Commit | Line | Data |
---|---|---|
a4bd217b JG |
1 | /* |
2 | * Copyright (C) 2016 CNEX Labs | |
3 | * Initial release: Javier Gonzalez <javier@cnexlabs.com> | |
4 | * | |
5 | * Based upon the circular ringbuffer. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License version | |
9 | * 2 as published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, but | |
12 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * pblk-rb.c - pblk's write buffer | |
17 | */ | |
18 | ||
19 | #include <linux/circ_buf.h> | |
20 | ||
21 | #include "pblk.h" | |
22 | ||
23 | static DECLARE_RWSEM(pblk_rb_lock); | |
24 | ||
25 | void pblk_rb_data_free(struct pblk_rb *rb) | |
26 | { | |
27 | struct pblk_rb_pages *p, *t; | |
28 | ||
29 | down_write(&pblk_rb_lock); | |
30 | list_for_each_entry_safe(p, t, &rb->pages, list) { | |
31 | free_pages((unsigned long)page_address(p->pages), p->order); | |
32 | list_del(&p->list); | |
33 | kfree(p); | |
34 | } | |
35 | up_write(&pblk_rb_lock); | |
36 | } | |
37 | ||
38 | /* | |
39 | * Initialize ring buffer. The data and metadata buffers must be previously | |
40 | * allocated and their size must be a power of two | |
41 | * (Documentation/circular-buffers.txt) | |
42 | */ | |
43 | int pblk_rb_init(struct pblk_rb *rb, struct pblk_rb_entry *rb_entry_base, | |
44 | unsigned int power_size, unsigned int power_seg_sz) | |
45 | { | |
46 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
47 | unsigned int init_entry = 0; | |
48 | unsigned int alloc_order = power_size; | |
49 | unsigned int max_order = MAX_ORDER - 1; | |
50 | unsigned int order, iter; | |
51 | ||
52 | down_write(&pblk_rb_lock); | |
53 | rb->entries = rb_entry_base; | |
54 | rb->seg_size = (1 << power_seg_sz); | |
55 | rb->nr_entries = (1 << power_size); | |
56 | rb->mem = rb->subm = rb->sync = rb->l2p_update = 0; | |
57 | rb->sync_point = EMPTY_ENTRY; | |
58 | ||
59 | spin_lock_init(&rb->w_lock); | |
60 | spin_lock_init(&rb->s_lock); | |
61 | ||
62 | INIT_LIST_HEAD(&rb->pages); | |
63 | ||
64 | if (alloc_order >= max_order) { | |
65 | order = max_order; | |
66 | iter = (1 << (alloc_order - max_order)); | |
67 | } else { | |
68 | order = alloc_order; | |
69 | iter = 1; | |
70 | } | |
71 | ||
72 | do { | |
73 | struct pblk_rb_entry *entry; | |
74 | struct pblk_rb_pages *page_set; | |
75 | void *kaddr; | |
76 | unsigned long set_size; | |
77 | int i; | |
78 | ||
79 | page_set = kmalloc(sizeof(struct pblk_rb_pages), GFP_KERNEL); | |
80 | if (!page_set) { | |
81 | up_write(&pblk_rb_lock); | |
82 | return -ENOMEM; | |
83 | } | |
84 | ||
85 | page_set->order = order; | |
86 | page_set->pages = alloc_pages(GFP_KERNEL, order); | |
87 | if (!page_set->pages) { | |
88 | kfree(page_set); | |
89 | pblk_rb_data_free(rb); | |
90 | up_write(&pblk_rb_lock); | |
91 | return -ENOMEM; | |
92 | } | |
93 | kaddr = page_address(page_set->pages); | |
94 | ||
95 | entry = &rb->entries[init_entry]; | |
96 | entry->data = kaddr; | |
97 | entry->cacheline = pblk_cacheline_to_addr(init_entry++); | |
98 | entry->w_ctx.flags = PBLK_WRITABLE_ENTRY; | |
99 | ||
100 | set_size = (1 << order); | |
101 | for (i = 1; i < set_size; i++) { | |
102 | entry = &rb->entries[init_entry]; | |
103 | entry->cacheline = pblk_cacheline_to_addr(init_entry++); | |
104 | entry->data = kaddr + (i * rb->seg_size); | |
105 | entry->w_ctx.flags = PBLK_WRITABLE_ENTRY; | |
106 | bio_list_init(&entry->w_ctx.bios); | |
107 | } | |
108 | ||
109 | list_add_tail(&page_set->list, &rb->pages); | |
110 | iter--; | |
111 | } while (iter > 0); | |
112 | up_write(&pblk_rb_lock); | |
113 | ||
114 | #ifdef CONFIG_NVM_DEBUG | |
115 | atomic_set(&rb->inflight_sync_point, 0); | |
116 | #endif | |
117 | ||
118 | /* | |
119 | * Initialize rate-limiter, which controls access to the write buffer | |
120 | * but user and GC I/O | |
121 | */ | |
122 | pblk_rl_init(&pblk->rl, rb->nr_entries); | |
123 | ||
124 | return 0; | |
125 | } | |
126 | ||
127 | /* | |
128 | * pblk_rb_calculate_size -- calculate the size of the write buffer | |
129 | */ | |
130 | unsigned int pblk_rb_calculate_size(unsigned int nr_entries) | |
131 | { | |
132 | /* Alloc a write buffer that can at least fit 128 entries */ | |
133 | return (1 << max(get_count_order(nr_entries), 7)); | |
134 | } | |
135 | ||
136 | void *pblk_rb_entries_ref(struct pblk_rb *rb) | |
137 | { | |
138 | return rb->entries; | |
139 | } | |
140 | ||
141 | static void clean_wctx(struct pblk_w_ctx *w_ctx) | |
142 | { | |
143 | int flags; | |
144 | ||
145 | try: | |
146 | flags = READ_ONCE(w_ctx->flags); | |
147 | if (!(flags & PBLK_SUBMITTED_ENTRY)) | |
148 | goto try; | |
149 | ||
150 | /* Release flags on context. Protect from writes and reads */ | |
151 | smp_store_release(&w_ctx->flags, PBLK_WRITABLE_ENTRY); | |
152 | pblk_ppa_set_empty(&w_ctx->ppa); | |
153 | } | |
154 | ||
155 | #define pblk_rb_ring_count(head, tail, size) CIRC_CNT(head, tail, size) | |
156 | #define pblk_rb_ring_space(rb, head, tail, size) \ | |
157 | (CIRC_SPACE(head, tail, size)) | |
158 | ||
159 | /* | |
160 | * Buffer space is calculated with respect to the back pointer signaling | |
161 | * synchronized entries to the media. | |
162 | */ | |
163 | static unsigned int pblk_rb_space(struct pblk_rb *rb) | |
164 | { | |
165 | unsigned int mem = READ_ONCE(rb->mem); | |
166 | unsigned int sync = READ_ONCE(rb->sync); | |
167 | ||
168 | return pblk_rb_ring_space(rb, mem, sync, rb->nr_entries); | |
169 | } | |
170 | ||
171 | /* | |
172 | * Buffer count is calculated with respect to the submission entry signaling the | |
173 | * entries that are available to send to the media | |
174 | */ | |
175 | unsigned int pblk_rb_read_count(struct pblk_rb *rb) | |
176 | { | |
177 | unsigned int mem = READ_ONCE(rb->mem); | |
178 | unsigned int subm = READ_ONCE(rb->subm); | |
179 | ||
180 | return pblk_rb_ring_count(mem, subm, rb->nr_entries); | |
181 | } | |
182 | ||
183 | unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int nr_entries) | |
184 | { | |
185 | unsigned int subm; | |
186 | ||
187 | subm = READ_ONCE(rb->subm); | |
188 | /* Commit read means updating submission pointer */ | |
189 | smp_store_release(&rb->subm, | |
190 | (subm + nr_entries) & (rb->nr_entries - 1)); | |
191 | ||
192 | return subm; | |
193 | } | |
194 | ||
195 | static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int *l2p_upd, | |
196 | unsigned int to_update) | |
197 | { | |
198 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
199 | struct pblk_line *line; | |
200 | struct pblk_rb_entry *entry; | |
201 | struct pblk_w_ctx *w_ctx; | |
202 | unsigned int i; | |
203 | ||
204 | for (i = 0; i < to_update; i++) { | |
205 | entry = &rb->entries[*l2p_upd]; | |
206 | w_ctx = &entry->w_ctx; | |
207 | ||
208 | pblk_update_map_dev(pblk, w_ctx->lba, w_ctx->ppa, | |
209 | entry->cacheline); | |
210 | ||
211 | line = &pblk->lines[pblk_tgt_ppa_to_line(w_ctx->ppa)]; | |
212 | kref_put(&line->ref, pblk_line_put); | |
213 | clean_wctx(w_ctx); | |
214 | *l2p_upd = (*l2p_upd + 1) & (rb->nr_entries - 1); | |
215 | } | |
216 | ||
217 | return 0; | |
218 | } | |
219 | ||
220 | /* | |
221 | * When we move the l2p_update pointer, we update the l2p table - lookups will | |
222 | * point to the physical address instead of to the cacheline in the write buffer | |
223 | * from this moment on. | |
224 | */ | |
225 | static int pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int nr_entries, | |
226 | unsigned int mem, unsigned int sync) | |
227 | { | |
228 | unsigned int space, count; | |
229 | int ret = 0; | |
230 | ||
231 | lockdep_assert_held(&rb->w_lock); | |
232 | ||
233 | /* Update l2p only as buffer entries are being overwritten */ | |
234 | space = pblk_rb_ring_space(rb, mem, rb->l2p_update, rb->nr_entries); | |
235 | if (space > nr_entries) | |
236 | goto out; | |
237 | ||
238 | count = nr_entries - space; | |
239 | /* l2p_update used exclusively under rb->w_lock */ | |
240 | ret = __pblk_rb_update_l2p(rb, &rb->l2p_update, count); | |
241 | ||
242 | out: | |
243 | return ret; | |
244 | } | |
245 | ||
246 | /* | |
247 | * Update the l2p entry for all sectors stored on the write buffer. This means | |
248 | * that all future lookups to the l2p table will point to a device address, not | |
249 | * to the cacheline in the write buffer. | |
250 | */ | |
251 | void pblk_rb_sync_l2p(struct pblk_rb *rb) | |
252 | { | |
253 | unsigned int sync; | |
254 | unsigned int to_update; | |
255 | ||
256 | spin_lock(&rb->w_lock); | |
257 | ||
258 | /* Protect from reads and writes */ | |
259 | sync = smp_load_acquire(&rb->sync); | |
260 | ||
261 | to_update = pblk_rb_ring_count(sync, rb->l2p_update, rb->nr_entries); | |
262 | __pblk_rb_update_l2p(rb, &rb->l2p_update, to_update); | |
263 | ||
264 | spin_unlock(&rb->w_lock); | |
265 | } | |
266 | ||
267 | /* | |
268 | * Write @nr_entries to ring buffer from @data buffer if there is enough space. | |
269 | * Typically, 4KB data chunks coming from a bio will be copied to the ring | |
270 | * buffer, thus the write will fail if not all incoming data can be copied. | |
271 | * | |
272 | */ | |
273 | static void __pblk_rb_write_entry(struct pblk_rb *rb, void *data, | |
274 | struct pblk_w_ctx w_ctx, | |
275 | struct pblk_rb_entry *entry) | |
276 | { | |
277 | memcpy(entry->data, data, rb->seg_size); | |
278 | ||
279 | entry->w_ctx.lba = w_ctx.lba; | |
280 | entry->w_ctx.ppa = w_ctx.ppa; | |
281 | } | |
282 | ||
283 | void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data, | |
284 | struct pblk_w_ctx w_ctx, unsigned int ring_pos) | |
285 | { | |
286 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
287 | struct pblk_rb_entry *entry; | |
288 | int flags; | |
289 | ||
290 | entry = &rb->entries[ring_pos]; | |
291 | flags = READ_ONCE(entry->w_ctx.flags); | |
292 | #ifdef CONFIG_NVM_DEBUG | |
293 | /* Caller must guarantee that the entry is free */ | |
294 | BUG_ON(!(flags & PBLK_WRITABLE_ENTRY)); | |
295 | #endif | |
296 | ||
297 | __pblk_rb_write_entry(rb, data, w_ctx, entry); | |
298 | ||
299 | pblk_update_map_cache(pblk, w_ctx.lba, entry->cacheline); | |
300 | flags = w_ctx.flags | PBLK_WRITTEN_DATA; | |
301 | ||
302 | /* Release flags on write context. Protect from writes */ | |
303 | smp_store_release(&entry->w_ctx.flags, flags); | |
304 | } | |
305 | ||
306 | void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data, | |
307 | struct pblk_w_ctx w_ctx, struct pblk_line *gc_line, | |
308 | unsigned int ring_pos) | |
309 | { | |
310 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
311 | struct pblk_rb_entry *entry; | |
312 | int flags; | |
313 | ||
314 | entry = &rb->entries[ring_pos]; | |
315 | flags = READ_ONCE(entry->w_ctx.flags); | |
316 | #ifdef CONFIG_NVM_DEBUG | |
317 | /* Caller must guarantee that the entry is free */ | |
318 | BUG_ON(!(flags & PBLK_WRITABLE_ENTRY)); | |
319 | #endif | |
320 | ||
321 | __pblk_rb_write_entry(rb, data, w_ctx, entry); | |
322 | ||
323 | if (!pblk_update_map_gc(pblk, w_ctx.lba, entry->cacheline, gc_line)) | |
324 | entry->w_ctx.lba = ADDR_EMPTY; | |
325 | ||
326 | flags = w_ctx.flags | PBLK_WRITTEN_DATA; | |
327 | ||
328 | /* Release flags on write context. Protect from writes */ | |
329 | smp_store_release(&entry->w_ctx.flags, flags); | |
330 | } | |
331 | ||
332 | static int pblk_rb_sync_point_set(struct pblk_rb *rb, struct bio *bio, | |
333 | unsigned int pos) | |
334 | { | |
335 | struct pblk_rb_entry *entry; | |
336 | unsigned int subm, sync_point; | |
337 | int flags; | |
338 | ||
339 | subm = READ_ONCE(rb->subm); | |
340 | ||
341 | #ifdef CONFIG_NVM_DEBUG | |
342 | atomic_inc(&rb->inflight_sync_point); | |
343 | #endif | |
344 | ||
345 | if (pos == subm) | |
346 | return 0; | |
347 | ||
348 | sync_point = (pos == 0) ? (rb->nr_entries - 1) : (pos - 1); | |
349 | entry = &rb->entries[sync_point]; | |
350 | ||
351 | flags = READ_ONCE(entry->w_ctx.flags); | |
352 | flags |= PBLK_FLUSH_ENTRY; | |
353 | ||
354 | /* Release flags on context. Protect from writes */ | |
355 | smp_store_release(&entry->w_ctx.flags, flags); | |
356 | ||
357 | /* Protect syncs */ | |
358 | smp_store_release(&rb->sync_point, sync_point); | |
359 | ||
360 | spin_lock_irq(&rb->s_lock); | |
361 | bio_list_add(&entry->w_ctx.bios, bio); | |
362 | spin_unlock_irq(&rb->s_lock); | |
363 | ||
364 | return 1; | |
365 | } | |
366 | ||
367 | static int __pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries, | |
368 | unsigned int *pos) | |
369 | { | |
370 | unsigned int mem; | |
371 | unsigned int sync; | |
372 | ||
373 | sync = READ_ONCE(rb->sync); | |
374 | mem = READ_ONCE(rb->mem); | |
375 | ||
376 | if (pblk_rb_ring_space(rb, mem, sync, rb->nr_entries) < nr_entries) | |
377 | return 0; | |
378 | ||
379 | if (pblk_rb_update_l2p(rb, nr_entries, mem, sync)) | |
380 | return 0; | |
381 | ||
382 | *pos = mem; | |
383 | ||
384 | return 1; | |
385 | } | |
386 | ||
387 | static int pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries, | |
388 | unsigned int *pos) | |
389 | { | |
390 | if (!__pblk_rb_may_write(rb, nr_entries, pos)) | |
391 | return 0; | |
392 | ||
393 | /* Protect from read count */ | |
394 | smp_store_release(&rb->mem, (*pos + nr_entries) & (rb->nr_entries - 1)); | |
395 | return 1; | |
396 | } | |
397 | ||
398 | static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries, | |
399 | unsigned int *pos, struct bio *bio, | |
400 | int *io_ret) | |
401 | { | |
402 | unsigned int mem; | |
403 | ||
404 | if (!__pblk_rb_may_write(rb, nr_entries, pos)) | |
405 | return 0; | |
406 | ||
407 | mem = (*pos + nr_entries) & (rb->nr_entries - 1); | |
408 | *io_ret = NVM_IO_DONE; | |
409 | ||
410 | if (bio->bi_opf & REQ_PREFLUSH) { | |
411 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
412 | ||
413 | #ifdef CONFIG_NVM_DEBUG | |
414 | atomic_long_inc(&pblk->nr_flush); | |
415 | #endif | |
416 | if (pblk_rb_sync_point_set(&pblk->rwb, bio, mem)) | |
417 | *io_ret = NVM_IO_OK; | |
418 | } | |
419 | ||
420 | /* Protect from read count */ | |
421 | smp_store_release(&rb->mem, mem); | |
422 | return 1; | |
423 | } | |
424 | ||
425 | /* | |
426 | * Atomically check that (i) there is space on the write buffer for the | |
427 | * incoming I/O, and (ii) the current I/O type has enough budget in the write | |
428 | * buffer (rate-limiter). | |
429 | */ | |
430 | int pblk_rb_may_write_user(struct pblk_rb *rb, struct bio *bio, | |
431 | unsigned int nr_entries, unsigned int *pos) | |
432 | { | |
433 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
434 | int flush_done; | |
435 | ||
436 | spin_lock(&rb->w_lock); | |
437 | if (!pblk_rl_user_may_insert(&pblk->rl, nr_entries)) { | |
438 | spin_unlock(&rb->w_lock); | |
439 | return NVM_IO_REQUEUE; | |
440 | } | |
441 | ||
442 | if (!pblk_rb_may_write_flush(rb, nr_entries, pos, bio, &flush_done)) { | |
443 | spin_unlock(&rb->w_lock); | |
444 | return NVM_IO_REQUEUE; | |
445 | } | |
446 | ||
447 | pblk_rl_user_in(&pblk->rl, nr_entries); | |
448 | spin_unlock(&rb->w_lock); | |
449 | ||
450 | return flush_done; | |
451 | } | |
452 | ||
453 | /* | |
454 | * Look at pblk_rb_may_write_user comment | |
455 | */ | |
456 | int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries, | |
457 | unsigned int *pos) | |
458 | { | |
459 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
460 | ||
461 | spin_lock(&rb->w_lock); | |
462 | if (!pblk_rl_gc_may_insert(&pblk->rl, nr_entries)) { | |
463 | spin_unlock(&rb->w_lock); | |
464 | return 0; | |
465 | } | |
466 | ||
467 | if (!pblk_rb_may_write(rb, nr_entries, pos)) { | |
468 | spin_unlock(&rb->w_lock); | |
469 | return 0; | |
470 | } | |
471 | ||
472 | pblk_rl_gc_in(&pblk->rl, nr_entries); | |
473 | spin_unlock(&rb->w_lock); | |
474 | ||
475 | return 1; | |
476 | } | |
477 | ||
478 | /* | |
479 | * The caller of this function must ensure that the backpointer will not | |
480 | * overwrite the entries passed on the list. | |
481 | */ | |
482 | unsigned int pblk_rb_read_to_bio_list(struct pblk_rb *rb, struct bio *bio, | |
483 | struct list_head *list, | |
484 | unsigned int max) | |
485 | { | |
486 | struct pblk_rb_entry *entry, *tentry; | |
487 | struct page *page; | |
488 | unsigned int read = 0; | |
489 | int ret; | |
490 | ||
491 | list_for_each_entry_safe(entry, tentry, list, index) { | |
492 | if (read > max) { | |
493 | pr_err("pblk: too many entries on list\n"); | |
494 | goto out; | |
495 | } | |
496 | ||
497 | page = virt_to_page(entry->data); | |
498 | if (!page) { | |
499 | pr_err("pblk: could not allocate write bio page\n"); | |
500 | goto out; | |
501 | } | |
502 | ||
503 | ret = bio_add_page(bio, page, rb->seg_size, 0); | |
504 | if (ret != rb->seg_size) { | |
505 | pr_err("pblk: could not add page to write bio\n"); | |
506 | goto out; | |
507 | } | |
508 | ||
509 | list_del(&entry->index); | |
510 | read++; | |
511 | } | |
512 | ||
513 | out: | |
514 | return read; | |
515 | } | |
516 | ||
517 | /* | |
518 | * Read available entries on rb and add them to the given bio. To avoid a memory | |
519 | * copy, a page reference to the write buffer is used to be added to the bio. | |
520 | * | |
521 | * This function is used by the write thread to form the write bio that will | |
522 | * persist data on the write buffer to the media. | |
523 | */ | |
524 | unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct bio *bio, | |
525 | struct pblk_c_ctx *c_ctx, | |
526 | unsigned int pos, | |
527 | unsigned int nr_entries, | |
528 | unsigned int count) | |
529 | { | |
530 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
531 | struct pblk_rb_entry *entry; | |
532 | struct page *page; | |
533 | unsigned int pad = 0, read = 0, to_read = nr_entries; | |
534 | unsigned int user_io = 0, gc_io = 0; | |
535 | unsigned int i; | |
536 | int flags; | |
537 | int ret; | |
538 | ||
539 | if (count < nr_entries) { | |
540 | pad = nr_entries - count; | |
541 | to_read = count; | |
542 | } | |
543 | ||
544 | c_ctx->sentry = pos; | |
545 | c_ctx->nr_valid = to_read; | |
546 | c_ctx->nr_padded = pad; | |
547 | ||
548 | for (i = 0; i < to_read; i++) { | |
549 | entry = &rb->entries[pos]; | |
550 | ||
551 | /* A write has been allowed into the buffer, but data is still | |
552 | * being copied to it. It is ok to busy wait. | |
553 | */ | |
554 | try: | |
555 | flags = READ_ONCE(entry->w_ctx.flags); | |
556 | if (!(flags & PBLK_WRITTEN_DATA)) | |
557 | goto try; | |
558 | ||
559 | if (flags & PBLK_IOTYPE_USER) | |
560 | user_io++; | |
561 | else if (flags & PBLK_IOTYPE_GC) | |
562 | gc_io++; | |
563 | else | |
564 | WARN(1, "pblk: unknown IO type\n"); | |
565 | ||
566 | page = virt_to_page(entry->data); | |
567 | if (!page) { | |
568 | pr_err("pblk: could not allocate write bio page\n"); | |
569 | flags &= ~PBLK_WRITTEN_DATA; | |
570 | flags |= PBLK_SUBMITTED_ENTRY; | |
571 | /* Release flags on context. Protect from writes */ | |
572 | smp_store_release(&entry->w_ctx.flags, flags); | |
573 | goto out; | |
574 | } | |
575 | ||
576 | ret = bio_add_page(bio, page, rb->seg_size, 0); | |
577 | if (ret != rb->seg_size) { | |
578 | pr_err("pblk: could not add page to write bio\n"); | |
579 | flags &= ~PBLK_WRITTEN_DATA; | |
580 | flags |= PBLK_SUBMITTED_ENTRY; | |
581 | /* Release flags on context. Protect from writes */ | |
582 | smp_store_release(&entry->w_ctx.flags, flags); | |
583 | goto out; | |
584 | } | |
585 | ||
586 | if (flags & PBLK_FLUSH_ENTRY) { | |
587 | unsigned int sync_point; | |
588 | ||
589 | sync_point = READ_ONCE(rb->sync_point); | |
590 | if (sync_point == pos) { | |
591 | /* Protect syncs */ | |
592 | smp_store_release(&rb->sync_point, EMPTY_ENTRY); | |
593 | } | |
594 | ||
595 | flags &= ~PBLK_FLUSH_ENTRY; | |
596 | #ifdef CONFIG_NVM_DEBUG | |
597 | atomic_dec(&rb->inflight_sync_point); | |
598 | #endif | |
599 | } | |
600 | ||
601 | flags &= ~PBLK_WRITTEN_DATA; | |
602 | flags |= PBLK_SUBMITTED_ENTRY; | |
603 | ||
604 | /* Release flags on context. Protect from writes */ | |
605 | smp_store_release(&entry->w_ctx.flags, flags); | |
606 | ||
607 | pos = (pos + 1) & (rb->nr_entries - 1); | |
608 | } | |
609 | ||
610 | read = to_read; | |
611 | pblk_rl_out(&pblk->rl, user_io, gc_io); | |
612 | #ifdef CONFIG_NVM_DEBUG | |
613 | atomic_long_add(pad, &((struct pblk *) | |
614 | (container_of(rb, struct pblk, rwb)))->padded_writes); | |
615 | #endif | |
616 | out: | |
617 | return read; | |
618 | } | |
619 | ||
620 | /* | |
621 | * Copy to bio only if the lba matches the one on the given cache entry. | |
622 | * Otherwise, it means that the entry has been overwritten, and the bio should | |
623 | * be directed to disk. | |
624 | */ | |
625 | int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba, | |
626 | u64 pos, int bio_iter) | |
627 | { | |
628 | struct pblk_rb_entry *entry; | |
629 | struct pblk_w_ctx *w_ctx; | |
630 | void *data; | |
631 | int flags; | |
632 | int ret = 1; | |
633 | ||
634 | spin_lock(&rb->w_lock); | |
635 | ||
636 | #ifdef CONFIG_NVM_DEBUG | |
637 | /* Caller must ensure that the access will not cause an overflow */ | |
638 | BUG_ON(pos >= rb->nr_entries); | |
639 | #endif | |
640 | entry = &rb->entries[pos]; | |
641 | w_ctx = &entry->w_ctx; | |
642 | flags = READ_ONCE(w_ctx->flags); | |
643 | ||
644 | /* Check if the entry has been overwritten or is scheduled to be */ | |
645 | if (w_ctx->lba != lba || flags & PBLK_WRITABLE_ENTRY) { | |
646 | ret = 0; | |
647 | goto out; | |
648 | } | |
649 | ||
650 | /* Only advance the bio if it hasn't been advanced already. If advanced, | |
651 | * this bio is at least a partial bio (i.e., it has partially been | |
652 | * filled with data from the cache). If part of the data resides on the | |
653 | * media, we will read later on | |
654 | */ | |
655 | if (unlikely(!bio->bi_iter.bi_idx)) | |
656 | bio_advance(bio, bio_iter * PBLK_EXPOSED_PAGE_SIZE); | |
657 | ||
658 | data = bio_data(bio); | |
659 | memcpy(data, entry->data, rb->seg_size); | |
660 | ||
661 | out: | |
662 | spin_unlock(&rb->w_lock); | |
663 | return ret; | |
664 | } | |
665 | ||
666 | struct pblk_w_ctx *pblk_rb_w_ctx(struct pblk_rb *rb, unsigned int pos) | |
667 | { | |
668 | unsigned int entry = pos & (rb->nr_entries - 1); | |
669 | ||
670 | return &rb->entries[entry].w_ctx; | |
671 | } | |
672 | ||
673 | unsigned int pblk_rb_sync_init(struct pblk_rb *rb, unsigned long *flags) | |
674 | __acquires(&rb->s_lock) | |
675 | { | |
676 | if (flags) | |
677 | spin_lock_irqsave(&rb->s_lock, *flags); | |
678 | else | |
679 | spin_lock_irq(&rb->s_lock); | |
680 | ||
681 | return rb->sync; | |
682 | } | |
683 | ||
684 | void pblk_rb_sync_end(struct pblk_rb *rb, unsigned long *flags) | |
685 | __releases(&rb->s_lock) | |
686 | { | |
687 | lockdep_assert_held(&rb->s_lock); | |
688 | ||
689 | if (flags) | |
690 | spin_unlock_irqrestore(&rb->s_lock, *flags); | |
691 | else | |
692 | spin_unlock_irq(&rb->s_lock); | |
693 | } | |
694 | ||
695 | unsigned int pblk_rb_sync_advance(struct pblk_rb *rb, unsigned int nr_entries) | |
696 | { | |
697 | unsigned int sync; | |
698 | unsigned int i; | |
699 | ||
700 | lockdep_assert_held(&rb->s_lock); | |
701 | ||
702 | sync = READ_ONCE(rb->sync); | |
703 | ||
704 | for (i = 0; i < nr_entries; i++) | |
705 | sync = (sync + 1) & (rb->nr_entries - 1); | |
706 | ||
707 | /* Protect from counts */ | |
708 | smp_store_release(&rb->sync, sync); | |
709 | ||
710 | return sync; | |
711 | } | |
712 | ||
713 | unsigned int pblk_rb_sync_point_count(struct pblk_rb *rb) | |
714 | { | |
715 | unsigned int subm, sync_point; | |
716 | unsigned int count; | |
717 | ||
718 | /* Protect syncs */ | |
719 | sync_point = smp_load_acquire(&rb->sync_point); | |
720 | if (sync_point == EMPTY_ENTRY) | |
721 | return 0; | |
722 | ||
723 | subm = READ_ONCE(rb->subm); | |
724 | ||
725 | /* The sync point itself counts as a sector to sync */ | |
726 | count = pblk_rb_ring_count(sync_point, subm, rb->nr_entries) + 1; | |
727 | ||
728 | return count; | |
729 | } | |
730 | ||
731 | /* | |
732 | * Scan from the current position of the sync pointer to find the entry that | |
733 | * corresponds to the given ppa. This is necessary since write requests can be | |
734 | * completed out of order. The assumption is that the ppa is close to the sync | |
735 | * pointer thus the search will not take long. | |
736 | * | |
737 | * The caller of this function must guarantee that the sync pointer will no | |
738 | * reach the entry while it is using the metadata associated with it. With this | |
739 | * assumption in mind, there is no need to take the sync lock. | |
740 | */ | |
741 | struct pblk_rb_entry *pblk_rb_sync_scan_entry(struct pblk_rb *rb, | |
742 | struct ppa_addr *ppa) | |
743 | { | |
744 | unsigned int sync, subm, count; | |
745 | unsigned int i; | |
746 | ||
747 | sync = READ_ONCE(rb->sync); | |
748 | subm = READ_ONCE(rb->subm); | |
749 | count = pblk_rb_ring_count(subm, sync, rb->nr_entries); | |
750 | ||
751 | for (i = 0; i < count; i++) | |
752 | sync = (sync + 1) & (rb->nr_entries - 1); | |
753 | ||
754 | return NULL; | |
755 | } | |
756 | ||
757 | int pblk_rb_tear_down_check(struct pblk_rb *rb) | |
758 | { | |
759 | struct pblk_rb_entry *entry; | |
760 | int i; | |
761 | int ret = 0; | |
762 | ||
763 | spin_lock(&rb->w_lock); | |
764 | spin_lock_irq(&rb->s_lock); | |
765 | ||
766 | if ((rb->mem == rb->subm) && (rb->subm == rb->sync) && | |
767 | (rb->sync == rb->l2p_update) && | |
768 | (rb->sync_point == EMPTY_ENTRY)) { | |
769 | goto out; | |
770 | } | |
771 | ||
772 | if (!rb->entries) { | |
773 | ret = 1; | |
774 | goto out; | |
775 | } | |
776 | ||
777 | for (i = 0; i < rb->nr_entries; i++) { | |
778 | entry = &rb->entries[i]; | |
779 | ||
780 | if (!entry->data) { | |
781 | ret = 1; | |
782 | goto out; | |
783 | } | |
784 | } | |
785 | ||
786 | out: | |
787 | spin_unlock(&rb->w_lock); | |
788 | spin_unlock_irq(&rb->s_lock); | |
789 | ||
790 | return ret; | |
791 | } | |
792 | ||
793 | unsigned int pblk_rb_wrap_pos(struct pblk_rb *rb, unsigned int pos) | |
794 | { | |
795 | return (pos & (rb->nr_entries - 1)); | |
796 | } | |
797 | ||
798 | int pblk_rb_pos_oob(struct pblk_rb *rb, u64 pos) | |
799 | { | |
800 | return (pos >= rb->nr_entries); | |
801 | } | |
802 | ||
803 | ssize_t pblk_rb_sysfs(struct pblk_rb *rb, char *buf) | |
804 | { | |
805 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
806 | struct pblk_c_ctx *c; | |
807 | ssize_t offset; | |
808 | int queued_entries = 0; | |
809 | ||
810 | spin_lock_irq(&rb->s_lock); | |
811 | list_for_each_entry(c, &pblk->compl_list, list) | |
812 | queued_entries++; | |
813 | spin_unlock_irq(&rb->s_lock); | |
814 | ||
815 | if (rb->sync_point != EMPTY_ENTRY) | |
816 | offset = scnprintf(buf, PAGE_SIZE, | |
817 | "%u\t%u\t%u\t%u\t%u\t%u\t%u - %u/%u/%u - %d\n", | |
818 | rb->nr_entries, | |
819 | rb->mem, | |
820 | rb->subm, | |
821 | rb->sync, | |
822 | rb->l2p_update, | |
823 | #ifdef CONFIG_NVM_DEBUG | |
824 | atomic_read(&rb->inflight_sync_point), | |
825 | #else | |
826 | 0, | |
827 | #endif | |
828 | rb->sync_point, | |
829 | pblk_rb_read_count(rb), | |
830 | pblk_rb_space(rb), | |
831 | pblk_rb_sync_point_count(rb), | |
832 | queued_entries); | |
833 | else | |
834 | offset = scnprintf(buf, PAGE_SIZE, | |
835 | "%u\t%u\t%u\t%u\t%u\t%u\tNULL - %u/%u/%u - %d\n", | |
836 | rb->nr_entries, | |
837 | rb->mem, | |
838 | rb->subm, | |
839 | rb->sync, | |
840 | rb->l2p_update, | |
841 | #ifdef CONFIG_NVM_DEBUG | |
842 | atomic_read(&rb->inflight_sync_point), | |
843 | #else | |
844 | 0, | |
845 | #endif | |
846 | pblk_rb_read_count(rb), | |
847 | pblk_rb_space(rb), | |
848 | pblk_rb_sync_point_count(rb), | |
849 | queued_entries); | |
850 | ||
851 | return offset; | |
852 | } |