subbuf_size; | |
378 | chanb->subbuf_size = subbuf_size; | |
379 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
380 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
381 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
382 | chanb->extra_reader_sb = | |
383 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
384 | chanb->num_subbuf = num_subbuf; | |
385 | strlcpy(chanb->name, name, NAME_MAX); | |
5a8fd222 | 386 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
f3bc08c5 MD |
387 | |
388 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
389 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) | |
390 | return -ENOMEM; | |
391 | } | |
392 | ||
393 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
394 | /* Allocating the buffer per-cpu structures */ | |
395 | chanb->buf = alloc_percpu(struct lib_ring_buffer); | |
396 | if (!chanb->buf) | |
397 | goto free_cpumask; | |
398 | ||
1e367326 MD |
399 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
400 | chanb->cpuhp_prepare.component = LTTNG_RING_BUFFER_BACKEND; | |
401 | ret = cpuhp_state_add_instance(lttng_rb_hp_prepare, | |
402 | &chanb->cpuhp_prepare.node); | |
403 | if (ret) | |
404 | goto free_bufs; | |
405 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
406 | ||
407 | { | |
408 | /* | |
409 | * In case of non-hotplug cpu, if the ring-buffer is allocated | |
410 | * in early initcall, it will not be notified of secondary cpus. | |
411 | * In that off case, we need to allocate for all possible cpus. | |
412 | */ | |
f3bc08c5 | 413 | #ifdef CONFIG_HOTPLUG_CPU |
1e367326 MD |
414 | /* |
415 | * buf->backend.allocated test takes care of concurrent CPU | |
416 | * hotplug. | |
417 | * Priority higher than frontend, so we create the ring buffer | |
418 | * before we start the timer. | |
419 | */ | |
420 | chanb->cpu_hp_notifier.notifier_call = | |
421 | lib_ring_buffer_cpu_hp_callback; | |
422 | chanb->cpu_hp_notifier.priority = 5; | |
423 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
424 | ||
425 | get_online_cpus(); | |
426 | for_each_online_cpu(i) { | |
427 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
428 | chanb, i); | |
429 | if (ret) | |
430 | goto free_bufs; /* cpu hotplug locked */ | |
431 | } | |
432 | put_online_cpus(); | |
f3bc08c5 | 433 | #else |
1e367326 MD |
434 | for_each_possible_cpu(i) { |
435 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
436 | chanb, i); | |
437 | if (ret) | |
438 | goto free_bufs; | |
439 | } | |
f3bc08c5 | 440 | #endif |
1e367326 MD |
441 | } |
442 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 MD |
443 | } else { |
444 | chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL); | |
445 | if (!chanb->buf) | |
446 | goto free_cpumask; | |
447 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); | |
448 | if (ret) | |
449 | goto free_bufs; | |
450 | } | |
451 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
452 | ||
453 | return 0; | |
454 | ||
455 | free_bufs: | |
456 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
1e367326 | 457 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
5f14d8ae MD |
458 | /* |
459 | * Teardown of lttng_rb_hp_prepare instance | |
460 | * on "add" error is handled within cpu hotplug, | |
461 | * no teardown to do from the caller. | |
462 | */ | |
1e367326 MD |
463 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
464 | #ifdef CONFIG_HOTPLUG_CPU | |
465 | put_online_cpus(); | |
466 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
467 | #endif | |
468 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 | 469 | for_each_possible_cpu(i) { |
1e367326 MD |
470 | struct lib_ring_buffer *buf = |
471 | per_cpu_ptr(chanb->buf, i); | |
f3bc08c5 MD |
472 | |
473 | if (!buf->backend.allocated) | |
474 | continue; | |
475 | lib_ring_buffer_free(buf); | |
476 | } | |
f3bc08c5 MD |
477 | free_percpu(chanb->buf); |
478 | } else | |
479 | kfree(chanb->buf); | |
480 | free_cpumask: | |
481 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
482 | free_cpumask_var(chanb->cpumask); | |
483 | return -ENOMEM; | |
484 | } | |
485 | ||
486 | /** | |
487 | * channel_backend_unregister_notifiers - unregister notifiers | |
488 | * @chan: the channel | |
489 | * | |
490 | * Holds CPU hotplug. | |
491 | */ | |
492 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) | |
493 | { | |
5a8fd222 | 494 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 495 | |
1e367326 MD |
496 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
497 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) | |
498 | int ret; | |
499 | ||
500 | ret = cpuhp_state_remove_instance(lttng_rb_hp_prepare, | |
501 | &chanb->cpuhp_prepare.node); | |
502 | WARN_ON(ret); | |
503 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 | 504 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); |
1e367326 MD |
505 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
506 | } | |
f3bc08c5 MD |
507 | } |
508 | ||
509 | /** | |
510 | * channel_backend_free - destroy the channel | |
511 | * @chan: the channel | |
512 | * | |
513 | * Destroy all channel buffers and frees the channel. | |
514 | */ | |
515 | void channel_backend_free(struct channel_backend *chanb) | |
516 | { | |
5a8fd222 | 517 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
518 | unsigned int i; |
519 | ||
520 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
521 | for_each_possible_cpu(i) { | |
522 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
523 | ||
524 | if (!buf->backend.allocated) | |
525 | continue; | |
526 | lib_ring_buffer_free(buf); | |
527 | } | |
528 | free_cpumask_var(chanb->cpumask); | |
529 | free_percpu(chanb->buf); | |
530 | } else { | |
531 | struct lib_ring_buffer *buf = chanb->buf; | |
532 | ||
533 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
534 | lib_ring_buffer_free(buf); | |
535 | kfree(buf); | |
536 | } | |
537 | } | |
538 | ||
539 | /** | |
540 | * lib_ring_buffer_write - write data to a ring_buffer buffer. | |
541 | * @bufb : buffer backend | |
542 | * @offset : offset within the buffer | |
543 | * @src : source address | |
544 | * @len : length to write | |
545 | * @pagecpy : page size copied so far | |
546 | */ | |
547 | void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, | |
bfe529f9 | 548 | const void *src, size_t len, size_t pagecpy) |
f3bc08c5 MD |
549 | { |
550 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 551 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
552 | size_t sbidx, index; |
553 | struct lib_ring_buffer_backend_pages *rpages; | |
554 | unsigned long sb_bindex, id; | |
555 | ||
556 | do { | |
557 | len -= pagecpy; | |
558 | src += pagecpy; | |
559 | offset += pagecpy; | |
560 | sbidx = offset >> chanb->subbuf_size_order; | |
561 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
562 | ||
563 | /* | |
564 | * Underlying layer should never ask for writes across | |
565 | * subbuffers. | |
566 | */ | |
567 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
568 | ||
569 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
570 | id = bufb->buf_wsb[sbidx].id; | |
571 | sb_bindex = subbuffer_id_get_index(config, id); | |
572 | rpages = bufb->array[sb_bindex]; | |
573 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
574 | && subbuffer_id_is_noref(config, id)); | |
575 | lib_ring_buffer_do_copy(config, | |
576 | rpages->p[index].virt | |
577 | + (offset & ~PAGE_MASK), | |
578 | src, pagecpy); | |
579 | } while (unlikely(len != pagecpy)); | |
580 | } | |
581 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); | |
582 | ||
4ea00e4f JD |
583 | |
584 | /** | |
585 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. | |
586 | * @bufb : buffer backend | |
587 | * @offset : offset within the buffer | |
588 | * @c : the byte to write | |
589 | * @len : length to write | |
590 | * @pagecpy : page size copied so far | |
591 | */ | |
592 | void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, | |
593 | size_t offset, | |
bfe529f9 | 594 | int c, size_t len, size_t pagecpy) |
4ea00e4f JD |
595 | { |
596 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 597 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
598 | size_t sbidx, index; |
599 | struct lib_ring_buffer_backend_pages *rpages; | |
600 | unsigned long sb_bindex, id; | |
601 | ||
602 | do { | |
603 | len -= pagecpy; | |
604 | offset += pagecpy; | |
605 | sbidx = offset >> chanb->subbuf_size_order; | |
606 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
607 | ||
608 | /* | |
609 | * Underlying layer should never ask for writes across | |
610 | * subbuffers. | |
611 | */ | |
612 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
613 | ||
614 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
615 | id = bufb->buf_wsb[sbidx].id; | |
616 | sb_bindex = subbuffer_id_get_index(config, id); | |
617 | rpages = bufb->array[sb_bindex]; | |
618 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
619 | && subbuffer_id_is_noref(config, id)); | |
620 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
621 | + (offset & ~PAGE_MASK), | |
622 | c, pagecpy); | |
623 | } while (unlikely(len != pagecpy)); | |
624 | } | |
625 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); | |
626 | ||
16f78f3a MD |
627 | /** |
628 | * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer. | |
629 | * @bufb : buffer backend | |
630 | * @offset : offset within the buffer | |
631 | * @src : source address | |
632 | * @len : length to write | |
633 | * @pagecpy : page size copied so far | |
634 | * @pad : character to use for padding | |
635 | */ | |
636 | void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb, | |
637 | size_t offset, const char *src, size_t len, | |
638 | size_t pagecpy, int pad) | |
639 | { | |
640 | struct channel_backend *chanb = &bufb->chan->backend; | |
641 | const struct lib_ring_buffer_config *config = &chanb->config; | |
642 | size_t sbidx, index; | |
643 | struct lib_ring_buffer_backend_pages *rpages; | |
644 | unsigned long sb_bindex, id; | |
645 | int src_terminated = 0; | |
646 | ||
647 | CHAN_WARN_ON(chanb, !len); | |
648 | offset += pagecpy; | |
649 | do { | |
650 | len -= pagecpy; | |
651 | if (!src_terminated) | |
652 | src += pagecpy; | |
653 | sbidx = offset >> chanb->subbuf_size_order; | |
654 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
655 | ||
656 | /* | |
657 | * Underlying layer should never ask for writes across | |
658 | * subbuffers. | |
659 | */ | |
660 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
661 | ||
662 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
663 | id = bufb->buf_wsb[sbidx].id; | |
664 | sb_bindex = subbuffer_id_get_index(config, id); | |
665 | rpages = bufb->array[sb_bindex]; | |
666 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
667 | && subbuffer_id_is_noref(config, id)); | |
668 | ||
669 | if (likely(!src_terminated)) { | |
670 | size_t count, to_copy; | |
671 | ||
672 | to_copy = pagecpy; | |
673 | if (pagecpy == len) | |
674 | to_copy--; /* Final '\0' */ | |
675 | count = lib_ring_buffer_do_strcpy(config, | |
676 | rpages->p[index].virt | |
677 | + (offset & ~PAGE_MASK), | |
678 | src, to_copy); | |
679 | offset += count; | |
680 | /* Padding */ | |
681 | if (unlikely(count < to_copy)) { | |
682 | size_t pad_len = to_copy - count; | |
683 | ||
684 | /* Next pages will have padding */ | |
685 | src_terminated = 1; | |
686 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
687 | + (offset & ~PAGE_MASK), | |
688 | pad, pad_len); | |
689 | offset += pad_len; | |
690 | } | |
691 | } else { | |
692 | size_t pad_len; | |
693 | ||
694 | pad_len = pagecpy; | |
695 | if (pagecpy == len) | |
696 | pad_len--; /* Final '\0' */ | |
697 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
698 | + (offset & ~PAGE_MASK), | |
699 | pad, pad_len); | |
700 | offset += pad_len; | |
701 | } | |
702 | } while (unlikely(len != pagecpy)); | |
703 | /* Ending '\0' */ | |
704 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
705 | '\0', 1); | |
706 | } | |
707 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy); | |
4ea00e4f JD |
708 | |
709 | /** | |
7b8ea3a5 | 710 | * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. |
4ea00e4f JD |
711 | * @bufb : buffer backend |
712 | * @offset : offset within the buffer | |
713 | * @src : source address | |
714 | * @len : length to write | |
715 | * @pagecpy : page size copied so far | |
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 | */ | |
7b8ea3a5 | 721 | void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
4ea00e4f JD |
722 | size_t offset, |
723 | const void __user *src, size_t len, | |
bfe529f9 | 724 | size_t pagecpy) |
4ea00e4f JD |
725 | { |
726 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 727 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
728 | size_t sbidx, index; |
729 | struct lib_ring_buffer_backend_pages *rpages; | |
730 | unsigned long sb_bindex, id; | |
731 | int ret; | |
732 | ||
733 | do { | |
734 | len -= pagecpy; | |
735 | src += pagecpy; | |
736 | offset += 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)); | |
7b8ea3a5 | 752 | ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt |
4ea00e4f JD |
753 | + (offset & ~PAGE_MASK), |
754 | src, pagecpy) != 0; | |
755 | if (ret > 0) { | |
d87a9f03 | 756 | /* Copy failed. */ |
4ea00e4f JD |
757 | _lib_ring_buffer_memset(bufb, offset, 0, len, 0); |
758 | break; /* stop copy */ | |
759 | } | |
760 | } while (unlikely(len != pagecpy)); | |
761 | } | |
7b8ea3a5 | 762 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); |
4ea00e4f | 763 | |
16f78f3a MD |
764 | /** |
765 | * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer. | |
766 | * @bufb : buffer backend | |
767 | * @offset : offset within the buffer | |
768 | * @src : source address | |
769 | * @len : length to write | |
770 | * @pagecpy : page size copied so far | |
771 | * @pad : character to use for padding | |
772 | * | |
773 | * This function deals with userspace pointers, it should never be called | |
774 | * directly without having the src pointer checked with access_ok() | |
775 | * previously. | |
776 | */ | |
777 | void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, | |
778 | size_t offset, const char __user *src, size_t len, | |
779 | size_t pagecpy, int pad) | |
780 | { | |
781 | struct channel_backend *chanb = &bufb->chan->backend; | |
782 | const struct lib_ring_buffer_config *config = &chanb->config; | |
783 | size_t sbidx, index; | |
784 | struct lib_ring_buffer_backend_pages *rpages; | |
785 | unsigned long sb_bindex, id; | |
786 | int src_terminated = 0; | |
787 | ||
788 | offset += pagecpy; | |
789 | do { | |
790 | len -= pagecpy; | |
791 | if (!src_terminated) | |
792 | src += pagecpy; | |
793 | sbidx = offset >> chanb->subbuf_size_order; | |
794 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
795 | ||
796 | /* | |
797 | * Underlying layer should never ask for writes across | |
798 | * subbuffers. | |
799 | */ | |
800 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
801 | ||
802 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
803 | id = bufb->buf_wsb[sbidx].id; | |
804 | sb_bindex = subbuffer_id_get_index(config, id); | |
805 | rpages = bufb->array[sb_bindex]; | |
806 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
807 | && subbuffer_id_is_noref(config, id)); | |
808 | ||
809 | if (likely(!src_terminated)) { | |
810 | size_t count, to_copy; | |
811 | ||
812 | to_copy = pagecpy; | |
813 | if (pagecpy == len) | |
814 | to_copy--; /* Final '\0' */ | |
815 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, | |
816 | rpages->p[index].virt | |
817 | + (offset & ~PAGE_MASK), | |
818 | src, to_copy); | |
819 | offset += count; | |
820 | /* Padding */ | |
821 | if (unlikely(count < to_copy)) { | |
822 | size_t pad_len = to_copy - count; | |
823 | ||
824 | /* Next pages will have padding */ | |
825 | src_terminated = 1; | |
826 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
827 | + (offset & ~PAGE_MASK), | |
828 | pad, pad_len); | |
829 | offset += pad_len; | |
830 | } | |
831 | } else { | |
832 | size_t pad_len; | |
833 | ||
834 | pad_len = pagecpy; | |
835 | if (pagecpy == len) | |
836 | pad_len--; /* Final '\0' */ | |
837 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
838 | + (offset & ~PAGE_MASK), | |
839 | pad, pad_len); | |
840 | offset += pad_len; | |
841 | } | |
842 | } while (unlikely(len != pagecpy)); | |
843 | /* Ending '\0' */ | |
844 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
845 | '\0', 1); | |
846 | } | |
847 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic); | |
848 | ||
f3bc08c5 MD |
849 | /** |
850 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
851 | * @bufb : buffer backend | |
852 | * @offset : offset within the buffer | |
853 | * @dest : destination address | |
854 | * @len : length to copy to destination | |
855 | * | |
856 | * Should be protected by get_subbuf/put_subbuf. | |
857 | * Returns the length copied. | |
858 | */ | |
859 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, | |
860 | void *dest, size_t len) | |
861 | { | |
862 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 863 | const struct lib_ring_buffer_config *config = &chanb->config; |
bfe529f9 | 864 | size_t index, pagecpy, orig_len; |
f3bc08c5 MD |
865 | struct lib_ring_buffer_backend_pages *rpages; |
866 | unsigned long sb_bindex, id; | |
867 | ||
868 | orig_len = len; | |
869 | offset &= chanb->buf_size - 1; | |
870 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
871 | if (unlikely(!len)) | |
872 | return 0; | |
873 | for (;;) { | |
874 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
875 | id = bufb->buf_rsb.id; | |
876 | sb_bindex = subbuffer_id_get_index(config, id); | |
877 | rpages = bufb->array[sb_bindex]; | |
878 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
879 | && subbuffer_id_is_noref(config, id)); | |
880 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), | |
881 | pagecpy); | |
882 | len -= pagecpy; | |
883 | if (likely(!len)) | |
884 | break; | |
885 | dest += pagecpy; | |
886 | offset += pagecpy; | |
887 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
888 | /* | |
889 | * Underlying layer should never ask for reads across | |
890 | * subbuffers. | |
891 | */ | |
892 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
893 | } | |
894 | return orig_len; | |
895 | } | |
896 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); | |
897 | ||
898 | /** | |
899 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace | |
900 | * @bufb : buffer backend | |
901 | * @offset : offset within the buffer | |
902 | * @dest : destination userspace address | |
903 | * @len : length to copy to destination | |
904 | * | |
905 | * Should be protected by get_subbuf/put_subbuf. | |
906 | * access_ok() must have been performed on dest addresses prior to call this | |
907 | * function. | |
908 | * Returns -EFAULT on error, 0 if ok. | |
909 | */ | |
910 | int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, | |
911 | size_t offset, void __user *dest, size_t len) | |
912 | { | |
913 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 914 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 915 | size_t index; |
88dfd899 | 916 | ssize_t pagecpy; |
f3bc08c5 MD |
917 | struct lib_ring_buffer_backend_pages *rpages; |
918 | unsigned long sb_bindex, id; | |
919 | ||
f3bc08c5 MD |
920 | offset &= chanb->buf_size - 1; |
921 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
922 | if (unlikely(!len)) | |
923 | return 0; | |
924 | for (;;) { | |
925 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
926 | id = bufb->buf_rsb.id; | |
927 | sb_bindex = subbuffer_id_get_index(config, id); | |
928 | rpages = bufb->array[sb_bindex]; | |
929 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
930 | && subbuffer_id_is_noref(config, id)); | |
931 | if (__copy_to_user(dest, | |
932 | rpages->p[index].virt + (offset & ~PAGE_MASK), | |
933 | pagecpy)) | |
934 | return -EFAULT; | |
935 | len -= pagecpy; | |
936 | if (likely(!len)) | |
937 | break; | |
938 | dest += pagecpy; | |
939 | offset += pagecpy; | |
940 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
941 | /* | |
942 | * Underlying layer should never ask for reads across | |
943 | * subbuffers. | |
944 | */ | |
945 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
946 | } | |
947 | return 0; | |
948 | } | |
949 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); | |
950 | ||
951 | /** | |
952 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
953 | * @bufb : buffer backend | |
954 | * @offset : offset within the buffer | |
955 | * @dest : destination address | |
956 | * @len : destination's length | |
957 | * | |
61eb4c39 | 958 | * Return string's length, or -EINVAL on error. |
f3bc08c5 | 959 | * Should be protected by get_subbuf/put_subbuf. |
61eb4c39 | 960 | * Destination length should be at least 1 to hold '\0'. |
f3bc08c5 MD |
961 | */ |
962 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, | |
963 | void *dest, size_t len) | |
964 | { | |
965 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 966 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
967 | size_t index; |
968 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; | |
969 | char *str; | |
970 | struct lib_ring_buffer_backend_pages *rpages; | |
971 | unsigned long sb_bindex, id; | |
972 | ||
973 | offset &= chanb->buf_size - 1; | |
974 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
975 | orig_offset = offset; | |
61eb4c39 MD |
976 | if (unlikely(!len)) |
977 | return -EINVAL; | |
f3bc08c5 MD |
978 | for (;;) { |
979 | id = bufb->buf_rsb.id; | |
980 | sb_bindex = subbuffer_id_get_index(config, id); | |
981 | rpages = bufb->array[sb_bindex]; | |
982 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
983 | && subbuffer_id_is_noref(config, id)); | |
984 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); | |
985 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
986 | strpagelen = strnlen(str, pagelen); | |
987 | if (len) { | |
988 | pagecpy = min_t(size_t, len, strpagelen); | |
989 | if (dest) { | |
990 | memcpy(dest, str, pagecpy); | |
991 | dest += pagecpy; | |
992 | } | |
993 | len -= pagecpy; | |
994 | } | |
995 | offset += strpagelen; | |
996 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
997 | if (strpagelen < pagelen) | |
998 | break; | |
999 | /* | |
1000 | * Underlying layer should never ask for reads across | |
1001 | * subbuffers. | |
1002 | */ | |
1003 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
1004 | } | |
1005 | if (dest && len) | |
1006 | ((char *)dest)[0] = 0; | |
1007 | return offset - orig_offset; | |
1008 | } | |
1009 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); | |
1010 | ||
1011 | /** | |
0112cb7b | 1012 | * lib_ring_buffer_read_get_pfn - Get a page frame number to read from |
f3bc08c5 MD |
1013 | * @bufb : buffer backend |
1014 | * @offset : offset within the buffer | |
1015 | * @virt : pointer to page address (output) | |
1016 | * | |
1017 | * Should be protected by get_subbuf/put_subbuf. | |
0112cb7b | 1018 | * Returns the pointer to the page frame number unsigned long. |
f3bc08c5 | 1019 | */ |
0112cb7b | 1020 | unsigned long *lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, |
f3bc08c5 MD |
1021 | size_t offset, void ***virt) |
1022 | { | |
1023 | size_t index; | |
1024 | struct lib_ring_buffer_backend_pages *rpages; | |
1025 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1026 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1027 | unsigned long sb_bindex, id; |
1028 | ||
1029 | offset &= chanb->buf_size - 1; | |
1030 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1031 | id = bufb->buf_rsb.id; | |
1032 | sb_bindex = subbuffer_id_get_index(config, id); | |
1033 | rpages = bufb->array[sb_bindex]; | |
1034 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1035 | && subbuffer_id_is_noref(config, id)); | |
1036 | *virt = &rpages->p[index].virt; | |
0112cb7b | 1037 | return &rpages->p[index].pfn; |
f3bc08c5 | 1038 | } |
0112cb7b | 1039 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn); |
f3bc08c5 MD |
1040 | |
1041 | /** | |
1042 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
1043 | * @bufb : buffer backend | |
1044 | * @offset : offset within the buffer. | |
1045 | * | |
1046 | * Return the address where a given offset is located (for read). | |
1047 | * Should be used to get the current subbuffer header pointer. Given we know | |
759d02c1 MD |
1048 | * it's never on a page boundary, it's safe to read/write directly |
1049 | * from/to this address, as long as the read/write is never bigger than a | |
1050 | * page size. | |
f3bc08c5 MD |
1051 | */ |
1052 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, | |
1053 | size_t offset) | |
1054 | { | |
1055 | size_t index; | |
1056 | struct lib_ring_buffer_backend_pages *rpages; | |
1057 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1058 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1059 | unsigned long sb_bindex, id; |
1060 | ||
1061 | offset &= chanb->buf_size - 1; | |
1062 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1063 | id = bufb->buf_rsb.id; | |
1064 | sb_bindex = subbuffer_id_get_index(config, id); | |
1065 | rpages = bufb->array[sb_bindex]; | |
1066 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1067 | && subbuffer_id_is_noref(config, id)); | |
1068 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1069 | } | |
1070 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); | |
1071 | ||
1072 | /** | |
1073 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
1074 | * @bufb : buffer backend | |
1075 | * @offset : offset within the buffer. | |
1076 | * | |
1077 | * Return the address where a given offset is located. | |
1078 | * Should be used to get the current subbuffer header pointer. Given we know | |
1079 | * it's always at the beginning of a page, it's safe to write directly to this | |
1080 | * address, as long as the write is never bigger than a page size. | |
1081 | */ | |
1082 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, | |
1083 | size_t offset) | |
1084 | { | |
1085 | size_t sbidx, index; | |
1086 | struct lib_ring_buffer_backend_pages *rpages; | |
1087 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1088 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1089 | unsigned long sb_bindex, id; |
1090 | ||
1091 | offset &= chanb->buf_size - 1; | |
1092 | sbidx = offset >> chanb->subbuf_size_order; | |
1093 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1094 | id = bufb->buf_wsb[sbidx].id; | |
1095 | sb_bindex = subbuffer_id_get_index(config, id); | |
1096 | rpages = bufb->array[sb_bindex]; | |
1097 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1098 | && subbuffer_id_is_noref(config, id)); | |
1099 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1100 | } | |
1101 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |