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> | |
60f9ca27 | 15 | #include <linux/oom.h> |
f3bc08c5 MD |
16 | #include <linux/cpu.h> |
17 | #include <linux/mm.h> | |
df388b78 | 18 | #include <linux/vmalloc.h> |
f3bc08c5 | 19 | |
c075712b MD |
20 | #include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_all() */ |
21 | #include <wrapper/ringbuffer/config.h> | |
22 | #include <wrapper/ringbuffer/backend.h> | |
23 | #include <wrapper/ringbuffer/frontend.h> | |
f3bc08c5 MD |
24 | |
25 | /** | |
26 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
27 | * @config: ring buffer instance configuration | |
28 | * @buf: the buffer struct | |
29 | * @size: total size of the buffer | |
30 | * @num_subbuf: number of subbuffers | |
31 | * @extra_reader_sb: need extra subbuffer for reader | |
32 | */ | |
33 | static | |
34 | int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config, | |
35 | struct lib_ring_buffer_backend *bufb, | |
36 | size_t size, size_t num_subbuf, | |
37 | int extra_reader_sb) | |
38 | { | |
39 | struct channel_backend *chanb = &bufb->chan->backend; | |
40 | unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0; | |
41 | unsigned long subbuf_size, mmap_offset = 0; | |
42 | unsigned long num_subbuf_alloc; | |
43 | struct page **pages; | |
f3bc08c5 MD |
44 | unsigned long i; |
45 | ||
46 | num_pages = size >> PAGE_SHIFT; | |
60f9ca27 FD |
47 | |
48 | /* | |
49 | * Verify that the number of pages requested for that buffer is smaller | |
50 | * than the number of available pages on the system. si_mem_available() | |
51 | * returns an _estimate_ of the number of available pages. | |
52 | */ | |
53 | if (num_pages > si_mem_available()) | |
54 | goto not_enough_pages; | |
55 | ||
56 | /* | |
57 | * Set the current user thread as the first target of the OOM killer. | |
58 | * If the estimate received by si_mem_available() was off, and we do | |
59 | * end up running out of memory because of this buffer allocation, we | |
60 | * want to kill the offending app first. | |
61 | */ | |
62 | set_current_oom_origin(); | |
63 | ||
f3bc08c5 MD |
64 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); |
65 | subbuf_size = chanb->subbuf_size; | |
66 | num_subbuf_alloc = num_subbuf; | |
67 | ||
68 | if (extra_reader_sb) { | |
69 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ | |
70 | num_subbuf_alloc++; | |
71 | } | |
72 | ||
df388b78 | 73 | pages = vmalloc_node(ALIGN(sizeof(*pages) * num_pages, |
f3bc08c5 | 74 | 1 << INTERNODE_CACHE_SHIFT), |
df388b78 | 75 | cpu_to_node(max(bufb->cpu, 0))); |
f3bc08c5 MD |
76 | if (unlikely(!pages)) |
77 | goto pages_error; | |
78 | ||
48f5e0b5 | 79 | bufb->array = lttng_kvmalloc_node(ALIGN(sizeof(*bufb->array) |
f3bc08c5 MD |
80 | * num_subbuf_alloc, |
81 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
82 | GFP_KERNEL | __GFP_NOWARN, |
83 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
84 | if (unlikely(!bufb->array)) |
85 | goto array_error; | |
86 | ||
87 | for (i = 0; i < num_pages; i++) { | |
88 | pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)), | |
df388b78 | 89 | GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 0); |
f3bc08c5 MD |
90 | if (unlikely(!pages[i])) |
91 | goto depopulate; | |
f3bc08c5 MD |
92 | } |
93 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; | |
94 | ||
95 | /* Allocate backend pages array elements */ | |
96 | for (i = 0; i < num_subbuf_alloc; i++) { | |
97 | bufb->array[i] = | |
48f5e0b5 | 98 | lttng_kvzalloc_node(ALIGN( |
f3bc08c5 MD |
99 | sizeof(struct lib_ring_buffer_backend_pages) + |
100 | sizeof(struct lib_ring_buffer_backend_page) | |
101 | * num_pages_per_subbuf, | |
102 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
103 | GFP_KERNEL | __GFP_NOWARN, |
104 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
105 | if (!bufb->array[i]) |
106 | goto free_array; | |
107 | } | |
108 | ||
109 | /* Allocate write-side subbuffer table */ | |
48f5e0b5 | 110 | bufb->buf_wsb = lttng_kvzalloc_node(ALIGN( |
f3bc08c5 MD |
111 | sizeof(struct lib_ring_buffer_backend_subbuffer) |
112 | * num_subbuf, | |
113 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
114 | GFP_KERNEL | __GFP_NOWARN, |
115 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
116 | if (unlikely(!bufb->buf_wsb)) |
117 | goto free_array; | |
118 | ||
119 | for (i = 0; i < num_subbuf; i++) | |
120 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
121 | ||
122 | /* Assign read-side subbuffer table */ | |
123 | if (extra_reader_sb) | |
124 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
125 | num_subbuf_alloc - 1); | |
126 | else | |
127 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
128 | ||
5b3cf4f9 | 129 | /* Allocate subbuffer packet counter table */ |
48f5e0b5 | 130 | bufb->buf_cnt = lttng_kvzalloc_node(ALIGN( |
5b3cf4f9 JD |
131 | sizeof(struct lib_ring_buffer_backend_counts) |
132 | * num_subbuf, | |
133 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
134 | GFP_KERNEL | __GFP_NOWARN, |
135 | cpu_to_node(max(bufb->cpu, 0))); | |
5b3cf4f9 JD |
136 | if (unlikely(!bufb->buf_cnt)) |
137 | goto free_wsb; | |
138 | ||
f3bc08c5 MD |
139 | /* Assign pages to page index */ |
140 | for (i = 0; i < num_subbuf_alloc; i++) { | |
141 | for (j = 0; j < num_pages_per_subbuf; j++) { | |
142 | CHAN_WARN_ON(chanb, page_idx > num_pages); | |
0112cb7b MD |
143 | bufb->array[i]->p[j].virt = page_address(pages[page_idx]); |
144 | bufb->array[i]->p[j].pfn = page_to_pfn(pages[page_idx]); | |
f3bc08c5 MD |
145 | page_idx++; |
146 | } | |
147 | if (config->output == RING_BUFFER_MMAP) { | |
148 | bufb->array[i]->mmap_offset = mmap_offset; | |
149 | mmap_offset += subbuf_size; | |
150 | } | |
151 | } | |
152 | ||
153 | /* | |
154 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
155 | * will not fault. | |
156 | */ | |
6d2a620c | 157 | wrapper_vmalloc_sync_all(); |
60f9ca27 | 158 | clear_current_oom_origin(); |
df388b78 | 159 | vfree(pages); |
f3bc08c5 MD |
160 | return 0; |
161 | ||
5b3cf4f9 | 162 | free_wsb: |
48f5e0b5 | 163 | lttng_kvfree(bufb->buf_wsb); |
f3bc08c5 MD |
164 | free_array: |
165 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) | |
48f5e0b5 | 166 | lttng_kvfree(bufb->array[i]); |
f3bc08c5 MD |
167 | depopulate: |
168 | /* Free all allocated pages */ | |
169 | for (i = 0; (i < num_pages && pages[i]); i++) | |
170 | __free_page(pages[i]); | |
48f5e0b5 | 171 | lttng_kvfree(bufb->array); |
f3bc08c5 | 172 | array_error: |
df388b78 | 173 | vfree(pages); |
f3bc08c5 | 174 | pages_error: |
60f9ca27 FD |
175 | clear_current_oom_origin(); |
176 | not_enough_pages: | |
f3bc08c5 MD |
177 | return -ENOMEM; |
178 | } | |
179 | ||
180 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
181 | struct channel_backend *chanb, int cpu) | |
182 | { | |
5a8fd222 | 183 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
184 | |
185 | bufb->chan = container_of(chanb, struct channel, backend); | |
186 | bufb->cpu = cpu; | |
187 | ||
188 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
189 | chanb->num_subbuf, | |
190 | chanb->extra_reader_sb); | |
191 | } | |
192 | ||
193 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) | |
194 | { | |
195 | struct channel_backend *chanb = &bufb->chan->backend; | |
196 | unsigned long i, j, num_subbuf_alloc; | |
197 | ||
198 | num_subbuf_alloc = chanb->num_subbuf; | |
199 | if (chanb->extra_reader_sb) | |
200 | num_subbuf_alloc++; | |
201 | ||
48f5e0b5 MJ |
202 | lttng_kvfree(bufb->buf_wsb); |
203 | lttng_kvfree(bufb->buf_cnt); | |
f3bc08c5 MD |
204 | for (i = 0; i < num_subbuf_alloc; i++) { |
205 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) | |
0112cb7b | 206 | __free_page(pfn_to_page(bufb->array[i]->p[j].pfn)); |
48f5e0b5 | 207 | lttng_kvfree(bufb->array[i]); |
f3bc08c5 | 208 | } |
48f5e0b5 | 209 | lttng_kvfree(bufb->array); |
f3bc08c5 MD |
210 | bufb->allocated = 0; |
211 | } | |
212 | ||
213 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) | |
214 | { | |
215 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 216 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
217 | unsigned long num_subbuf_alloc; |
218 | unsigned int i; | |
219 | ||
220 | num_subbuf_alloc = chanb->num_subbuf; | |
221 | if (chanb->extra_reader_sb) | |
222 | num_subbuf_alloc++; | |
223 | ||
224 | for (i = 0; i < chanb->num_subbuf; i++) | |
225 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
226 | if (chanb->extra_reader_sb) | |
227 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
228 | num_subbuf_alloc - 1); | |
229 | else | |
230 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
231 | ||
232 | for (i = 0; i < num_subbuf_alloc; i++) { | |
233 | /* Don't reset mmap_offset */ | |
234 | v_set(config, &bufb->array[i]->records_commit, 0); | |
235 | v_set(config, &bufb->array[i]->records_unread, 0); | |
236 | bufb->array[i]->data_size = 0; | |
237 | /* Don't reset backend page and virt addresses */ | |
238 | } | |
239 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
240 | v_set(config, &bufb->records_read, 0); | |
241 | } | |
242 | ||
243 | /* | |
244 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
245 | * each buffer when calling channel_backend_reset. | |
246 | */ | |
247 | void channel_backend_reset(struct channel_backend *chanb) | |
248 | { | |
249 | struct channel *chan = container_of(chanb, struct channel, backend); | |
5a8fd222 | 250 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
251 | |
252 | /* | |
253 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
254 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
255 | * priv, notifiers, config, cpumask and name. | |
256 | */ | |
257 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
258 | } | |
259 | ||
1e367326 MD |
260 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
261 | ||
262 | /* | |
263 | * No need to implement a "dead" callback to do a buffer switch here, | |
264 | * because it will happen when tracing is stopped, or will be done by | |
265 | * switch timer CPU DEAD callback. | |
266 | * We don't free buffers when CPU go away, because it would make trace | |
267 | * data vanish, which is unwanted. | |
268 | */ | |
269 | int lttng_cpuhp_rb_backend_prepare(unsigned int cpu, | |
270 | struct lttng_cpuhp_node *node) | |
271 | { | |
272 | struct channel_backend *chanb = container_of(node, | |
273 | struct channel_backend, cpuhp_prepare); | |
274 | const struct lib_ring_buffer_config *config = &chanb->config; | |
275 | struct lib_ring_buffer *buf; | |
276 | int ret; | |
277 | ||
278 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
279 | ||
280 | buf = per_cpu_ptr(chanb->buf, cpu); | |
281 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
282 | if (ret) { | |
283 | printk(KERN_ERR | |
284 | "ring_buffer_cpu_hp_callback: cpu %d " | |
285 | "buffer creation failed\n", cpu); | |
286 | return ret; | |
287 | } | |
288 | return 0; | |
289 | } | |
290 | EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_backend_prepare); | |
291 | ||
292 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
293 | ||
f3bc08c5 | 294 | #ifdef CONFIG_HOTPLUG_CPU |
1e367326 | 295 | |
f3bc08c5 MD |
296 | /** |
297 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback | |
298 | * @nb: notifier block | |
299 | * @action: hotplug action to take | |
300 | * @hcpu: CPU number | |
301 | * | |
302 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
303 | */ | |
304 | static | |
e8f071d5 | 305 | int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, |
f3bc08c5 MD |
306 | unsigned long action, |
307 | void *hcpu) | |
308 | { | |
309 | unsigned int cpu = (unsigned long)hcpu; | |
310 | struct channel_backend *chanb = container_of(nb, struct channel_backend, | |
311 | cpu_hp_notifier); | |
5a8fd222 | 312 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
313 | struct lib_ring_buffer *buf; |
314 | int ret; | |
315 | ||
316 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
317 | ||
318 | switch (action) { | |
319 | case CPU_UP_PREPARE: | |
320 | case CPU_UP_PREPARE_FROZEN: | |
321 | buf = per_cpu_ptr(chanb->buf, cpu); | |
322 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
323 | if (ret) { | |
324 | printk(KERN_ERR | |
325 | "ring_buffer_cpu_hp_callback: cpu %d " | |
326 | "buffer creation failed\n", cpu); | |
327 | return NOTIFY_BAD; | |
328 | } | |
329 | break; | |
330 | case CPU_DEAD: | |
331 | case CPU_DEAD_FROZEN: | |
332 | /* No need to do a buffer switch here, because it will happen | |
333 | * when tracing is stopped, or will be done by switch timer CPU | |
334 | * DEAD callback. */ | |
335 | break; | |
336 | } | |
337 | return NOTIFY_OK; | |
338 | } | |
1e367326 | 339 | |
f3bc08c5 MD |
340 | #endif |
341 | ||
1e367326 MD |
342 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
343 | ||
f3bc08c5 MD |
344 | /** |
345 | * channel_backend_init - initialize a channel backend | |
346 | * @chanb: channel backend | |
347 | * @name: channel name | |
348 | * @config: client ring buffer configuration | |
349 | * @priv: client private data | |
350 | * @parent: dentry of parent directory, %NULL for root directory | |
351 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
352 | * @num_subbuf: number of sub-buffers (power of 2) | |
353 | * | |
354 | * Returns channel pointer if successful, %NULL otherwise. | |
355 | * | |
356 | * Creates per-cpu channel buffers using the sizes and attributes | |
357 | * specified. The created channel buffer files will be named | |
358 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
359 | * | |
360 | * Called with CPU hotplug disabled. | |
361 | */ | |
362 | int channel_backend_init(struct channel_backend *chanb, | |
363 | const char *name, | |
364 | const struct lib_ring_buffer_config *config, | |
365 | void *priv, size_t subbuf_size, size_t num_subbuf) | |
366 | { | |
367 | struct channel *chan = container_of(chanb, struct channel, backend); | |
368 | unsigned int i; | |
369 | int ret; | |
370 | ||
371 | if (!name) | |
372 | return -EPERM; | |
373 | ||
f3bc08c5 | 374 | /* Check that the subbuffer size is larger than a page. */ |
2fb46300 MD |
375 | if (subbuf_size < PAGE_SIZE) |
376 | return -EINVAL; | |
f3bc08c5 MD |
377 | |
378 | /* | |
bbda3a00 MD |
379 | * Make sure the number of subbuffers and subbuffer size are |
380 | * power of 2 and nonzero. | |
f3bc08c5 | 381 | */ |
bbda3a00 | 382 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
863497fa | 383 | return -EINVAL; |
bbda3a00 | 384 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
863497fa | 385 | return -EINVAL; |
5140d2b3 MD |
386 | /* |
387 | * Overwrite mode buffers require at least 2 subbuffers per | |
388 | * buffer. | |
389 | */ | |
390 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
391 | return -EINVAL; | |
f3bc08c5 MD |
392 | |
393 | ret = subbuffer_id_check_index(config, num_subbuf); | |
394 | if (ret) | |
395 | return ret; | |
396 | ||
397 | chanb->priv = priv; | |
398 | chanb->buf_size = num_subbuf * subbuf_size; | |
399 | chanb->subbuf_size = subbuf_size; | |
400 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
401 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
402 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
403 | chanb->extra_reader_sb = | |
404 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
405 | chanb->num_subbuf = num_subbuf; | |
406 | strlcpy(chanb->name, name, NAME_MAX); | |
5a8fd222 | 407 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
f3bc08c5 MD |
408 | |
409 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
410 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) | |
411 | return -ENOMEM; | |
412 | } | |
413 | ||
414 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
415 | /* Allocating the buffer per-cpu structures */ | |
416 | chanb->buf = alloc_percpu(struct lib_ring_buffer); | |
417 | if (!chanb->buf) | |
418 | goto free_cpumask; | |
419 | ||
1e367326 MD |
420 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
421 | chanb->cpuhp_prepare.component = LTTNG_RING_BUFFER_BACKEND; | |
422 | ret = cpuhp_state_add_instance(lttng_rb_hp_prepare, | |
423 | &chanb->cpuhp_prepare.node); | |
424 | if (ret) | |
425 | goto free_bufs; | |
426 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
427 | ||
428 | { | |
429 | /* | |
430 | * In case of non-hotplug cpu, if the ring-buffer is allocated | |
431 | * in early initcall, it will not be notified of secondary cpus. | |
432 | * In that off case, we need to allocate for all possible cpus. | |
433 | */ | |
f3bc08c5 | 434 | #ifdef CONFIG_HOTPLUG_CPU |
1e367326 MD |
435 | /* |
436 | * buf->backend.allocated test takes care of concurrent CPU | |
437 | * hotplug. | |
438 | * Priority higher than frontend, so we create the ring buffer | |
439 | * before we start the timer. | |
440 | */ | |
441 | chanb->cpu_hp_notifier.notifier_call = | |
442 | lib_ring_buffer_cpu_hp_callback; | |
443 | chanb->cpu_hp_notifier.priority = 5; | |
444 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
445 | ||
446 | get_online_cpus(); | |
447 | for_each_online_cpu(i) { | |
448 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
449 | chanb, i); | |
450 | if (ret) | |
451 | goto free_bufs; /* cpu hotplug locked */ | |
452 | } | |
453 | put_online_cpus(); | |
f3bc08c5 | 454 | #else |
1e367326 MD |
455 | for_each_possible_cpu(i) { |
456 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
457 | chanb, i); | |
458 | if (ret) | |
459 | goto free_bufs; | |
460 | } | |
f3bc08c5 | 461 | #endif |
1e367326 MD |
462 | } |
463 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 MD |
464 | } else { |
465 | chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL); | |
466 | if (!chanb->buf) | |
467 | goto free_cpumask; | |
468 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); | |
469 | if (ret) | |
470 | goto free_bufs; | |
471 | } | |
472 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
473 | ||
474 | return 0; | |
475 | ||
476 | free_bufs: | |
477 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
1e367326 | 478 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
9837fedc MD |
479 | /* |
480 | * Teardown of lttng_rb_hp_prepare instance | |
481 | * on "add" error is handled within cpu hotplug, | |
482 | * no teardown to do from the caller. | |
483 | */ | |
1e367326 MD |
484 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
485 | #ifdef CONFIG_HOTPLUG_CPU | |
486 | put_online_cpus(); | |
487 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
488 | #endif | |
489 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 | 490 | for_each_possible_cpu(i) { |
1e367326 MD |
491 | struct lib_ring_buffer *buf = |
492 | per_cpu_ptr(chanb->buf, i); | |
f3bc08c5 MD |
493 | |
494 | if (!buf->backend.allocated) | |
495 | continue; | |
496 | lib_ring_buffer_free(buf); | |
497 | } | |
f3bc08c5 MD |
498 | free_percpu(chanb->buf); |
499 | } else | |
500 | kfree(chanb->buf); | |
501 | free_cpumask: | |
502 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
503 | free_cpumask_var(chanb->cpumask); | |
504 | return -ENOMEM; | |
505 | } | |
506 | ||
507 | /** | |
508 | * channel_backend_unregister_notifiers - unregister notifiers | |
509 | * @chan: the channel | |
510 | * | |
511 | * Holds CPU hotplug. | |
512 | */ | |
513 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) | |
514 | { | |
5a8fd222 | 515 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 516 | |
1e367326 MD |
517 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
518 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) | |
519 | int ret; | |
520 | ||
521 | ret = cpuhp_state_remove_instance(lttng_rb_hp_prepare, | |
522 | &chanb->cpuhp_prepare.node); | |
523 | WARN_ON(ret); | |
524 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 | 525 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); |
1e367326 MD |
526 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
527 | } | |
f3bc08c5 MD |
528 | } |
529 | ||
530 | /** | |
531 | * channel_backend_free - destroy the channel | |
532 | * @chan: the channel | |
533 | * | |
534 | * Destroy all channel buffers and frees the channel. | |
535 | */ | |
536 | void channel_backend_free(struct channel_backend *chanb) | |
537 | { | |
5a8fd222 | 538 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
539 | unsigned int i; |
540 | ||
541 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
542 | for_each_possible_cpu(i) { | |
543 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
544 | ||
545 | if (!buf->backend.allocated) | |
546 | continue; | |
547 | lib_ring_buffer_free(buf); | |
548 | } | |
549 | free_cpumask_var(chanb->cpumask); | |
550 | free_percpu(chanb->buf); | |
551 | } else { | |
552 | struct lib_ring_buffer *buf = chanb->buf; | |
553 | ||
554 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
555 | lib_ring_buffer_free(buf); | |
556 | kfree(buf); | |
557 | } | |
558 | } | |
559 | ||
560 | /** | |
561 | * lib_ring_buffer_write - write data to a ring_buffer buffer. | |
562 | * @bufb : buffer backend | |
563 | * @offset : offset within the buffer | |
564 | * @src : source address | |
565 | * @len : length to write | |
566 | * @pagecpy : page size copied so far | |
567 | */ | |
568 | void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, | |
bfe529f9 | 569 | const void *src, size_t len, size_t pagecpy) |
f3bc08c5 MD |
570 | { |
571 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 572 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
573 | size_t sbidx, index; |
574 | struct lib_ring_buffer_backend_pages *rpages; | |
575 | unsigned long sb_bindex, id; | |
576 | ||
577 | do { | |
578 | len -= pagecpy; | |
579 | src += pagecpy; | |
580 | offset += pagecpy; | |
581 | sbidx = offset >> chanb->subbuf_size_order; | |
582 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
583 | ||
584 | /* | |
585 | * Underlying layer should never ask for writes across | |
586 | * subbuffers. | |
587 | */ | |
588 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
589 | ||
590 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
591 | id = bufb->buf_wsb[sbidx].id; | |
592 | sb_bindex = subbuffer_id_get_index(config, id); | |
593 | rpages = bufb->array[sb_bindex]; | |
594 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
595 | && subbuffer_id_is_noref(config, id)); | |
596 | lib_ring_buffer_do_copy(config, | |
597 | rpages->p[index].virt | |
598 | + (offset & ~PAGE_MASK), | |
599 | src, pagecpy); | |
600 | } while (unlikely(len != pagecpy)); | |
601 | } | |
602 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); | |
603 | ||
4ea00e4f JD |
604 | |
605 | /** | |
606 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. | |
607 | * @bufb : buffer backend | |
608 | * @offset : offset within the buffer | |
609 | * @c : the byte to write | |
610 | * @len : length to write | |
611 | * @pagecpy : page size copied so far | |
612 | */ | |
613 | void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, | |
614 | size_t offset, | |
bfe529f9 | 615 | int c, size_t len, size_t pagecpy) |
4ea00e4f JD |
616 | { |
617 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 618 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
619 | size_t sbidx, index; |
620 | struct lib_ring_buffer_backend_pages *rpages; | |
621 | unsigned long sb_bindex, id; | |
622 | ||
623 | do { | |
624 | len -= pagecpy; | |
625 | offset += pagecpy; | |
626 | sbidx = offset >> chanb->subbuf_size_order; | |
627 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
628 | ||
629 | /* | |
630 | * Underlying layer should never ask for writes across | |
631 | * subbuffers. | |
632 | */ | |
633 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
634 | ||
635 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
636 | id = bufb->buf_wsb[sbidx].id; | |
637 | sb_bindex = subbuffer_id_get_index(config, id); | |
638 | rpages = bufb->array[sb_bindex]; | |
639 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
640 | && subbuffer_id_is_noref(config, id)); | |
641 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
642 | + (offset & ~PAGE_MASK), | |
643 | c, pagecpy); | |
644 | } while (unlikely(len != pagecpy)); | |
645 | } | |
646 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); | |
647 | ||
16f78f3a MD |
648 | /** |
649 | * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer. | |
650 | * @bufb : buffer backend | |
651 | * @offset : offset within the buffer | |
652 | * @src : source address | |
653 | * @len : length to write | |
654 | * @pagecpy : page size copied so far | |
655 | * @pad : character to use for padding | |
656 | */ | |
657 | void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb, | |
658 | size_t offset, const char *src, size_t len, | |
659 | size_t pagecpy, int pad) | |
660 | { | |
661 | struct channel_backend *chanb = &bufb->chan->backend; | |
662 | const struct lib_ring_buffer_config *config = &chanb->config; | |
663 | size_t sbidx, index; | |
664 | struct lib_ring_buffer_backend_pages *rpages; | |
665 | unsigned long sb_bindex, id; | |
666 | int src_terminated = 0; | |
667 | ||
668 | CHAN_WARN_ON(chanb, !len); | |
669 | offset += pagecpy; | |
670 | do { | |
671 | len -= pagecpy; | |
672 | if (!src_terminated) | |
673 | src += pagecpy; | |
674 | sbidx = offset >> chanb->subbuf_size_order; | |
675 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
676 | ||
677 | /* | |
678 | * Underlying layer should never ask for writes across | |
679 | * subbuffers. | |
680 | */ | |
681 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
682 | ||
683 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
684 | id = bufb->buf_wsb[sbidx].id; | |
685 | sb_bindex = subbuffer_id_get_index(config, id); | |
686 | rpages = bufb->array[sb_bindex]; | |
687 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
688 | && subbuffer_id_is_noref(config, id)); | |
689 | ||
690 | if (likely(!src_terminated)) { | |
691 | size_t count, to_copy; | |
692 | ||
693 | to_copy = pagecpy; | |
694 | if (pagecpy == len) | |
695 | to_copy--; /* Final '\0' */ | |
696 | count = lib_ring_buffer_do_strcpy(config, | |
697 | rpages->p[index].virt | |
698 | + (offset & ~PAGE_MASK), | |
699 | src, to_copy); | |
700 | offset += count; | |
701 | /* Padding */ | |
702 | if (unlikely(count < to_copy)) { | |
703 | size_t pad_len = to_copy - count; | |
704 | ||
705 | /* Next pages will have padding */ | |
706 | src_terminated = 1; | |
707 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
708 | + (offset & ~PAGE_MASK), | |
709 | pad, pad_len); | |
710 | offset += pad_len; | |
711 | } | |
712 | } else { | |
713 | size_t pad_len; | |
714 | ||
715 | pad_len = pagecpy; | |
716 | if (pagecpy == len) | |
717 | pad_len--; /* Final '\0' */ | |
718 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
719 | + (offset & ~PAGE_MASK), | |
720 | pad, pad_len); | |
721 | offset += pad_len; | |
722 | } | |
723 | } while (unlikely(len != pagecpy)); | |
724 | /* Ending '\0' */ | |
725 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
726 | '\0', 1); | |
727 | } | |
728 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy); | |
4ea00e4f JD |
729 | |
730 | /** | |
7b8ea3a5 | 731 | * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. |
4ea00e4f JD |
732 | * @bufb : buffer backend |
733 | * @offset : offset within the buffer | |
734 | * @src : source address | |
735 | * @len : length to write | |
736 | * @pagecpy : page size copied so far | |
737 | * | |
738 | * This function deals with userspace pointers, it should never be called | |
739 | * directly without having the src pointer checked with access_ok() | |
740 | * previously. | |
741 | */ | |
7b8ea3a5 | 742 | void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
4ea00e4f JD |
743 | size_t offset, |
744 | const void __user *src, size_t len, | |
bfe529f9 | 745 | size_t pagecpy) |
4ea00e4f JD |
746 | { |
747 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 748 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
749 | size_t sbidx, index; |
750 | struct lib_ring_buffer_backend_pages *rpages; | |
751 | unsigned long sb_bindex, id; | |
752 | int ret; | |
753 | ||
754 | do { | |
755 | len -= pagecpy; | |
756 | src += pagecpy; | |
757 | offset += pagecpy; | |
758 | sbidx = offset >> chanb->subbuf_size_order; | |
759 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
760 | ||
761 | /* | |
762 | * Underlying layer should never ask for writes across | |
763 | * subbuffers. | |
764 | */ | |
765 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
766 | ||
767 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
768 | id = bufb->buf_wsb[sbidx].id; | |
769 | sb_bindex = subbuffer_id_get_index(config, id); | |
770 | rpages = bufb->array[sb_bindex]; | |
771 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
772 | && subbuffer_id_is_noref(config, id)); | |
7b8ea3a5 | 773 | ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt |
4ea00e4f JD |
774 | + (offset & ~PAGE_MASK), |
775 | src, pagecpy) != 0; | |
776 | if (ret > 0) { | |
d87a9f03 | 777 | /* Copy failed. */ |
4ea00e4f JD |
778 | _lib_ring_buffer_memset(bufb, offset, 0, len, 0); |
779 | break; /* stop copy */ | |
780 | } | |
781 | } while (unlikely(len != pagecpy)); | |
782 | } | |
7b8ea3a5 | 783 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); |
4ea00e4f | 784 | |
16f78f3a MD |
785 | /** |
786 | * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer. | |
787 | * @bufb : buffer backend | |
788 | * @offset : offset within the buffer | |
789 | * @src : source address | |
790 | * @len : length to write | |
791 | * @pagecpy : page size copied so far | |
792 | * @pad : character to use for padding | |
793 | * | |
794 | * This function deals with userspace pointers, it should never be called | |
795 | * directly without having the src pointer checked with access_ok() | |
796 | * previously. | |
797 | */ | |
798 | void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, | |
799 | size_t offset, const char __user *src, size_t len, | |
800 | size_t pagecpy, int pad) | |
801 | { | |
802 | struct channel_backend *chanb = &bufb->chan->backend; | |
803 | const struct lib_ring_buffer_config *config = &chanb->config; | |
804 | size_t sbidx, index; | |
805 | struct lib_ring_buffer_backend_pages *rpages; | |
806 | unsigned long sb_bindex, id; | |
807 | int src_terminated = 0; | |
808 | ||
809 | offset += pagecpy; | |
810 | do { | |
811 | len -= pagecpy; | |
812 | if (!src_terminated) | |
813 | src += pagecpy; | |
814 | sbidx = offset >> chanb->subbuf_size_order; | |
815 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
816 | ||
817 | /* | |
818 | * Underlying layer should never ask for writes across | |
819 | * subbuffers. | |
820 | */ | |
821 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
822 | ||
823 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
824 | id = bufb->buf_wsb[sbidx].id; | |
825 | sb_bindex = subbuffer_id_get_index(config, id); | |
826 | rpages = bufb->array[sb_bindex]; | |
827 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
828 | && subbuffer_id_is_noref(config, id)); | |
829 | ||
830 | if (likely(!src_terminated)) { | |
831 | size_t count, to_copy; | |
832 | ||
833 | to_copy = pagecpy; | |
834 | if (pagecpy == len) | |
835 | to_copy--; /* Final '\0' */ | |
836 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, | |
837 | rpages->p[index].virt | |
838 | + (offset & ~PAGE_MASK), | |
839 | src, to_copy); | |
840 | offset += count; | |
841 | /* Padding */ | |
842 | if (unlikely(count < to_copy)) { | |
843 | size_t pad_len = to_copy - count; | |
844 | ||
845 | /* Next pages will have padding */ | |
846 | src_terminated = 1; | |
847 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
848 | + (offset & ~PAGE_MASK), | |
849 | pad, pad_len); | |
850 | offset += pad_len; | |
851 | } | |
852 | } else { | |
853 | size_t pad_len; | |
854 | ||
855 | pad_len = pagecpy; | |
856 | if (pagecpy == len) | |
857 | pad_len--; /* Final '\0' */ | |
858 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
859 | + (offset & ~PAGE_MASK), | |
860 | pad, pad_len); | |
861 | offset += pad_len; | |
862 | } | |
863 | } while (unlikely(len != pagecpy)); | |
864 | /* Ending '\0' */ | |
865 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
866 | '\0', 1); | |
867 | } | |
868 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic); | |
869 | ||
f3bc08c5 MD |
870 | /** |
871 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
872 | * @bufb : buffer backend | |
873 | * @offset : offset within the buffer | |
874 | * @dest : destination address | |
875 | * @len : length to copy to destination | |
876 | * | |
877 | * Should be protected by get_subbuf/put_subbuf. | |
878 | * Returns the length copied. | |
879 | */ | |
880 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, | |
881 | void *dest, size_t len) | |
882 | { | |
883 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 884 | const struct lib_ring_buffer_config *config = &chanb->config; |
bfe529f9 | 885 | size_t index, pagecpy, orig_len; |
f3bc08c5 MD |
886 | struct lib_ring_buffer_backend_pages *rpages; |
887 | unsigned long sb_bindex, id; | |
888 | ||
889 | orig_len = len; | |
890 | offset &= chanb->buf_size - 1; | |
891 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
892 | if (unlikely(!len)) | |
893 | return 0; | |
894 | for (;;) { | |
895 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
896 | id = bufb->buf_rsb.id; | |
897 | sb_bindex = subbuffer_id_get_index(config, id); | |
898 | rpages = bufb->array[sb_bindex]; | |
899 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
900 | && subbuffer_id_is_noref(config, id)); | |
901 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), | |
902 | pagecpy); | |
903 | len -= pagecpy; | |
904 | if (likely(!len)) | |
905 | break; | |
906 | dest += pagecpy; | |
907 | offset += pagecpy; | |
908 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
909 | /* | |
910 | * Underlying layer should never ask for reads across | |
911 | * subbuffers. | |
912 | */ | |
913 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
914 | } | |
915 | return orig_len; | |
916 | } | |
917 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); | |
918 | ||
919 | /** | |
920 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace | |
921 | * @bufb : buffer backend | |
922 | * @offset : offset within the buffer | |
923 | * @dest : destination userspace address | |
924 | * @len : length to copy to destination | |
925 | * | |
926 | * Should be protected by get_subbuf/put_subbuf. | |
927 | * access_ok() must have been performed on dest addresses prior to call this | |
928 | * function. | |
929 | * Returns -EFAULT on error, 0 if ok. | |
930 | */ | |
931 | int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, | |
932 | size_t offset, void __user *dest, size_t len) | |
933 | { | |
934 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 935 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 936 | size_t index; |
88dfd899 | 937 | ssize_t pagecpy; |
f3bc08c5 MD |
938 | struct lib_ring_buffer_backend_pages *rpages; |
939 | unsigned long sb_bindex, id; | |
940 | ||
f3bc08c5 MD |
941 | offset &= chanb->buf_size - 1; |
942 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
943 | if (unlikely(!len)) | |
944 | return 0; | |
945 | for (;;) { | |
946 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
947 | id = bufb->buf_rsb.id; | |
948 | sb_bindex = subbuffer_id_get_index(config, id); | |
949 | rpages = bufb->array[sb_bindex]; | |
950 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
951 | && subbuffer_id_is_noref(config, id)); | |
952 | if (__copy_to_user(dest, | |
953 | rpages->p[index].virt + (offset & ~PAGE_MASK), | |
954 | pagecpy)) | |
955 | return -EFAULT; | |
956 | len -= pagecpy; | |
957 | if (likely(!len)) | |
958 | break; | |
959 | dest += pagecpy; | |
960 | offset += pagecpy; | |
961 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
962 | /* | |
963 | * Underlying layer should never ask for reads across | |
964 | * subbuffers. | |
965 | */ | |
966 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
967 | } | |
968 | return 0; | |
969 | } | |
970 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); | |
971 | ||
972 | /** | |
973 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
974 | * @bufb : buffer backend | |
975 | * @offset : offset within the buffer | |
976 | * @dest : destination address | |
977 | * @len : destination's length | |
978 | * | |
61eb4c39 | 979 | * Return string's length, or -EINVAL on error. |
f3bc08c5 | 980 | * Should be protected by get_subbuf/put_subbuf. |
61eb4c39 | 981 | * Destination length should be at least 1 to hold '\0'. |
f3bc08c5 MD |
982 | */ |
983 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, | |
984 | void *dest, size_t len) | |
985 | { | |
986 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 987 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
988 | size_t index; |
989 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; | |
990 | char *str; | |
991 | struct lib_ring_buffer_backend_pages *rpages; | |
992 | unsigned long sb_bindex, id; | |
993 | ||
994 | offset &= chanb->buf_size - 1; | |
995 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
996 | orig_offset = offset; | |
61eb4c39 MD |
997 | if (unlikely(!len)) |
998 | return -EINVAL; | |
f3bc08c5 MD |
999 | for (;;) { |
1000 | id = bufb->buf_rsb.id; | |
1001 | sb_bindex = subbuffer_id_get_index(config, id); | |
1002 | rpages = bufb->array[sb_bindex]; | |
1003 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1004 | && subbuffer_id_is_noref(config, id)); | |
1005 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1006 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
1007 | strpagelen = strnlen(str, pagelen); | |
1008 | if (len) { | |
1009 | pagecpy = min_t(size_t, len, strpagelen); | |
1010 | if (dest) { | |
1011 | memcpy(dest, str, pagecpy); | |
1012 | dest += pagecpy; | |
1013 | } | |
1014 | len -= pagecpy; | |
1015 | } | |
1016 | offset += strpagelen; | |
1017 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1018 | if (strpagelen < pagelen) | |
1019 | break; | |
1020 | /* | |
1021 | * Underlying layer should never ask for reads across | |
1022 | * subbuffers. | |
1023 | */ | |
1024 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
1025 | } | |
1026 | if (dest && len) | |
1027 | ((char *)dest)[0] = 0; | |
1028 | return offset - orig_offset; | |
1029 | } | |
1030 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); | |
1031 | ||
1032 | /** | |
0112cb7b | 1033 | * lib_ring_buffer_read_get_pfn - Get a page frame number to read from |
f3bc08c5 MD |
1034 | * @bufb : buffer backend |
1035 | * @offset : offset within the buffer | |
1036 | * @virt : pointer to page address (output) | |
1037 | * | |
1038 | * Should be protected by get_subbuf/put_subbuf. | |
0112cb7b | 1039 | * Returns the pointer to the page frame number unsigned long. |
f3bc08c5 | 1040 | */ |
0112cb7b | 1041 | unsigned long *lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, |
f3bc08c5 MD |
1042 | size_t offset, void ***virt) |
1043 | { | |
1044 | size_t index; | |
1045 | struct lib_ring_buffer_backend_pages *rpages; | |
1046 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1047 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1048 | unsigned long sb_bindex, id; |
1049 | ||
1050 | offset &= chanb->buf_size - 1; | |
1051 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1052 | id = bufb->buf_rsb.id; | |
1053 | sb_bindex = subbuffer_id_get_index(config, id); | |
1054 | rpages = bufb->array[sb_bindex]; | |
1055 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1056 | && subbuffer_id_is_noref(config, id)); | |
1057 | *virt = &rpages->p[index].virt; | |
0112cb7b | 1058 | return &rpages->p[index].pfn; |
f3bc08c5 | 1059 | } |
0112cb7b | 1060 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn); |
f3bc08c5 MD |
1061 | |
1062 | /** | |
1063 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
1064 | * @bufb : buffer backend | |
1065 | * @offset : offset within the buffer. | |
1066 | * | |
1067 | * Return the address where a given offset is located (for read). | |
1068 | * Should be used to get the current subbuffer header pointer. Given we know | |
759d02c1 MD |
1069 | * it's never on a page boundary, it's safe to read/write directly |
1070 | * from/to this address, as long as the read/write is never bigger than a | |
1071 | * page size. | |
f3bc08c5 MD |
1072 | */ |
1073 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, | |
1074 | size_t offset) | |
1075 | { | |
1076 | size_t index; | |
1077 | struct lib_ring_buffer_backend_pages *rpages; | |
1078 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1079 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1080 | unsigned long sb_bindex, id; |
1081 | ||
1082 | offset &= chanb->buf_size - 1; | |
1083 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1084 | id = bufb->buf_rsb.id; | |
1085 | sb_bindex = subbuffer_id_get_index(config, id); | |
1086 | rpages = bufb->array[sb_bindex]; | |
1087 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1088 | && subbuffer_id_is_noref(config, id)); | |
1089 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1090 | } | |
1091 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); | |
1092 | ||
1093 | /** | |
1094 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
1095 | * @bufb : buffer backend | |
1096 | * @offset : offset within the buffer. | |
1097 | * | |
1098 | * Return the address where a given offset is located. | |
1099 | * Should be used to get the current subbuffer header pointer. Given we know | |
1100 | * it's always at the beginning of a page, it's safe to write directly to this | |
1101 | * address, as long as the write is never bigger than a page size. | |
1102 | */ | |
1103 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, | |
1104 | size_t offset) | |
1105 | { | |
1106 | size_t sbidx, index; | |
1107 | struct lib_ring_buffer_backend_pages *rpages; | |
1108 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1109 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1110 | unsigned long sb_bindex, id; |
1111 | ||
1112 | offset &= chanb->buf_size - 1; | |
1113 | sbidx = offset >> chanb->subbuf_size_order; | |
1114 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1115 | id = bufb->buf_wsb[sbidx].id; | |
1116 | sb_bindex = subbuffer_id_get_index(config, id); | |
1117 | rpages = bufb->array[sb_bindex]; | |
1118 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1119 | && subbuffer_id_is_noref(config, id)); | |
1120 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1121 | } | |
1122 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |