Commit | Line | Data |
---|---|---|
1c8284eb MD |
1 | /* |
2 | * ltt-relay-alloc.c | |
3 | * | |
4 | * Copyright (C) 2008,2009 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) | |
5 | * | |
6 | * Dual LGPL v2.1/GPL v2 license. | |
7 | */ | |
8 | ||
9 | #include <linux/errno.h> | |
10 | #include <linux/stddef.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/string.h> | |
14 | #include <linux/vmalloc.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/cpu.h> | |
17 | #include <linux/bitops.h> | |
18 | #include <linux/delay.h> | |
19 | ||
20 | #include "ltt-relay.h" | |
21 | #include "ltt-tracer.h" | |
22 | #include "ltt-relay-lockless.h" /* for cpu hotplug */ | |
23 | ||
24 | /** | |
25 | * ltt_chanbuf_allocate - allocate a channel buffer | |
26 | * @buf: the buffer struct | |
27 | * @size: total size of the buffer | |
28 | * @n_sb: number of subbuffers | |
29 | * @extra_reader_sb: need extra subbuffer for reader | |
30 | */ | |
31 | static | |
32 | int ltt_chanbuf_allocate(struct ltt_chanbuf_alloc *buf, size_t size, | |
33 | size_t n_sb, int extra_reader_sb) | |
34 | { | |
35 | long i, j, n_pages, n_pages_per_sb, page_idx = 0; | |
36 | struct page **pages; | |
37 | void **virt; | |
38 | ||
39 | n_pages = size >> PAGE_SHIFT; | |
40 | n_pages_per_sb = n_pages >> get_count_order(n_sb); | |
41 | if (extra_reader_sb) | |
42 | n_pages += n_pages_per_sb; /* Add pages for reader */ | |
43 | ||
44 | pages = kmalloc_node(max_t(size_t, sizeof(*pages) * n_pages, | |
45 | 1 << INTERNODE_CACHE_SHIFT), | |
46 | GFP_KERNEL, cpu_to_node(buf->cpu)); | |
47 | if (unlikely(!pages)) | |
48 | goto pages_error; | |
49 | ||
50 | virt = kmalloc_node(ALIGN(sizeof(*virt) * n_pages, | |
51 | 1 << INTERNODE_CACHE_SHIFT), | |
52 | GFP_KERNEL, cpu_to_node(buf->cpu)); | |
53 | if (unlikely(!virt)) | |
54 | goto virt_error; | |
55 | ||
56 | for (i = 0; i < n_pages; i++) { | |
57 | pages[i] = alloc_pages_node(cpu_to_node(buf->cpu), | |
58 | GFP_KERNEL | __GFP_ZERO, 0); | |
59 | if (unlikely(!pages[i])) | |
60 | goto depopulate; | |
61 | virt[i] = page_address(pages[i]); | |
62 | } | |
63 | buf->nr_pages = n_pages; | |
64 | buf->_pages = pages; | |
65 | buf->_virt = virt; | |
66 | ||
67 | /* Allocate write-side page index */ | |
68 | buf->buf_wsb = kzalloc_node(max_t(size_t, | |
69 | sizeof(struct chanbuf_sb) * n_sb, | |
70 | 1 << INTERNODE_CACHE_SHIFT), | |
71 | GFP_KERNEL, cpu_to_node(buf->cpu)); | |
72 | if (unlikely(!buf->buf_wsb)) | |
73 | goto depopulate; | |
74 | ||
75 | for (i = 0; i < n_sb; i++) { | |
76 | buf->buf_wsb[i].pages = | |
77 | kzalloc_node(max_t(size_t, | |
78 | sizeof(struct chanbuf_page) * n_pages_per_sb, | |
79 | 1 << INTERNODE_CACHE_SHIFT), | |
80 | GFP_KERNEL, cpu_to_node(buf->cpu)); | |
81 | if (!buf->buf_wsb[i].pages) | |
82 | goto free_buf_wsb; | |
83 | } | |
84 | ||
85 | if (extra_reader_sb) { | |
86 | /* Allocate read-side page index */ | |
87 | buf->buf_rsb.pages = | |
88 | kzalloc_node(max_t(size_t, | |
89 | sizeof(struct chanbuf_page) * n_pages_per_sb, | |
90 | 1 << INTERNODE_CACHE_SHIFT), | |
91 | GFP_KERNEL, cpu_to_node(buf->cpu)); | |
92 | if (unlikely(!buf->buf_rsb.pages)) | |
93 | goto free_buf_wsb; | |
94 | } else { | |
95 | buf->buf_rsb.pages = buf->buf_wsb[0].pages; | |
96 | } | |
97 | ||
98 | /* Assign pages to write-side page index */ | |
99 | for (i = 0; i < n_sb; i++) { | |
100 | for (j = 0; j < n_pages_per_sb; j++) { | |
101 | WARN_ON(page_idx > n_pages); | |
102 | buf->buf_wsb[i].pages[j].virt = virt[page_idx]; | |
103 | buf->buf_wsb[i].pages[j].page = pages[page_idx]; | |
104 | page_idx++; | |
105 | } | |
106 | RCHAN_SB_SET_NOREF(buf->buf_wsb[i].pages); | |
107 | } | |
108 | ||
109 | if (extra_reader_sb) { | |
110 | for (j = 0; j < n_pages_per_sb; j++) { | |
111 | WARN_ON(page_idx > n_pages); | |
112 | buf->buf_rsb.pages[j].virt = virt[page_idx]; | |
113 | buf->buf_rsb.pages[j].page = pages[page_idx]; | |
114 | page_idx++; | |
115 | } | |
116 | RCHAN_SB_SET_NOREF(buf->buf_rsb.pages); | |
117 | } | |
118 | ||
119 | /* | |
120 | * If kmalloc ever uses vmalloc underneath, make sure the buffer pages | |
121 | * will not fault. | |
122 | */ | |
123 | vmalloc_sync_all(); | |
124 | return 0; | |
125 | ||
126 | free_buf_wsb: | |
127 | for (i = 0; i < n_sb; i++) { | |
128 | RCHAN_SB_CLEAR_NOREF(buf->buf_wsb[i].pages); | |
129 | kfree(buf->buf_wsb[i].pages); | |
130 | } | |
131 | kfree(buf->buf_wsb); | |
132 | depopulate: | |
133 | /* | |
134 | * Free all pages from [ i - 1 down to 0 ]. | |
135 | * If i = 0, don't free anything. | |
136 | */ | |
137 | for (i--; i >= 0; i--) | |
138 | __free_page(pages[i]); | |
139 | kfree(virt); | |
140 | virt_error: | |
141 | kfree(pages); | |
142 | pages_error: | |
143 | return -ENOMEM; | |
144 | } | |
145 | ||
146 | int ltt_chanbuf_alloc_create(struct ltt_chanbuf_alloc *buf, | |
147 | struct ltt_chan_alloc *chan, int cpu) | |
148 | { | |
149 | int ret = 0; | |
150 | ||
151 | ret = ltt_chanbuf_allocate(buf, chan->buf_size, chan->n_sb, | |
152 | chan->extra_reader_sb); | |
153 | if (ret) | |
154 | goto end; | |
155 | ||
156 | buf->chan = chan; | |
157 | buf->cpu = cpu; | |
158 | end: | |
159 | return ret; | |
160 | } | |
161 | ||
162 | void ltt_chanbuf_alloc_free(struct ltt_chanbuf_alloc *buf) | |
163 | { | |
164 | struct ltt_chan_alloc *chan = buf->chan; | |
165 | struct page **pages; | |
166 | long i; | |
167 | ||
168 | /* Destroy index */ | |
169 | if (chan->extra_reader_sb) { | |
170 | RCHAN_SB_CLEAR_NOREF(buf->buf_rsb.pages); | |
171 | kfree(buf->buf_rsb.pages); | |
172 | } | |
173 | for (i = 0; i < chan->n_sb; i++) { | |
174 | RCHAN_SB_CLEAR_NOREF(buf->buf_wsb[i].pages); | |
175 | kfree(buf->buf_wsb[i].pages); | |
176 | } | |
177 | kfree(buf->buf_wsb); | |
178 | ||
179 | /* Destroy pages */ | |
180 | pages = buf->_pages; | |
181 | for (i = 0; i < buf->nr_pages; i++) | |
182 | __free_page(pages[i]); | |
183 | kfree(buf->_pages); | |
184 | kfree(buf->_virt); | |
185 | buf->allocated = 0; | |
186 | } | |
187 | ||
188 | /** | |
189 | * ltt_relay_hotcpu_callback - CPU hotplug callback | |
190 | * @nb: notifier block | |
191 | * @action: hotplug action to take | |
192 | * @hcpu: CPU number | |
193 | * | |
194 | * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) | |
195 | */ | |
196 | static | |
197 | int __cpuinit ltt_relay_hotcpu_callback(struct notifier_block *nb, | |
198 | unsigned long action, | |
199 | void *hcpu) | |
200 | { | |
201 | unsigned int cpu = (unsigned long)hcpu; | |
202 | struct ltt_trace *trace; | |
203 | struct ltt_chan *chan; | |
204 | struct ltt_chanbuf *buf; | |
205 | int ret, i; | |
206 | ||
207 | switch (action) { | |
208 | case CPU_UP_PREPARE: | |
209 | case CPU_UP_PREPARE_FROZEN: | |
210 | /* | |
211 | * CPU hotplug lock protects trace lock from this callback. | |
212 | */ | |
213 | __list_for_each_entry_rcu(trace, <t_traces.head, list) { | |
214 | for (i = 0; i < trace->nr_channels; i++) { | |
215 | chan = &trace->channels[i]; | |
216 | buf = per_cpu_ptr(chan->a.buf, cpu); | |
217 | ret = ltt_chanbuf_create(buf, &chan->a, cpu); | |
218 | if (ret) { | |
219 | printk(KERN_ERR | |
220 | "ltt_relay_hotcpu_callback: cpu %d " | |
221 | "buffer creation failed\n", cpu); | |
222 | return NOTIFY_BAD; | |
223 | } | |
224 | ||
225 | } | |
226 | } | |
227 | break; | |
228 | case CPU_DEAD: | |
229 | case CPU_DEAD_FROZEN: | |
230 | /* No need to do a buffer switch here, because it will happen | |
231 | * when tracing is stopped, or will be done by switch timer CPU | |
232 | * DEAD callback. */ | |
233 | break; | |
234 | } | |
235 | return NOTIFY_OK; | |
236 | } | |
237 | ||
238 | /* | |
239 | * Must be called with either trace lock or rcu read lock sched held. | |
240 | */ | |
241 | void ltt_chan_for_each_channel(void (*cb) (struct ltt_chanbuf *buf), int cpu) | |
242 | { | |
243 | struct ltt_trace *trace; | |
244 | struct ltt_chan *chan; | |
245 | struct ltt_chanbuf *buf; | |
246 | int i; | |
247 | ||
248 | __list_for_each_entry_rcu(trace, <t_traces.head, list) { | |
249 | for (i = 0; i < trace->nr_channels; i++) { | |
250 | chan = &trace->channels[i]; | |
251 | if (!chan->active) | |
252 | continue; | |
253 | buf = per_cpu_ptr(chan->a.buf, cpu); | |
254 | cb(buf); | |
255 | } | |
256 | } | |
257 | } | |
258 | ||
259 | /** | |
260 | * ltt_chan_create - create a new relay channel | |
261 | * @chan: channel | |
262 | * @trace: trace | |
263 | * @base_filename: base name of files to create | |
264 | * @parent: dentry of parent directory, %NULL for root directory | |
265 | * @sb_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
266 | * @n_sb: number of sub-buffers (power of 2) | |
267 | * @extra_reader_sb: allocate an extra subbuffer for the reader | |
268 | * @overwrite: channel is in overwrite mode | |
269 | * | |
270 | * Returns channel pointer if successful, %NULL otherwise. | |
271 | * | |
272 | * Creates per-cpu channel buffers using the sizes and attributes | |
273 | * specified. The created channel buffer files will be named | |
274 | * base_filename_0...base_filename_N-1. File permissions will | |
275 | * be %S_IRUSR. | |
276 | */ | |
277 | int ltt_chan_alloc_init(struct ltt_chan_alloc *chan, struct ltt_trace *trace, | |
278 | const char *base_filename, | |
279 | struct dentry *parent, size_t sb_size, | |
280 | size_t n_sb, int extra_reader_sb, int overwrite) | |
281 | { | |
282 | unsigned int i; | |
283 | int ret; | |
284 | ||
285 | if (!base_filename) | |
286 | return -EPERM; | |
287 | ||
288 | if (!(sb_size && n_sb)) | |
289 | return -EPERM; | |
290 | ||
291 | /* Check that the subbuffer size is larger than a page. */ | |
292 | WARN_ON_ONCE(sb_size < PAGE_SIZE); | |
293 | ||
294 | /* | |
295 | * Make sure the number of subbuffers and subbuffer size are power of 2. | |
296 | */ | |
297 | WARN_ON_ONCE(hweight32(sb_size) != 1); | |
298 | WARN_ON(hweight32(n_sb) != 1); | |
299 | ||
300 | chan->trace = trace; | |
301 | chan->buf_size = n_sb * sb_size; | |
302 | chan->sb_size = sb_size; | |
303 | chan->sb_size_order = get_count_order(sb_size); | |
304 | chan->n_sb_order = get_count_order(n_sb); | |
305 | chan->extra_reader_sb = extra_reader_sb; | |
306 | chan->n_sb = n_sb; | |
307 | chan->parent = parent; | |
308 | strlcpy(chan->filename, base_filename, NAME_MAX); | |
309 | kref_init(&chan->kref); | |
310 | kref_get(&chan->trace->kref); | |
311 | ||
312 | /* Allocating the child structure */ | |
313 | chan->buf = alloc_percpu(struct ltt_chanbuf); | |
314 | if (!chan->buf) | |
315 | goto free_chan; | |
316 | ||
317 | for_each_online_cpu(i) { | |
318 | ret = ltt_chanbuf_create(per_cpu_ptr(chan->buf, i), chan, i); | |
319 | if (ret) | |
320 | goto free_bufs; | |
321 | } | |
322 | ||
323 | return 0; | |
324 | ||
325 | free_bufs: | |
326 | for_each_possible_cpu(i) { | |
327 | struct ltt_chanbuf *buf = per_cpu_ptr(chan->buf, i); | |
328 | ||
329 | if (!buf->a.allocated) | |
330 | continue; | |
331 | ltt_chanbuf_remove_file(buf); | |
332 | ltt_chanbuf_free(buf); | |
333 | } | |
334 | free_percpu(chan->buf); | |
335 | free_chan: | |
336 | kref_put(&chan->kref, ltt_chan_free); | |
337 | return -ENOMEM; | |
338 | } | |
339 | ||
340 | /** | |
341 | * ltt_chan_alloc_remove_files - remove channel files. | |
342 | * @chan: the channel | |
343 | * | |
344 | * Remove all channel files and wait for dentry use counts to become zero. | |
345 | */ | |
346 | void ltt_chan_alloc_remove_files(struct ltt_chan_alloc *chan) | |
347 | { | |
348 | unsigned int i; | |
349 | struct dentry *dentry; | |
350 | ||
351 | for_each_possible_cpu(i) { | |
352 | struct ltt_chanbuf *buf = per_cpu_ptr(chan->buf, i); | |
353 | ||
354 | if (!buf->a.allocated) | |
355 | continue; | |
356 | dentry = dget(buf->a.dentry); | |
357 | ltt_chanbuf_remove_file(buf); | |
358 | /* TODO: wait / wakeup instead */ | |
359 | /* | |
360 | * Wait for every reference to the dentry to be gone, | |
361 | * except us. | |
362 | */ | |
363 | while (atomic_read(&dentry->d_count) != 1) | |
364 | msleep(100); | |
365 | dput(dentry); | |
366 | } | |
367 | } | |
368 | ||
369 | /** | |
370 | * ltt_chan_alloc_free - destroy the channel | |
371 | * @chan: the channel | |
372 | * | |
373 | * Destroy all channel buffers and frees the channel. | |
374 | */ | |
375 | void ltt_chan_alloc_free(struct ltt_chan_alloc *chan) | |
376 | { | |
377 | unsigned int i; | |
378 | ||
379 | for_each_possible_cpu(i) { | |
380 | struct ltt_chanbuf *buf = per_cpu_ptr(chan->buf, i); | |
381 | ||
382 | if (!buf->a.allocated) | |
383 | continue; | |
384 | ltt_chanbuf_free(buf); | |
385 | } | |
386 | free_percpu(chan->buf); | |
387 | kref_put(&chan->trace->kref, ltt_release_trace); | |
388 | wake_up_interruptible(&chan->trace->kref_wq); | |
389 | } | |
390 | ||
391 | /** | |
392 | * _ltt_relay_write - write data to a ltt_relay buffer. | |
393 | * @bufa : buffer | |
394 | * @offset : offset within the buffer | |
395 | * @src : source address | |
396 | * @len : length to write | |
397 | * @pagecpy : page size copied so far | |
398 | */ | |
399 | void _ltt_relay_write(struct ltt_chanbuf_alloc *bufa, size_t offset, | |
400 | const void *src, size_t len, ssize_t pagecpy) | |
401 | { | |
402 | struct ltt_chan_alloc *chana = bufa->chan; | |
403 | size_t sbidx, index; | |
404 | struct chanbuf_page *rpages; | |
405 | ||
406 | do { | |
407 | len -= pagecpy; | |
408 | src += pagecpy; | |
409 | offset += pagecpy; | |
410 | sbidx = offset >> chana->sb_size_order; | |
411 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
412 | ||
413 | /* | |
414 | * Underlying layer should never ask for writes across | |
415 | * subbuffers. | |
416 | */ | |
417 | WARN_ON(offset >= chana->buf_size); | |
418 | ||
419 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
420 | rpages = bufa->buf_wsb[sbidx].pages; | |
421 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
422 | ltt_relay_do_copy(rpages[index].virt + (offset & ~PAGE_MASK), | |
423 | src, pagecpy); | |
424 | } while (unlikely(len != pagecpy)); | |
425 | } | |
426 | EXPORT_SYMBOL_GPL(_ltt_relay_write); | |
427 | ||
428 | /** | |
429 | * _ltt_relay_strncpy_fixup - Fix an incomplete string in a ltt_relay buffer. | |
430 | * @bufa : buffer | |
431 | * @offset : offset within the buffer | |
432 | * @len : length to write | |
433 | * @copied: string actually copied | |
434 | * @terminated: does string end with \0 | |
435 | * | |
436 | * Fills string with "X" if incomplete. | |
437 | */ | |
438 | void _ltt_relay_strncpy_fixup(struct ltt_chanbuf_alloc *bufa, size_t offset, | |
439 | size_t len, size_t copied, int terminated) | |
440 | { | |
441 | struct ltt_chan_alloc *chana = bufa->chan; | |
442 | size_t sbidx, index; | |
443 | ssize_t pagecpy; | |
444 | struct chanbuf_page *rpages; | |
445 | ||
446 | if (copied == len) { | |
447 | /* | |
448 | * Deal with non-terminated string. | |
449 | */ | |
450 | WARN_ON_ONCE(terminated); | |
451 | offset += copied - 1; | |
452 | sbidx = offset >> chana->sb_size_order; | |
453 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
454 | /* | |
455 | * Underlying layer should never ask for writes across | |
456 | * subbuffers. | |
457 | */ | |
458 | WARN_ON(offset >= chana->buf_size); | |
459 | rpages = bufa->buf_wsb[sbidx].pages; | |
460 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
461 | ltt_relay_do_memset(rpages[index].virt + (offset & ~PAGE_MASK), | |
462 | '\0', 1); | |
463 | return; | |
464 | } | |
465 | ||
466 | /* | |
467 | * Deal with incomplete string. | |
468 | * Overwrite string's \0 with X too. | |
469 | */ | |
470 | pagecpy = copied - 1; | |
471 | do { | |
472 | WARN_ON_ONCE(!terminated); | |
473 | len -= pagecpy; | |
474 | offset += pagecpy; | |
475 | sbidx = offset >> chana->sb_size_order; | |
476 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
477 | ||
478 | /* | |
479 | * Underlying layer should never ask for writes across | |
480 | * subbuffers. | |
481 | */ | |
482 | WARN_ON(offset >= chana->buf_size); | |
483 | ||
484 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
485 | rpages = bufa->buf_wsb[sbidx].pages; | |
486 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
487 | ltt_relay_do_memset(rpages[index].virt + (offset & ~PAGE_MASK), | |
488 | 'X', pagecpy); | |
489 | } while (unlikely(len != pagecpy)); | |
490 | /* | |
491 | * Overwrite last 'X' with '\0'. | |
492 | */ | |
493 | offset += pagecpy - 1; | |
494 | sbidx = offset >> chana->sb_size_order; | |
495 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
496 | /* | |
497 | * Underlying layer should never ask for writes across subbuffers. | |
498 | */ | |
499 | WARN_ON(offset >= chana->buf_size); | |
500 | rpages = bufa->buf_wsb[sbidx].pages; | |
501 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
502 | ltt_relay_do_memset(rpages[index].virt + (offset & ~PAGE_MASK), | |
503 | '\0', 1); | |
504 | } | |
505 | EXPORT_SYMBOL_GPL(_ltt_relay_strncpy_fixup); | |
506 | ||
507 | /** | |
508 | * _ltt_relay_strncpy - copy a string to a ltt_relay buffer. | |
509 | * @bufa : buffer | |
510 | * @offset : offset within the buffer | |
511 | * @src : source address | |
512 | * @len : length to write | |
513 | * @pagecpy : page size copied so far | |
514 | */ | |
515 | void _ltt_relay_strncpy(struct ltt_chanbuf_alloc *bufa, size_t offset, | |
516 | const void *src, size_t len, ssize_t pagecpy) | |
517 | { | |
518 | struct ltt_chan_alloc *chana = bufa->chan; | |
519 | size_t sbidx, index, copied; | |
520 | struct chanbuf_page *rpages; | |
521 | int terminated; | |
522 | ||
523 | do { | |
524 | len -= pagecpy; | |
525 | src += pagecpy; | |
526 | offset += pagecpy; | |
527 | sbidx = offset >> chana->sb_size_order; | |
528 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
529 | ||
530 | /* | |
531 | * Underlying layer should never ask for writes across | |
532 | * subbuffers. | |
533 | */ | |
534 | WARN_ON(offset >= chana->buf_size); | |
535 | ||
536 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
537 | rpages = bufa->buf_wsb[sbidx].pages; | |
538 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
539 | copied = ltt_relay_do_strncpy(rpages[index].virt | |
540 | + (offset & ~PAGE_MASK), | |
541 | src, pagecpy, &terminated); | |
542 | if (copied < pagecpy || ((len == pagecpy) && !terminated)) { | |
543 | _ltt_relay_strncpy_fixup(bufa, offset, len, copied, | |
544 | terminated); | |
545 | break; | |
546 | } | |
547 | } while (unlikely(len != pagecpy)); | |
548 | } | |
549 | EXPORT_SYMBOL_GPL(_ltt_relay_strncpy); | |
550 | ||
551 | /** | |
552 | * ltt_relay_read - read data from ltt_relay_buffer. | |
553 | * @bufa : buffer | |
554 | * @offset : offset within the buffer | |
555 | * @dest : destination address | |
556 | * @len : length to write | |
557 | * | |
558 | * Should be protected by get_subbuf/put_subbuf. | |
559 | */ | |
560 | int ltt_relay_read(struct ltt_chanbuf_alloc *bufa, size_t offset, void *dest, | |
561 | size_t len) | |
562 | { | |
563 | struct ltt_chan_alloc *chana = bufa->chan; | |
564 | size_t index; | |
565 | ssize_t pagecpy, orig_len; | |
566 | struct chanbuf_page *rpages; | |
567 | ||
568 | orig_len = len; | |
569 | offset &= chana->buf_size - 1; | |
570 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
571 | if (unlikely(!len)) | |
572 | return 0; | |
573 | for (;;) { | |
574 | pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); | |
575 | rpages = bufa->buf_rsb.pages; | |
576 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
577 | memcpy(dest, rpages[index].virt + (offset & ~PAGE_MASK), | |
578 | pagecpy); | |
579 | len -= pagecpy; | |
580 | if (likely(!len)) | |
581 | break; | |
582 | dest += pagecpy; | |
583 | offset += pagecpy; | |
584 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
585 | /* | |
586 | * Underlying layer should never ask for reads across | |
587 | * subbuffers. | |
588 | */ | |
589 | WARN_ON(offset >= chana->buf_size); | |
590 | } | |
591 | return orig_len; | |
592 | } | |
593 | EXPORT_SYMBOL_GPL(ltt_relay_read); | |
594 | ||
595 | /** | |
596 | * ltt_relay_read_cstr - read a C-style string from ltt_relay_buffer. | |
597 | * @bufa : buffer | |
598 | * @offset : offset within the buffer | |
599 | * @dest : destination address | |
600 | * @len : destination's length | |
601 | * | |
602 | * return string's length | |
603 | * Should be protected by get_subbuf/put_subbuf. | |
604 | */ | |
605 | int ltt_relay_read_cstr(struct ltt_chanbuf_alloc *bufa, size_t offset, | |
606 | void *dest, size_t len) | |
607 | { | |
608 | struct ltt_chan_alloc *chana = bufa->chan; | |
609 | size_t index; | |
610 | ssize_t pagecpy, pagelen, strpagelen, orig_offset; | |
611 | char *str; | |
612 | struct chanbuf_page *rpages; | |
613 | ||
614 | offset &= chana->buf_size - 1; | |
615 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
616 | orig_offset = offset; | |
617 | for (;;) { | |
618 | rpages = bufa->buf_rsb.pages; | |
619 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
620 | str = (char *)rpages[index].virt + (offset & ~PAGE_MASK); | |
621 | pagelen = PAGE_SIZE - (offset & ~PAGE_MASK); | |
622 | strpagelen = strnlen(str, pagelen); | |
623 | if (len) { | |
624 | pagecpy = min_t(size_t, len, strpagelen); | |
625 | if (dest) { | |
626 | memcpy(dest, str, pagecpy); | |
627 | dest += pagecpy; | |
628 | } | |
629 | len -= pagecpy; | |
630 | } | |
631 | offset += strpagelen; | |
632 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
633 | if (strpagelen < pagelen) | |
634 | break; | |
635 | /* | |
636 | * Underlying layer should never ask for reads across | |
637 | * subbuffers. | |
638 | */ | |
639 | WARN_ON(offset >= chana->buf_size); | |
640 | } | |
641 | if (dest && len) | |
642 | ((char *)dest)[0] = 0; | |
643 | return offset - orig_offset; | |
644 | } | |
645 | EXPORT_SYMBOL_GPL(ltt_relay_read_cstr); | |
646 | ||
647 | /** | |
648 | * ltt_relay_read_get_page - Get a whole page to read from | |
649 | * @bufa : buffer | |
650 | * @offset : offset within the buffer | |
651 | * | |
652 | * Should be protected by get_subbuf/put_subbuf. | |
653 | */ | |
654 | struct page *ltt_relay_read_get_page(struct ltt_chanbuf_alloc *bufa, | |
655 | size_t offset) | |
656 | { | |
657 | size_t index; | |
658 | struct chanbuf_page *rpages; | |
659 | struct ltt_chan_alloc *chana = bufa->chan; | |
660 | ||
661 | offset &= chana->buf_size - 1; | |
662 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
663 | rpages = bufa->buf_rsb.pages; | |
664 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
665 | return rpages[index].page; | |
666 | } | |
667 | EXPORT_SYMBOL_GPL(ltt_relay_read_get_page); | |
668 | ||
669 | /** | |
670 | * ltt_relay_read_offset_address - get address of a location within the buffer | |
671 | * @bufa : buffer | |
672 | * @offset : offset within the buffer. | |
673 | * | |
674 | * Return the address where a given offset is located (for read). | |
675 | * Should be used to get the current subbuffer header pointer. Given we know | |
676 | * it's never on a page boundary, it's safe to write directly to this address, | |
677 | * as long as the write is never bigger than a page size. | |
678 | */ | |
679 | void *ltt_relay_read_offset_address(struct ltt_chanbuf_alloc *bufa, | |
680 | size_t offset) | |
681 | { | |
682 | size_t index; | |
683 | struct chanbuf_page *rpages; | |
684 | struct ltt_chan_alloc *chana = bufa->chan; | |
685 | ||
686 | offset &= chana->buf_size - 1; | |
687 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
688 | rpages = bufa->buf_rsb.pages; | |
689 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
690 | return rpages[index].virt + (offset & ~PAGE_MASK); | |
691 | } | |
692 | EXPORT_SYMBOL_GPL(ltt_relay_read_offset_address); | |
693 | ||
694 | /** | |
695 | * ltt_relay_offset_address - get address of a location within the buffer | |
696 | * @bufa : buffer | |
697 | * @offset : offset within the buffer. | |
698 | * | |
699 | * Return the address where a given offset is located. | |
700 | * Should be used to get the current subbuffer header pointer. Given we know | |
701 | * it's never on a page boundary, it's safe to write directly to this address, | |
702 | * as long as the write is never bigger than a page size. | |
703 | */ | |
704 | void *ltt_relay_offset_address(struct ltt_chanbuf_alloc *bufa, size_t offset) | |
705 | { | |
706 | size_t sbidx, index; | |
707 | struct chanbuf_page *rpages; | |
708 | struct ltt_chan_alloc *chana = bufa->chan; | |
709 | ||
710 | offset &= chana->buf_size - 1; | |
711 | sbidx = offset >> chana->sb_size_order; | |
712 | index = (offset & (chana->sb_size - 1)) >> PAGE_SHIFT; | |
713 | rpages = bufa->buf_wsb[sbidx].pages; | |
714 | WARN_ON_ONCE(RCHAN_SB_IS_NOREF(rpages)); | |
715 | return rpages[index].virt + (offset & ~PAGE_MASK); | |
716 | } | |
717 | EXPORT_SYMBOL_GPL(ltt_relay_offset_address); | |
718 | ||
719 | static __init int ltt_relay_alloc_init(void) | |
720 | { | |
721 | hotcpu_notifier(ltt_relay_hotcpu_callback, 5); | |
722 | ltt_relay_init(); | |
723 | return 0; | |
724 | } | |
725 | ||
726 | static void __exit ltt_relay_alloc_exit(void) | |
727 | { | |
728 | ltt_relay_exit(); | |
729 | } | |
730 | ||
731 | module_init(ltt_relay_alloc_init); | |
732 | module_exit(ltt_relay_alloc_exit); |