Commit | Line | Data |
---|---|---|
f3bc08c5 MD |
1 | /* |
2 | * ring_buffer_backend.c | |
3 | * | |
886d51a3 | 4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 | 5 | * |
886d51a3 MD |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; only | |
9 | * version 2.1 of the License. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
f3bc08c5 MD |
19 | */ |
20 | ||
f3bc08c5 MD |
21 | #include <linux/stddef.h> |
22 | #include <linux/module.h> | |
23 | #include <linux/string.h> | |
24 | #include <linux/bitops.h> | |
25 | #include <linux/delay.h> | |
26 | #include <linux/errno.h> | |
27 | #include <linux/slab.h> | |
1790d63f | 28 | #include <linux/oom.h> |
f3bc08c5 MD |
29 | #include <linux/cpu.h> |
30 | #include <linux/mm.h> | |
df388b78 | 31 | #include <linux/vmalloc.h> |
f3bc08c5 | 32 | |
c075712b MD |
33 | #include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_all() */ |
34 | #include <wrapper/ringbuffer/config.h> | |
35 | #include <wrapper/ringbuffer/backend.h> | |
36 | #include <wrapper/ringbuffer/frontend.h> | |
f3bc08c5 MD |
37 | |
38 | /** | |
39 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
40 | * @config: ring buffer instance configuration | |
41 | * @buf: the buffer struct | |
42 | * @size: total size of the buffer | |
43 | * @num_subbuf: number of subbuffers | |
44 | * @extra_reader_sb: need extra subbuffer for reader | |
45 | */ | |
46 | static | |
47 | int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config, | |
48 | struct lib_ring_buffer_backend *bufb, | |
49 | size_t size, size_t num_subbuf, | |
50 | int extra_reader_sb) | |
51 | { | |
52 | struct channel_backend *chanb = &bufb->chan->backend; | |
53 | unsigned long j, num_pages, num_pages_per_subbuf, page_idx = 0; | |
54 | unsigned long subbuf_size, mmap_offset = 0; | |
55 | unsigned long num_subbuf_alloc; | |
56 | struct page **pages; | |
f3bc08c5 MD |
57 | unsigned long i; |
58 | ||
59 | num_pages = size >> PAGE_SHIFT; | |
1790d63f FD |
60 | |
61 | /* | |
62 | * Verify that the number of pages requested for that buffer is smaller | |
63 | * than the number of available pages on the system. si_mem_available() | |
64 | * returns an _estimate_ of the number of available pages. | |
65 | */ | |
66 | if (num_pages > si_mem_available()) | |
67 | goto not_enough_pages; | |
68 | ||
69 | /* | |
70 | * Set the current user thread as the first target of the OOM killer. | |
71 | * If the estimate received by si_mem_available() was off, and we do | |
72 | * end up running out of memory because of this buffer allocation, we | |
73 | * want to kill the offending app first. | |
74 | */ | |
75 | set_current_oom_origin(); | |
76 | ||
f3bc08c5 MD |
77 | num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf); |
78 | subbuf_size = chanb->subbuf_size; | |
79 | num_subbuf_alloc = num_subbuf; | |
80 | ||
81 | if (extra_reader_sb) { | |
82 | num_pages += num_pages_per_subbuf; /* Add pages for reader */ | |
83 | num_subbuf_alloc++; | |
84 | } | |
85 | ||
df388b78 | 86 | pages = vmalloc_node(ALIGN(sizeof(*pages) * num_pages, |
f3bc08c5 | 87 | 1 << INTERNODE_CACHE_SHIFT), |
df388b78 | 88 | cpu_to_node(max(bufb->cpu, 0))); |
f3bc08c5 MD |
89 | if (unlikely(!pages)) |
90 | goto pages_error; | |
91 | ||
fd0cebd8 | 92 | bufb->array = lttng_kvmalloc_node(ALIGN(sizeof(*bufb->array) |
f3bc08c5 MD |
93 | * num_subbuf_alloc, |
94 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
95 | GFP_KERNEL | __GFP_NOWARN, |
96 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
97 | if (unlikely(!bufb->array)) |
98 | goto array_error; | |
99 | ||
100 | for (i = 0; i < num_pages; i++) { | |
101 | pages[i] = alloc_pages_node(cpu_to_node(max(bufb->cpu, 0)), | |
df388b78 | 102 | GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 0); |
f3bc08c5 MD |
103 | if (unlikely(!pages[i])) |
104 | goto depopulate; | |
f3bc08c5 MD |
105 | } |
106 | bufb->num_pages_per_subbuf = num_pages_per_subbuf; | |
107 | ||
108 | /* Allocate backend pages array elements */ | |
109 | for (i = 0; i < num_subbuf_alloc; i++) { | |
110 | bufb->array[i] = | |
fd0cebd8 | 111 | lttng_kvzalloc_node(ALIGN( |
f3bc08c5 MD |
112 | sizeof(struct lib_ring_buffer_backend_pages) + |
113 | sizeof(struct lib_ring_buffer_backend_page) | |
114 | * num_pages_per_subbuf, | |
115 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
116 | GFP_KERNEL | __GFP_NOWARN, |
117 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
118 | if (!bufb->array[i]) |
119 | goto free_array; | |
120 | } | |
121 | ||
122 | /* Allocate write-side subbuffer table */ | |
fd0cebd8 | 123 | bufb->buf_wsb = lttng_kvzalloc_node(ALIGN( |
f3bc08c5 MD |
124 | sizeof(struct lib_ring_buffer_backend_subbuffer) |
125 | * num_subbuf, | |
126 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
127 | GFP_KERNEL | __GFP_NOWARN, |
128 | cpu_to_node(max(bufb->cpu, 0))); | |
f3bc08c5 MD |
129 | if (unlikely(!bufb->buf_wsb)) |
130 | goto free_array; | |
131 | ||
132 | for (i = 0; i < num_subbuf; i++) | |
133 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
134 | ||
135 | /* Assign read-side subbuffer table */ | |
136 | if (extra_reader_sb) | |
137 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
138 | num_subbuf_alloc - 1); | |
139 | else | |
140 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
141 | ||
5b3cf4f9 | 142 | /* Allocate subbuffer packet counter table */ |
fd0cebd8 | 143 | bufb->buf_cnt = lttng_kvzalloc_node(ALIGN( |
5b3cf4f9 JD |
144 | sizeof(struct lib_ring_buffer_backend_counts) |
145 | * num_subbuf, | |
146 | 1 << INTERNODE_CACHE_SHIFT), | |
df388b78 MD |
147 | GFP_KERNEL | __GFP_NOWARN, |
148 | cpu_to_node(max(bufb->cpu, 0))); | |
5b3cf4f9 JD |
149 | if (unlikely(!bufb->buf_cnt)) |
150 | goto free_wsb; | |
151 | ||
f3bc08c5 MD |
152 | /* Assign pages to page index */ |
153 | for (i = 0; i < num_subbuf_alloc; i++) { | |
154 | for (j = 0; j < num_pages_per_subbuf; j++) { | |
155 | CHAN_WARN_ON(chanb, page_idx > num_pages); | |
0112cb7b MD |
156 | bufb->array[i]->p[j].virt = page_address(pages[page_idx]); |
157 | bufb->array[i]->p[j].pfn = page_to_pfn(pages[page_idx]); | |
f3bc08c5 MD |
158 | page_idx++; |
159 | } | |
160 | if (config->output == RING_BUFFER_MMAP) { | |
161 | bufb->array[i]->mmap_offset = mmap_offset; | |
162 | mmap_offset += subbuf_size; | |
163 | } | |
164 | } | |
165 | ||
166 | /* | |
167 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
168 | * will not fault. | |
169 | */ | |
6d2a620c | 170 | wrapper_vmalloc_sync_all(); |
1790d63f | 171 | clear_current_oom_origin(); |
df388b78 | 172 | vfree(pages); |
f3bc08c5 MD |
173 | return 0; |
174 | ||
5b3cf4f9 | 175 | free_wsb: |
fd0cebd8 | 176 | lttng_kvfree(bufb->buf_wsb); |
f3bc08c5 MD |
177 | free_array: |
178 | for (i = 0; (i < num_subbuf_alloc && bufb->array[i]); i++) | |
fd0cebd8 | 179 | lttng_kvfree(bufb->array[i]); |
f3bc08c5 MD |
180 | depopulate: |
181 | /* Free all allocated pages */ | |
182 | for (i = 0; (i < num_pages && pages[i]); i++) | |
183 | __free_page(pages[i]); | |
fd0cebd8 | 184 | lttng_kvfree(bufb->array); |
f3bc08c5 | 185 | array_error: |
df388b78 | 186 | vfree(pages); |
f3bc08c5 | 187 | pages_error: |
1790d63f FD |
188 | clear_current_oom_origin(); |
189 | not_enough_pages: | |
f3bc08c5 MD |
190 | return -ENOMEM; |
191 | } | |
192 | ||
193 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
194 | struct channel_backend *chanb, int cpu) | |
195 | { | |
5a8fd222 | 196 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
197 | |
198 | bufb->chan = container_of(chanb, struct channel, backend); | |
199 | bufb->cpu = cpu; | |
200 | ||
201 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
202 | chanb->num_subbuf, | |
203 | chanb->extra_reader_sb); | |
204 | } | |
205 | ||
206 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) | |
207 | { | |
208 | struct channel_backend *chanb = &bufb->chan->backend; | |
209 | unsigned long i, j, num_subbuf_alloc; | |
210 | ||
211 | num_subbuf_alloc = chanb->num_subbuf; | |
212 | if (chanb->extra_reader_sb) | |
213 | num_subbuf_alloc++; | |
214 | ||
fd0cebd8 MJ |
215 | lttng_kvfree(bufb->buf_wsb); |
216 | lttng_kvfree(bufb->buf_cnt); | |
f3bc08c5 MD |
217 | for (i = 0; i < num_subbuf_alloc; i++) { |
218 | for (j = 0; j < bufb->num_pages_per_subbuf; j++) | |
0112cb7b | 219 | __free_page(pfn_to_page(bufb->array[i]->p[j].pfn)); |
fd0cebd8 | 220 | lttng_kvfree(bufb->array[i]); |
f3bc08c5 | 221 | } |
fd0cebd8 | 222 | lttng_kvfree(bufb->array); |
f3bc08c5 MD |
223 | bufb->allocated = 0; |
224 | } | |
225 | ||
226 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) | |
227 | { | |
228 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 229 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
230 | unsigned long num_subbuf_alloc; |
231 | unsigned int i; | |
232 | ||
233 | num_subbuf_alloc = chanb->num_subbuf; | |
234 | if (chanb->extra_reader_sb) | |
235 | num_subbuf_alloc++; | |
236 | ||
237 | for (i = 0; i < chanb->num_subbuf; i++) | |
238 | bufb->buf_wsb[i].id = subbuffer_id(config, 0, 1, i); | |
239 | if (chanb->extra_reader_sb) | |
240 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
241 | num_subbuf_alloc - 1); | |
242 | else | |
243 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
244 | ||
245 | for (i = 0; i < num_subbuf_alloc; i++) { | |
246 | /* Don't reset mmap_offset */ | |
247 | v_set(config, &bufb->array[i]->records_commit, 0); | |
248 | v_set(config, &bufb->array[i]->records_unread, 0); | |
249 | bufb->array[i]->data_size = 0; | |
250 | /* Don't reset backend page and virt addresses */ | |
251 | } | |
252 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
253 | v_set(config, &bufb->records_read, 0); | |
254 | } | |
255 | ||
256 | /* | |
257 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
258 | * each buffer when calling channel_backend_reset. | |
259 | */ | |
260 | void channel_backend_reset(struct channel_backend *chanb) | |
261 | { | |
262 | struct channel *chan = container_of(chanb, struct channel, backend); | |
5a8fd222 | 263 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
264 | |
265 | /* | |
266 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
267 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
268 | * priv, notifiers, config, cpumask and name. | |
269 | */ | |
270 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
271 | } | |
272 | ||
1e367326 MD |
273 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
274 | ||
275 | /* | |
276 | * No need to implement a "dead" callback to do a buffer switch here, | |
277 | * because it will happen when tracing is stopped, or will be done by | |
278 | * switch timer CPU DEAD callback. | |
279 | * We don't free buffers when CPU go away, because it would make trace | |
280 | * data vanish, which is unwanted. | |
281 | */ | |
282 | int lttng_cpuhp_rb_backend_prepare(unsigned int cpu, | |
283 | struct lttng_cpuhp_node *node) | |
284 | { | |
285 | struct channel_backend *chanb = container_of(node, | |
286 | struct channel_backend, cpuhp_prepare); | |
287 | const struct lib_ring_buffer_config *config = &chanb->config; | |
288 | struct lib_ring_buffer *buf; | |
289 | int ret; | |
290 | ||
291 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
292 | ||
293 | buf = per_cpu_ptr(chanb->buf, cpu); | |
294 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
295 | if (ret) { | |
296 | printk(KERN_ERR | |
297 | "ring_buffer_cpu_hp_callback: cpu %d " | |
298 | "buffer creation failed\n", cpu); | |
299 | return ret; | |
300 | } | |
301 | return 0; | |
302 | } | |
303 | EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_backend_prepare); | |
304 | ||
305 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
306 | ||
f3bc08c5 | 307 | #ifdef CONFIG_HOTPLUG_CPU |
1e367326 | 308 | |
f3bc08c5 MD |
309 | /** |
310 | * lib_ring_buffer_cpu_hp_callback - CPU hotplug callback | |
311 | * @nb: notifier block | |
312 | * @action: hotplug action to take | |
313 | * @hcpu: CPU number | |
314 | * | |
315 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
316 | */ | |
317 | static | |
e8f071d5 | 318 | int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, |
f3bc08c5 MD |
319 | unsigned long action, |
320 | void *hcpu) | |
321 | { | |
322 | unsigned int cpu = (unsigned long)hcpu; | |
323 | struct channel_backend *chanb = container_of(nb, struct channel_backend, | |
324 | cpu_hp_notifier); | |
5a8fd222 | 325 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
326 | struct lib_ring_buffer *buf; |
327 | int ret; | |
328 | ||
329 | CHAN_WARN_ON(chanb, config->alloc == RING_BUFFER_ALLOC_GLOBAL); | |
330 | ||
331 | switch (action) { | |
332 | case CPU_UP_PREPARE: | |
333 | case CPU_UP_PREPARE_FROZEN: | |
334 | buf = per_cpu_ptr(chanb->buf, cpu); | |
335 | ret = lib_ring_buffer_create(buf, chanb, cpu); | |
336 | if (ret) { | |
337 | printk(KERN_ERR | |
338 | "ring_buffer_cpu_hp_callback: cpu %d " | |
339 | "buffer creation failed\n", cpu); | |
340 | return NOTIFY_BAD; | |
341 | } | |
342 | break; | |
343 | case CPU_DEAD: | |
344 | case CPU_DEAD_FROZEN: | |
345 | /* No need to do a buffer switch here, because it will happen | |
346 | * when tracing is stopped, or will be done by switch timer CPU | |
347 | * DEAD callback. */ | |
348 | break; | |
349 | } | |
350 | return NOTIFY_OK; | |
351 | } | |
1e367326 | 352 | |
f3bc08c5 MD |
353 | #endif |
354 | ||
1e367326 MD |
355 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
356 | ||
f3bc08c5 MD |
357 | /** |
358 | * channel_backend_init - initialize a channel backend | |
359 | * @chanb: channel backend | |
360 | * @name: channel name | |
361 | * @config: client ring buffer configuration | |
362 | * @priv: client private data | |
363 | * @parent: dentry of parent directory, %NULL for root directory | |
364 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
365 | * @num_subbuf: number of sub-buffers (power of 2) | |
366 | * | |
367 | * Returns channel pointer if successful, %NULL otherwise. | |
368 | * | |
369 | * Creates per-cpu channel buffers using the sizes and attributes | |
370 | * specified. The created channel buffer files will be named | |
371 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
372 | * | |
373 | * Called with CPU hotplug disabled. | |
374 | */ | |
375 | int channel_backend_init(struct channel_backend *chanb, | |
376 | const char *name, | |
377 | const struct lib_ring_buffer_config *config, | |
378 | void *priv, size_t subbuf_size, size_t num_subbuf) | |
379 | { | |
380 | struct channel *chan = container_of(chanb, struct channel, backend); | |
381 | unsigned int i; | |
382 | int ret; | |
383 | ||
384 | if (!name) | |
385 | return -EPERM; | |
386 | ||
f3bc08c5 | 387 | /* Check that the subbuffer size is larger than a page. */ |
2fb46300 MD |
388 | if (subbuf_size < PAGE_SIZE) |
389 | return -EINVAL; | |
f3bc08c5 MD |
390 | |
391 | /* | |
bbda3a00 MD |
392 | * Make sure the number of subbuffers and subbuffer size are |
393 | * power of 2 and nonzero. | |
f3bc08c5 | 394 | */ |
bbda3a00 | 395 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
863497fa | 396 | return -EINVAL; |
bbda3a00 | 397 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
863497fa | 398 | return -EINVAL; |
5140d2b3 MD |
399 | /* |
400 | * Overwrite mode buffers require at least 2 subbuffers per | |
401 | * buffer. | |
402 | */ | |
403 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
404 | return -EINVAL; | |
f3bc08c5 MD |
405 | |
406 | ret = subbuffer_id_check_index(config, num_subbuf); | |
407 | if (ret) | |
408 | return ret; | |
409 | ||
410 | chanb->priv = priv; | |
411 | chanb->buf_size = num_subbuf * subbuf_size; | |
412 | chanb->subbuf_size = subbuf_size; | |
413 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
414 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
415 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
416 | chanb->extra_reader_sb = | |
417 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
418 | chanb->num_subbuf = num_subbuf; | |
419 | strlcpy(chanb->name, name, NAME_MAX); | |
5a8fd222 | 420 | memcpy(&chanb->config, config, sizeof(chanb->config)); |
f3bc08c5 MD |
421 | |
422 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
423 | if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) | |
424 | return -ENOMEM; | |
425 | } | |
426 | ||
427 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
428 | /* Allocating the buffer per-cpu structures */ | |
429 | chanb->buf = alloc_percpu(struct lib_ring_buffer); | |
430 | if (!chanb->buf) | |
431 | goto free_cpumask; | |
432 | ||
1e367326 MD |
433 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
434 | chanb->cpuhp_prepare.component = LTTNG_RING_BUFFER_BACKEND; | |
435 | ret = cpuhp_state_add_instance(lttng_rb_hp_prepare, | |
436 | &chanb->cpuhp_prepare.node); | |
437 | if (ret) | |
438 | goto free_bufs; | |
439 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
440 | ||
441 | { | |
442 | /* | |
443 | * In case of non-hotplug cpu, if the ring-buffer is allocated | |
444 | * in early initcall, it will not be notified of secondary cpus. | |
445 | * In that off case, we need to allocate for all possible cpus. | |
446 | */ | |
f3bc08c5 | 447 | #ifdef CONFIG_HOTPLUG_CPU |
1e367326 MD |
448 | /* |
449 | * buf->backend.allocated test takes care of concurrent CPU | |
450 | * hotplug. | |
451 | * Priority higher than frontend, so we create the ring buffer | |
452 | * before we start the timer. | |
453 | */ | |
454 | chanb->cpu_hp_notifier.notifier_call = | |
455 | lib_ring_buffer_cpu_hp_callback; | |
456 | chanb->cpu_hp_notifier.priority = 5; | |
457 | register_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
458 | ||
459 | get_online_cpus(); | |
460 | for_each_online_cpu(i) { | |
461 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
462 | chanb, i); | |
463 | if (ret) | |
464 | goto free_bufs; /* cpu hotplug locked */ | |
465 | } | |
466 | put_online_cpus(); | |
f3bc08c5 | 467 | #else |
1e367326 MD |
468 | for_each_possible_cpu(i) { |
469 | ret = lib_ring_buffer_create(per_cpu_ptr(chanb->buf, i), | |
470 | chanb, i); | |
471 | if (ret) | |
472 | goto free_bufs; | |
473 | } | |
f3bc08c5 | 474 | #endif |
1e367326 MD |
475 | } |
476 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 MD |
477 | } else { |
478 | chanb->buf = kzalloc(sizeof(struct lib_ring_buffer), GFP_KERNEL); | |
479 | if (!chanb->buf) | |
480 | goto free_cpumask; | |
481 | ret = lib_ring_buffer_create(chanb->buf, chanb, -1); | |
482 | if (ret) | |
483 | goto free_bufs; | |
484 | } | |
485 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
486 | ||
487 | return 0; | |
488 | ||
489 | free_bufs: | |
490 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
1e367326 | 491 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) |
fbbb0005 MD |
492 | /* |
493 | * Teardown of lttng_rb_hp_prepare instance | |
494 | * on "add" error is handled within cpu hotplug, | |
495 | * no teardown to do from the caller. | |
496 | */ | |
1e367326 MD |
497 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
498 | #ifdef CONFIG_HOTPLUG_CPU | |
499 | put_online_cpus(); | |
500 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); | |
501 | #endif | |
502 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 | 503 | for_each_possible_cpu(i) { |
1e367326 MD |
504 | struct lib_ring_buffer *buf = |
505 | per_cpu_ptr(chanb->buf, i); | |
f3bc08c5 MD |
506 | |
507 | if (!buf->backend.allocated) | |
508 | continue; | |
509 | lib_ring_buffer_free(buf); | |
510 | } | |
f3bc08c5 MD |
511 | free_percpu(chanb->buf); |
512 | } else | |
513 | kfree(chanb->buf); | |
514 | free_cpumask: | |
515 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) | |
516 | free_cpumask_var(chanb->cpumask); | |
517 | return -ENOMEM; | |
518 | } | |
519 | ||
520 | /** | |
521 | * channel_backend_unregister_notifiers - unregister notifiers | |
522 | * @chan: the channel | |
523 | * | |
524 | * Holds CPU hotplug. | |
525 | */ | |
526 | void channel_backend_unregister_notifiers(struct channel_backend *chanb) | |
527 | { | |
5a8fd222 | 528 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 529 | |
1e367326 MD |
530 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
531 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) | |
532 | int ret; | |
533 | ||
534 | ret = cpuhp_state_remove_instance(lttng_rb_hp_prepare, | |
535 | &chanb->cpuhp_prepare.node); | |
536 | WARN_ON(ret); | |
537 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ | |
f3bc08c5 | 538 | unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); |
1e367326 MD |
539 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */ |
540 | } | |
f3bc08c5 MD |
541 | } |
542 | ||
543 | /** | |
544 | * channel_backend_free - destroy the channel | |
545 | * @chan: the channel | |
546 | * | |
547 | * Destroy all channel buffers and frees the channel. | |
548 | */ | |
549 | void channel_backend_free(struct channel_backend *chanb) | |
550 | { | |
5a8fd222 | 551 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
552 | unsigned int i; |
553 | ||
554 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
555 | for_each_possible_cpu(i) { | |
556 | struct lib_ring_buffer *buf = per_cpu_ptr(chanb->buf, i); | |
557 | ||
558 | if (!buf->backend.allocated) | |
559 | continue; | |
560 | lib_ring_buffer_free(buf); | |
561 | } | |
562 | free_cpumask_var(chanb->cpumask); | |
563 | free_percpu(chanb->buf); | |
564 | } else { | |
565 | struct lib_ring_buffer *buf = chanb->buf; | |
566 | ||
567 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
568 | lib_ring_buffer_free(buf); | |
569 | kfree(buf); | |
570 | } | |
571 | } | |
572 | ||
573 | /** | |
574 | * lib_ring_buffer_write - write data to a ring_buffer buffer. | |
575 | * @bufb : buffer backend | |
576 | * @offset : offset within the buffer | |
577 | * @src : source address | |
578 | * @len : length to write | |
579 | * @pagecpy : page size copied so far | |
580 | */ | |
581 | void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, | |
bfe529f9 | 582 | const void *src, size_t len, size_t pagecpy) |
f3bc08c5 MD |
583 | { |
584 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 585 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
586 | size_t sbidx, index; |
587 | struct lib_ring_buffer_backend_pages *rpages; | |
588 | unsigned long sb_bindex, id; | |
589 | ||
590 | do { | |
591 | len -= pagecpy; | |
592 | src += pagecpy; | |
593 | offset += pagecpy; | |
594 | sbidx = offset >> chanb->subbuf_size_order; | |
595 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
596 | ||
597 | /* | |
598 | * Underlying layer should never ask for writes across | |
599 | * subbuffers. | |
600 | */ | |
601 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
602 | ||
603 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
604 | id = bufb->buf_wsb[sbidx].id; | |
605 | sb_bindex = subbuffer_id_get_index(config, id); | |
606 | rpages = bufb->array[sb_bindex]; | |
607 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
608 | && subbuffer_id_is_noref(config, id)); | |
609 | lib_ring_buffer_do_copy(config, | |
610 | rpages->p[index].virt | |
611 | + (offset & ~PAGE_MASK), | |
612 | src, pagecpy); | |
613 | } while (unlikely(len != pagecpy)); | |
614 | } | |
615 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); | |
616 | ||
4ea00e4f JD |
617 | |
618 | /** | |
619 | * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. | |
620 | * @bufb : buffer backend | |
621 | * @offset : offset within the buffer | |
622 | * @c : the byte to write | |
623 | * @len : length to write | |
624 | * @pagecpy : page size copied so far | |
625 | */ | |
626 | void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, | |
627 | size_t offset, | |
bfe529f9 | 628 | int c, size_t len, size_t pagecpy) |
4ea00e4f JD |
629 | { |
630 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 631 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
632 | size_t sbidx, index; |
633 | struct lib_ring_buffer_backend_pages *rpages; | |
634 | unsigned long sb_bindex, id; | |
635 | ||
636 | do { | |
637 | len -= pagecpy; | |
638 | offset += pagecpy; | |
639 | sbidx = offset >> chanb->subbuf_size_order; | |
640 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
641 | ||
642 | /* | |
643 | * Underlying layer should never ask for writes across | |
644 | * subbuffers. | |
645 | */ | |
646 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
647 | ||
648 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
649 | id = bufb->buf_wsb[sbidx].id; | |
650 | sb_bindex = subbuffer_id_get_index(config, id); | |
651 | rpages = bufb->array[sb_bindex]; | |
652 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
653 | && subbuffer_id_is_noref(config, id)); | |
654 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
655 | + (offset & ~PAGE_MASK), | |
656 | c, pagecpy); | |
657 | } while (unlikely(len != pagecpy)); | |
658 | } | |
659 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); | |
660 | ||
16f78f3a MD |
661 | /** |
662 | * lib_ring_buffer_strcpy - write string data to a ring_buffer buffer. | |
663 | * @bufb : buffer backend | |
664 | * @offset : offset within the buffer | |
665 | * @src : source address | |
666 | * @len : length to write | |
667 | * @pagecpy : page size copied so far | |
668 | * @pad : character to use for padding | |
669 | */ | |
670 | void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb, | |
671 | size_t offset, const char *src, size_t len, | |
672 | size_t pagecpy, int pad) | |
673 | { | |
674 | struct channel_backend *chanb = &bufb->chan->backend; | |
675 | const struct lib_ring_buffer_config *config = &chanb->config; | |
676 | size_t sbidx, index; | |
677 | struct lib_ring_buffer_backend_pages *rpages; | |
678 | unsigned long sb_bindex, id; | |
679 | int src_terminated = 0; | |
680 | ||
681 | CHAN_WARN_ON(chanb, !len); | |
682 | offset += pagecpy; | |
683 | do { | |
684 | len -= pagecpy; | |
685 | if (!src_terminated) | |
686 | src += pagecpy; | |
687 | sbidx = offset >> chanb->subbuf_size_order; | |
688 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
689 | ||
690 | /* | |
691 | * Underlying layer should never ask for writes across | |
692 | * subbuffers. | |
693 | */ | |
694 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
695 | ||
696 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
697 | id = bufb->buf_wsb[sbidx].id; | |
698 | sb_bindex = subbuffer_id_get_index(config, id); | |
699 | rpages = bufb->array[sb_bindex]; | |
700 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
701 | && subbuffer_id_is_noref(config, id)); | |
702 | ||
703 | if (likely(!src_terminated)) { | |
704 | size_t count, to_copy; | |
705 | ||
706 | to_copy = pagecpy; | |
707 | if (pagecpy == len) | |
708 | to_copy--; /* Final '\0' */ | |
709 | count = lib_ring_buffer_do_strcpy(config, | |
710 | rpages->p[index].virt | |
711 | + (offset & ~PAGE_MASK), | |
712 | src, to_copy); | |
713 | offset += count; | |
714 | /* Padding */ | |
715 | if (unlikely(count < to_copy)) { | |
716 | size_t pad_len = to_copy - count; | |
717 | ||
718 | /* Next pages will have padding */ | |
719 | src_terminated = 1; | |
720 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
721 | + (offset & ~PAGE_MASK), | |
722 | pad, pad_len); | |
723 | offset += pad_len; | |
724 | } | |
725 | } else { | |
726 | size_t pad_len; | |
727 | ||
728 | pad_len = pagecpy; | |
729 | if (pagecpy == len) | |
730 | pad_len--; /* Final '\0' */ | |
731 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
732 | + (offset & ~PAGE_MASK), | |
733 | pad, pad_len); | |
734 | offset += pad_len; | |
735 | } | |
736 | } while (unlikely(len != pagecpy)); | |
737 | /* Ending '\0' */ | |
738 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
739 | '\0', 1); | |
740 | } | |
741 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy); | |
4ea00e4f JD |
742 | |
743 | /** | |
7b8ea3a5 | 744 | * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. |
4ea00e4f JD |
745 | * @bufb : buffer backend |
746 | * @offset : offset within the buffer | |
747 | * @src : source address | |
748 | * @len : length to write | |
749 | * @pagecpy : page size copied so far | |
750 | * | |
751 | * This function deals with userspace pointers, it should never be called | |
752 | * directly without having the src pointer checked with access_ok() | |
753 | * previously. | |
754 | */ | |
7b8ea3a5 | 755 | void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, |
4ea00e4f JD |
756 | size_t offset, |
757 | const void __user *src, size_t len, | |
bfe529f9 | 758 | size_t pagecpy) |
4ea00e4f JD |
759 | { |
760 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 761 | const struct lib_ring_buffer_config *config = &chanb->config; |
4ea00e4f JD |
762 | size_t sbidx, index; |
763 | struct lib_ring_buffer_backend_pages *rpages; | |
764 | unsigned long sb_bindex, id; | |
765 | int ret; | |
766 | ||
767 | do { | |
768 | len -= pagecpy; | |
769 | src += pagecpy; | |
770 | offset += pagecpy; | |
771 | sbidx = offset >> chanb->subbuf_size_order; | |
772 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
773 | ||
774 | /* | |
775 | * Underlying layer should never ask for writes across | |
776 | * subbuffers. | |
777 | */ | |
778 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
779 | ||
780 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
781 | id = bufb->buf_wsb[sbidx].id; | |
782 | sb_bindex = subbuffer_id_get_index(config, id); | |
783 | rpages = bufb->array[sb_bindex]; | |
784 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
785 | && subbuffer_id_is_noref(config, id)); | |
7b8ea3a5 | 786 | ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt |
4ea00e4f JD |
787 | + (offset & ~PAGE_MASK), |
788 | src, pagecpy) != 0; | |
789 | if (ret > 0) { | |
d87a9f03 | 790 | /* Copy failed. */ |
4ea00e4f JD |
791 | _lib_ring_buffer_memset(bufb, offset, 0, len, 0); |
792 | break; /* stop copy */ | |
793 | } | |
794 | } while (unlikely(len != pagecpy)); | |
795 | } | |
7b8ea3a5 | 796 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); |
4ea00e4f | 797 | |
16f78f3a MD |
798 | /** |
799 | * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string data to a ring_buffer buffer. | |
800 | * @bufb : buffer backend | |
801 | * @offset : offset within the buffer | |
802 | * @src : source address | |
803 | * @len : length to write | |
804 | * @pagecpy : page size copied so far | |
805 | * @pad : character to use for padding | |
806 | * | |
807 | * This function deals with userspace pointers, it should never be called | |
808 | * directly without having the src pointer checked with access_ok() | |
809 | * previously. | |
810 | */ | |
811 | void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, | |
812 | size_t offset, const char __user *src, size_t len, | |
813 | size_t pagecpy, int pad) | |
814 | { | |
815 | struct channel_backend *chanb = &bufb->chan->backend; | |
816 | const struct lib_ring_buffer_config *config = &chanb->config; | |
817 | size_t sbidx, index; | |
818 | struct lib_ring_buffer_backend_pages *rpages; | |
819 | unsigned long sb_bindex, id; | |
820 | int src_terminated = 0; | |
821 | ||
822 | offset += pagecpy; | |
823 | do { | |
824 | len -= pagecpy; | |
825 | if (!src_terminated) | |
826 | src += pagecpy; | |
827 | sbidx = offset >> chanb->subbuf_size_order; | |
828 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
829 | ||
830 | /* | |
831 | * Underlying layer should never ask for writes across | |
832 | * subbuffers. | |
833 | */ | |
834 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
835 | ||
836 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
837 | id = bufb->buf_wsb[sbidx].id; | |
838 | sb_bindex = subbuffer_id_get_index(config, id); | |
839 | rpages = bufb->array[sb_bindex]; | |
840 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
841 | && subbuffer_id_is_noref(config, id)); | |
842 | ||
843 | if (likely(!src_terminated)) { | |
844 | size_t count, to_copy; | |
845 | ||
846 | to_copy = pagecpy; | |
847 | if (pagecpy == len) | |
848 | to_copy--; /* Final '\0' */ | |
849 | count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, | |
850 | rpages->p[index].virt | |
851 | + (offset & ~PAGE_MASK), | |
852 | src, to_copy); | |
853 | offset += count; | |
854 | /* Padding */ | |
855 | if (unlikely(count < to_copy)) { | |
856 | size_t pad_len = to_copy - count; | |
857 | ||
858 | /* Next pages will have padding */ | |
859 | src_terminated = 1; | |
860 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
861 | + (offset & ~PAGE_MASK), | |
862 | pad, pad_len); | |
863 | offset += pad_len; | |
864 | } | |
865 | } else { | |
866 | size_t pad_len; | |
867 | ||
868 | pad_len = pagecpy; | |
869 | if (pagecpy == len) | |
870 | pad_len--; /* Final '\0' */ | |
871 | lib_ring_buffer_do_memset(rpages->p[index].virt | |
872 | + (offset & ~PAGE_MASK), | |
873 | pad, pad_len); | |
874 | offset += pad_len; | |
875 | } | |
876 | } while (unlikely(len != pagecpy)); | |
877 | /* Ending '\0' */ | |
878 | lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), | |
879 | '\0', 1); | |
880 | } | |
881 | EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy_from_user_inatomic); | |
882 | ||
f3bc08c5 MD |
883 | /** |
884 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
885 | * @bufb : buffer backend | |
886 | * @offset : offset within the buffer | |
887 | * @dest : destination address | |
888 | * @len : length to copy to destination | |
889 | * | |
890 | * Should be protected by get_subbuf/put_subbuf. | |
891 | * Returns the length copied. | |
892 | */ | |
893 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, | |
894 | void *dest, size_t len) | |
895 | { | |
896 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 897 | const struct lib_ring_buffer_config *config = &chanb->config; |
bfe529f9 | 898 | size_t index, pagecpy, orig_len; |
f3bc08c5 MD |
899 | struct lib_ring_buffer_backend_pages *rpages; |
900 | unsigned long sb_bindex, id; | |
901 | ||
902 | orig_len = len; | |
903 | offset &= chanb->buf_size - 1; | |
904 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
905 | if (unlikely(!len)) | |
906 | return 0; | |
907 | for (;;) { | |
908 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
909 | id = bufb->buf_rsb.id; | |
910 | sb_bindex = subbuffer_id_get_index(config, id); | |
911 | rpages = bufb->array[sb_bindex]; | |
912 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
913 | && subbuffer_id_is_noref(config, id)); | |
914 | memcpy(dest, rpages->p[index].virt + (offset & ~PAGE_MASK), | |
915 | pagecpy); | |
916 | len -= pagecpy; | |
917 | if (likely(!len)) | |
918 | break; | |
919 | dest += pagecpy; | |
920 | offset += pagecpy; | |
921 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
922 | /* | |
923 | * Underlying layer should never ask for reads across | |
924 | * subbuffers. | |
925 | */ | |
926 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
927 | } | |
928 | return orig_len; | |
929 | } | |
930 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read); | |
931 | ||
932 | /** | |
933 | * __lib_ring_buffer_copy_to_user - read data from ring_buffer to userspace | |
934 | * @bufb : buffer backend | |
935 | * @offset : offset within the buffer | |
936 | * @dest : destination userspace address | |
937 | * @len : length to copy to destination | |
938 | * | |
939 | * Should be protected by get_subbuf/put_subbuf. | |
940 | * access_ok() must have been performed on dest addresses prior to call this | |
941 | * function. | |
942 | * Returns -EFAULT on error, 0 if ok. | |
943 | */ | |
944 | int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, | |
945 | size_t offset, void __user *dest, size_t len) | |
946 | { | |
947 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 948 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 | 949 | size_t index; |
88dfd899 | 950 | ssize_t pagecpy; |
f3bc08c5 MD |
951 | struct lib_ring_buffer_backend_pages *rpages; |
952 | unsigned long sb_bindex, id; | |
953 | ||
f3bc08c5 MD |
954 | offset &= chanb->buf_size - 1; |
955 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
956 | if (unlikely(!len)) | |
957 | return 0; | |
958 | for (;;) { | |
959 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
960 | id = bufb->buf_rsb.id; | |
961 | sb_bindex = subbuffer_id_get_index(config, id); | |
962 | rpages = bufb->array[sb_bindex]; | |
963 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
964 | && subbuffer_id_is_noref(config, id)); | |
965 | if (__copy_to_user(dest, | |
966 | rpages->p[index].virt + (offset & ~PAGE_MASK), | |
967 | pagecpy)) | |
968 | return -EFAULT; | |
969 | len -= pagecpy; | |
970 | if (likely(!len)) | |
971 | break; | |
972 | dest += pagecpy; | |
973 | offset += pagecpy; | |
974 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
975 | /* | |
976 | * Underlying layer should never ask for reads across | |
977 | * subbuffers. | |
978 | */ | |
979 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
980 | } | |
981 | return 0; | |
982 | } | |
983 | EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); | |
984 | ||
985 | /** | |
986 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
987 | * @bufb : buffer backend | |
988 | * @offset : offset within the buffer | |
989 | * @dest : destination address | |
990 | * @len : destination's length | |
991 | * | |
61eb4c39 | 992 | * Return string's length, or -EINVAL on error. |
f3bc08c5 | 993 | * Should be protected by get_subbuf/put_subbuf. |
61eb4c39 | 994 | * Destination length should be at least 1 to hold '\0'. |
f3bc08c5 MD |
995 | */ |
996 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, | |
997 | void *dest, size_t len) | |
998 | { | |
999 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1000 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1001 | size_t index; |
1002 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; | |
1003 | char *str; | |
1004 | struct lib_ring_buffer_backend_pages *rpages; | |
1005 | unsigned long sb_bindex, id; | |
1006 | ||
1007 | offset &= chanb->buf_size - 1; | |
1008 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1009 | orig_offset = offset; | |
61eb4c39 MD |
1010 | if (unlikely(!len)) |
1011 | return -EINVAL; | |
f3bc08c5 MD |
1012 | for (;;) { |
1013 | id = bufb->buf_rsb.id; | |
1014 | sb_bindex = subbuffer_id_get_index(config, id); | |
1015 | rpages = bufb->array[sb_bindex]; | |
1016 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1017 | && subbuffer_id_is_noref(config, id)); | |
1018 | str = (char *)rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1019 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
1020 | strpagelen = strnlen(str, pagelen); | |
1021 | if (len) { | |
1022 | pagecpy = min_t(size_t, len, strpagelen); | |
1023 | if (dest) { | |
1024 | memcpy(dest, str, pagecpy); | |
1025 | dest += pagecpy; | |
1026 | } | |
1027 | len -= pagecpy; | |
1028 | } | |
1029 | offset += strpagelen; | |
1030 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1031 | if (strpagelen < pagelen) | |
1032 | break; | |
1033 | /* | |
1034 | * Underlying layer should never ask for reads across | |
1035 | * subbuffers. | |
1036 | */ | |
1037 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
1038 | } | |
1039 | if (dest && len) | |
1040 | ((char *)dest)[0] = 0; | |
1041 | return offset - orig_offset; | |
1042 | } | |
1043 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_cstr); | |
1044 | ||
1045 | /** | |
0112cb7b | 1046 | * lib_ring_buffer_read_get_pfn - Get a page frame number to read from |
f3bc08c5 MD |
1047 | * @bufb : buffer backend |
1048 | * @offset : offset within the buffer | |
1049 | * @virt : pointer to page address (output) | |
1050 | * | |
1051 | * Should be protected by get_subbuf/put_subbuf. | |
0112cb7b | 1052 | * Returns the pointer to the page frame number unsigned long. |
f3bc08c5 | 1053 | */ |
0112cb7b | 1054 | unsigned long *lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, |
f3bc08c5 MD |
1055 | size_t offset, void ***virt) |
1056 | { | |
1057 | size_t index; | |
1058 | struct lib_ring_buffer_backend_pages *rpages; | |
1059 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1060 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1061 | unsigned long sb_bindex, id; |
1062 | ||
1063 | offset &= chanb->buf_size - 1; | |
1064 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1065 | id = bufb->buf_rsb.id; | |
1066 | sb_bindex = subbuffer_id_get_index(config, id); | |
1067 | rpages = bufb->array[sb_bindex]; | |
1068 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1069 | && subbuffer_id_is_noref(config, id)); | |
1070 | *virt = &rpages->p[index].virt; | |
0112cb7b | 1071 | return &rpages->p[index].pfn; |
f3bc08c5 | 1072 | } |
0112cb7b | 1073 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_get_pfn); |
f3bc08c5 MD |
1074 | |
1075 | /** | |
1076 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
1077 | * @bufb : buffer backend | |
1078 | * @offset : offset within the buffer. | |
1079 | * | |
1080 | * Return the address where a given offset is located (for read). | |
1081 | * Should be used to get the current subbuffer header pointer. Given we know | |
759d02c1 MD |
1082 | * it's never on a page boundary, it's safe to read/write directly |
1083 | * from/to this address, as long as the read/write is never bigger than a | |
1084 | * page size. | |
f3bc08c5 MD |
1085 | */ |
1086 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, | |
1087 | size_t offset) | |
1088 | { | |
1089 | size_t index; | |
1090 | struct lib_ring_buffer_backend_pages *rpages; | |
1091 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1092 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1093 | unsigned long sb_bindex, id; |
1094 | ||
1095 | offset &= chanb->buf_size - 1; | |
1096 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1097 | id = bufb->buf_rsb.id; | |
1098 | sb_bindex = subbuffer_id_get_index(config, id); | |
1099 | rpages = bufb->array[sb_bindex]; | |
1100 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1101 | && subbuffer_id_is_noref(config, id)); | |
1102 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1103 | } | |
1104 | EXPORT_SYMBOL_GPL(lib_ring_buffer_read_offset_address); | |
1105 | ||
1106 | /** | |
1107 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
1108 | * @bufb : buffer backend | |
1109 | * @offset : offset within the buffer. | |
1110 | * | |
1111 | * Return the address where a given offset is located. | |
1112 | * Should be used to get the current subbuffer header pointer. Given we know | |
1113 | * it's always at the beginning of a page, it's safe to write directly to this | |
1114 | * address, as long as the write is never bigger than a page size. | |
1115 | */ | |
1116 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, | |
1117 | size_t offset) | |
1118 | { | |
1119 | size_t sbidx, index; | |
1120 | struct lib_ring_buffer_backend_pages *rpages; | |
1121 | struct channel_backend *chanb = &bufb->chan->backend; | |
5a8fd222 | 1122 | const struct lib_ring_buffer_config *config = &chanb->config; |
f3bc08c5 MD |
1123 | unsigned long sb_bindex, id; |
1124 | ||
1125 | offset &= chanb->buf_size - 1; | |
1126 | sbidx = offset >> chanb->subbuf_size_order; | |
1127 | index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; | |
1128 | id = bufb->buf_wsb[sbidx].id; | |
1129 | sb_bindex = subbuffer_id_get_index(config, id); | |
1130 | rpages = bufb->array[sb_bindex]; | |
1131 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
1132 | && subbuffer_id_is_noref(config, id)); | |
1133 | return rpages->p[index].virt + (offset & ~PAGE_MASK); | |
1134 | } | |
1135 | EXPORT_SYMBOL_GPL(lib_ring_buffer_offset_address); |