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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 | |
5fb94e9c | 41 | * (Documentation/core-api/circular-buffers.rst) |
a4bd217b JG |
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; | |
8154d296 | 57 | rb->flush_point = EMPTY_ENTRY; |
a4bd217b JG |
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 | ||
880eda54 | 114 | #ifdef CONFIG_NVM_PBLK_DEBUG |
8154d296 | 115 | atomic_set(&rb->inflight_flush_point, 0); |
a4bd217b JG |
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 | ||
a4bd217b | 145 | flags = READ_ONCE(w_ctx->flags); |
e37d0798 JG |
146 | WARN_ONCE(!(flags & PBLK_SUBMITTED_ENTRY), |
147 | "pblk: overwriting unsubmitted data\n"); | |
a4bd217b JG |
148 | |
149 | /* Release flags on context. Protect from writes and reads */ | |
150 | smp_store_release(&w_ctx->flags, PBLK_WRITABLE_ENTRY); | |
151 | pblk_ppa_set_empty(&w_ctx->ppa); | |
07698466 | 152 | w_ctx->lba = ADDR_EMPTY; |
a4bd217b JG |
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 | ||
ee8d5c1a JG |
183 | unsigned int pblk_rb_sync_count(struct pblk_rb *rb) |
184 | { | |
185 | unsigned int mem = READ_ONCE(rb->mem); | |
186 | unsigned int sync = READ_ONCE(rb->sync); | |
187 | ||
188 | return pblk_rb_ring_count(mem, sync, rb->nr_entries); | |
189 | } | |
190 | ||
a4bd217b JG |
191 | unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int nr_entries) |
192 | { | |
193 | unsigned int subm; | |
194 | ||
195 | subm = READ_ONCE(rb->subm); | |
196 | /* Commit read means updating submission pointer */ | |
197 | smp_store_release(&rb->subm, | |
198 | (subm + nr_entries) & (rb->nr_entries - 1)); | |
199 | ||
200 | return subm; | |
201 | } | |
202 | ||
05ed3447 | 203 | static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int to_update) |
a4bd217b JG |
204 | { |
205 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
206 | struct pblk_line *line; | |
207 | struct pblk_rb_entry *entry; | |
208 | struct pblk_w_ctx *w_ctx; | |
b20ba1bc | 209 | unsigned int user_io = 0, gc_io = 0; |
a4bd217b | 210 | unsigned int i; |
b20ba1bc | 211 | int flags; |
a4bd217b JG |
212 | |
213 | for (i = 0; i < to_update; i++) { | |
05ed3447 | 214 | entry = &rb->entries[rb->l2p_update]; |
a4bd217b JG |
215 | w_ctx = &entry->w_ctx; |
216 | ||
b20ba1bc JG |
217 | flags = READ_ONCE(entry->w_ctx.flags); |
218 | if (flags & PBLK_IOTYPE_USER) | |
219 | user_io++; | |
220 | else if (flags & PBLK_IOTYPE_GC) | |
221 | gc_io++; | |
222 | else | |
223 | WARN(1, "pblk: unknown IO type\n"); | |
224 | ||
a4bd217b JG |
225 | pblk_update_map_dev(pblk, w_ctx->lba, w_ctx->ppa, |
226 | entry->cacheline); | |
227 | ||
b1bcfda1 | 228 | line = &pblk->lines[pblk_ppa_to_line(w_ctx->ppa)]; |
a4bd217b JG |
229 | kref_put(&line->ref, pblk_line_put); |
230 | clean_wctx(w_ctx); | |
05ed3447 | 231 | rb->l2p_update = (rb->l2p_update + 1) & (rb->nr_entries - 1); |
a4bd217b JG |
232 | } |
233 | ||
b20ba1bc JG |
234 | pblk_rl_out(&pblk->rl, user_io, gc_io); |
235 | ||
a4bd217b JG |
236 | return 0; |
237 | } | |
238 | ||
239 | /* | |
240 | * When we move the l2p_update pointer, we update the l2p table - lookups will | |
241 | * point to the physical address instead of to the cacheline in the write buffer | |
242 | * from this moment on. | |
243 | */ | |
244 | static int pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int nr_entries, | |
245 | unsigned int mem, unsigned int sync) | |
246 | { | |
247 | unsigned int space, count; | |
248 | int ret = 0; | |
249 | ||
250 | lockdep_assert_held(&rb->w_lock); | |
251 | ||
252 | /* Update l2p only as buffer entries are being overwritten */ | |
253 | space = pblk_rb_ring_space(rb, mem, rb->l2p_update, rb->nr_entries); | |
254 | if (space > nr_entries) | |
255 | goto out; | |
256 | ||
257 | count = nr_entries - space; | |
258 | /* l2p_update used exclusively under rb->w_lock */ | |
05ed3447 | 259 | ret = __pblk_rb_update_l2p(rb, count); |
a4bd217b JG |
260 | |
261 | out: | |
262 | return ret; | |
263 | } | |
264 | ||
265 | /* | |
266 | * Update the l2p entry for all sectors stored on the write buffer. This means | |
267 | * that all future lookups to the l2p table will point to a device address, not | |
268 | * to the cacheline in the write buffer. | |
269 | */ | |
270 | void pblk_rb_sync_l2p(struct pblk_rb *rb) | |
271 | { | |
272 | unsigned int sync; | |
273 | unsigned int to_update; | |
274 | ||
275 | spin_lock(&rb->w_lock); | |
276 | ||
277 | /* Protect from reads and writes */ | |
278 | sync = smp_load_acquire(&rb->sync); | |
279 | ||
280 | to_update = pblk_rb_ring_count(sync, rb->l2p_update, rb->nr_entries); | |
05ed3447 | 281 | __pblk_rb_update_l2p(rb, to_update); |
a4bd217b JG |
282 | |
283 | spin_unlock(&rb->w_lock); | |
284 | } | |
285 | ||
286 | /* | |
287 | * Write @nr_entries to ring buffer from @data buffer if there is enough space. | |
288 | * Typically, 4KB data chunks coming from a bio will be copied to the ring | |
289 | * buffer, thus the write will fail if not all incoming data can be copied. | |
290 | * | |
291 | */ | |
292 | static void __pblk_rb_write_entry(struct pblk_rb *rb, void *data, | |
293 | struct pblk_w_ctx w_ctx, | |
294 | struct pblk_rb_entry *entry) | |
295 | { | |
296 | memcpy(entry->data, data, rb->seg_size); | |
297 | ||
298 | entry->w_ctx.lba = w_ctx.lba; | |
299 | entry->w_ctx.ppa = w_ctx.ppa; | |
300 | } | |
301 | ||
302 | void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data, | |
303 | struct pblk_w_ctx w_ctx, unsigned int ring_pos) | |
304 | { | |
305 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
306 | struct pblk_rb_entry *entry; | |
307 | int flags; | |
308 | ||
309 | entry = &rb->entries[ring_pos]; | |
310 | flags = READ_ONCE(entry->w_ctx.flags); | |
880eda54 | 311 | #ifdef CONFIG_NVM_PBLK_DEBUG |
a4bd217b JG |
312 | /* Caller must guarantee that the entry is free */ |
313 | BUG_ON(!(flags & PBLK_WRITABLE_ENTRY)); | |
314 | #endif | |
315 | ||
316 | __pblk_rb_write_entry(rb, data, w_ctx, entry); | |
317 | ||
318 | pblk_update_map_cache(pblk, w_ctx.lba, entry->cacheline); | |
319 | flags = w_ctx.flags | PBLK_WRITTEN_DATA; | |
320 | ||
321 | /* Release flags on write context. Protect from writes */ | |
322 | smp_store_release(&entry->w_ctx.flags, flags); | |
323 | } | |
324 | ||
325 | void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data, | |
d340121e JG |
326 | struct pblk_w_ctx w_ctx, struct pblk_line *line, |
327 | u64 paddr, unsigned int ring_pos) | |
a4bd217b JG |
328 | { |
329 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
330 | struct pblk_rb_entry *entry; | |
331 | int flags; | |
332 | ||
333 | entry = &rb->entries[ring_pos]; | |
334 | flags = READ_ONCE(entry->w_ctx.flags); | |
880eda54 | 335 | #ifdef CONFIG_NVM_PBLK_DEBUG |
a4bd217b JG |
336 | /* Caller must guarantee that the entry is free */ |
337 | BUG_ON(!(flags & PBLK_WRITABLE_ENTRY)); | |
338 | #endif | |
339 | ||
340 | __pblk_rb_write_entry(rb, data, w_ctx, entry); | |
341 | ||
d340121e | 342 | if (!pblk_update_map_gc(pblk, w_ctx.lba, entry->cacheline, line, paddr)) |
a4bd217b JG |
343 | entry->w_ctx.lba = ADDR_EMPTY; |
344 | ||
345 | flags = w_ctx.flags | PBLK_WRITTEN_DATA; | |
346 | ||
347 | /* Release flags on write context. Protect from writes */ | |
348 | smp_store_release(&entry->w_ctx.flags, flags); | |
349 | } | |
350 | ||
8154d296 | 351 | static int pblk_rb_flush_point_set(struct pblk_rb *rb, struct bio *bio, |
cc9c9a00 | 352 | unsigned int pos) |
a4bd217b JG |
353 | { |
354 | struct pblk_rb_entry *entry; | |
533657c1 | 355 | unsigned int sync, flush_point; |
a4bd217b | 356 | |
3c05ef11 | 357 | pblk_rb_sync_init(rb, NULL); |
533657c1 HH |
358 | sync = READ_ONCE(rb->sync); |
359 | ||
3c05ef11 HH |
360 | if (pos == sync) { |
361 | pblk_rb_sync_end(rb, NULL); | |
533657c1 | 362 | return 0; |
3c05ef11 | 363 | } |
a4bd217b | 364 | |
880eda54 | 365 | #ifdef CONFIG_NVM_PBLK_DEBUG |
8154d296 | 366 | atomic_inc(&rb->inflight_flush_point); |
a4bd217b JG |
367 | #endif |
368 | ||
8154d296 HH |
369 | flush_point = (pos == 0) ? (rb->nr_entries - 1) : (pos - 1); |
370 | entry = &rb->entries[flush_point]; | |
a4bd217b | 371 | |
8154d296 HH |
372 | /* Protect flush points */ |
373 | smp_store_release(&rb->flush_point, flush_point); | |
a4bd217b | 374 | |
b36bbf9d HH |
375 | if (bio) |
376 | bio_list_add(&entry->w_ctx.bios, bio); | |
588726d3 | 377 | |
b36bbf9d | 378 | pblk_rb_sync_end(rb, NULL); |
a4bd217b | 379 | |
b36bbf9d | 380 | return bio ? 1 : 0; |
a4bd217b JG |
381 | } |
382 | ||
383 | static int __pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries, | |
384 | unsigned int *pos) | |
385 | { | |
386 | unsigned int mem; | |
387 | unsigned int sync; | |
388 | ||
389 | sync = READ_ONCE(rb->sync); | |
390 | mem = READ_ONCE(rb->mem); | |
391 | ||
392 | if (pblk_rb_ring_space(rb, mem, sync, rb->nr_entries) < nr_entries) | |
393 | return 0; | |
394 | ||
395 | if (pblk_rb_update_l2p(rb, nr_entries, mem, sync)) | |
396 | return 0; | |
397 | ||
398 | *pos = mem; | |
399 | ||
400 | return 1; | |
401 | } | |
402 | ||
403 | static int pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries, | |
404 | unsigned int *pos) | |
405 | { | |
406 | if (!__pblk_rb_may_write(rb, nr_entries, pos)) | |
407 | return 0; | |
408 | ||
409 | /* Protect from read count */ | |
410 | smp_store_release(&rb->mem, (*pos + nr_entries) & (rb->nr_entries - 1)); | |
411 | return 1; | |
412 | } | |
413 | ||
588726d3 JG |
414 | void pblk_rb_flush(struct pblk_rb *rb) |
415 | { | |
416 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
417 | unsigned int mem = READ_ONCE(rb->mem); | |
418 | ||
8154d296 | 419 | if (pblk_rb_flush_point_set(rb, NULL, mem)) |
588726d3 JG |
420 | return; |
421 | ||
cc9c9a00 | 422 | pblk_write_kick(pblk); |
588726d3 JG |
423 | } |
424 | ||
a4bd217b JG |
425 | static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries, |
426 | unsigned int *pos, struct bio *bio, | |
427 | int *io_ret) | |
428 | { | |
429 | unsigned int mem; | |
430 | ||
431 | if (!__pblk_rb_may_write(rb, nr_entries, pos)) | |
432 | return 0; | |
433 | ||
434 | mem = (*pos + nr_entries) & (rb->nr_entries - 1); | |
435 | *io_ret = NVM_IO_DONE; | |
436 | ||
437 | if (bio->bi_opf & REQ_PREFLUSH) { | |
438 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
439 | ||
5d149bfa | 440 | atomic64_inc(&pblk->nr_flush); |
8154d296 | 441 | if (pblk_rb_flush_point_set(&pblk->rwb, bio, mem)) |
a4bd217b JG |
442 | *io_ret = NVM_IO_OK; |
443 | } | |
444 | ||
445 | /* Protect from read count */ | |
446 | smp_store_release(&rb->mem, mem); | |
6ca2f71f | 447 | |
a4bd217b JG |
448 | return 1; |
449 | } | |
450 | ||
451 | /* | |
452 | * Atomically check that (i) there is space on the write buffer for the | |
453 | * incoming I/O, and (ii) the current I/O type has enough budget in the write | |
454 | * buffer (rate-limiter). | |
455 | */ | |
456 | int pblk_rb_may_write_user(struct pblk_rb *rb, struct bio *bio, | |
457 | unsigned int nr_entries, unsigned int *pos) | |
458 | { | |
459 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
588726d3 | 460 | int io_ret; |
a4bd217b JG |
461 | |
462 | spin_lock(&rb->w_lock); | |
588726d3 JG |
463 | io_ret = pblk_rl_user_may_insert(&pblk->rl, nr_entries); |
464 | if (io_ret) { | |
a4bd217b | 465 | spin_unlock(&rb->w_lock); |
588726d3 | 466 | return io_ret; |
a4bd217b JG |
467 | } |
468 | ||
588726d3 | 469 | if (!pblk_rb_may_write_flush(rb, nr_entries, pos, bio, &io_ret)) { |
a4bd217b JG |
470 | spin_unlock(&rb->w_lock); |
471 | return NVM_IO_REQUEUE; | |
472 | } | |
473 | ||
474 | pblk_rl_user_in(&pblk->rl, nr_entries); | |
475 | spin_unlock(&rb->w_lock); | |
476 | ||
588726d3 | 477 | return io_ret; |
a4bd217b JG |
478 | } |
479 | ||
480 | /* | |
481 | * Look at pblk_rb_may_write_user comment | |
482 | */ | |
483 | int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries, | |
484 | unsigned int *pos) | |
485 | { | |
486 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
487 | ||
488 | spin_lock(&rb->w_lock); | |
489 | if (!pblk_rl_gc_may_insert(&pblk->rl, nr_entries)) { | |
490 | spin_unlock(&rb->w_lock); | |
491 | return 0; | |
492 | } | |
493 | ||
494 | if (!pblk_rb_may_write(rb, nr_entries, pos)) { | |
495 | spin_unlock(&rb->w_lock); | |
496 | return 0; | |
497 | } | |
498 | ||
499 | pblk_rl_gc_in(&pblk->rl, nr_entries); | |
500 | spin_unlock(&rb->w_lock); | |
501 | ||
502 | return 1; | |
503 | } | |
504 | ||
a4bd217b JG |
505 | /* |
506 | * Read available entries on rb and add them to the given bio. To avoid a memory | |
507 | * copy, a page reference to the write buffer is used to be added to the bio. | |
508 | * | |
509 | * This function is used by the write thread to form the write bio that will | |
510 | * persist data on the write buffer to the media. | |
511 | */ | |
d624f371 | 512 | unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct nvm_rq *rqd, |
875d94f3 JG |
513 | unsigned int pos, unsigned int nr_entries, |
514 | unsigned int count) | |
a4bd217b JG |
515 | { |
516 | struct pblk *pblk = container_of(rb, struct pblk, rwb); | |
d624f371 JG |
517 | struct request_queue *q = pblk->dev->q; |
518 | struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd); | |
875d94f3 | 519 | struct bio *bio = rqd->bio; |
a4bd217b JG |
520 | struct pblk_rb_entry *entry; |
521 | struct page *page; | |
d624f371 | 522 | unsigned int pad = 0, to_read = nr_entries; |
a4bd217b JG |
523 | unsigned int i; |
524 | int flags; | |
a4bd217b JG |
525 | |
526 | if (count < nr_entries) { | |
527 | pad = nr_entries - count; | |
528 | to_read = count; | |
529 | } | |
530 | ||
531 | c_ctx->sentry = pos; | |
532 | c_ctx->nr_valid = to_read; | |
533 | c_ctx->nr_padded = pad; | |
534 | ||
535 | for (i = 0; i < to_read; i++) { | |
536 | entry = &rb->entries[pos]; | |
537 | ||
538 | /* A write has been allowed into the buffer, but data is still | |
539 | * being copied to it. It is ok to busy wait. | |
540 | */ | |
541 | try: | |
542 | flags = READ_ONCE(entry->w_ctx.flags); | |
10888129 JG |
543 | if (!(flags & PBLK_WRITTEN_DATA)) { |
544 | io_schedule(); | |
a4bd217b | 545 | goto try; |
10888129 | 546 | } |
a4bd217b | 547 | |
a4bd217b JG |
548 | page = virt_to_page(entry->data); |
549 | if (!page) { | |
550 | pr_err("pblk: could not allocate write bio page\n"); | |
551 | flags &= ~PBLK_WRITTEN_DATA; | |
552 | flags |= PBLK_SUBMITTED_ENTRY; | |
553 | /* Release flags on context. Protect from writes */ | |
554 | smp_store_release(&entry->w_ctx.flags, flags); | |
d624f371 | 555 | return NVM_IO_ERR; |
a4bd217b JG |
556 | } |
557 | ||
d624f371 JG |
558 | if (bio_add_pc_page(q, bio, page, rb->seg_size, 0) != |
559 | rb->seg_size) { | |
a4bd217b JG |
560 | pr_err("pblk: could not add page to write bio\n"); |
561 | flags &= ~PBLK_WRITTEN_DATA; | |
562 | flags |= PBLK_SUBMITTED_ENTRY; | |
563 | /* Release flags on context. Protect from writes */ | |
564 | smp_store_release(&entry->w_ctx.flags, flags); | |
d624f371 | 565 | return NVM_IO_ERR; |
a4bd217b JG |
566 | } |
567 | ||
a4bd217b JG |
568 | flags &= ~PBLK_WRITTEN_DATA; |
569 | flags |= PBLK_SUBMITTED_ENTRY; | |
570 | ||
571 | /* Release flags on context. Protect from writes */ | |
572 | smp_store_release(&entry->w_ctx.flags, flags); | |
573 | ||
574 | pos = (pos + 1) & (rb->nr_entries - 1); | |
575 | } | |
576 | ||
d624f371 JG |
577 | if (pad) { |
578 | if (pblk_bio_add_pages(pblk, bio, GFP_KERNEL, pad)) { | |
579 | pr_err("pblk: could not pad page in write bio\n"); | |
580 | return NVM_IO_ERR; | |
581 | } | |
d624f371 | 582 | |
5d149bfa HH |
583 | if (pad < pblk->min_write_pgs) |
584 | atomic64_inc(&pblk->pad_dist[pad - 1]); | |
585 | else | |
586 | pr_warn("pblk: padding more than min. sectors\n"); | |
587 | ||
588 | atomic64_add(pad, &pblk->pad_wa); | |
589 | } | |
76758390 | 590 | |
880eda54 | 591 | #ifdef CONFIG_NVM_PBLK_DEBUG |
5d149bfa | 592 | atomic_long_add(pad, &pblk->padded_writes); |
a4bd217b | 593 | #endif |
d624f371 JG |
594 | |
595 | return NVM_IO_OK; | |
a4bd217b JG |
596 | } |
597 | ||
598 | /* | |
599 | * Copy to bio only if the lba matches the one on the given cache entry. | |
600 | * Otherwise, it means that the entry has been overwritten, and the bio should | |
601 | * be directed to disk. | |
602 | */ | |
603 | int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba, | |
75cb8e93 | 604 | struct ppa_addr ppa, int bio_iter, bool advanced_bio) |
a4bd217b | 605 | { |
07698466 | 606 | struct pblk *pblk = container_of(rb, struct pblk, rwb); |
a4bd217b JG |
607 | struct pblk_rb_entry *entry; |
608 | struct pblk_w_ctx *w_ctx; | |
07698466 JG |
609 | struct ppa_addr l2p_ppa; |
610 | u64 pos = pblk_addr_to_cacheline(ppa); | |
a4bd217b JG |
611 | void *data; |
612 | int flags; | |
613 | int ret = 1; | |
614 | ||
a4bd217b | 615 | |
880eda54 | 616 | #ifdef CONFIG_NVM_PBLK_DEBUG |
a4bd217b JG |
617 | /* Caller must ensure that the access will not cause an overflow */ |
618 | BUG_ON(pos >= rb->nr_entries); | |
619 | #endif | |
620 | entry = &rb->entries[pos]; | |
621 | w_ctx = &entry->w_ctx; | |
622 | flags = READ_ONCE(w_ctx->flags); | |
623 | ||
07698466 JG |
624 | spin_lock(&rb->w_lock); |
625 | spin_lock(&pblk->trans_lock); | |
626 | l2p_ppa = pblk_trans_map_get(pblk, lba); | |
627 | spin_unlock(&pblk->trans_lock); | |
628 | ||
a4bd217b | 629 | /* Check if the entry has been overwritten or is scheduled to be */ |
07698466 JG |
630 | if (!pblk_ppa_comp(l2p_ppa, ppa) || w_ctx->lba != lba || |
631 | flags & PBLK_WRITABLE_ENTRY) { | |
a4bd217b JG |
632 | ret = 0; |
633 | goto out; | |
634 | } | |
635 | ||
636 | /* Only advance the bio if it hasn't been advanced already. If advanced, | |
637 | * this bio is at least a partial bio (i.e., it has partially been | |
638 | * filled with data from the cache). If part of the data resides on the | |
639 | * media, we will read later on | |
640 | */ | |
75cb8e93 | 641 | if (unlikely(!advanced_bio)) |
a4bd217b JG |
642 | bio_advance(bio, bio_iter * PBLK_EXPOSED_PAGE_SIZE); |
643 | ||
644 | data = bio_data(bio); | |
645 | memcpy(data, entry->data, rb->seg_size); | |
646 | ||
647 | out: | |
648 | spin_unlock(&rb->w_lock); | |
649 | return ret; | |
650 | } | |
651 | ||
652 | struct pblk_w_ctx *pblk_rb_w_ctx(struct pblk_rb *rb, unsigned int pos) | |
653 | { | |
654 | unsigned int entry = pos & (rb->nr_entries - 1); | |
655 | ||
656 | return &rb->entries[entry].w_ctx; | |
657 | } | |
658 | ||
659 | unsigned int pblk_rb_sync_init(struct pblk_rb *rb, unsigned long *flags) | |
660 | __acquires(&rb->s_lock) | |
661 | { | |
662 | if (flags) | |
663 | spin_lock_irqsave(&rb->s_lock, *flags); | |
664 | else | |
665 | spin_lock_irq(&rb->s_lock); | |
666 | ||
667 | return rb->sync; | |
668 | } | |
669 | ||
670 | void pblk_rb_sync_end(struct pblk_rb *rb, unsigned long *flags) | |
671 | __releases(&rb->s_lock) | |
672 | { | |
673 | lockdep_assert_held(&rb->s_lock); | |
674 | ||
675 | if (flags) | |
676 | spin_unlock_irqrestore(&rb->s_lock, *flags); | |
677 | else | |
678 | spin_unlock_irq(&rb->s_lock); | |
679 | } | |
680 | ||
681 | unsigned int pblk_rb_sync_advance(struct pblk_rb *rb, unsigned int nr_entries) | |
682 | { | |
533657c1 | 683 | unsigned int sync, flush_point; |
a4bd217b JG |
684 | lockdep_assert_held(&rb->s_lock); |
685 | ||
686 | sync = READ_ONCE(rb->sync); | |
533657c1 HH |
687 | flush_point = READ_ONCE(rb->flush_point); |
688 | ||
689 | if (flush_point != EMPTY_ENTRY) { | |
690 | unsigned int secs_to_flush; | |
a4bd217b | 691 | |
533657c1 HH |
692 | secs_to_flush = pblk_rb_ring_count(flush_point, sync, |
693 | rb->nr_entries); | |
694 | if (secs_to_flush < nr_entries) { | |
695 | /* Protect flush points */ | |
696 | smp_store_release(&rb->flush_point, EMPTY_ENTRY); | |
697 | } | |
698 | } | |
699 | ||
700 | sync = (sync + nr_entries) & (rb->nr_entries - 1); | |
a4bd217b JG |
701 | |
702 | /* Protect from counts */ | |
703 | smp_store_release(&rb->sync, sync); | |
704 | ||
705 | return sync; | |
706 | } | |
707 | ||
533657c1 | 708 | /* Calculate how many sectors to submit up to the current flush point. */ |
8154d296 | 709 | unsigned int pblk_rb_flush_point_count(struct pblk_rb *rb) |
a4bd217b | 710 | { |
533657c1 HH |
711 | unsigned int subm, sync, flush_point; |
712 | unsigned int submitted, to_flush; | |
a4bd217b | 713 | |
8154d296 HH |
714 | /* Protect flush points */ |
715 | flush_point = smp_load_acquire(&rb->flush_point); | |
716 | if (flush_point == EMPTY_ENTRY) | |
a4bd217b JG |
717 | return 0; |
718 | ||
533657c1 HH |
719 | /* Protect syncs */ |
720 | sync = smp_load_acquire(&rb->sync); | |
721 | ||
a4bd217b | 722 | subm = READ_ONCE(rb->subm); |
533657c1 | 723 | submitted = pblk_rb_ring_count(subm, sync, rb->nr_entries); |
a4bd217b JG |
724 | |
725 | /* The sync point itself counts as a sector to sync */ | |
533657c1 | 726 | to_flush = pblk_rb_ring_count(flush_point, sync, rb->nr_entries) + 1; |
a4bd217b | 727 | |
533657c1 | 728 | return (submitted < to_flush) ? (to_flush - submitted) : 0; |
a4bd217b JG |
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) && | |
8154d296 | 768 | (rb->flush_point == EMPTY_ENTRY)) { |
a4bd217b JG |
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 | ||
8154d296 | 815 | if (rb->flush_point != EMPTY_ENTRY) |
a4bd217b JG |
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, | |
880eda54 | 823 | #ifdef CONFIG_NVM_PBLK_DEBUG |
8154d296 | 824 | atomic_read(&rb->inflight_flush_point), |
a4bd217b JG |
825 | #else |
826 | 0, | |
827 | #endif | |
8154d296 | 828 | rb->flush_point, |
a4bd217b JG |
829 | pblk_rb_read_count(rb), |
830 | pblk_rb_space(rb), | |
8154d296 | 831 | pblk_rb_flush_point_count(rb), |
a4bd217b JG |
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, | |
880eda54 | 841 | #ifdef CONFIG_NVM_PBLK_DEBUG |
8154d296 | 842 | atomic_read(&rb->inflight_flush_point), |
a4bd217b JG |
843 | #else |
844 | 0, | |
845 | #endif | |
846 | pblk_rb_read_count(rb), | |
847 | pblk_rb_space(rb), | |
8154d296 | 848 | pblk_rb_flush_point_count(rb), |
a4bd217b JG |
849 | queued_entries); |
850 | ||
851 | return offset; | |
852 | } |